Commissioning Cables and Terminations
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Transcript of Commissioning Cables and Terminations
Note: The source of the technical material in this volume is the ProfessionalEngineering Development Program (PEDP) of Engineering Services.
Warning: The material contained in this document was developed for SaudiAramco and is intended for the exclusive use of Saudi Aramco’semployees. Any material contained in this document which is notalready in the public domain may not be copied, reproduced, sold, given,or disclosed to third parties, or otherwise used in whole, or in part,without the written permission of the Vice President, EngineeringServices, Saudi Aramco.
Chapter : Electrical For additional information on this subject, contactFile Reference: EEX30103 W. A. Roussel on 874-1320
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Commissioning Cables And Terminations
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Contents Page
SAUDI ARAMCO APPLICATIONS ANDREQUIREMENTS FOR LOW VOLTAGE CABLES.......................... 1
EVALUATING LOW VOLTAGE CABLES UPON RECEIPT............. 4
EVALUATING LOW VOLTAGE CABLETESTING AND INSTALLATION ....................................................... 6
LOW VOLTAGE CABLE SYSTEMOPERATIONAL TESTING PHASE................................................. 15
SAUDI ARAMCO REQUIREMENTS FORMEDIUM/HIGH VOLTAGE CABLES .............................................. 16
EVALUATING MEDIUM/HIGH VOLTAGECABLES UPON RECEIPT .............................................................. 18
EVALUATING MEDIUM/HIGH VOLTAGE CABLETESTING AND INSTALLATION ..................................................... 20
MEDIUM/HIGH VOLTAGE CABLESYSTEM OPERATIONAL TESTINGPHASE 26
WORK AID 1: REFERENCES FOREVALUATING LOW VOLTAGE CABLES UPONRECEIPT 27
WORK AID 2: REFERENCES FOREVALUATING LOW VOLTAGE CABLEINSTALLATION AND TESTING ..................................................... 32
WORK AID 3:REFERENCES FOREVALUATING MEDIUM/HIGH VOLTAGECABLES UPON RECEIPT .............................................................. 49
WORK AID 4: REFERENCES FOREVALUATING MEDIUM/HIGH VOLTAGECABLE INSTALLATION AND TESTING ........................................ 54
GLOSSARY..................................................................................... 84
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SAUDI ARAMCO APPLICATIONS AND REQUIREMENTS FOR LOW VOLTAGECABLES
Low voltage cables in Saudi Aramco electric power systems are defined as cables that arerated to carry voltages 1000 V and below.
Low voltage power cables are usually cables that supply power to small feeders, which, inturn, supply power to small motors, lights, or auxiliary equipment. Low voltage cables alsosupply control power to breakers, protective devices, and auxiliary and safety systems. Whena low voltage cable is selected for an installation, the cable should be of the proper type andsize to handle the nominal and fault transient currents without damage from excess heatgeneration or a loss of system voltage regulation. The proper cable, cable splices, and cableterminations are selected by the facility design personnel before the cable is installed.
This section will describe the following topics that pertain to the applications andrequirements for low voltage cables:
• Types of Low Voltage Cables• Types of Low Voltage Cable Terminations and Splices
Types of Low Voltage Cables
A power cable is defined as a conductor or a group of conductors that supplies current for theproper operation of a machine, apparatus, or system during start-up, normal operation, andtransient conditions. The types of cables that are acceptable for use in Saudi Aramcoinstallations are described in SAES-P-104, SADP-P-104, and Module EEX 206.04, Selectingand Sizing Cables for Saudi Aramco Installations. A list of the types of low voltage powercables that are acceptable for use in Saudi Aramco installations is provided in Figure 13 ofWork Aid 1.
The following is a list of the common abbreviations that are used for cables and wires. Theseabbreviations should be understood in order to interpret some of the information that isprovided in Figure 13 of Work Aid 1.
AC - Armor CladALS - Aluminum Sheathed CableCLX - Corrugated Sheathed (Okonite Trademark)CSP - Chloresulphonated Polyethylene (Hypalon)DB - Direct BuriedEPR - Ethylene Propylene Rubber (EPD, EPDM)FC - Flat CableIAC - Interlocked Armor Cable
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Types of Low Voltage Cables (Cont'd)
MC - Metal Clad CableMV - Medium Voltage CableNM - Nonmetallic Sheathed CableNMC - Nonmetallic Sheathed, Corrosion Resistant CablePE - PolyethylenePILC(A) - Paper Insulated Lead Covered (Armored) CablePVC - Poly Vinyl ChlorideSBR - Styrene Butadiene RubberSE - Service Entrance CableSNM - Shielded Nonmetallic-Sheathed CableSWA - Steel Wire ArmorTC - Tray CableUF - Underground Feeder CableUSE - Underground Service Entrance CableVCLC(A) - Varnished Cambric Lead Covered (Armored) CableWP - Weatherproof
When power cable is selected, the type of cable that is chosen is based on the particularapplication of the cable and the conditions to which the cable will be subjected. For SaudiAramco installations, the selection of a type and size of a power cable is based on thefollowing criteria:
• The technical requirements of the new installation (or installationmodification), which include parameters such as voltage level, currentloading, ambient temperature, voltage regulation, and fault current.
• The installation requirements of the existing (or planned) facilities, suchas the use of ducts, conduit, or trays.
• The economic requirements that are based on the selection of a suitablecable. The economic requirements should take into account therequired accessories and auxiliary structures that are associated with theselected cable, as well as the actual installation of the cable.
Control cables that are used in Saudi Aramco installations are also low voltage cables. Acontrol cable is defined as a conductor or a group of conductors that regulates or guides theoperation of a machine, apparatus, or system. Electrical control cables consist of variouscombinations of circuits that are used to control the operation of electrical systems. Examplesof electrical control cable use include electric power control, starting and stopping
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Types of Low Voltage Cables (Cont'd)
of equipment, relay operations, switch operations, direct system status indications, andequipment automation. Electronic control cables consist of various combinations of circuitsthat are used to control the operation of electronic systems. Examples of electronic controlcable use include data logging, computer interconnection, data inputs, data outputs, systemcontrol, and instrumentation. A list of the applications of control cables that are acceptablefor use in Saudi Aramco installations is provided in Figure 15 of Work Aid 1.
The Insulated Cable Engineers Association (ICEA) has classified single- and multi-conductorcontrol cable installations into four types of service. A table that describes the four ICEAcontrol cable service classifications is provided in Work Aid 1.
Types of Low Voltage Cable Terminations and Splices
When a cable is ordered from the manufacturer that meets the specifications of an installation,the cable should function properly throughout its operational life. The main causes of cablefailure are damage during installation and improper splices or terminations. The preferredmethods for terminating solid-dielectric cables and recommended cable terminators areprovided in Work Aid 1. A separate table that highlights the types of cable terminations andsplices that are allowed in Saudi Aramco installations and the types of cable terminations andsplices that are not allowed in Saudi Aramco installations are provided in Work Aid 2.
Because a cable that is connected to a load in an energized state carries current, the cablegenerates heat during use. High temperatures can cause embrittlement and degradation of theinsulation that can lead to shorts between phases or from phase to ground. When a cableconductor is terminated, the termination has more electrical resistance than the cableconductor. The increased electrical resistance at a termination generates more heat than thecable conductor that it terminates. The heat that is generated at a cable termination isdissipated through the outer covering or insulating material of the termination. Because of theincreased electrical resistance at a termination, some terminals have temperature ratings.Information on the temperature ratings of a terminal can be found in the terminal constructionkit that is provided by the manufacturer.
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EVALUATING LOW VOLTAGE CABLES UPON RECEIPT
The installation of wire and cable systems is a process that takes place over a period of time.The installation begins with an identified need for a new installation (e.g., a new processingplant). Because power is necessary for the new installation to function, a new wire or cablepower distribution or control system is designed. After the system design is approved, theequipment for the wire or cable installation (e.g., cable or conduit) is ordered. Once thecables are received, they must be evaluated to ensure that they are proper for the installation.The purpose of the evaluation is to verify that the correct cable was received from themanufacturer and that the proper installation specifications and parameters are met. Thissection of the Module provides information on the following topics that are pertinent toevaluating low voltage cables upon receipt:
• Visual Inspection• Verify Against Specifications
Visual Inspection
When low voltage cable is received from the manufacturer, a visual inspection should beperformed. The purpose of the visual inspection is to verify that the cable that was receivedfrom the manufacturer is in good physical condition. A cable is in good physical condition ifit has no chips, cuts, nicks, gouges, or other possible shipping damage or manufacturerdefects. Because cables are usually shipped and stored on reels, the cable must be unrolled toperform a detailed inspection. Due to the difficulties that are involved in unreeling largelengths of cable, a short length of the cable is usually unrolled at the receiving point, and acursory inspection is performed. A detailed inspection of the low voltage cable is performedwhen the cable is being pulled into the raceway or cable tray at the installation site.
Verify Against Specifications
When a new facility or facility modification is at the equipment installation stage, the designof the installation has already been completed. The type of low voltage cable that is selectedfor a specific power system should be shown in the drawings, prints, or specifications for theinstallation. The purpose of verifying low voltage cable against the specifications is to ensurethat the cable that is to be installed meets Saudi Aramco and industry standards.
Generally, the verification against specifications consists of a determination of whether thesize and type of cable that is to be installed matches the size and type of cable that is requiredfor the installation. In some cases, this determination is accomplished by reading an electricalplan that identifies the cable sizes and types. The Engineer then only has to inspect themanufacturer's markings on each cable and compare them to the requirements
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Verify Against Specifications (Cont'd)
on the electrical plan to determine whether the correct cable is being used. In other situations,the Electrical Engineer must rely on his knowledge of the correct application of cable sizesand types and must then determine whether the correct cable is being used.
A list of the items that should be included in a preinstallation inspection to verify a lowvoltage cable against specifications is provided in Work Aid 1.
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EVALUATING LOW VOLTAGE CABLE TESTING AND INSTALLATION
Throughout the complicated and detailed installation and commissioning process for electricpower distribution wire or cable, various installation tests and inspections should beperformed. The installation tests and inspections ensure that the installation meets SaudiAramco and industry requirements and specifications.
Electrical tests are performed to check the ability of a conductor to operate for a reasonablefuture period of time under all operating conditions and loads. Failure of a cable under testconditions will usually cause an in-test breakdown of the cable, or it will indicate the need forits immediate replacement. Industry experience has shown that the failure rate of cables ishighest for relatively new cables. When a cable is being commissioned, an acceptance orinstallation test should be made after the cable is installed but before the cable is placed intonormal service. These acceptance or installation tests should detect shipping or installationdamage, gross cable defects, or errors in workmanship in splices and terminations.
During the wire or cable installation process, installation inspections should be performed.The purpose of the installation inspections is to verify that the proper cable installationmaterials are used, that the installation specifications and parameters are met, and that theproper installation procedures are followed. The installation inspections are conducted toensure that the wire or cable will function properly after installation.
This section of the Module provides information on the following topics that are pertinent toevaluating low voltage cable testing and installation:
• Insulation Resistance (Megger) Test• Hi-Pot 2 kV DC Test• Cable Tensiometer (Strain Gage) and Pulling Devices• Point-to-Point Verification of Cables
Insulation Resistance (Megger) Test
The purpose of the insulation resistance (megger) test is to directly measure the insulationresistance of the cable. The megohmmeter test is most useful for low voltage cables. In themegohmmeter test, the megger is used to set up an electromagnetic field, and the field that iscreated is used to produce leakage currents that will flow through the insulation that isbetween the cable conductor and ground. The amount of leakage current flow that is detectedthrough use of the megger results in a megger meter readout of insulation resistance (inmegohms).
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Insulation Resistance (Megger) Test (Cont'd)
For low voltage cables, megohmmeter test voltages are provided on the Saudi Aramco Pre-Commissioning Form, P-004, Low Voltage Cables, which is provided in Figure 18 of WorkAid 2. Figure1 shows the megger voltage values that Form P-004 lists for low voltage cablecommissioning in Saudi Aramco facilities.
Cable Rating Megger Used
250 V and below 250 V
250 V to 600 V 1000 V
Above 600 V and less than1200 V 2500 V
Table of Low Voltage Cable Megger Voltages (From Saudi AramcoPre-Commissioning Form, P-004, Low Voltage Cables)
Figure 1
To conduct the megohmmeter test, the megger is connected between two of the cableconductors (phases), and the megger is operated. Similar megger readings are taken betweeneach remaining conductor (phase) pair combination and between each cable conductor(phase) and ground. When a megger is used to measure low voltage cable insulationresistance, the megger is operated for 60 seconds. At the end of the 60-second period, themegger readings are taken even though the megger pointer may still be climbing. Thepractice of 60-second megger readings will provide reliable comparisons for future analysis.
Figure 2 shows a typical curve of insulation resistance. In Figure 2, a 60-second resistancevalue is taken and recorded. The typical curve illustrates that the resistance value (inmegohms) does not rise linearly over time. This nonlinear rise of resistance is due to thecapacitive properties of the insulating material.
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Insulation Resistance (Megger) Test (Cont'd)
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Typical Curve of Insulation ResistanceFigure 2
When the cable insulation resistance test is performed, both ends of the cable must bedisconnected to avoid errors due to components that are connected to the other end of thecable. Figure 3 shows how a megger is used to measure phase 1 of a three-conductor cable.
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Insulation Resistance (Megger) Test (Cont'd)
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Megger of Phase 1Figure 3
For new cable installations, the megohmmeter test should be conducted on all new cablesbefore they are unreeled and immediately after they are installed. The megohmmeter test willdetect gross imperfections or damage that would result in cable failure upon energization.When new cable is spliced to old cable, a megohmmeter test should be performed on thecomplete circuit prior to commissioning.
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Insulation Resistance (Megger) Test (Cont'd)
The Electrical Engineer should evaluate the insulation resistance (megger) test values toensure that the insulation resistance values that were recorded are greater than themanufacturer's minimum values. If the manufacturer's minimum values are not provided, thevalues of the insulation resistance should be greater than the rated voltage + 1 kV inmegohms. Any value of insulation resistance that is less than the minimum specificationsshould be investigated by the Electrical Engineer who performs the test data evaluation.
An example series of megger tests was performed on a three-conductor cable. Figure4 showstypical megger test data records. Evaluation of the example test results shows that all threephases of the cable have adequate insulation resistance, both phase-to-phase and phase-to-ground. The example test data indicate that the cable is satisfactory to use.
Resistance Test (Megger)Phase Meg. OhmsPhase 1 to 2 700 M½Phase 2 to 3 630 M½Phase 3 to 1 700 M½Phase 1 to G 300 M½Phase 2 to G 230 M½Phase 3 to G 310 M½
Sample Megger ResultsFigure 4
The ratio of two time-resistance readings (such as a 60-second reading that is divided by a 30-second reading) is called a dielectric absorption ratio. If the ratio is a ten-minute reading thatis divided by a one-minute reading, the value is called the polarization index. The dielectricabsorption ratio reading can be used to evaluate the condition of the cable insulation. When ahand-cranked megger instrument is used, the insulation resistance reading is taken for only 60seconds. When a power-operated megger instrument is used, a reading is taken for a full tenminutes. Readings that are taken at one minute and ten minutes will yield the polarizationindex. An explanation of the evaluation of the megger readings is provided in Work Aid 2.
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Hi-Pot 2 kV DC Test
Although the dc high potential test is listed on Form P-004, this test is optional and is notconducted in Saudi Aramco on low voltage cables. The purpose of a dc high potential (hi-pot) test on low voltage cables is to identify internal faults in or damage to the low voltagecable insulation system. The hi-pot test will identify these faults so that corrective action canbe taken. The hi-pot test should be performed or conducted before initially energizing a cablebut after a megohmmeter test. Normally, the dc hi-pot test is conducted one month after thecable has been initially energized. The dc hi-pot testing technique for cables involves themeasurement of increased dc voltage that is applied to the cable insulation under test. Thevalue of the leakage current as the test voltage is increased through several steps is tracked,and this value becomes a criterion of the condition of the insulation.
When the dc hi-pot test is correctly performed, the test will have no deteriorating effect ongood insulation as long as the test voltage is kept within prescribed limits. The effect of thedc hi-pot testing on poor insulation or poor workmanship is to increase the deterioration of thematerial and, in many cases, a fault can be induced by the test. An introduction of a fault to acable with poor insulation or poor workmanship is desirable. Once the probable fault area isbroken down, the location of the fault can be found and a repair can be initiated.
Although gross imperfections or damage can be detected immediately, the dc hi-pot test isrelatively ineffective in the detection of moderate defects or damage in new cableinstallations. As stated previously, gross imperfections or damage can be detected from asimpler megohmmeter test. After a period of ac energization, deterioration will start inproblem areas. The dc hi-pot test is most effective once the deterioration has begun.
Before the dc hi-pot test is conducted, certain precautions must be taken. Any cable that isunder test should have both end terminations free from all equipment. Cables of the samecircuit that are not under test should be grounded in addition to all cable support equipment(e.g., metallic armor, sheaths, conduit, and trays). A visual check of all exposed portions ofthe cable run should be made to determine whether any abnormalities exist in the cable. Thecondition and continuity of all grounding equipment (e.g., clamps, wires, and rods) shouldalso be noted.
For low voltage cables, dc hi-pot test voltages are provided on the Saudi Aramco Pre-Commissioning Form, P-004, Low Voltage Cables, which is provided in Work Aid 2. Amaximum voltage value of 2000 V is used during the dc hi-pot test for low voltage cables thatare rated for voltages from 250 V to 1000 V. The dc hi-pot test is conducted in a minimum offour steps. Voltage is increased to the maximum voltage value in steps that are an order ofmagnitude of the rated ac rms voltage of the cable. Each voltage step is held
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Hi-Pot 2 kV DC Test (Cont'd)
for a one-minute duration. For 600 V cable, voltage increments of approximately 500 Vshould be used.
During the dc hi-pot test, the leakage current should be plotted against time at the end of eachtiming interval. Figure 5 illustrates representative current-time curves over a ten-minute testperiod. The curves in Figure 5 show that good insulation exhibits a steady decrease inleakage current with time, and bad insulation exhibits a rise in leakage current. Any rise inleakage current during this test is a signal to stop the test. The polarization index can becalculated from this test data by dividing the leakage current after one minute by the leakagecurrent that is obtained after ten minutes, as follows:
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Hi-Pot Current-Time CharacteristicsFigure 5
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Hi-Pot 2 kV DC Test (Cont'd)
High voltage dc test potentials are lethal. All safety precautions and operational proceduresmust be carefully followed. The rate of increase of the test voltages should be approximatelyuniform. The maximum rate of increase of the test voltages is 100 percent in ten seconds, andthe minimum rate of increase is 100 percent in 60 seconds. The test should be stopped at thefirst indication of an upward bend or knee in the curve.
A knee in the curve indicates the need for cleaning and drying of cable insulation, and, if thetest is not stopped, the leakage current may increase to a value that may damage theinsulation. When the dc hi-pot test is completed, the charge in the cable should be allowed todrain off. The test charge drain is accomplished by setting the test voltage dial to zero. Thecharge drains off through leakage in the test set and voltmeter circuits. A one-megohmresistor can be added to the drainage path if desired. When the cable has dropped to tenpercent of its test voltage, it should be solidly grounded for at least 30 minutes after removalof the dc test voltage.
Complete isolation of cables from splices, terminations, and associated equipment (e.g.,switches and current transformers) is not always practical. Any equipment that is not isolatedfrom the cable that is tested will be tested along with the cable. In many cases, because theconnected equipment will not withstand the applied test voltage, the voltage test potentialshould be reduced accordingly.
Cable Tensionometer (Strain Gage) and Pulling Devices
If the cable is to be installed in a cable tray or conduit, the cable pull method is determinedprior to the cable installation. The curves and bends within the selected installation route, thetype of pulling equipment, and the lengths of each route segment are all used to calculatespecific pulling tensions that will act on the cable and cable pulling equipment throughout thepull. Maximum cable tensions are calculated for various pulling directions and cable lengths,and a final cable pulling schedule is determined. The proper cables and pulling equipment arethen staged at the various pulling points throughout the length of the cable pull.
The highest probability for cable damage occurs during the installation process. If the correctcable pulling methods are used and if the maximum pulling tensions are not exceeded, thecable should be installed without damage to the cable or to the cable support system. Thepurpose of conducting an evaluation of the cable pulling process is to ensure that the cablepulling methods are correct and that the cable pulling tensions do not exceed the maximumvalues that were determined during the design phase of the installation.
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To evaluate the cable pulling process, personnel should visually observe that the correct cableand cable pulling equipment or devices are used in the cable pull through performance ofvisual checks at both ends of the pull (or pulls). Cable tensiometer (strain gage) checks areperformed throughout the pull (or pulls) to ensure that the maximum cable pulling tensionsare not exceeded.
A general procedure to evaluate the strain gage and pulling devices is provided in Work Aid2.
Point-to-Point Verification of Cables
During a cable installation process, the cable is installed along the route that was chosen forthe installation. A facility installation can have many different power and control cables thatare required to be installed, and the cables sometimes share routes (e.g., conduit and cabletrays) for engineering and economic reasons. A point-to-point verification of the cableinstallation is performed before and during the cable installation process to ensure that thecorrect cable is being installed along the correct route.
In an industrial facility, plant or system conditions can change over time. Because a time lagcan occur between the initial design of a cable installation and the actual installation process,the cable route should also be checked during the point-to-point verification. The cable routecheck that is performed during the point-to-point verification can uncover routing problemsthat may not have existed at the design phase of the cable installation. Additionally, somerouting problems may not become clear until the cable is actually being installed. A list of theitems that should be included in a point-to-point verification of low voltage cables is providedin Work Aid 2.
During the point-to-point verification, the installation of the cable terminations and splicesshould be inspected. The purpose of performing the evaluation of the low voltage cableterminations and splices is to determine whether the low voltage cables have been correctlyterminated or spliced. The main causes of cable failure are damage during installation andimproper splices or terminations. An evaluation of cable splices and terminations can uncoverproblems or installation errors. The identification of problems or errors prior to placing acable in service can prevent costly repairs or replacements later in the operational life of thecable.
To conduct the low voltage cable termination and splice evaluation, inspection personnelshould visually check all terminations and splices during a "walk down" of the installation. Avisual check of all terminations and splices is performed to ensure that the terminations
and splices match the drawings, prints, or specifications for the installation. A list of the itemsthat should be included in the low voltage cable termination and splice evaluation is providedin Work Aid2. A general cable termination and splice evaluation procedure is also providedin Work Aid 2.
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LOW VOLTAGE CABLE SYSTEM OPERATIONAL TESTING PHASE
The operational testing phase of the commissioning cycle provides an opportunity for SaudiAramco personnel to perform the following:
• System source feed compatibility checks• Complete system functional test
System source feed compatibility checks are performed on low voltage cables throughapplication of the full system voltage onto the cable. With the voltage applied, voltagephasing, synchronizing, device rotation, and other source feed compatibility checks areperformed. Parallel or alternate power source feed operations are also performed to ensurethe total operation of the major components of the low voltage cable system.
A complete system functional test is performed on low voltage cables to ensure that the entirelow voltage cable system functions in accordance with the system design. During thecomplete system functional test of low voltage cables, the cables are allowed to assume afully-loaded condition for a period of time that is adequate to obtain the maximum systemtemperature. In special circumstances, cable temperatures are monitored after the loaded timeperiod. The low voltage cable temperatures can be monitored locally through use oftemperature monitoring equipment or through use of thermographic surveys. When suchmonitoring is conducted, particular attention should be paid to splice and termination pointsduring the complete system functional test. Infrared thermography can be used to detect hotspots and abnormal cable temperature conditions.
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SAUDI ARAMCO REQUIREMENTS FOR MEDIUM/HIGH VOLTAGE CABLES
Medium voltage cables in Saudi Aramco electric power systems are defined as cables that arerated to carry voltages that are greater than 1000 V but that are less than 69 kV. High voltagecables are cables that are 69 kV and greater. Medium and high voltage cables are selected foran installation in a manner similar to the selection of low voltage cable; the cable should be ofthe proper type and size to handle nominal and fault transient currents without damage fromexcess heat generation or a loss of system voltage regulation. The proper cable, cable splices,and cable terminations are selected by the facility design personnel before the cable isinstalled.
This section of the Module provides information on the following topics that are pertinent tothe requirements for medium/high voltage cables:
• Types of Medium/High Voltage Cables• Types of Medium/High Voltage Cable Terminations and Splices
Types of Medium/High Voltage Cables
The types of cables that are permitted in Saudi Aramco installations are described in SAES-P-104, SADP-P-104, and Module EEX 206.04, Selecting and Sizing Cables for Saudi AramcoInstallations. A list of the types of medium/high voltage power cables that are permitted inSaudi Aramco installations is provided in Figure 24 of Work Aid 3. A list of the commonabbreviations that are used for cables and wires is provided in the first section of thisinformation sheet.
The basis for the selection of medium/high voltage power cable is as follows:
• The technical requirements of the new installation (or installation modification).
• The installation requirements of the existing (or planned) facilities.
• The economic requirements of the existing (or planned) facilities.
Types of Medium/High Voltage Cable Terminations and Splices
As with low voltage cables, when a medium/high voltage cable that has been ordered from themanufacturer and if the cable meets the specifications of the installation, the cable shouldproperly operate throughout its projected operational life. The main causes of cable failureare damage during installation and improper splices or terminations. The preferred
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Types of Medium/High Voltage Cable Terminations and Splices (Cont'd)
methods for terminating medium/high voltage, solid-dielectric cables and recommended cableterminators are provided in Work Aid 3. A separate table that highlights the types of cableterminations and splices that are permitted in Saudi Aramco installations and the types ofcable terminations and splices that are not permitted in Saudi Aramco installations areprovided in Work Aid 4.
Because a cable in an energized state carries current, the cable generates heat during use.High temperatures can cause embrittlement and degradation of the insulation, which can leadto shorts between phases or from phase to ground. When a cable conductor is terminated, thetermination has more electrical resistance than the cable conductor. The increased electricalresistance at a termination generates more heat than the cable conductor that it terminates.The heat that is generated at a cable termination is dissipated through the outer covering orinsulating material of the termination. Because of the increased electrical resistance at atermination, some terminals have temperature ratings. Information on the temperature ratingsof a terminal can be found in the terminal construction kit that is provided by themanufacturer.
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EVALUATING MEDIUM/HIGH VOLTAGE CABLES UPON RECEIPT
The installation of wire and cable systems is a process that takes place over a period of time.The installation begins with an identified need for a new installation (e.g., a new processingplant). Because power is necessary for the new facility to function, a new wire or cable powerdistribution or control system is designed, and the equipment is ordered from themanufacturer. Medium/high voltage cables that are received from the manufacturer must beevaluated to ensure that they are proper for the installation. The purpose of the evaluation isto verify that the correct cable was received from the manufacturer and that the properinstallation specifications and parameters are met. This section of the Module providesinformation on the following topics that are pertinent to evaluating medium/high voltagecables upon receipt:
• Visual Inspection• Verify Against Specifications• Determine/Locate Manufacturer Test Documentation
Visual Inspection
When medium/high voltage cable is received from the manufacturer, a visual inspection ofthe cable should be performed to verify that the cable that was received from themanufacturer is in good physical condition. A cable is in good physical condition if it has novisible chips, cuts, nicks, gouges, or other possible shipping damage or manufacturer defects.If the medium/high voltage cable is shielded or armored, a visual inspection can only be madeof the outermost layer. Because cables are usually shipped and stored on reels, the cable mustbe unrolled to perform a detailed inspection. Because of the difficulties that are involved inunreeling large lengths of heavy medium/high voltage cables, a cursory inspection isperformed at the receiving point. A detailed inspection of medium/high voltage cable isperformed when the cable is being pulled into the raceway or cable tray at the installation site.
Verify Against Specifications
When a new facility or facility modification is at the equipment installation stage, the designof the installation has already been completed. The type of medium/high voltage cable that isselected for a specific power system should be shown in the drawings, prints, or specificationsfor the installation. Medium/high voltage power cables should be verified against the SaudiAramco and industry specifications to ensure that the cable that is to be installed meets thesespecifications.
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Verify Against Specifications (Cont'd)
Generally, the verification against specifications consists of a determination of whether thesize and type of cable that is to be installed matches the size and type of cable that is requiredfor the installation. In some cases, this determination is accomplished by reading an electricalplan that identifies the cable sizes and types. The Engineer then only has to inspect themanufacturer's markings on each cable and compare them to the requirements on theelectrical plan to determine whether the correct cable is being used. In other situations, theElectrical Engineer must rely on his knowledge of the correct application of cable sizes andtypes and must then determine whether the correct cable is being used.
A list of the items that should be included in a preinstallation inspection to verify amedium/high voltage cable against specifications is provided in Work Aid 3.
Determine/Locate Manufacturer Test Documentation
The manufacturer should perform inspections and tests on medium/high voltage cable beforethe cable is shipped to Saudi Aramco. When a medium/high voltage cable is received fromthe manufacturer, any cable test data should be provided in the shipment. The receivingpersonnel should examine the cable manufacturer inspection and test documentation andverify that the received cable has the ability to provide the service for which it is intended.The verification is performed through comparison of the manufacturer inspection and testdocumentation with the Saudi Aramco medium/high voltage cable installation drawings orprints. When the medium/high voltage cable is satisfactorily verified, the manufacturerinspection and test data become a permanent part of the cable material history.
Inspections, tests, and repairs are performed on medium/high voltage cable from theinstallation and commissioning of the cable to the final removal of the cable from service.Any data from the inspections, tests, and repairs are documented and kept as part of thematerial history of the associated medium/high voltage cable. Material history records ofmedium/high voltage cable installations can show possible trends toward failure. Becausesteps can be taken (or maintenance can be performed) to correct a problem before damageoccurs, knowledge of impending failure is important. The ability to correct a problem beforedamage occurs can minimize equipment down-time and reduce overall plant costs. Materialhistory records can also amplify specific cable design flaws that would allow DesignEngineers to choose different cable or cable support equipment for future installations.
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EVALUATING MEDIUM/HIGH VOLTAGE CABLE TESTING ANDINSTALLATION
Various installation tests and inspections are performed on medium/high voltage cable toensure that the installation meets Saudi Aramco and industry requirements and specifications.The installation tests and inspections that are performed on medium/high voltage cable aresimilar to the installation tests and inspections that are performed on low voltage cable.
Electrical tests are performed to check the ability of a conductor to operate for a reasonablefuture period of time under all operating conditions and loads. When a medium/high voltagecable is being commissioned, an acceptance or installation test should be made after the cableis installed but before the cable is placed in normal service. These acceptance or installationtests should detect shipping or installation damage, gross cable defects, or errors inworkmanship in splices and terminations.
Installation inspections are performed to verify that proper medium/high voltage cableinstallation materials are used, that installation specifications and parameters are met, and thatproper installation procedures are followed. The installation inspection is conducted to ensurethat the wire or cable will function properly when installed.
This section of the Module provides information on the following topics that are pertinent toevaluating medium/high voltage cable testing and installation:
• Insulation Resistance (Megger) Test• DC Hi-Pot Test• Cable Tensionometer (Strain Gage) and Pulling Devices• Point-to-Point Verification of Cables
Insulation Resistance (Megger) Test
The purpose of the medium/high voltage cable insulation resistance (megger) test is todirectly measure the cable insulation resistance. Due to the extremely high resistance of well-made, medium/high voltage cable, a megohmmeter test will only detect gross defects inmaterial or workmanship. Because of the "pass/fail" nature of the insulation resistance test, itonly proves valuable as an initial acceptance test on high voltage cable. The megohmmetertest that is performed on medium/high voltage cables is conducted in an identical manner tothe megohmmeter test that is performed on low voltage cables. For medium/high voltagecables, the megohmmeter test voltage should be 5,000 V for cables that are rated for 5,000 Vand above.
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Insulation Resistance (Megger) Test (Cont'd)
For new medium/high voltage cable installations, the megohmmeter test should be conductedon all new cables before unreeling and immediately after installation. The megohmmeter testwill detect gross imperfections or damage that would result in cable failure upon energization.When new cable is spliced to old cable, a megohmmeter test should be performed on thecomplete circuit prior to commissioning.
The Electrical Engineer should evaluate the insulation resistance (megger) test values toensure that the insulation resistance values that were recorded are greater than themanufacturer's minimum values. If the manufacturer's minimum values are not provided, thevalues of the insulation resistance should be greater than the rated voltage + 1 kV inmegohms. For example, a 13.2 kV rated system should have a measured insulation resistancethat is greater than 14.2 megohms. Any value of insulation resistance that is less than theminimum specifications should be investigated by the Electrical Engineer who performs thetest data evaluation.
The dielectric absorption ratio and polarization index are useful in the performance of anevaluation of the test data. Explanations of the evaluation of the dielectric absorption ratioand polarization index are provided in Work Aid 4.
DC Hi-Pot Test
The dc hi-pot test is required for new cables (5 kV and above) and splices between new cablesprior to commissioning. When new cable is spliced to old cable, a dc hi-pot test of the newcable is performed prior to the installation of the splice. The purpose of the dc hi-pot test thatis performed on medium/high voltage cables is to identify internal faults in, or damage to, themedium/high voltage cable insulation system. The dc hi-pot test will show these faults so thatcorrective action can be taken. The dc hi-pot test should be done before initially energizing amedium/high voltage cable but after a megohmmeter test. Normally, the dc hi-pot test isconducted one month after the cable has been initially energized. The dc hi-pot testingtechnique that is used for medium/high voltage cables involves the measurement of increaseddc voltage that is applied to the insulation under test. The value of the leakage current istracked as the test voltage is increased through several steps, and this value becomes acriterion of the condition of the insulation.
The precautions that are taken and the general procedure of the medium/high voltage cable dchi-pot test are similar to the low voltage cable dc hi-pot test. The major difference betweenthe low and medium/high voltage cable dc hi-pot tests is the voltage values that are usedduring the test. The medium/high voltage cable dc hi-pot test is conducted throughapplication of the voltage value that is indicated in Figure 6. The maximum voltage value
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DC Hi-Pot Test (Cont'd)
is reached in a minimum of four steps. Each step should be an order of the rated ac rmsvoltage of the cable. Each voltage step should be maintained for a one-minute duration. Themaximum allowable test level should be maintained for the time periods that are indicated inFigure 6. For commissioning cables that are spliced to old cables, the final dc test voltageshould not exceed 65 percent of the test voltage. For commissioning cables that are spliced toextremely old cables with low megger readings, a final voltage that is equal to two times theoperating voltage plus two kilovolts is recommended. Representative leakage current-timecurves over a ten-minute period for the medium/high voltage cable dc hi-pot test (based onSaudi Aramco Pre-Commissioning Form P-005, Medium Voltage Cables, and P-006, HighVoltage Cables) are provided in Work Aid 4.
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DC Hi-Pot Test (Cont'd)
DC Test Voltages - EPR and XLPE Cables(ICEA / AEIC Tests)
Insulation Maximum DC Test Voltages (kV)Cable Thickness 100% 80% (3) 75% (2) 65% (4)Rating(kV)
100%A
133%B A B A B A B A B
5 8 15 25 35 69EPR 69XLP115
mm2.282.924.456.608.76
16.5116.5120.32
mils90
115175260345650650800
mm2.923.565.598.13
10.67---
mils115140220320420---
354570
100125240240300
455580
120155---
28365680
100192192240
36446496
124---
2634537594
180180225
34416090
116---
2329466581
156156195
29365278
101---
A = 100 percent insulation level.B = 133 percent insulation level.
(1) Thicknesses are for conductor sizes 500 sq mm (1 000 MCM) or less.Test voltages apply to all conductor sizes.
(2) The 75 percent test may be made at any time during installation.Application time is 5 consecutive minutes.
(3) The 80 percent test may be made after installation but before the cable is placed inservice. Application time is 15 minutes.
(4) The 65 percent test may be made after the cable is installed and placed in service.Application time is 5 minutes. The 65 percent test applies to cables that are less
than five years old.
Medium/High Voltage Cable DC Hi-Pot Test Voltages(Based on Saudi Aramco Pre-Commissioning Forms P-005, Medium Voltage Cables,
and P-006, High Voltage Cables)Figure 6
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DC Hi-Pot Test (Cont'd)
During the conduct of the medium/high voltage dc hi-pot test, the rate of increase of the testvoltages should be approximately uniform. The maximum rate of increase of the test voltagesis 100 percent in ten seconds, and the minimum rate of increase is 100 percent in 60 seconds.
The test should be stopped at the first indication of an upward bend or knee in the curve. Aknee in the curve indicates the need for cleaning and drying, and, if the test is not stopped, theleakage current may increase to a value that may damage the insulation.
At the completion of the test, the charge in the cable should be allowed to drain off. The testcharge drain is accomplished by setting the test voltage dial to zero. The charge drains offthrough leakage in the test set and voltmeter circuits. A one-megohm resistor can be added tothe drainage path if desired. When the cable has dropped to ten percent of its test voltage, itshould be solidly grounded for at least 30 minutes after removal of the dc test voltage.
Cable Tensionometer (Strain Gage) and Pulling Devices
Prior to a medium/high voltage cable installation, if cable is being installed in a cable tray orconduit, the specific pulling tensions that will act on the cable and cable pulling equipmentthroughout the pull are calculated. Based on the maximum cable tensions that are calculatedfor various pulling directions and cable lengths, a final cable pulling schedule is determined.The proper cables and pulling equipment are then staged at the various pulling pointsthroughout the length of the cable pull.
The highest probability for cable damage occurs during the installation process. If the correctcable pulling methods are used, and if the maximum pulling tensions are not exceeded, thecable should be installed without damage to the cable or the cable support system. Thepurpose of conducting an installation inspection of the cable pulling process is to ensure thatthe cable pulling methods are correct and that the cable pulling tensions do not exceed themaximum values that were determined during the design phase of the installation.
To evaluate the cable pulling process, personnel should visually observe that the correct cableand cable pulling equipment or devices are used in the cable pull through performance ofvisual checks at both ends of the pull (or pulls). Cable tensiometer (strain gage) checks areperformed throughout the pull (or pulls) to ensure that the maximum cable pulling tensionsare not exceeded.
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Point-to-Point Verification of Cables
A general procedure to evaluate the strain gage and pulling devices is provided in Work Aid4.
During a cable installation process, the cable is installed along the route that was chosen forthe installation. A facility installation can have many different medium/high voltage powercables that are required to be installed, and the cables sometimes share routes (e.g., conduitand cable trays) for engineering and economic reasons. A point-to-point verification of thecable installation is performed before and during the cable installation process to ensure thatthe correct cable is being installed along the correct route.
Because a time lag can exist between the initial design of a cable installation and the actualinstallation process, the cable route should also be checked during the point-to-pointverification. In an industrial facility, plant or system conditions can change over time. Thecable route check that is performed during the point-to-point verification can uncover routingproblems that may not have existed at the design phase of the cable installation. Additionally,some routing problems may not become clear until the cable is actually being installed. A listof the items that should be included in a point-to-point verification of medium/high voltagecables is provided in Work Aid 4.
During the point-to-point verification, the installation of the cable terminations and splicesshould be inspected. The purpose of performing the evaluation of the medium/high voltagecable terminations and splices is to determine whether the medium/high voltage cables havebeen correctly terminated or spliced. The main causes of cable failure are damage duringinstallation and improper splices or terminations. An evaluation of cable splices andterminations can uncover problems or installation errors. The identification of problems orerrors prior to placing a cable in service can prevent costly repairs or replacements later in theoperational life of the cable.
To conduct the medium/high voltage cable terminations and splices evaluation, inspectionpersonnel should visually check all terminations and splices during a "walk down" of theinstallation to ensure that they match the drawings, prints, or specifications for the installation.A list of the items that should be included in the medium/high voltage cable terminations andsplices evaluation is provided in Work Aid 4. A general cable termination and spliceevaluation procedure is also provided in Work Aid 4.
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MEDIUM/HIGH VOLTAGE CABLE SYSTEM OPERATIONAL TESTING PHASE
The operational testing phase of the commissioning cycle provides an opportunity for SaudiAramco personnel to perform the following:
• System source feed compatibility checks• Complete system functional test
System source feed compatibility checks are performed on medium/high voltage cablesthrough application of the full system voltage onto the cable. For example, a voltage value of13.8 kV ac is used for 15 kV cables to be operated at 13.8 kV. With the voltage applied,voltage phasing, synchronizing, device rotation, and other source feed compatibility checksare performed. Parallel or alternate power source feed operations are also performed toensure the total operation of the major components of the medium/high voltage cable system.
A complete system functional test is performed on medium/high voltage cables to ensure thatthe entire low voltage cable system functions in accordance with the system design. Duringthe complete system functional test of medium/high voltage cables, the cables are allowed toassume a fully-loaded condition for a period of time that is adequate to obtain the maximumsystem temperature. After the loaded time period, the cable temperatures are monitored. Themedium/high voltage cable temperatures can be monitored locally through use of temperaturemonitoring equipment or through use of thermographic surveys. Particular attention shouldbe paid to splice and termination points during the complete system functional test. Infraredthermography can be used to detect hot spots and abnormal cable temperature conditions.
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WORK AID 1: REFERENCES FOR EVALUATING LOW VOLTAGE CABLESUPON RECEIPT
Low Voltage Cable Types
Figures 13 through 17 may (although it is not mandatory) be used as a reference to evaluatethe low voltage cable types upon receipt of the low voltage cable. Figure 13 provides a list ofcables that are used for different applications.
Voltage
ClassApplicatio
nLocation/Classification Cable type
Temp.
Rating
oC
No. ofConductors
Min./Max.Conductor
Size
600V Air Non-HazardousClass 1, Div. 2
Dry or Wet MCMI
9085
3/C1/C or 3/C
14-100014-4/0
Class 1, Div. 1 Dry or Wet MI 85 1/C or 3/C 14-4/0Tray RHH/RHW/US
E90/75 1/C 250-1000
3/C 14-1000Non-Hazardous Dry or Wet MC
TCXPLE/PVC
9090/7590
3/C3/C1/C
14-100014-10002.5-500 mm2
Class 1, Division 2 Dry or Wet MCTCXPLE/PVC
9090/7590
3/C3/C1/C
14-100014-10002.5-500 mm2
Conduit Non-Hazardous orClass 1, Division 1or Class 1,Division 2
Dry, Wetor Wet andOily
RHH/RHW/USETCTHWTHHN/THWNNYAXPLE/PVC
90/7590/757590/758590
1/C or 3/C3/C1/C1/C1/C1/C
14-100014-100014-100014-10002.5-500 mm22.5-500 mm2
DirectBurial Non-Hazardous or
Class 1, Division 2Wet orWet andOily
RHH/RHW/USEMCTCXPLE/PVC
75907590
1/C or 3/C3/C3/C1/C
8-100014-100014-10002.5-500 mm2
Portable Class 1, Div .1 or 2 Dry or Wet G 90 3/C 8-1000
Table of Low Voltage Power Cable Example Applications GuideFigure 13
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WORK AID 1 (Cont'd)
ServiceClassification *
Use Voltage Rating
Type A Type A are used for supervisory monitoring,data recording, and information transfer.
300 V
Type B Type B are used for protective devices andgeneral use.
600 V
Type C Type C are used for connection to circuits withheavy or magnetic trip or break devices.
1000 V
Type D Type D are used in conjunction with highvoltage lines.
5000 V phase-to-ground
* For Saudi Aramco installations, Type A and B service control cables will generally beused.
Table of ICEA Control Cable ClassificationsFigure 14
Electrical ElectronicSignal Levels 50 VAC - 600 VAC
-or-dc
Millivolts - 50V-or-
Pulse Milliamperes (60 Hz or higher)Size Range 10 AWG - 18 AWG
(6mm2 - 2.5mm2)16 AWG - 22 AWG
Construction Non-paired, concentric lay PairedShielding Not generally required Required on all pairs and overall
Table of Electrical and Electronic Control Cable ApplicationsFigure 15
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WORK AID 1 (Cont'd)
Low Voltage Cable Terminations and Splices
Figure 16 table shows the preferred methods for terminating solid-dielectric cables:
Termination Type Voltage Rating and Use NotesPremoldedterminations
Indoor terminations up to 35kV
The premolded terminations that areused should be manufactured byElastimold or meet Elastimoldspecifications.
Heat-shrinkableterminations
All locations up to 35 kV
Elbows (premoldedseparable insulatedconnectors)
All locations up to 35 kV Elbow terminations should bemanufactured by Elastimold or meetElastimold specifications.
Porcelain dry type(e.g., pothead)
All locations up to 69 kV Porcelain dry-type terminationsshould be manufactured by Joslyn ormeet Joslyn specifications.
Taped terminations Indoor terminations. Taped terminations should bemanufactured by 3M or meet 3Mspecifications.
Preferred Methods of Terminating Solid-Dielectric CablesFigure 16
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WORK AID 1 (Cont'd)
Figure 17 shows the recommended cable terminators for types MC, MV, and TC cables thatenter enclosures that are in either unclassified or Class 1, Div. 2 areas:
Cable Type Location Terminator Type(1)MC Wet
Dry
OZ SPKHK or equal(2)(3)
OZ SPKGK orequal(2)
MV or TC (in conduit) Wet
Dry
OZ CRN or equal(3)
Direct Entry
(1) In combination with a sealing fitting when sealing is required in Class 1,Division 2 areas. The cable sheath should be extended into the sealing fittingso that the sealing compound surrounds the edge of the cable sheath.
(2) Refer to Saudi Aramco Standard Drawing AC-036538.(3) A sealing compound should be used to prevent moisture entry in the cable or
conduit.
Recommended Cable Terminators for MC, MV, and TC CableFigure 17
General Procedure to Evaluate Low Voltage Cable Upon Receipt
The following general procedure should be used to evaluate low voltage cables upon receipt:1. Perform a visual inspection of the received cable for manufacturer defects and
shipping or transportation damage (e.g., nicks, cuts, and gouges).
2. Verify the low voltage cable against the installation specification by checking that thefollowing are in compliance with the electrical installation drawings:
• Voltage rating of the cable• Cable ampacity• Conductor size (in AWG or KCMIL)• Cable construction material
• Cable insulation type • Metallic shield, concentric neutral (if one is required), and cable outer jacket
3. Verify that the low voltage cable is in compliance with the following applicable SaudiAramco low voltage cable requirements (from SAES-P-104):
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WORK AID 1 (Cont'd)
• Verify that low voltage wire and cable (600 V or 600/1000 V andbelow) have a minimum rating of 75_C and comply with ANSI/NFPA70, IEC 502, or SSA 55. Verify that wire and cable that aremanufactured in accordance with IEC 502 or SSA 55 are flameretardant in accordance with IEC 332.
• Verify that the concentric neutral wire, metallic armor, and metallicsheaths are protected with a PVC or equivalent jacket.
• Verify that power and control conductors are stranded copper (exceptthat solid copper conductors 6 mm2 (10 AWG) and smaller may beused in non-industrial locations and for specialty applications). Verifythat wire or cable stranding is ASTM B 8 Class B or C or IEC-228 Class2. Verify that all flexible cords, portable cables, and motor leads havefiner stranding in accordance with appropriate ICEA and UL Standardsor manufacturers' recommendations.
• Verify that splicing of conductors is kept to a minimum.
• Verify that conductors of multi-conductor control cables are numberedor color coded by colors other than green, white, or gray.
• Verify that the minimum size of (power and control) conductors that arerated for 600 V and below is 2.5 mm2 (14 AWG).
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WORK AID 2: REFERENCES FOR EVALUATING LOW VOLTAGE CABLEINSTALLATION AND TESTING
Saudi Aramco Pre-Commissioning Form, P-004, Low Voltage Cables
The Saudi Aramco Pre-Commissioning Form, P-004, Low Voltage Cables provides a fieldinstallation check list for low voltage cable installations. P-004 has a broad check list ofvisual and mechanical inspections, as well as the listed electrical tests that are required for lowvoltage cable installations. Space is also provided on the form for test data.
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WORK AID 2 (Cont'd)
FORM # P-004 (7/94) SHT 1 of 2
Saudi Aramco Pre-Commissioning FormLow Voltage Cables
Equipment Type: User Reference:Equipment No.: Description:BI/JO NO.: Plant No./LocationRef. Drawings & DocumentsManufacturer:Model No.: Serial:Commissioning Date:
Field Installation Tests
Visual and Mechanical Inspection
YES NO1. Inspect cables for physical damage and properconnection in accordance with single line diagram.2. Cable connections shall be torque tested tomanufacturer’s recommended values or valuesrecommended in P-000.3. Verify proper terminals and crimping die areused on cable and that crimping procedure isproper.4. Verify cable color coding.
Electrical TestsYES NO
1. Perform Megger Test on each cable with respectto ground and adjacent cables. For cables 250 voltand less use 250 volt megger, for cables 250 volt to600 volt use 1000 volt megger, for cables above600 volts and less than 1200 volts use 2500 voltmegger.2. Perform D.C. High Potential Test on cable withrespect to ground and adjacent cables. HighPotential test cables 250 volt to 1000 volt at 2000volts.
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3. Perform continuity test to insure proper cableconnection.
NOTE: This non-mandatory form may be used as the starting point to assemble a pre-commissioning checklist. Entriesshould be revised, added and deleted and approval adjusted to reflect the needs of the Project Acceptance Committee.
SAPMT INSPECTION OTHER DEPT. OPERATIONSAPPROVALSSignature &Date
Saudi Aramco Pre-Commissioning Form, P-004, Low Voltage CablesFigure 18
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WORK AID 2 (Cont'd)
FORM # P-004 (7/94) SHT 2 of 2
Saudi Aramco Pre-Commissioning FormLow Voltage Cables
Equipment Type: User Reference:Equipment No.: Description:BI/JO NO.: Plant No./LocationRef. Drawings & DocumentsManufacturer:Model No.: Serial:Commissioning Date:
Field Test Data
CableIdent.
CableSize
CableType
CableVoltageRating
Connection MeggerResultsMegohms
DC HipotResultsMicroamps
A-B, C & GRDB-C, A & GRDC-A, B & GRDA-B, C & GRDB-C, A & GRDC-A, B & GRDA-B, C & GRDB-C, A & GRDC-A, B & GRDA-B, C & GRDB-C, A & GRDC-A, B & GRDA-B, C & GRDB-C, A & GRDC-A, B & GRDA-B, C & GRDB-C, A & GRDC-A, B & GRDA-B, C & GRDB-C, A & GRDC-A, B & GRD
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NOTE: This non-mandatory form may be used as the starting point to assemble a pre-commissioning checklist. Entriesshould be revised, added and deleted and approval adjusted to reflect the needs of the Project Acceptance Committee.
SAPMT INSPECTION OTHER DEPT. OPERATIONSAPPROVALSSignature &Date
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WORK AID 2 (Cont'd)
Information, Formulas, and Tables for Use in Evaluating the Results of InsulationResistance (Megger) Tests
Low voltage (600 V and below) cables, including splices to existing cables, must be 500 V dcmegger tested after installation (but prior to backfill in the case of direct buried cables) andprior to placing in service.
The following are the types of megger tests that can be conducted:
• Short time or spot reading• Time resistance• Dielectric absorption ratio
When the dielectric absorption ratio megger test is performed, the polarization index can bedetermined through use of the following equation, in which the readings are of resistance:
Figure 19 provides insulation conditions for dielectric absorption (60/30) ratio results andpolarization index (10/1) ratio results.
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WORK AID 2 (Cont'd)
InsulationCondition
60/30 - SecondRatio
10/1 - Minute Ratio(Polarization Index)
Dangerous
Questionable
Good
Excellent
----
1.0 to 1.25
1.4 to 1.6
Above 1.6
Less than 1
1.0 to 2
2 to 4
Above 4
Dielectric Absorption Ratio ChartFigure 19
Information, Formulas, and Tables for Use in Evaluating the Results of DC Hi-Pot Tests
The dc hi-pot test should be secured if one of the following situation occurs:
• The duration of the test has expired• A rapid rise in leakage current occurs• The polarization index < 1
The following are the characteristics of a satisfactory dc hi-pot test:
• The leakage current gets smaller over time.
• The polarization index > 1.
• The leakage current increases on a straight line as voltage isincreased. No "knee" is noticeable in the leakage current curve.
Figure 20 shows a failure forecast table that is used with dc hi-pot test results to predict whena cable failure could occur.
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WORK AID 2 (Cont'd)
ELASTOMERIC (EPR) FAILURE FORECAST FROMDC HIGH POTENTIAL TESTING
DC Test Potential at Start ofCurrent Runaway
(% of AC rms Voltage)Estimated Failure Time
(Years)200 0.0300 0.5500 2.0800 Over 6
Table of Elastomeric (EPR) Cable Failure ForecastFigure 20
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WORK AID 2 (Cont'd)
An example of dc hi-pot test data is shown in Figure 21. Figure 21 shows both good and badinsulation test data.
Use Word 6.0c or later to
view Macintosh picture.
Example of DC Hi-Pot Test (Good and Bad Cable Insulation)Figure 21
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WORK AID 2 (Cont'd)
Evaluating the Cable Tensionometer (Strain Gage) and Pulling Devices
The following are the inspections and checks that should be performed during the evaluationof the cable tensionometer (strain gage) and pulling devices evaluation:
• Check that the proper cable pulling hardware is provided.
• Check the actual conduit or cable tray bend radii to ensure conformity tothe original pulling tension calculations.
• Check the cable reel assignments and cutting schedules.
• Check the minimum and maximum pulling specifications (e.g.,tensions).
• Check the arrows on the cable reels for the direction to pull the cable offof the reel.
• Inspect the cable for jacket damage.
• Ensure that all water and debris are removed from underground conduitprior to the cable pull.
Point-to-Point Verification of Cables
The following are the inspections and checks that should be performed during the point-to-point verification of a cable installation:
• Verify that circuit separation is maintained between the cable and anyother cables in the run.
• Verify the clearance between the cable and process piping or otherprocess facilities.
• If a raceway (e.g., cable tray and conduit) is used for the installation,verify that the cable is correctly installed in the raceway.
• Verify that the cable supports and fasteners are installed correctly andthat there is no cable damage.
• Spot check the cable installation terminations and splices.
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WORK AID 2 (Cont'd)
Figure 22 shows Saudi Aramco and industry splices and terminations installationrequirements.
Generalrequirements
Compression-type connectors are the preferred method for splicing orterminating cable conductor ends. Compression (crimped) typeconnectors must be used for terminating stranded conductors.All compression connectors must be tinned copper, and they must have amanufacturer's reference compression die number and conductor sizeprinted or stamped on the connector.The metallic composition of the crimp connector and the metalliccomposition of the cable conductor should be similar.The use of solder lugs is prohibited.Cable terminators that rely on inwardly protruding flat springs (tines) forgrounding the metallic sheath or armor are prohibited.Armored cable (unless specifically designated as Type AC per NECArticle 333) must be manufactured to IEC 502 and must have galvanizedsteel wire armor or galvanized double steel tape armor. For installationand application purposes, the cable is considered to be equivalent to typeMC (metal clad) cable, except suitable armored cable terminators (glands)must be used to terminate and ground the armor.Type MC cable and armored cable must be permitted to be installedexposed where it is not subject to damage by vehicular traffic or similarhazards. Other types of cable must not be installed exposed aboveground, and must be installed in cable trays, conduit, or, where flexibilityis required, in flexible conduit.To prevent water from entering the end of the cable, heat shrinkable bootsshould be placed over the crotch of a three-phase cable and shrunk intoplace.Lugs for bolting terminations to buswork or equipment should be orderedwith NEMA standard spacing (15 mm holes on 45 mm centers).Equipment and buswork termination pads also should be specified withNEMA standard spacing. Cable terminal lugs should be a one hole, twohole NEMA, four hole NEMA, or pin terminal design.
Saudi Aramco and Industry Splices and Terminations Installation RequirementsFigure 22
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WORK AID 2 (Cont'd)
Outdoorrequirements
Outdoor riser terminations of shielded, solid dielectric cables must have acreepage path to ground of 40 mm (1.5 in) per kV phase to phase andshould use either heat-shrinkable termination kits, with skirts or porcelaindry type terminators (Joslyn PSC or equal).If three-conductor cables are used, the cable crotch should be sealed.PILC and VCLC high voltage cable terminations require the use ofcompound filled potheads or suitable heat-shrinkable terminations.
Indoorrequirements
Indoor terminations of shielded, solid-dielectric cable should providestress relief and should have a minimum creepage path to ground of 25mm/kV (1 in/kV) phase to phase.Stress relief for indoor shielded, solid-dielectric cables may be providedby stress relieving tape, premolded stress cones, heat shrink stress tubing,or taped cones. Normally all that is required for an enclosed terminationis to strip the cable jacket and shield to the designated length, connect(e.g., crimp) a termination lug, and install a stress cone.
Saudi Aramco and Industry Splices and Terminations Installation RequirementsFigure 22 (Cont'd)
The following is a general terminations and splices visual inspection/evaluation procedure forlow voltage cable installations:
1. The inspection personnel should verify that none of the following are present:
• Wrap-around, rigid snap-on, or adhesive-type markers to identify wiringat terminal blocks.
• Solder lugs.
• Twist-on connectors (wirenuts).
• Cable terminators that rely on inwardly-protruding flat springs (tines)for grounding the metallic sheath or armor.
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WORK AID 2 (Cont'd)
2. The inspection personnel should check that the terminations are one of the SaudiAramco preferred methods.
3. The inspection personnel should check that the terminators that are used for theinstallation are one of the recommended types.
4. The inspection personnel should check the installation against the splices andterminations installation requirements that are shown in Figure 22.
The following is an excerpt from GI 2.710, New Construction Check List Example, thatillustrates the overall check list and sign-off for major pieces of electrical equipment.
3. Electrical Equipment
All substations, powercable, electrical equipment,including lighting andwiring, to be checked forproper application,operation, and grounds.Distribution panels, switchesproperly identified, and allenergization certificaterequests signed.
Construction Agency
Power Distribution Dept.
Project Inspection
Commissioning (Note 1)
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WORK AID 2 (Cont'd)
Figure 23 shows an excerpt from GI 2.710, General Instruction Manual, that illustrates theinspections and tests that should be performed on major pieces of electrical equipment prior tothe turnover of a facility.
DIVISION OF RESPONSIBILITIES FOR TURNOVER SUPPLEMENT NO. 2.710-6MECHANICALCOMPLETION
STARTUP
(Pre-Turnover) (Post-MCC)
ProjectInspection
Operations/Commissioning
Commissioningwith Constr.
Agency (Note 2) Proponent1. General2. Civil/Structural3. Electrical4. Piping5. Mechanical Equipment6. Fire & Safety Systems7. Communications8. Instrumentation9. Catalyst, Chemical and
Dessicants
XRWIOE&IMPPDDFPLPP&CSDCC&OS
- Perform Work- Review and Approve- Witness (Event)- Inspect (Work)- Operate Process Equipment - By Operator- Maintenance’s Start-Up Electrical & Instrument Specialist- Maintenance’s Start-Up Machinist- Maintenance’s Start-Up Fitter- Power Distribution Department- Fire Prevention- Loss Prevention- Process & Control Systems Department- Computer, Communications and Office Systems
NOTE 1: Construction Agency is responsible for performing all work prior to Mechanical Completion, unless assignedotherwise as indicated with an X.
NOTE 2: Per paragraph 4.3.1.6 of G.I.2.710, Construction Agency will provide an agreed number of ContractorCommissioning Assistance Personnel to work under the direction of the Proponent Commissioning Supervisor orhis Nominee. Alternatively, and as directed by Proponent, Operations/Commissioning will utilize E&I, P or PDDpersonnel for Commissioning Assistance.
NOTE 3: PDD will inspect and sign-off for all Power Distribution Systems above 480V; 480V and below will be inspectedby Project Inspection and witnessed by Operations/Commissioning.
NOTE 4: Minimum of 10% of Megger Testing to be witnessed, balance to be monitored.
NOTE 5: Routine cleaning/flushing to be witnessed by Inspection and reviewed by Commissioning. All other specialtycleaning (lube oil systems, etc.) to be witnessed by Commissioning.
GI 2.710 ExcerptFigure 23
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WORK AID 2 (Cont'd)
DIVISION OF RESPONSIBILITIES FOR TURNOVER SUPPLEMENT NO. 2.710-6MECHANICALCOMPLETION
STARTUP
(Pre-Turnover) (Post-MCC)
ProjectInspection
Operations/Commissioning
Commissioningwith Constr.
Agency (Note 2) Proponent
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3. ELECTRICAL
a. Perform dielectric strength tests on powertransformer and disconnect switch insulating oil andinstall when satisfactory.
b. Check condition of grease in grease lubricatedmotor and generator bearings.
c. Perform all necessary prestart-up non-operatingtests and Hi Pot checks on all power cables,generators, Switchgear, MCCs, transformers andgrounding resistors following manufacturers’instructions and guidelines given in the applicableSaudi Aramco Pre-Commissioning Forms Manualavailable from Consulting Services Department.
d. Measure and record the insulation resistance(Megger Testing) of all power (480 V or less),instrument wiring (including thermocouple leads)and lighting circuits from conductor to conductorand from each conductor to ground.
e. Perform applicable checks, adjustments and fieldtests using, if necessary in order to maintainschedule, temporary construction power.
f. Calibrate and set substation relays on all circuitbreakers. Set time delays. Set and test faultpressure relays and transformer taps.
g. Energize substations and load centers by connectionto electrical distribution systems (Energized byauthorized electrical systems operator afterobtaining approved “Energization AuthorizationCertificate”).
h. Check operability of emergency and instrumentpower systems as well as emergency lightingsystem.
i. Issue work permits to Contractor for carrying outchecks on electrical equipment, after facilities areenergized per item (g) if partial MCC signed.
j. Paint or tag all electrical apparatus (Push buttonboxes, connection boxes, etc) according to SaudiAramco’s color code or regulations.
k. Construction Agency will use existing establishedwork permit procedure for remaining constructionperiod, once electrical equipment is energized. (Ifthe existing Tag and Lock-Out Procedure needs tobe revised, it shall be approved by Loss Preventionand implemented as part of this effort).
l. Perform a final functional checkout for allequipment and systems.
I
I
I(Note 4)
I
I
I
I
PDD-W
I
PDD/W(Note 3)
R
RPDD/W (Note 2)
PDD/W
PDD/W
W
R
R
XPDD/W
X
X
O-I
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GI 2.710 ExcerptFigure 23 (Cont'd)
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WORK AID 3:REFERENCES FOR EVALUATING MEDIUM/HIGH VOLTAGECABLES UPON RECEIPT
Medium/High Voltage Cable Types
Figures 24 through 26 may (although it is not mandatory) be used as a reference to evaluatethe medium/high voltage cable types upon receipt of the medium/high voltage cable. Figure24 provides a list of cables that are used for different applications.
VoltageClass Application Location/Classification Cable type
Temp.Rating
oC
No. ofConductors
Min./Max.Conductor Size
5000V Conduit Non-Hazardous orClass 1, Div. 1 or 2
Dry, Wet orWet and Oily
MV 90 1/C or 3/C 8-1000
DirectBurial
Non-Hazardous orClass 1, Division 2
Wet orWet and Oily
MCMV
9090
3/C1/C or 3/C
8-10008-1000
Air Non-Hazardous orClass 1, Division 2
Dry or Wet MC 90 3/C 8-1000
Tray Non-Hazardous Dry or Wet MCMV
9090
3/C1/C3/C
8-1000250-10008-1000
Class 1, Division 2 Dry or Wet MCMV
9090
3/C1/C3/C
8-1000250-10008-1000
Portable Class 1, Div. 1 or 2 Dry or Wet SHD 90 3/C 8-100015,000V Conduit Non-Hazardous or
Class 1, Div. 1 or 2Dry, Wet orWet and Oily
MVURD
9090
1/C or 3/C1/C
2-10008-1000
DirectBurial
Non-Hazardous orClass 1, Division 2
Wet orWet and Oily
MCMVURD
9090
3/C1/C or 3/C
2-10002-10008-1000
Air Non-Hazardous orClass 1, Division 2
Dry or Wet MC 90 3/C 2-1000
Tray Non-Hazardous Dry or Wet MC 90 3/C 2-1000MV 90 3/C
1/C2-1000250-1000
URD 90 1/C 8-1000Class 1, Division 2 Dry or Wet MC 90 3/C 2-1000
MV 90 3/C1/C
2-1000250-1000
Portable Class 1, Div. 1 or 2 Dry or Wet SHD 90 3/C 2-100035,000V Conduit Non-Hazardous or
Class 1, Div. 1 or 2Dry, Wet orWet and Oily
MVURD
9090
1/C1C
1/0-10008-1000
DirectBurial
Non-Hazardous orClass 1, Division 2
Wet orWet and Oily
MVMCURD
909090
1C3/C1/C
1/0-10001/0-10008-1000
Air Non-Hazardous orClass 1, Division 2
Dry or Wet MC 90 3/C 1/0-1000
Tray Non-Hazardous orClass 1, Division 2
Dry or Wet MVMCURD
909090
1/C3/C1/C
1/0-10001/0-10008-1000
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69,000V Cond., Dir.Burial
Non-Hazardous orClass 1, Division 2
Dry, Wet orWet and Oily
EPR/XLPE 90 1/C 4/0-1000
Table of Medium/High Voltage Power Cable Example Applications GuideFigure 24
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WORK AID 3 (Cont'd)
Medium/High Voltage Cable Terminations and Splices
Figure 25 shows the preferred methods for terminating solid-dielectric cables:
Termination Type Voltage Rating and Use NotesPremoldedterminations
Indoor terminations up to 35kV
The premolded terminations that areused should be manufactured byElastimold or meet Elastimoldspecifications.
Heat-shrinkableterminations
All locations up to 69 kV Example: Elastimold or equal.
Elbows (premoldedseparable insulatedconnectors)
All locations up to 35 kV Elbow terminations should bemanufactured by Elastimold or meetElastimold specifications.
Porcelain dry type(e.g., pothead)
All locations up to 69 kV Porcelain dry-type terminationsshould be manufactured by Joslyn ormeet Joslyn specifications.
Taped terminations Indoor terminations Taped terminations should bemanufactured by 3M or meet 3Mspecifications.
Preferred Methods of Terminating Solid-Dielectric CablesFigure 25
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WORK AID 3 (Cont'd)
Figure 26 shows the recommended cable terminators for types MC, MV, and TC cablesentering enclosures that are in either unclassified or Class 1, Div. 2 areas:
Cable Type Location Terminator Type(1)MC Wet
Dry
OZ SPKHK or equal(2)(3)
OZ SPKGK orequal(2)
MV or TC (in conduit) Wet
Dry
OZ CRN or equal(3)
Direct Entry
(1) In combination with a sealing fitting when sealing is required in Class 1,Division 2 areas. The cable sheath should be extended into the sealing fittingso that the sealing compound surrounds the edge of the cable sheath.
(2) Refer to Saudi Aramco Standard Drawing AC-036538.(3) A sealing compound should be used to prevent moisture entry in the cable or
conduit.
Recommended Cable Terminators for MC, MV, and TC CableFigure 26
General Procedure to Evaluate Medium/High Voltage Cable Upon Receipt
The following general procedure should be used to evaluate medium/high voltage cables uponreceipt:
1. Perform a visual inspection of the received cable for manufacturer defects andshipping or transportation damage (e.g., nicks, cuts, gouges).
2. Verify the medium/high voltage cable against the installation specification bychecking that the following are in compliance with the electrical installation drawings:
• Voltage rating of the cable• Cable ampacity• Conductor size (in AWG or KCMIL)
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WORK AID 3 (Cont'd)
• Cable construction material• Cable insulation type• Metallic shield, concentric neutral (if one is required), and cable outer
jacket
3. Verify that the medium/high voltage cable is in compliance with the followingapplicable Saudi Aramco cable requirements (from SAES-P-104):
• Verify that medium voltage power cable, 5 kV through 35 kV,(excluding submarine, submersible pump (down hole), portable, andmotor lead cable) complies with 15-SAMSS-502.
• Verify that concentric neutral wire, metallic armor, and metallic sheathsare protected with a PVC or equivalent jacket.
• Verify that the minimum size of conductors are as follows:
- 5 kV: 10 mm2 (8 AWG)- 15 kV: 35 mm2 (2 AWG)- 35 kV: 50 mm2 (1/0 AWG)- 69 kV: 120 mm2 (4/0 AWG)
• The splicing of conductors must be kept to a minimum. A maximum oftwo splices must be permitted in any one circuit for new installations ofcables that are rated above 1,000 V. Splices and terminations on cablesthat are rated above 1,000 V must be made by personnel who arecertified in accordance with Saudi Aramco General Instruction 2.705.
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WORK AID 4: REFERENCES FOR EVALUATING MEDIUM/HIGH VOLTAGECABLE INSTALLATION AND TESTING
Saudi Aramco Pre-Commissioning Forms, P-005 and P-006, Medium and High VoltageCables
The Saudi Aramco Pre-Commissioning Forms, P-005, and P-006, Medium and High VoltageCables (Figures 27 and 28), respectively, provide a field installation check list for mediumand high voltage cable installations. The pre-commissioning form has a broad check list ofvisual and mechanical inspections, as well as the listed electrical tests that are required formedium and high voltage cable installations. Space is also provided on the form for test data.
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WORK AID 4 (Cont'd)
FORM # P-005 (7/94) SHT 1 of 4Saudi Aramco Pre-Commissioning Form
Medium Voltage CablesEquipment Type: User Reference:Equipment No.: Description:BI/JO NO.: Plant No./LocationRef. Drawings: & DocumentsManufacturer:Model No.: Serial:Commissioning Date:
Field Installation Checklist
Visual and Mechanical Inspection
YES NO1. Check cable reel assignments and cuttingschedules.
2. Check cable pulling schedule for direction ofpull and method of pulling in conduit for mediumvoltage cable.3. Check arrows on cable reels for direction forpulling off reel.
4. Check for correct cable test voltages, minimumpulling temperature and type of pulling compound.5. Inspect cables for jacket damage.
6. The conductors are identified as perspecification and drawings.7. Cable ends sealed after cutting.
8. All water and debris must be removed fromunderground conduit before pulling cable.9. Cable supports and spacing as per specificationsand drawings.10. Cable supports are adjacent to terminal fittings.
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11. Conduits clean, stub-ups protected, open endsplugged, damage during construction repaired.12. Field bend radius correct per specification andcodes. Bends free of deformities.13. Expansion joints as shown on drawings.
NOTE: This non-mandatory form may be used as the starting point to assemble a pre-commissioning checklist. Entriesshould be revised, added and deleted and approval adjusted to reflect the needs of the Project Acceptance Committee.
SAPMT INSPECTION OTHER DEPT. OPERATIONSAPPROVALSSignature &Date
Saudi Aramco Pre-Commissioning Form, P-005, Medium Voltage CablesFigure 27
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WORK AID 4 (Cont'd)
FORM # P-005 (7/94) SHT 2 of 4Saudi Aramco Pre-Commissioning Form
Medium Voltage CablesEquipment Type: User Reference:Equipment No.: Description:BI/JO NO.: Plant No./LocationRef. Drawings: & DocumentsManufacturer:Model No.: Serial:Commissioning Date:
Visual and Mechanical Inspection (Continued)
YES NO14. Spacing between instrument and power conduitand/or cables as per specifications.15. Spacing from hot pipes and from hot surfacesmaintained.
16. Proper fittings are installed with threads fullyengaged, proper sealing compound is used, thereare no wrench cuts, conduit ends have bushings andcovers installed.17. Seals and drains are installed per drawings.
18. Aluminum, PVC or PVC coated conduits areinstalled where specified on drawings.19. Flexible conduit is installed with properbending radius and with standard fittings.20. Metal junction boxes leveled and supported perdrawings with proper hubs, locknuts and bushingsinstalled.21. Seals poured.
Electrical TestYES NO
1. Cables on reels must be isolated andmeggered before unreeling.
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2. Prepare installed cables for test by ensuringthe circuit is de-energized, remove anytemporary grounds and disconnect cable fromequipment. If equipment cannot bedisconnected, a reduced voltage should be usedfor the test.
NOTE: This non-mandatory form may be used as the starting point to assemble a pre-commissioning checklist. Entriesshould be revised, added and deleted and approval adjusted to reflect the needs of the Project Acceptance Committee.
SAPMT INSPECTION OTHER DEPT. OPERATIONSAPPROVALSSignature &Date
Saudi Aramco Pre-Commissioning Form, P-005, Medium Voltage CablesFigure 27 (Cont'd)
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WORK AID 4 (Cont'd)
FORM # P-005 (7/94) SHT 3 of 4Saudi Aramco Pre-Commissioning Form
Medium Voltage CablesEquipment Type: User Reference:Equipment No.: Description:BI/JO NO.: Plant No./LocationRef. Drawings: & DocumentsManufacturer:Model No.: Serial:Commissioning Date:
Electrical Test (Continued)
YES NO3. Insulate cable cores from ground.
4. Erect safety barriers and post safety man atcable end remote from the test equipment.
5. Check the insulation resistance of the cableusing a megger tester. The test voltage shouldbe 5000 volts for 5000 volt and above cables.Measure the insulation resistance of each coreand any metallic armor or sheath grounded atone end only.6. Each cable shall be high potential tested asfollows: each core to ground, with the shield,other cores and any metallic armor or sheathgrounded at one end only.7. For commissioning new cables, the final D.C.test voltage is the 80% test voltage in the tablesbelow.
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8. For commissioning new cables that arespliced to old cables, and for testing old cables,the final D.C. test voltage shall be determined bythe proponent of the cables, and should notexceed the 65% test voltage in the tables below(40% of these values is recommended after 5years). A voltage equal to 2X operating voltage+ 2 kV is recommended for extremely old cableswith low megger readings.9. The D.C. high voltage shall be applied in aminimum of four steps (each step approximatelyequal to the rated rms voltage of the cable) ofone (1) minute duration each except for the finaltest voltage which shall be maintained for fifteen(15) minutes.
NOTE: This non-mandatory form may be used as the starting point to assemble a pre-commissioning checklist. Entriesshould be revised, added and deleted and approval adjusted to reflect the needs of the Project Acceptance Committee.
SAPMT INSPECTION OTHER DEPT. OPERATIONSAPPROVALSSignature & Date
Saudi Aramco Pre-Commissioning Form, P-005, Medium Voltage CablesFigure 27 (Cont'd)
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WORK AID 4 (Cont'd)
FORM # P-005 (7/94) SHT 4 of 4Saudi Aramco Pre-Commissioning Form
Medium Voltage CablesEquipment Type: User Reference:Equipment No.: Description:BI/JO NO.: Plant No./LocationRef. Drawings: & DocumentsManufacturer:Model No.: Serial:Commissioning Date:
Electrical Test (Continued)
YES NO10. On completion of tests the cable shall be leftwith all cores and shields grounded for one hour toallow the residual charge to dissipate.
XLPE OR EPR CABLES MANUFACTURED TO AEIC CS5 OR CS6 AND 15-SAMSS-502
Rated Voltage InsulationThick.
80% TestVoltage
65% TestVoltage
40% TestVoltage
5 kV 115 Mils 36 kV 29 kV 18 kV15 kV 220 Mils 64 kV 52 kV 32 kV35 kV 345 Mils 100 kV 81 kV 50 kV
XLPE OR EPR CABLES MANUFACTURED TO IEC-502 AND 15-SAMSS-502Rated Voltage Insulation
Thick.80% TestVoltage
65% TestVoltage
40% TestVoltage
6/10 kV 3.4 MM 37 kV DC 29 kV DC 18.5 kV12/20 kV 5.5 MM 64 kV DC 52 kV DC 32 kV
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NOTES: 80% and 65% refer to percentages of the factory test voltages specified inAEIC CS5 and CS6. AEIC CS5 and CS6 permit testing at the 65% test voltage “atanytime during the period of the guarantee.” Test values for cables older than 5 yearsare listed in the 40% column.
NOTE: This non-mandatory form may be used as the starting point to assemble a pre-commissioning checklist. Entriesshould be revised, added and deleted and approval adjusted to reflect the needs of the Project Acceptance Committee.
SAPMT INSPECTION OTHER DEPT. OPERATIONSAPPROVALSSignature & Date
Saudi Aramco Pre-Commissioning Form, P-005, Medium Voltage CablesFigure 27 (Cont'd)
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WORK AID 4 (Cont'd)
FORM # P-006 (7/94) SHT 1 of 4Saudi Aramco Pre-Commissioning Form
High Voltage CablesEquipment Type: User Reference:Equipment No.: Description:BI/JO NO.: Plant No./LocationRef. Drawings: & DocumentsManufacturer:Model No.: Serial:Commissioning Date:
Field Installation Checklist
Visual and Mechanical Inspection
YES NO1. Check cable reel assignments and cuttingschedules.
2. Check cable pulling schedule for direction of pulland method of pulling.3. Check arrows on high voltage cable reels fordirection for pulling off reel.4. Check for correct cable test voltages, minimumpulling temperature and type of pulling compound ifapplicable.5. Inspect cables for jacket damage.
6. The conductors are identified as per specificationand drawings.7. Cable ends sealed after cutting.
8. Cable support and spacing as per specificationsand drawings.
9. Cable supports are adjacent to terminal fittings.
10. Field bend radius correct per specification andcodes. Bends free of deformities.11. Expansion joints as shown on drawings.
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12. Spacing between instrument and power conduitand/or cables as per specifications.13. Spacing from hot pipes and from hot surfacesmaintained.
NOTE: This non-mandatory form may be used as the starting point to assemble a pre-commissioning checklist. Entriesshould be revised, added and deleted and approval adjusted to reflect the needs of the Project Acceptance Committee.
SAPMT INSPECTION OTHER DEPT. OPERATIONSAPPROVALSSignature & Date
Saudi Aramco Pre-Commissioning Form, P-006, High Voltage CablesFigure 28
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WORK AID 4 (Cont'd)
FORM # P-006 (7/94) SHT 2 of 4Saudi Aramco Pre-Commissioning Form
High Voltage CablesEquipment Type: User Reference:Equipment No.: Description:BI/JO NO.: Plant No./LocationRef. Drawings: & DocumentsManufacturer:Model No.: Serial:Commissioning Date:
Visual and Mechanical Inspection (Continued)
YES NO14. Proper fittings are installed with threads fully engaged,proper sealing compound is used, there are no wrench cuts,conduit ends have bushings and covers installed.15. Seals and drains are installed per drawings.
16. Aluminum, PVC or PVC coated conduits are installedwhere specified on drawings.17. Metal junction boxes leveled and supported per drawingswith proper hubs, locknuts and bushings installed.18. Seals poured.
Electrical TestsYES NO
1. Cables on reels must be isolated and meggered beforeunreeling.2. Prepare installed cables for test by ensuring the circuit is de-energized, remove any temporary grounds and disconnect cablefrom equipment.3. Insulate cable cores from ground.
4. Erect safety barriers and post safety man at cable end remotefrom the test equipment.5. Check the insulation resistance of the cable using a meggertester. The test voltage should be 5000 volts. Measure theinsulation resistance of each core and any metallic armor orsheath grounded at one end only.
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6. Each cable shall be high potential tested as follows: eachcore to ground, with the shield, other cores and any metallicarmor or sheath grounded at one end only.
NOTE: This non-mandatory form may be used as the starting point to assemble a pre-commissioning checklist. Entriesshould be revised, added and deleted and approval adjusted to reflect the needs of the Project Acceptance Committee.
SAPMT INSPECTION OTHER DEPT. OPERATIONSAPPROVALSSignature & Date
Saudi Aramco Pre-Commissioning Form, P-006, High Voltage CablesFigure 28 (Cont'd)
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WORK AID 4 (Cont'd)
FORM # P-006 (7/94) SHT 3 of 4Saudi Aramco Pre-Commissioning Form
High Voltage CablesEquipment Type: User Reference:Equipment No.: Description:BI/JO NO.: Plant No./LocationRef. Drawings: & DocumentsManufacturer:Model No.: Serial:Commissioning Date:
Electrical Tests (Continued)
YES NO7. For commissioning new cables, the final D.C. test voltage isthe 80% test voltage in the tables below.8. For commissioning new cables that are spliced to old cables,and for testing old cables, the final D.C. test voltage shall bedetermined by the proponent of the cables, and should notexceed the 65% test voltage in the tables below (40% of thesevalues is recommended after 5 years). A voltage equal to 2Xoperating voltage + 2 kV is recommended for very old cableswith low megger readings.9. The D.C. high voltage shall be applied such that the rate ofincrease of the test voltages should be approximately uniformand should be no more than 100 percent in 10 second nor lessthan 100 percent in 60 seconds. The final (max) test voltageshall be held for fifteen (15) minutes.10. On completion of tests the cable shall be left with all coresand shields grounded for one hour to allow the residual chargeto dissipate.
D.C. TEST VOLTAGES - EPR AND XLPE CABLES (ICEA/AEIC TESTS)CableRating (kV)
Insulation ThicknessMM/Mils
Max. D.C. Test Voltage (kV)
100% 80% 75% 65%69 EPR 16.51/650 240 192 180 15669 XLP 16.51/650 240 192 180 156115 20.32/800 300 240 225 195
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NOTE: At any time during installation, a dc proof test may be made at a voltage not exceeding 75% of the dctest voltage specified in the above table applied for 5 consecutive minutes. After installation and before thecable is placed in regular service, a high voltage dc test may be made at 80% of the dc test voltage specified forfifteen consecutive minutes. The cable may be tested after placing in service any time within the first 5 years at65% of the dc test voltage. Very old cables are tested at 1/2 the 80% values.
NOTE: This non-mandatory form may be used as the starting point to assemble a pre-commissioning checklist. Entriesshould be revised, added and deleted and approval adjusted to reflect the needs of the Project Acceptance Committee.
SAPMT INSPECTION OTHER DEPT. OPERATIONSAPPROVALSSignature & Date
Saudi Aramco Pre-Commissioning Form, P-006, High Voltage CablesFigure 28 (Cont'd)
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WORK AID 4 (Cont'd)
FORM # P-006 (7/94) SHT 4 of 4Saudi Aramco Pre-Commissioning Form
High Voltage CablesEquipment Type: User Reference:Equipment No.: Description:BI/JO NO.: Plant No./LocationRef. Drawings: & DocumentsManufacturer:Model No.: Serial:Commissioning Date:
HIGH VOLTAGE CABLE TEST RECORDB.I. or W.O. No. Cable No. Voltage RatingPlant Size & Type
High Potential Test (D.C.)
Test Voltage -Phase 1 toGND
Phase 2 toGND
Phase 3 toGND
Resistance(Megger)
Test
andHold Time
CurrentMicro Amps
CurrentMicro Amps
CurrentMicro Amps Phase Megohms
kV Phase 1 to 2kV Phase 2 to 3kV Phase 3 to 1kV Phase 1 to GkV Phase 2 to GkV Phase 3 to G
15 Sec Test Voltage (Megger)30 Sec 500/1000/2500/5000 Volt45 Sec1 Min General Data:2 Min3 Min Temp.Deg.F/
C4 Min % Rel. Hum.5 Min Insul Thick.6 Min Cable Test7 Min Voltage8 Min9 Min
10 Min11 Min12 Min13 Min
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14 Min15 Min
NOTE: This non-mandatory form may be used as the starting point to assemble a pre-commissioning checklist. Entriesshould be revised, added and deleted and approval adjusted to reflect the needs of the Project Acceptance Committee.
SAPMT INSPECTION OTHER DEPT. OPERATIONSAPPROVALSSignature & Date
Saudi Aramco Pre-Commissioning Form, P-006, High Voltage CablesFigure 28 (Cont'd)
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WORK AID 4 (Cont'd)
Information, Formulas, and Tables for Use in Evaluating the Results of InsulationResistance (Megger) Tests
Medium/High Voltage cables (5 kV and above) must be tested as follows:
(a) New installations of cable and splices must be 5 kV insulation resistance (megger)tested after installation. The 5 kV megger must be performed prior to commissioningbut prior to backfill in the case of direct buried cables.
(b) New cables to be spliced to existing cables must be megger tested prior to splicing asin (a) above. After splicing (but prior to backfill in the case of direct buried cables),the new and existing cable combination must be 5 kV megger tested.
The integrity of the overall sheath or jacket of cables that are rated 35 kV and higher must betested by conducting a 5 kV megger test between the cable insulation metallic shield andground. Direct buried cables must be tested and accepted prior to backfill of the cable trench.
The results of all commissioning megger tests that are performed on cable that is rated 5 kVand above must be documented on the appropriate Saudi Aramco pre-commissioning form.
The following are the types of megger tests that can be conducted:
• Short time or spot reading• Time resistance• Dielectric Absorption Ratio
When the dielectric absorption ratio megger test is performed, the polarization index can bedetermined through use of the following equation, which provides readings of resistance:
Figure 29 provides insulation conditions for 60/30 second ratio results and for 10/1 minuteratio results.
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WORK AID 4 (Cont'd)
InsulationCondition
60/30 - SecondRatio
10/1 - Minute Ratio(Polarization Index)
Dangerous
Questionable
Good
Excellent
----
1.0 to 1.25
1.4 to 1.6
Above 1.6
Less than 1
1.0 to 2
2 to 4
Above 4
Dielectric Absorption Ratio ChartFigure 29
Information, Formulas, and Tables for Use in Evaluating the Results of DC Hi-Pot Tests
Medium/High Voltage cables (5 kV and above) must be dc hi-pot tested as follows:
(a) New installations of cable and splices must be dc hi-pot tested after installation. Thedc hi-pot test should be conducted after the megger test. The dc hi-pot test must beperformed prior to commissioning but prior to backfill in the case of direct buriedcables. The voltage levels of the dc hi-pot test are specified in 15-SAMSS-502 and15-SAMSS-503.
(b) New cables to be spliced to existing cables must be dc hi-pot tested prior to splicing asin (a) above. After splicing (but prior to backfill in the case of direct buried cables),the new and existing cable combination may be dc hi-pot tested. The dc hi-pot testvoltage should be equal to or lower than the values specified under (c) below, asdetermined by the Proponent of the cable.
c) Maximum dc hi-pot test voltages for old cables:
• Cables up to 5 years old: 65% values, applicable AEICstandards.
• Cables above 5 years old: 40% values, applicable AEICstandards.
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WORK AID 4 (Cont'd)
The results of all dc hi-pot tests that are performed for commissioning on cable that is rated 5kV and above must be documented on the appropriate Saudi Aramco pre-commissioningform.
The dc hi-pot test should be secured if one of the following situation occurs:
• The duration of the test has expired• A rapid rise in leakage current occurs• The polarization index < 1
The following are the characteristics of a satisfactory dc hi-pot test:
• The leakage current gets smaller over time.
• The polarization index > 1.
• The leakage current increases on a straight line as voltage isincreased. No "knee" is noticeable in the leakage current curve.
Figure 30 shows a failure forecast table that is used with dc hi-pot test results to predict whena cable failure could occur.
ELASTOMERIC (EPR) FAILURE FORECAST FROMDC HIGH POTENTIAL TESTING
DC Test Potential at Start ofCurrent Runaway
(% of AC rms Voltage)Estimated Failure Time
(Years)200 0.0300 0.5500 2.0800 Over 6
Table of Elastomeric (EPR) Cable Failure ForecastFigure 30
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WORK AID 4 (Cont'd)
An example of dc hi-pot test data is shown in Figure 31. Figure 31 shows both good and badinsulation test data.
Use Word 6.0c or later to
view Macintosh picture.
Example of DC Hi-Pot Test (Good and Bad Cable Insulation)Figure 31
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WORK AID 4 (Cont'd)
Evaluating the Cable Tensionometer (Strain Gage) and Pulling Devices
The following are the inspections and checks that should be performed during the evaluationof the cable tensionometer (strain gage) and pulling devices evaluation:
• Check that the proper cable pulling hardware is provided.
• Check the actual conduit or cable tray bend radii to ensure conformity tothe original pulling tension calculations.
• Check the cable reel assignments and cutting schedules.
• Check the minimum and maximum pulling specifications (e.g.,tensions).
• Check the arrows on the cable reels for the direction to pull the cable offof the reel.
• Inspect the cable for jacket damage.
• Ensure that all water and debris are removed from underground conduitprior to the cable pull.
Point-to-Point Verification of Cables
The following are the inspections and checks that should be performed during the point-to-point verification of a cable installation:
• Verify that circuit separation is maintained between the cable and anyother cables in the run.
• Verify the clearance between the cable and process piping or otherprocess facilities.
• If a raceway (e.g., cable tray or conduit) is used for the installation,verify that the cable is correctly installed in the raceway.
• Verify that the cable supports and fasteners are installed correctly andthat there is no cable damage.
• Spot check the cable installation terminations and splices.
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WORK AID 4 (Cont'd)
Figure 32 shows Saudi Aramco and industry splices and terminations installationrequirements.
Generalrequirements
Compression-type connectors are the preferred method for splicing orterminating cable conductor ends. Compression (crimped) typeconnectors must be used for terminating stranded conductors.All compression connectors must be tinned copper and must have amanufacturer's reference compression die number and conductor sizeprinted or stamped on the connector.The metallic composition of the crimp connector and the metalliccomposition of the cable conductor should be similar.The use of solder lugs is prohibited.Cable terminators that rely on inwardly protruding flat springs (tines) forgrounding the metallic sheath or armor are prohibited.Armored cable (unless specifically designated as Type AC per NECArticle 333) must be manufactured to IEC 502 and must have galvanizedsteel wire armor or galvanized double steel tape armor. For installationand application purposes, the cable is considered to be equivalent to typeMC (metal clad) cable, except suitable armored cable terminators (glands)must be used to terminate and ground the armor.Type MC cable and armored cable must be permitted to be installedexposed where it is not subject to damage by vehicular traffic or similarhazards. Other types of cable must not be installed exposed aboveground, and must be installed in cable trays, conduit, or, where flexibilityis required, in flexible conduit.To prevent water from entering the end of the cable, heat shrinkable bootsshould be placed over the crotch of a three-phase cable and shrunk intoplace.Lugs for bolting terminations to buswork or equipment should be orderedwith NEMA standard spacing (15 mm holes on 45 mm centers).Equipment and buswork termination pads also should be specified withNEMA standard spacing. Cable terminal lugs should be a one hole, twohole NEMA, four hole NEMA, or pin terminal design.
Saudi Aramco and Industry Splices and Terminations Installation RequirementsFigure 32
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WORK AID 4 (Cont'd)
Outdoorrequirements
Outdoor riser terminations of shielded, solid dielectric cables must have acreepage path to ground of 40 mm (1.5 in) per kV phase to phase andshould use either heat-shrinkable termination kits, with skirts or porcelaindry-type terminators (Joslyn PSC or equal).If three-conductor cables are used, the cable crotch should be sealed.PILC and VCLC high voltage cable terminations require the use ofcompound filled potheads or suitable heat-shrinkable terminations.
Indoorrequirements
Indoor terminations of shielded, solid-dielectric cable should providestress relief and should have a minimum creepage path to ground of 25mm/kV (1 in/kV) phase to phase.Stress relief for indoor shielded, solid-dielectric cables may be providedby stress relieving tape, premolded stress cones, heat shrink stress tubing,or taped cones. Normally all that is required for an enclosed terminationis to strip the cable jacket and shield to the designated length, connect(e.g., crimp) a termination lug, and install a stress cone.Indoor HV shielded terminations that are exposed to atmosphericcontamination and moisture condensation should be treated as outdoorterminations. Non-porcelain slip-on terminations are allowed, however,providing a creepage path to ground of 33 mm/kV (1.3 in/kV) phase tophase is provided. Such terminators should provide several skirts toincrease the creepage path. If at all possible all exposed live parts shouldbe insulated with track resistant tape (3M or equal) or track resistant heatshrinkable tubing (Raychem or equal).
Saudi Aramco and Industry Splices and Terminations Installation RequirementsFigure 32 (Cont'd)
General Procedure to Evaluate Medium/High Voltage Cable Terminations and Splices
The following is a general terminations and splices visual inspection/evaluation procedure formedium/high voltage cable installations:
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WORK AID 4 (Cont'd)
1. The inspection personnel should verify that none of the following are present:
• Wrap-around, rigid snap-on, or adhesive-type markers to identify wiringat terminal blocks.
• Solder lugs.
• Twist-on connectors (wirenuts).
• Cable terminators that rely on inwardly-protruding flat springs (tines)for grounding the metallic sheath or armor.
2. The inspection personnel should check that the terminations are one of the preferredmethods.
3. The inspection personnel should check that the terminators that are used for theinstallation are one of the recommended types.
4. The inspection personnel should check the installation against the splices andterminations installation requirements that are shown in Figure 32.
The following is an excerpt from GI 2.710, New Construction Check List Example, thatillustrates the overall checklist and sign-off for major pieces of electrical equipment.
3. Electrical Equipment
All substations, powercable, electrical equipment,including lighting and wiring, tobe checked for proper application,operation, and grounds.Distribution panels, switchesproperly identified, and allenergization certificate requestssigned.
Construction Agency
Power Distribution Dept.
Project Inspection
Commissioning (Note 1)
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WORK AID 4 (Cont'd)
Figure 33 shows an excerpt from GI 2.710, General Instruction Manual, that illustrates theinspections and tests that should be performed on major pieces of electrical equipment prior tothe turnover of a facility.
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WORK AID 4 (Cont'd)
DIVISION OF RESPONSIBILITIES FOR TURNOVER SUPPLEMENT NO. 2.710-6MECHANICALCOMPLETION
STARTUP
(Pre-Turnover) (Post-MCC)
ProjectInspection
Operations/Commissioning
Commissioningwith Constr.
Agency (Note 2) Proponent1. General2. Civil/Structural3. Electrical4. Piping5. Mechanical Equipment6. Fire & Safety Systems7. Communications8. Instrumentation9. Catalyst, Chemical and
Dessicants
XRWIOE&IMPPDDFPLPP&CSDCC&OS
- Perform Work- Review and Approve- Witness (Event)- Inspect (Work)- Operate Process Equipment - By Operator- Maintenance’s Start-Up Electrical & Instrument Specialist- Maintenance’s Start-Up Machinist- Maintenance’s Start-Up Fitter- Power Distribution Department- Fire Prevention- Loss Prevention- Process & Control Systems Department- Computer, Communications and Office Systems
NOTE 1: Construction Agency is responsible for performing all work prior to Mechanical Completion, unless assignedotherwise as indicated with an X.
NOTE 2: Per paragraph 4.3.1.6 of G.I.2.710, Construction Agency will provide an agreed number of ContractorCommissioning Assistance Personnel to work under the direction of the Proponent Commissioning Supervisor orhis Nominee. Alternatively, and as directed by Proponent, Operations/Commissioning will utilize E&I, P or PDDpersonnel for Commissioning Assistance.
NOTE 3: PDD will inspect and sign-off for all Power Distribution Systems above 480V; 480V and below will be inspectedby Project Inspection and witnessed by Operations/Commissioning.
NOTE 4: Minimum of 10% of Megger Testing to be witnessed, balance to be monitored.
NOTE 5: Routine cleaning/flushing to be witnessed by Inspection and reviewed by Commissioning. All other specialtycleaning (lube oil systems, etc.) to be witnessed by Commissioning.
GI 2.710 ExcerptFigure 33
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WORK AID 4 (Cont'd)
DIVISION OF RESPONSIBILITIES FOR TURNOVER SUPPLEMENT NO. 2.710-6MECHANICALCOMPLETION
STARTUP
(Pre-Turnover) (Post-MCC)
ProjectInspection
Operations/Commissioning
Commissioningwith Constr.
Agency (Note 2) Proponent
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3. ELECTRICAL
a. Perform dielectric strength tests on powertransformer and disconnect switch insulating oil andinstall when satisfactory.
b. Check condition of grease in grease lubricatedmotor and generator bearings.
c. Perform all necessary prestart-up non-operatingtests and Hi Pot checks on all power cables,generators, Switchgear, MCCs, transformers andgrounding resistors following manufacturers’instructions and guidelines given in the applicableSaudi Aramco Pre-Commissioning Forms Manualavailable from Consulting Services Department.
d. Measure and record the insulation resistance(Megger Testing) of all power (480 V or less),instrument wiring (including thermocouple leads)and lighting circuits from conductor to conductorand from each conductor to ground.
e. Perform applicable checks, adjustments and fieldtests using, if necessary in order to maintainschedule, temporary construction power.
f. Calibrate and set substation relays on all circuitbreakers. Set time delays. Set and test faultpressure relays and transformer taps.
g. Energize substations and load centers by connectionto electrical distribution systems (Energized byauthorized electrical systems operator afterobtaining approved “Energization AuthorizationCertificate”).
h. Check operability of emergency and instrumentpower systems as well as emergency lightingsystem.
i. Issue work permits to Contractor for carrying outchecks on electrical equipment, after facilities areenergized per item (g) if partial MCC signed.
j. Paint or tag all electrical apparatus (Push buttonboxes, connection boxes, etc) according to SaudiAramco’s color code or regulations.
k. Construction Agency will use existing establishedwork permit procedure for remaining constructionperiod, once electrical equipment is energized. (Ifthe existing Tag and Lock-Out Procedure needs tobe revised, it shall be approved by Loss Preventionand implemented as part of this effort).
l. Perform a final functional checkout for allequipment and systems.
I
I
I(Note 4)
I
I
I
I
PDD-W
I
PDD/W(Note 3)
R
RPDD/W (Note 2)
PDD/W
PDD/W
W
R
R
XPDD/W
X
X
O-I
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GI 2.710 ExcerptFigure 33 (Cont'd)
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GLOSSARY
cable jacket A protective covering over the insulation of a conductor
cable splice The physical connection of two or more conductors to provide electricalcontinuity.
cable termination A device that seals the end of a cable and that provides an electricalconnection to the rest of the electric power system.
circular mil A unit of measure that is equal to the area of a circle that has a diameterof one mil.
creepage The shortest distance between two conducting parts measured along thesurface or joints of the insulating material between them.
crimp barrel The cylindrical portion of a crimp connector to which the mechanicalforce of deformation is applied. The deformation maintains theelectrical connection.
dielectric strength The electrical potential (voltage) gradient at which electrical failure orbreakdown occurs.
Elastimold A company that manufactures splice and termination material that isused in Saudi Aramco.
EPR Ethylene Propylene Rubber.
grounding eye The part of a prefabricated mechanical splice that interconnects theshields of the two cables and that forms an effective ground for thesplice.
half lapped A tape configuration in which half of the layer of the tape that is beingapplied overlaps the layer that was just applied by one-half of its width.
IEC International Electrotechnical Commission
IEEE The Institute of Electrical and Electronics Engineers
insulation The electrical resistance between two conductors that are separated byresistance an insulating material.
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insulator A device that has high electrical resistance and that is used forsupporting or separating conductors to prevent undesired flow of currentfrom them to other objects.
joint housing The part of a premolded mechanical splice that protects the crimpconnection from the elements.
kcmil 1,000 circular mils.
mastic A pasty material that is used as a protectant.
megohm A unit of resistance that is equal to 1,000,000 ohms.
megohmmeter An instrument that is used to measure the high resistance of electricalmaterials of the order of 20,000 megohms at 1000 V.
Mil 1/1,000 of an inch.
PDD Power Distribution Department
polarization The action or process of producing a counter electromotive forcethrough the application of an electric field. The result is a relativedisplacement of positive and negative bound charges.
stress cone A cone that is built inside a splice that gradually alleviates dielectricstress that is caused by a change in insulation thickness.
XLPE Cross-Linked Polyethylene.