Transformer Protection Sugg Spec1

7/29/2019 Transformer Protection Sugg Spec1

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SERVICE AND PRODUCTS FOR ELECTRIC UTILITIES

6190-118th Avenue North Largo, Florida 33773-3724 (727) 544-2326 FAX (727) 546-0121www.beckwithelectric.com

Subject: TRANSFORMERSUGGESTED SPECIFICATION

M-3311A Suggested Spec 120610

Protection, metering, and monitoring for 2/3/4 winding transformers shall be provided bya microprocessor-based package. The microprocessor-based package shall be suitable for

any transformer and CT winding configuration. The relay shall include extensive self-testing and alarm output contacts for indication of self-test warning, failure conditions, orremoval of input power.

The relay shall include the following protection functions, features, and options:

Overexcitation Protection (24): OptionalThe F24 function shall have a definite time setting and at least 4 families of Inverse Time Curves toprovide protection of over-excitation condition.

Undervoltage Protection (27): Optional

The F27 function for undervoltage and/or load shedding shall include an undervoltage inhibit feature todisable the undervoltage function for voltages below the inhibit set point to prevent misoperationduring fault conditions.

Negative Sequence Overcurrent (46)

The F46 function shall have Definite Time and Inverse Time characteristic for detection of openconductors and for increased sensitivity for phase to phase fault backup feeder protection. Eight timeovercurrent curves including the IEC Inverse, Very Inverse, Extremely Inverse, and Long Time Inverse

curves shall be included.

Winding Thermal Protection (49)The F46 winding thermal protection curve shall be based on the IEC-255-8 standard and provideprotection against possible damage during overload conditions.Breaker Failure Protection (50BF/50NBF)

The breaker failure shall include a phase overcurrent detector (50BF) for breaker failure detection anda neutral overcurrent detector (50BFN) to provide protection for breaker flashover each associatedtransformer winding.

Instantaneous and Time Phase Overcurrent Protection (50/51)

The relay shall include a 50/51 phase instantaneous and time overcurrent functions for each associatedtransformer winding. The F50 phase instantaneous overcurrent function shall provide fast tripping forhigh fault currents. The F51 phase time overcurrent function shall provide selective time coordinationprotection with down stream devices. Eleven time overcurrent curves including the IEC Inverse, VeryInverse, Extremely Inverse, and Long Time Inverse curves and the IEEE Moderately Inverse, VeryInverse, and Extremely Inverse curves shall be included. A 50/51 function shall be provided for eachassociated transformer winding.


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Instantaneous and Time Neutral Overcurrent Protection (50N/51N)

The relay shall include a 50N/51N neutral instantaneous and time overcurrent functions for eachassociated transformer winding. The F50N neutral instantaneous overcurrent function shall provide fasttripping for high fault currents. The F51N Residual time overcurrent function shall provide sensitive

ground fault protection. Eleven time overcurrent curves including the IEC Inverse, Very Inverse,Extremely Inverse, and Long Time Inverse curves and the IEEE Moderately Inverse, Very Inverse, andExtremely Inverse curves shall be included. A 50N/51N function shall be provided for each associatedtransformer winding.

Instantaneous and Time Ground Overcurrent Protection (50G/51G)The relay shall include at least two 50G/51G instantaneous and time ground overcurrent functions.The F50G/F51G overcurrent functions shall provide sensitive and selective coordination with up streamor downstream breakers. Eleven time overcurrent curves including the IEC Inverse, Very Inverse,Extremely Inverse, and Long Time Inverse curves and the IEEE Moderately Inverse, Very Inverse, andExtremely Inverse curves shall be included.

Over / Under Frequency (81O/81U): OptionalThe relay shall include at least 4 set points for over / under frequency operation for use in loadshedding applications. The frequency functions shall be automatically disabled when the voltage fallsbelow the measurable range.

Ground Differential (Restricted Earth Fault) Protection (87GD)The relay shall include at least one 87GD for two winding, two 87GD for three winding and three 87GDfunctions for four winding application. The 87GD function should use existing phase differential andground CTs eliminating the need for dedicated CTs. To obtain additional security for CT ratio errors andsaturation during external faults, 87GD function shall use a directional element based on product (-3Iox Ig cos ) to distinguish between internal and external faults. To provide fast operation for internalground faults with the load breaker open, the directional element shall adaptively change to non-directional when the calculated zero-sequence current from the phase CTs is very small (such as

140ma for 5A rated CT).

Phase Differential Function (87T)The 87T function shall employ a dual slope harmonic restraint characteristic. To prevent misoperationon low levels of 2nd harmonic for transformer inrush current, the 87T function should utilize both 2ndand 4th harmonic restraint to prevent misoperation during transformer energization. Cross phaseaveraging option shall be available to accommodate point on wave switching if required.

The 87T shall use an adaptive 5th harmonic restraint pickup level during system overexcitationconditions. The increase in 5th harmonic should not be used to block the differential element (87T)during this condition which will delay tripping. The increase in 5th harmonic shall be used toautomatically increase the 87T minimum pickup level to a higher user selectable value.

High Set Phase Differential Function (87H)The relay should include an unrestrained high set phase differential element 87H function for close-infault protection.

Programmable LogicThe relay shall include user programmable logic permitting custom creation of logic with relayfunctions, inputs, outputs, and time delay. The logic shall be created by simple option selection ondisplay screen graphics. Programming in mathematical equations shall not be required.


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Through-Fault Monitor Event Log

The relay shall have Through Fault Recorder, which records Through Faults. Each through fault recordshall contains the serial number of the fault, duration of the event, maximum RMS fault currentmagnitude for each phase during the fault, I2t and the time stamp of the fault. In addition, it shall also

store the total number of through faults since last reset, and total I2

t for each phase since last reset.The relay shall have the memory to store a total of 256 or more through faults.

Breaker Monitoring

The Breaker Monitoring function calculates an estimate of the per-phase wear on the breaker contactsby measuring and integrating the current (selected as I2t or It) passing through the breaker contactsduring the interruption interval. The per-phase values are summed as an accumulated total for eachphase, and then compared to a user-programmed threshold value. When the threshold is exceeded inany phase, the relay can activate a programmable output contact. The accumulated value for eachphase can be displayed as an actual value.

Transformer Winding & CT Connection Configuration

The relay shall accommodate all ANSI/IEEE and IEC transformer winding and CT connection

configurations. These configurations shall be easily selected from pop-down menus. The relay shallinternally compensate for the various CT and transformer winding configurations. When delta-connected CTs are used, the relay shall allow the 50, 51 and 46 functions to be set in terms of linecurrent quantities, and the metering status screen shall correctly displays the line currents, not deltacurrents.

Custom Transformer Winding & CT Connection ConfigurationThe relay shall be able to accommodate advanced applications such as a wye-delta transformer with azero sequence source (grounding transformer) inside the zone of protection of the delta winding. Forthis application, the standard zero sequence elimination on the wye winding can be turned off ensuringcorrect 87T differential operation.

Overcurrent SummingThe relay 50/50N and 51/51N overcurrent functions and the 87GD ground differential functions should

be able to accommodate current summing for breaker and half and ring bus applications.

Configuration MatrixThe relay shall provide a graphical display of the programmed inputs and outputs for each function.The display matrix shall be hyperlinked to each function setting element allowing elements to be turnedon and off for testing purposes. To ensure all function outputs are re-enabled after testing has beencompleted; the matrix display shall provide visual identification of function outputs that have beentemporary disabled.

Metering / Commissioning Display Tools

For metering purposes and to assist in commissioning, the relay shall provide a graphical display of the

following quantities; Phase currents for each transformer winding Positive , negative, and zero sequence currents for each transformer winding Fundamental restraint currents for each phase Fundamental differential currents for each phase Second, fourth, and fifth harmonic currents for each phase


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The relay shall provide graphical display of uncompensated and compensated phasors forcommissioning and wiring verification purposes.The relay shall provide real time metering of voltage, three-phase and neutral currents, real timedemand with user selectable intervals of 15, 30, or 60 minutes, and maximum demand with date and

time stamp.Metering accuracies shall be at least: Voltage: 0.5 V or 0.5%, whichever is greater (range 0 to 180V ac) Current: 5 A rating, 0.1 A or 3%, whichever is greater (range 0 to 14 A) 1 A rating, 0.02 A or 3%, whichever is greater (0 to 2.8 A) Frequency: 0.10 Hz (from 57 to 63 Hz for 60 Hz models; from 47 to 53 Hz for 50 Hz models)

Access/Communications/Integration CapabilitiesThe relay shall provide access via a front-panel HMI. The following communication ports shall beprovided: Two RS-232 serial ports, one located on the front of the relay for local communication via a laptop,

and one located on the rear of the relay for remote communication. One isolated RS-485 serial port on the rear of the relay for remote communication. RS-232 and RS-485 shall support Modbus and DNP communication protocols. One IRIG-B port.

Tripped Function Status Indication and Target Log CapabilitiesThe relay shall display tripped function status on the front of HMI. The relay shall also have the optionof being supplied with a Target Module Display that will indicate tripped function status by LEDs. Therelay shall provide a target log for each trip operation that includes the function(s) operated, thefunctions picked up, input/output status, time stamp, and phase and neutral currents at the time oftrip. A total of at least 10 target logs shall be stored in a first in, first out buffer, with the oldestrecords being automatically overwritten.

Sequence of Events Log

The relay shall store the Sequence of Events Log records all status information and all parametersmeasured or calculated by the relay when triggered by selectable relay events. The Sequence of EventsLog shall include 512 or more of the most recently recorded relay events. The triggering of the eventrecorder shall be user selectable from a user-friendly table containing pickup, trip and dropout of allelements and IPSLogic results, and pickup and dropout of all inputs and outputs. All events timestamped to 1 ms resolution.

Waveform Capture CapabilitiesAn oscillograph recorder shall provide comprehensive data recording of all monitored waveforms, andthe status of inputs and outputs, storing up to 152 cycles of data. The total record length is user-configurable for up to 4 partitions. The sampling rate shall be at least 16 times the power systemnominal frequency (50 or 60 Hz). The recorder shall be capable of being triggered by eitherdesignated status inputs, trip outputs, or via serial communications or from the optional front panelHMI. The recorder shall continuously store waveform data, keeping the most recent data in memory.When triggered, the recorder shall continue to store data in memory for a user-defined, post-triggerdelay period. Records may be stored in COMTRADE format.

User Software for Interface and AnalysisUser interface software shall be provided that is menu-driven and Windows based. Using the software,the user shall be able to: view setpoints, set elements, configure the elements, configure the trip/blockmatrix, create programmable logic schemes, view metering, view the target log, view the event log,


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download the oscillograph files, load files from a PC to the relay, load files from the relay to the PC, andprint all settings.

Waveform (oscillograph) viewing software shall be provided that can open, view and be used foranalysis of captured waveforms. Graphical display of the analog voltage and current traces, as well as

the status of the inputs and outputs will be viewable. In addition, harmonics and RMS values may beviewed. Analysis tools such as phasor diagrams, R-X diagrams and P-Q diagrams will be available.Zooming abilities, curser manipulation with attendant value display, and multiple cursor differencequantities shall be provided. Power factor and frequency traces will also be viewable.

Communications protocolsThe relay shall provide DNP 3.0 and MODBUS protocols. The relay shall have the option to provide DNP3.0 over TCP/IP and MODBUS over TCP/IP through an RJ45 Ethernet port.

Time sysnchronizationThe relay shall have IRIG-B Time Synchronization with 1 ms resolution time stamp on recorded eventsand oscillography.

I/O Count and Description

The following I/O shall be provided: Control/Status Inputs 6 dry type contact inputs, (24V dc internally wetted) For applications requiring externally wetted contact inputs, optional interface device shall be

available that can interface external voltages from 9V to 320V dc. Contact Outputs 8 outputs; 6 form a, and 2 form c. Fixed Power Supply failure alarm output contact; 1 form a. Fixed Self-Test failure alarm output contact; 1 form c.

Expanded I/O Count and DescriptionThe relay shall be capable of having additional I/O provided:

Additional Control/Status Inputs 12 dry type contact inputs, (24V dc internally wetted) Additional Contact Outputs 8 outputs; form a.

Power supply requirements

The relay shall be capable of having a redundant power supply as an option. The redundant powersupply shall be on hot standby to prevent power interruption to the relay during failure of one of thepower supplies or sources. The relay shall have independent sets of terminals for each power source,so that they can be connected through redundant cables and fuses to independent batteries and/or acpower sources to keep the protective relay operational during a battery/ac power source failure.

The relay shall accommodate redundant power supplies with different voltage ranges:High voltage: Shall operate properly from 80 V dc to 312.5 V dc or 85 V ac to 265 V ac, and shall

withstand 315 V dc or 300 V ac for 1 sec.Low Voltage: Shall operate properly from 18 V dc to 56 Vdc, and shall withstand 65 Vdc for 1 sec.

Physical Description (mounting variants)The relay shall be 19.00" wide x 5.21" high x 10.20" deep (48.3 cm x 13.2 cm x 25.9 cm)(standard 19", semi flush, three-unit high, rack-mount panel design, conforming to ANSI/EIA RS-310C and DIN 41494 Part 5 specification). As an option, the relay may be vertically mounted.


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Standards

The relay shall be able to meet the following standards:

Voltage Withstand

DIELECTRIC WITHSTANDIEC 255-5 3,500 V dc for 1 minute applied to each independent circuit to earth3,500 V dc for 1 minute applied between each independent circuit1,500 V dc for 1 minute applied to IRIG-B circuit to earth1,500 V dc for 1 minute applied between IRIG-B to each independent circuit1,500 V dc for 1 minute applied between RS-485 to each independent circuit

IMPULSEVOLTAGEIEC 255-5 5,000 V pk, +/- polarity applied to each independent circuit to earth5,000 V pk, +/- polarity applied between each independent circuit1.2 by 50 s, 500 ohms impedance, three surges at 1 every 5 seconds

INSULATION RESISTANCE

IEC 255-5 > 40 Megaohms

Electrical EnvironmentELECTROSTATIC DISCHARGE TEST

IEC 1000-4-2 Class 4 (8 kV)point contact dischargeNOTE: Digital data circuits (RS-232 communication ports) may be excluded.

FAST TRANSIENT DISTURBANCE TEST

IEC 1000-4-4 Class 4 (4 kV, 2.5 kHz)NOTE: Digital data circuits (RS-232 communication ports) may be excluded.

SURGE WITHSTAND CAPABILITYANSI/IEEE C37.90.1 2; 2,500 V pk-pk oscillatory applied to each independent circuit to earth, 5000 Vpk-pk applied between each independent circuit5,000 V pk Fast Transient applied to each independent circuit to earth5,000 V pk Fast Transient applied between each independent circuitNOTE: Digital data circuits (RS-232 & IRIG-B communication ports) may be excluded

Transformer Protection Sugg Spec1

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