Earthling System Electrical and Instruments Test Procedure

-----

0 NATIONAL IRANIAN OIL COMPANY ~ South Pars Gas Field Development OIEC NJ.G.CPhases 20 & 21

Pars Oil &, Gas Company OillncAlSfn~sJ ngwl/mng II.n"ConsbucfiOf1

DOCUMENT TITLE DOCUMENT No. Rev. : 0 I Class : 1 Earthling System Electrical and Instruments Test Procedure Test TOT -SP20210NCO999P3320015 Page 1 of 23

Procedure

Earthing System Electrical and Instruments Test

Procedure

(ONSHORE FACILITIES - PRECOMMISSIONING)

CONTRACT NO. : POGC572-88-35 PROJECT: SOUTH PARS GAS FIELD DEVELOPMENT

PHASES 20&21 COMPANY: PARS OIL & GAS COMPANY SITE: ASSALUYEH, IRAN

o 30/Sep/2013 Issued For Approval oleo

Rev. Date Description Originator Prepared Checked

A.Razzaghi

Approved

OilIndustriesEngineeringandConstruction

NATIONAL IRANIAN OIL COMPANY

South Pars Gas Field Development Phases 20 & 21

DOCUMENT TITLE DOCUMENT No. Rev.: 0 Class: 1 Earthling System Electrical and Instruments Test Procedure Test

Procedure TOT-SP2021-ON-CO-999-P332-0015 Page 2 of 23

TABULATION OF REVISED PAGES

Page Rev 0 Rev 1 Rev 2

Page Rev 0 Rev 1 Rev 2 1 X 2 X 3 X 4 X 5 X 6 X 7 X 8 X 9 X 10 X 11 X 12 X 13 X 14 X 15 X 16 X 17 X 18 X 19 X 20 X 21 X 22 X 23 X






TABLE OF CONTENT

1. Object...............................................................................................................................................52. Definitions........................................................................................................................................53. General.............................................................................................................................................54. Test Methods...................................................................................................................................6

4. 1 Insulation Resistance (IR) tests...............................................................................................64. 2 High voltage tests.......................................................................................................................6

5. Test procedures..............................................................................................................................66. Earthing systems - Test Sheet T-PX-26......................................................................................7

a. Continuity of protective conductors.............................................................................................7b. For main protective conductor,.....................................................................................................7

7. Equipment earth return path impedance test.............................................................................7a. Definitions........................................................................................................................................7b. Method.............................................................................................................................................8c. Motor fed from LV motor control centre......................................................................................8d. Lighting circuit fed from distribution board (See Example 2).................................................10e. HV Motor fed from HV switchboard (See Example 3)............................................................12

8. Grounding System Testing..........................................................................................................14a. Fall-of-Potential Method or 3-Point Test...................................................................................14b. Graphing & Evaluation.................................................................................................................16c. Invalid Tests..................................................................................................................................17d. Induced Frequency Testing or Clamp-On Testing..................................................................18e. Test Application............................................................................................................................19f. Ground Resistance Monitoring...................................................................................................20

9. Appendix........................................................................................................................................20






9.1. Appendix01: Electrical LV Power Cables (T-PX-09)...................................................................219.2. Appendix02: Electrical Earthing / Lightning System (T-PX-26).................................................229.3. Appendix03: Electrical Earthing (C-PX-26)..................................................................................23






1. Object

Pre-commissioning is a phase associated with the construction stage such that the completion

of pre-commissioning marks the end of the construction for any specific equipment. Its object is

to prepare and statically test the equipment, which has been constructed and installed, so that

the equipment is ready to undergo dynamic testing during the commissioning phase.

This document outlines the pre-commissioning activities and tests of the EARTHING SYSTEM.

2. Definitions

PRE-COMMISSIONING: Includes all activities required to make the facilities ready for

COMMISSIONING (Conformity Checks, Static Tests, Flushing and Cleaning).

3. General

Record check results as required on the relevant check-list forms (CPX-26) (Refer to Appendix).

Test voltages and frequency: The project procedures and Test Sheets shall take into account the project voltages and

frequency.

The power frequency dielectric test voltages shall be based on the following IEC

recommendations and shall be adjusted to take into account the fact that some equipment has

already been subjected to factory tests.

In no case the test voltage shall exceed the value indicated in the equipment VENDOR

maintenance manual.

IEC 60034 for Rotating Electrical machines

IEC 60060 High Voltage test techniques

IEC 60071 - Insulation co-ordination

IEC 60076 for Electrical Transformers

IEC 60502-2 for HV cables






IEC 62271 and IEC 60694 for HV and LV switchgears

4. Test Methods

4. 1 Insulation Resistance (IR) tests

IR testing shall be carried out by applying a D.C. voltage from an insulation tester at voltage

levels given in this specification.

4. 2 High voltage tests

Before high voltage tests are executed, insulation resistance tests shall be carried out.

High voltage testing shall be carried out by D.C. voltage at a level above the operating voltage.

High-voltage testing of electrical equipment, except LV cables, shall have been carried out at

the Manufacturer's works with A.C. at voltage levels in accordance with the IEC.

Repeated high voltage tests may introduce weak points in the insulation of windings, and

therefore such tests shall not be applied at site to generators, motors or transformers.

The HV tests at full voltage shall not be repeated two times. If however for special reasons

these tests are considered to be remade a second time, they shall be carried out only after

consultation with the Manufacturer and with a test voltage of 80 % of the initial full test voltage.

5. Test procedures

Prior of any test, relevant Project Specifications and MANUFACTURER's Test Procedures shall

be adhered to.

The CONTRACTOR shall carry out tests as laid down on the Test Sheet.

If the obtained IR or PI values fall below the minimum values, then the equipment should not be

energized or subjected to high voltage testing.

Appropriate action should be taken, e.g. drying, to normalize the figures.

In case of 'flash-over' during high voltage testing appropriate measures shall be taken (e.g.

cleaning, drying, repair) to eliminate the cause. Re-testing shall be performed after repair.






In the event that any of the tests fails to meet the specification requirements, it will be necessary

for the CONTRACTOR to list any discrepancies and to present them to the COMPANY

Engineer.

The Test Sheet will be completed, signed and dated, and presented to the COMPANY Engineer

for approval.

Copies of the Test Sheet will be issued to the Certifying Authority if required. The original shall

be inserted in the Ready for Commissioning dossier.

6. Earthing systems - Test Sheet T-PX-26

a. Continuity of protective conductors

A continuity test shall be made in order to check the continuity of the protective conductors,

including the equipotential bonding.

b. For main protective conductor,

Test results shall be obtained from cable test sheet T-PX-09 LV POWER CABLES AND

CONTROL CABLE.

7. Equipment earth return path impedance test

a. Definitions

To comply with IEC 60364-4-41, touch voltages shall not exceed 50 volts AC rms.

The earth impedance loop shall be lower than the RA calculated:

RA x Id < UL

RA = the earthing resistance of all exposed conductive parts connected by a protective

conductor to an earth electrode

Id = Fault current for the first dead fault between a phase conductor

UL = Conventional touch voltage.

Example:






Distribution system Id (mA) UL (V) RA (ohms)

LV 30 50 167

HV 30000 50 1.67

b. Method

All power supplies to the systems under test shall be isolated before commencing the tests.

All testing shall be carried out in accordance with the attached detail drawings using an AC

current injection test set.

The injected current shall be equal to 1.5 times the design current of the circuit under test

except that the current shall not exceed 25 A.

The loop impedance value measured is equal to:

E = (test set generator current) / (test set generator voltage)

This measurement is applicable for:

Verification of trip condition upon 2nd fault phase to earth in IT system. Verification of trip condition upon earth fault in TN system (circuits without ELCB).

It shall be performed for each switchboard/MCC on the longest cable run on onshore plants.

c. Motor fed from LV motor control centre

Connect injection test set between MCC Phase Busbar R and switchboard earth, manually close contactor (outgoing feeder) and determine loop impedance E4 by

shorting motor terminal R phase to motor earth conductor.

Short across high impedance earthing resistor F and close circuit breaker E to determine loop impedance E4.

Total earth return path impedance = E3 + E4. (This is a conservative value since the phase conductor resistances are also included).






Example 1: Typical return path impedance loop 440 V 3 phase motor circuit






d. Lighting circuit fed from distribution board (See Example 2)

Connect injection set between Phase T Busbar and Distribution Board Earth. Manually close Breaker A and determine loop impedance E3 by shorting the end light fitting

Terminal T to the Earth Conductor.

Short across high impedance earthing Resistor F and manually close circuit breaker E to determine Loop Impedance E4.

Total Earth Return Path Impedance = E3 + E4. (This is a conservative value since the phase conductor resistances are also included).

Note: Earth return path impedance tests on small power circuits shall be at the direction and the discretion of the COMPANY Engineer.

With the level of protection provided, it is only considered necessary to test one circuit per

distribution board providing results are satisfactory.






Example 2: Typical return impedance loop small power circuit






e. HV Motor fed from HV switchboard (See Example 3)

Connect injection test set between switchboard Phase Busbar R and switchboard earth, close breaker/contactor A and determine loop impedance E6 by shorting motor

terminal R phase to motor earth conductor.

Connect injection test set between switchboard Phase Busbar R and switchboard earth, close earthing transformer contactor B and determine loop impedance E5 by

shorting earthing transformer terminal R phase to transformer earth conductor.

Total earth return path impedance = E5 + E6.






Example 3: Earth return impedance path loop 6.6 kV motor circuits






8. Grounding System Testing

The measurement of ground resistance for an earth electrode system is very important. It

should be done when the electrode is first installed, and then at periodic intervals thereafter.

This ensures that the resistance-to-ground does not increase over time. There are two (2)

methods for testing an existing earth-electrode system. The first is the 3-point or fall-of-

Potential method and the second is the Induced Frequency test or clamp-on method. The 3-

point test requires complete isolation from the power utility. Not just power isolation, but also

removal of any neutral or other such ground connections extending outside the grounding

system. This test is the most suitable test for large grounding systems and is also suitable for

small electrodes. The induced frequency test can be performed while power is on and actually

requires the utility to be connected to the grounding system under test. This test is accurate only

for small electrodes, as it uses frequencies in the kilo Hertz range, which see long conductors

as inductive chokes and therefore do not reflect the 60 Hz resistance of the entire grounding

system.

a. Fall-of-Potential Method or 3-Point Test

The 3-point or fall-of-potential method is used to measure the resistance-to-ground of existing

grounding systems. The two primary requirements to successfully complete this test are the

ability to isolate the grounding system from the utility neutral and knowledge of the diagonal

length of the grounding system (i.e. a 10 x 10 grounding ring would have a 14 diagonal

length).

In this test, a short probe, referred to as probe Z, is driven into the earth at a distance of ten

times (10X) the diagonal length of the grounding system (rod X). A second probe (Y) is placed

in-line at a distance from rod X equal to the diagonal length of the grounding system.






At this point, a known current is applied across X & Z, while the resulting voltage is measured

across X & Y.

Ohms Law can then be applied (R=V/I) to calculate the measured resistance. Probe Y is then

moved out to a distance of 2X the diagonal length of the grounding system, in-line with X & Z, to

repeat the resistance measurement at the new interval.

This will continue, moving probe Y out to 3X, 4X ... 9X the diagonal length to complete the 3

point test with a total of nine (9) resistance measurements.

Record all the results in the related test sheet (TPX26) (Refer to Appendix).






b. Graphing & Evaluation

The 3-point test is evaluated by plotting the results as data points with the distance from rod X

along the X-axis and the resistance measurements along the Y-axis to develop a curve.

Roughly midway between the center of the electrode under test and the probe Z, a plateau or

flat spot should be found, as shown in the graph. The resistance of this plateau (actually, the






resistance measured at the location 62% from the center of the electrode under test, if the soil is perfectly homogeneous) is the resistance-to-ground of the tested grounding system.

c. Invalid Tests

If no semblance of a plateau is found and the graph is observed to raise steadily the test is

considered invalid. This can be due to the fact that probe Z was not placed far enough away

from rod X, and can usually indicate that the diagonal length of the grounding system was not

determined correctly. If the graph is observed to have a low plateau that extends the entire

length and only rises at the last test point, then this also may be also considered invalid. This is

because the utility or telecom neutral connection remains on the grounding system.






d. Induced Frequency Testing or Clamp-On Testing

The Induced Frequency testing or commonly called the Clamp-On test is one of the newest

test methods for measuring the resistance-to-ground of a grounding system or electrode. This

test uses a special transformer to induce an oscillating voltage (often 1.7 kHz) into the

grounding system. Unlike the 3-point Test which requires the grounding system to be

completely disconnected and isolated before testing, this method requires that the grounding

system under test be connected to the electric utilities (or other large grounding system such as

from the telephone company) grounding system (typically via the neutral return wire) to provide

the return path for the signal. This test is the only test that can be used on live or hot systems.

However, there are some limitations, primarily being:

1. The amount of amperage running through the tested system must be below the

equipment manufacturers limits.

2. The test signal must be injected at the proper location, so that the signal is forced

through the grounding system and into the earth.

3. This instrument actually measures the sum of the resistance of the grounding system

under test and the impedance of the utility neutral grounding, including the neutral

wiring. Due to the high frequency used, the impedance of the neutral wiring is non-

negligible and can be greater than the ground resistance of a very low resistance

grounding system, which can therefore not be measured accurately.

4. The ground resistance of a large grounding system at 60 Hz can be significantly lower

than at 1.7 kHz.

Many erroneous tests have been conducted where the technician only measured metallic loops

and not the true resistance-to-ground of the grounding system. The veracity of the Induced

Frequency Test has been questioned due to testing errors, however when properly applied to a






small to medium sized, self-standing grounding system, this test is rapid and reasonably

accurate.

e. Test Application

The proper use of this test method requires the utility neutral to be connected to away-type

transformer. The oscillating voltage is induced into the grounding system at a point where it will

be forced into the soil and return through the utility neutral. Extreme caution must be taken at

this point as erroneous readings and mistakes are often made. The most common of these

occur when clamping on or inducing the oscillating voltage into the grounding system at a point

where a continuous metallic path exists back to the point of the test. This can result in a

continuity test being performed rather than a ground resistance test.






Understanding the proper field application of this test is vital to obtaining accurate results. The

induced frequency test can test grounding systems that are in use and does not require the

interruption of service to take measurements.

f. Ground Resistance Monitoring

Ground resistance monitoring is the process of automated timed and/or continuous resistance-

to ground measurement. These dedicated systems use the induced frequency test method to

continuously monitor the performance of critical grounding systems. Some models may also

provide automated data reporting. These new meters can measure resistance-to-ground and

the current that flows on the grounding systems that are in use. Another benefit is that it does

not require interruption of the electrical service to take these measurements.

9. Appendix

TPX09 ElectricalLVPowerCablesTPX26 ElectricalEarthing/LightningSystemCPX26 ElectricalEarthingSystem






9.1. Appendix01: Electrical LV Power Cables (T-PX-09)

Tas k Num ber :Form :Dwg / PID :

Tas k Location : Us er Group :Es tim ated Tim e (MH) : Expended Tim e (MH) :Punch Lis t Item s :Module :Subsystem :

TPX09 - LV POWER CABLES

PRECOMMISSIONING TEST SHEETELECTRICAL

LV POW ER CABLES

0

T E S T IN G IN S T R U M E N T S U S E D

T Y P E / S E R IA L N : T Y P E / S E R IA L N :

T Y P E / S E R IA L N :E L E C T R IC A L T E S T S ( C A B L E D IS C O N N E C T E D )

U PS T R EA M C O N N EC T IO N A C C O R D IN G C A B L E S C H ED U L E

D O W N S T R EA M C O N N EC T IO N A C C O R D IN G C A B L E S C H ED U L E

C R O S S S EC T IO N A C C O R D IN G C A B L E S C H ED U L E

P H 1

P H 2

P H 3A R M O U R C O N T IN U IT Y

PR O T EC T IV E C O N D U C T O R C O N T IN U IT Y

P H 1 / P H 2 - P H 3 - E

P H 2 / P H 1 - P H 3 - E

P H 3 / P H 1 - P H 2 - E

C O R E / A R M O U R M o h m

C A B L E IS C O R R EC T L Y R E- C O N N EC T ED .

N o te : T h e M in im u m A c c e p ta b le V a lu e W ill b e : * 4 4 0 V c a b le s - 5 0 M o h m - 1 0 0 0 v M e g g e r * 2 4 0 V c a b le s - 1 0 M o h m - 5 0 0 v M e g g e r

( M o h m )

( M o h m )

( M o h m )

C O R ES / EA R T H M o h m

IN S U L A T IO N

C O R E C O N T IN U IT Y

C O N T IN U IT Y

S i g n

T P A / C O M P A N YC O M M IS S IO N IN GC O N S T R U C T IO NS U B C O N T R A C T O R

D a t eN a m e






9.2. Appendix02: Electrical Earthing / Lightning System (T-PX-26)

1.

T a s k N u m b e r :F o r m :D w g / P ID :

T a s k L o c a t i o n : U s e r G r o u p :E s t i m a te d T i m e ( M H ) : E x p e n d e d T i m e ( M H ) :P u n c h L i s t I te m s :M o d u le :S u b s y s t e m :

T P X 2 6 - E A R T H I N G S Y S T E M

P R E C O M M IS S IO N IN G T E S T S H E E TE L E C T R I C A L

E A R T H IN G / L IG H T N IN G S Y S T E M

0

2.

T E S T I N G I N S T R U M E N T S U S E D

T Y P E / S E R I A L N : T Y P E / S E R I A L N :

T Y P E / S E R I A L N :

T E S T R E S U L T S

G L O B A L E A R T H I N G R E S I S T A N C E O h m T E S T C U R R E N T A

E A R T H I N G R O D R E S I S T A N C E O h mE A R T H I N G / L I G H T N I N G E L E C T R O D S A R E T O B E T E S T E D I N D I V I D U A L L Y A N D A S A G R O U P

* I N D I V I D U A L L E L E C T R O D E R E S I S T A N C E :N o . 1 : . . O h m N o . 2 : . . O h m

N o . 3 : . . O h m N o . 4 : . . O h m

* I N D I V I D U A L L G R O U P R E S I S T A N C E A S A P P L I C A B L E : . . O h m

D R A W I N G N A S S O C I A T E D

C A B L E N L O O P

R E S I S T A N C EE A R T H D I S P A T C H E R (T O )E Q U I P M E N T N (F R O M )

3.

S i g n

C O M P A N YC O M M I S S I O N I N GC O N S T R U C T I O NS U B C O N T R A C T O R

D a t eN a m e






9.3. Appendix03: Electrical Earthing (C-PX-26)

T a s k N u m b e r :

I T E M

P R E C O M M IS S IO N IN G C H E C K L IS TE L E C T R I C A L

E A R T H IN G S Y S T E M

T a s k L o c a t i o n :

S u b s y s t e m :

C P X 2 6 - E A R T H I N G S Y S T E M

U s e r G r o u p :

E s t i m a te d T i m e ( M H ) : E x p e n d e d T i m e ( M H ) :

C H E C K L I S T

F o r m :

M o d u le :

1

2

3

4

5

6

7

8

9

1 0

1 1

1 2

1 3

1 4

1 5

1 6

1 7

1 8

1 9

2 0

2 1

N / A N o t A p p l i c a b l e P N o t a c c e p te d ( P u n c h ) C h e c k e d & A c c e p te dD r a w in g s & d o c . r e f . :

R E M A R K S :

P r o d u c e m a r k e d - u p d r a w i n g s i n a c c o r d a n c e w i th i n s ta l l a t i o n .

C h e c k L i g h tn i n g a i r te r m i n a l i n s ta l l e d a s p e r th e D r a w i n g s /S p e c i f i c a t i o n .

P r o d u c e a d e fe c ts l i s t fo r p u n c h l i s t i s s u e .

C h e c k e a r th i n g / l i g h tn i n g W e l l ( P i t ) l o c a t i o n a s p e r d r a w i n g s .

C h e c k c o n n e c t i o n e a r th c a b l e / e l e c t r o d e b e fo r e b a c k f i l l i n g .

C h e c k c o n t i n u i ty e l e c tr o d e - e a r th b a r / p l a n t e a r th r i n g .

C h e c k c o n t i n u i ty e l e c tr o d e - e a r th p i t to e a r th b a r .

C h e c k c o n t i n u i ty o f e q u i p m e n t l o o p p r o te c t i o n c o n d u c to r s .

C h e c k e a r th i n g n e tw o r k s s e g r e g a t i o n ( IS )

C h e c k e a r th r o d s c o r r e c t i n s ta l l a t i o n

C h e c k a l l e a r th b a r s i n s ta l l a t i o n a n d ta g g i n g a g a i n s t d r a w i n g s .

C h e c k e a r th i n g c a b l e s i n s ta l l a t i o n a n d ta g g i n g a g a i n s t d r a w i n g s .

C h e c k a l l c o n n e c t i o n s a r e t i g h t , c l e a n a n d c o a te d w i th a n a p p r o v e d a n t i - c o r r o s i v e g r e a s e .

C h e c k e a r th i n g c a b l e s c r o s s s e c t i o n a g a i n s t d r a w i n g s .

C h e c k d i s p a tc h e r c o n t i n u i ty a n d d r a w i n g .

C h e c k v i s u a l i n s p e c t i o n b e fo r e b a c k f i l l i n g .

C h e c k th e r m a l c o n n e c t i o n i n s u l a t i o n .

C h e c k th e r m a l c o n n e c t i o n b e fo r e b a c k f i l l i n g .

C h e c k r i s e r c o n d u i t i n s ta l l a t i o n w i th r e l a te d d r a w i n g .

C h e c k c o m p r e s s i o n o f c o n n e c t i o n s .

C h e c k i n s u l a t i o n o f c o m p r e s s i o n c o n n e c t i o n s .

D a t eN a m e

S i g n

T P A / C O M P A N YC O M M I S S I O N I N GC O N S T R U C T I O NS U B C O N T R A C T O R

Earthling System Electrical and Instruments Test Procedure

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