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Schweitzer Engineering Laboratories SEL-251, Instruction Manual

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Date Code 20000421

Applications

5-23

SEL-251, -2, -3 Instruction Manual

S

YSTEM 

R

ESTORATION 

A

FTER 

U

NDERFREQUENCY 

L

OAD 

S

HEDDING

After a feeder circuit breaker has been tripped by an underfrequency relay, the reclosing relay in
the SEL-251 Relay can reclose the breaker, after system frequency returns to normal.  Manual or
SCADA closing of the breaker is not necessary.  This can be of benefit in remote substations that
are not readily accessible by utility personnel or do not have SCADA-type control.  This
reclosing function is realized in the following example (see Figure 5.15 and Figure 5.16):

IN6  =  !52AR

Circuit Breaker Status (52B contact input)/Reclose Initiate

If input IN6 is de-energized and then energized, circuit breaker status is interpreted to be a
breaker in the process of opening (52B

F

 contacts assert for opening breakers) and this initiates

reclosing.

When an underfrequency condition is present, the underfrequency relay contacts (81U) close,
tripping the feeder circuit breaker and energizing the auxiliary relay (AUX).  In the feeder relay
circuit breaker status input circuit, the AUX contact ("b" seal) opens to prevent reclose initiation
by the assertion of the 52B

F

 contact (continue to keep input IN6 de-energized during the

underfrequency condition).

There can be a possible contact race between the 52B

F

 and AUX contacts in the feeder relay

circuit breaker status input circuit.  If the 52B

F

 contact closes before the AUX contact opens,

input IN6 will be energized and reclosing will be initiated for an underfrequency trip.

To avoid this problem, the circuit breaker status function internal to the relay has a 10-cycle
delay to qualify circuit breaker opening, when 52AR or !52AR is assigned to an input.  For this
application, if the AUX contact opens in less than 10 cycles after the 52B

F

 contact closes, the

circuit breaker status function deems the circuit breaker still closed and reclosing is not initiated.

When system frequency returns to normal, the 81U contacts open, de-energizing the AUX relay.
The 52B

F

 contact is already closed, so the closing of the AUX contact energizes input IN6.  After

the 10-cycle delay to qualify circuit breaker opening, the circuit breaker is deemed to have
opened and reclosing is initiated (the reclosing cycle starts).

In most applications, circuit breaker trips external to the relay (e.g., by control switch or
SCADA) must not cause reclose initiation.  If input option RE (Reclose Enable) is assigned to an
input, the RE input is de-energized to prevent automatic reclosing.  Certain control switch
contacts can be wired to the RE input to defeat reclosing for control switch trips.

Summary of Contents for SEL-251

Page 1: ...NCE OVERCURRENT RELAY GROUND OVERCURRENT RELAY MULTIPLE SHOT RECLOSING RELAY SELECTABLE SETTING GROUPS CIRCUIT BREAKER MONITOR FAULT LOCATOR SELOGIC CONTROL EQUATIONS INSTRUCTION MANUAL SCHWEITZER ENGINEERING LABORATORIES INC 2350 NE HOPKINS COURT PULLMAN WA USA 99163 5603 TEL 509 332 1890 FAX 509 332 7990 ...

Page 2: ...ou may not provide the software to any third party All brand or product names appearing in this document are the trademark or registered trademark of their respective holders Schweitzer Engineering Laboratories Inc SELOGIC and are registered trademarks of Schweitzer Engineering Laboratories Inc This product is covered by U S Patent Nos 5 041 737 5 477 408 5 479 315 and 5 602 707 Copyright SEL 1992...

Page 3: ...s will be recorded in this Summary of Revisions table 20000421 Section 2 Specifications Updated to include details for 1 amp nominal current input model Added frequency and rotation information Incorporated New SEL 200 Series Optical Isolator Logic Input Rating addendum Combined specifications for Conventional Terminal Block models and Plug In Connector models Incorporated SEL 151 151C 251 251C In...

Page 4: ... 3 Instruction Manual Revision Date Summary of Revisions 971121 Added Settings Sheets to end of Section 5 971107 Section 2 Corrected logic in Figure 2 22 971028 Section 2 Corrected Drawings in Figures 2 1 and 2 2 970418 Appendix A Added New Firmware Versions ...

Page 5: ...SPECIFICATIONS SECTION 3 COMMUNICATIONS SECTION 4 EVENT REPORTING SECTION 5 APPLICATIONS SECTION 6 INSTALLATION SECTION 7 MAINTENANCE AND TESTING SECTION 8 APPENDICES Appendix A Firmware Versions in this Manual Appendix B Main Board Jumper Connector and Socket Locations Appendix C Onebus Program to Compute Test Set Settings for Testing Distance Relays ...

Page 6: ......

Page 7: ...ction 1 2 Sophisticated Multiple Shot Reclosing Relay Includes Reset Inhibit and Sequence Coordination 1 3 Six Selectable Groups of Settings and Logic 1 3 Circuit Breaker Monitor Tracks Breaker Performance and Helps Maintenance Planning 1 3 Fault Locator Reduces Line Patrol and Outage Time 1 3 Analyze Operations Using Event Reports 1 3 Comprehensive Metering Supports Protection Operation and Deman...

Page 8: ......

Page 9: ... overcurrent elements Overcurrent elements inhibit recloser reset to prevent nuisance trip reclose cycling Sequence coordination avoids unnecessary tripping for faults beyond line reclosers Undervoltage logic detects high side transformer fuse operations Six selectable setting groups cover all feeder protection contingencies Circuit breaker monitor sums interrupted current in each pole to aid main...

Page 10: ...ctions timing and programmable inputs and outputs SELOGIC Control Equations add power and flexibility while simplifying programming Phase Ground and Negative Sequence Overcurrent Protection Phase and negative sequence overcurrent elements detect phase faults Negative sequence overcurrent elements reject three phase load to provide more sensitive coverage of phase to phase faults Phase overcurrent ...

Page 11: ...ker trip counters differentiate and tally relay initiated trips and external trips Running sums of interrupted current for relay and external trips indicate breaker wear and tear on a pole by pole basis Use these data to schedule breaker maintenance Trip failure logic provides alarm and breaker failure functions A close failure alarm indicates circuit breaker closing circuit or mechanism problems ...

Page 12: ...and outputs Ct secondaries are automatically shorted inside the plug in connector when removed from the relay During in service testing spare connectors can be wired to auxiliary test equipment and plugged directly into the relay The actual source and I O connectors may simply be unplugged before each test and reconnected afterwards If there is a need to replace a relay the connectors can be unplu...

Page 13: ...9 Trip Circuit Monitor Alarm Checks Trip Circuit and Verifies Circuit Breaker Status Input 2 9 SEL 251 Relay SELOGIC Control Equations 2 10 Assign Inputs to the Functions You Need 2 11 Select Combinations of Relay Elements for Tripping and Other Purposes 2 13 Time Delayed Variables ST KT and ZT 2 15 Use L for Inversion 2 16 Programming Output Contacts 2 16 Viewing Logic Equations 2 16 SELOGIC Cont...

Page 14: ...ltage Connections 2 9 Figure 2 5 Trip Circuit Monitor Alarm TCMA Logic 2 10 Figure 2 6 SEL 251 Relay SELOGIC Control Equations Block Diagram 2 13 Figure 2 7 Relay Word Bit Realizations 2 15 Figure 2 8 Relay Word Bit Realization 2 16 Figure 2 9 SEL 251 Relay Front Panel Target LEDs 2 17 Figure 2 10 Sequence Coordination Ground Residual Overcurrent Elements 2 19 Figure 2 11 Distribution Transformer ...

Page 15: ...rry 30 A make per IEEE C37 90 1989 100 A for one second 270 Vac 360 Vdc MOV for differential surge protection Pickup dropout time 5 ms Breaking Capacity L R 40 ms 48 V 0 5 A 10 000 operations 125 V 0 3 A 10 000 operations 250 V 0 2 A 10 000 operations Cyclic Capacity L R 40 ms 48 V 0 5 A 2 5 cycles per second 125 V 0 3 A 2 5 cycles per second 250 V 0 2 A 2 5 cycles per second Plug In Connectors Hi...

Page 16: ...No 125 Vdc 80 150 Vdc 4 mA No 250 Vdc 150 300 Vdc 4 mA No Plug In Connectors Nominal Input Rating Operating Range Burden at Rated Voltage Level Sensitive 24 Vdc 15 30 Vdc 4 mA No 48 Vdc 38 60 Vdc 5 mA Yes off below 29 Vdc 125 Vdc 100 150 Vdc 6 mA Yes off below 75 Vdc 250 Vdc 150 300 Vdc 4 mA No Power Supply 24 48 Volt 20 60 Vdc 125 250 Volt 85 350 Vdc or 85 264 Vac 10 watts nominal 14 watts max al...

Page 17: ...2 1 Fifth Edition 1990 Environmental testing Part 2 Tests Test Ad Cold Severity Level 16 hours at 40 C IEC 68 2 2 Fourth Edition 1974 Environmental testing Part 2 Tests Test Bd Dry heat Severity Level 16 hours at 85 C IEC 68 2 30 Second Edition 1980 Basic environmental testing procedures Part 2 Tests Test Db and guidance Damp heat cyclic 12 12 hour cycle Severity Level 55 C 6 cycles IEC 255 5 Firs...

Page 18: ...ion 1991 04 Electromagnetic compatibility for industrial process measurement and control equipment Part 2 Electrostatic discharge requirements Severity Level 3 IEC 801 3 Electromagnetic compatibility for industrial process measurement and control equipment Part 3 Radiated electromagnetic field requirements Severity Level 10 V m Exceptions 9 1 Frequency sweep approximated with 200 frequency steps p...

Page 19: ...Date Code 20000421 Specifications 2 5 SEL 251 2 3 Instruction Manual Figure 2 1 SEL 251 Relay Conventional Terminal Block Model Inputs Outputs and Targets Diagram ...

Page 20: ...2 6 Specifications Date Code 20000421 SEL 251 2 3 Instruction Manual Figure 2 2 SEL 251 Relay Plug In Connector Model Inputs Outputs and Targets Diagram ...

Page 21: ...d externally torque controllable 50H Phase Instantaneous Overcurrent Element Pickup 0 5 to 100 A 2 of setting 0 1 A secondary Internally and externally torque controllable 50C Phase Instantaneous Overcurrent Element Pickup 0 5 to 100 A 2 of setting 0 1 A secondary Can be used to override voltage control through TCI setting choice Negative Sequence Overcurrent Elements for Phase to Phase Faults See...

Page 22: ...t pickup accuracy is dependent upon the 51NP setting Pickup accuracy of the 51NP 50NL and 50NH elements is shown below in the given 51NP setting range 1 0 51NP 12 0 A sec Pickup 2 0 100 A sec 0 5 51NP 1 0 A sec Pickup 2 0 050 A sec 0 25 51NP 0 5 A sec Pickup 2 0 025 A sec Voltage Element for Healthy Low Voltage Indication or Internal Control 27 See Figure 2 21 27AB 27BC 27CA Phase to Phase Voltage...

Page 23: ...OSE output contact remains asserted If CLOSE output contact assertion exceeds the CFT time setting the close attempt is unsuccessful The relay opens the CLOSE output contact the reclosing relay locks out and the CF bit in the Relay Word asserts The CF bit asserts for 60 cycles Use the CF bit to alarm for close failures or slow close conditions and to trigger event reports Trip Circuit Monitor Alar...

Page 24: ...put circuit path Figure 2 5 Trip Circuit Monitor Alarm TCMA Logic Besides alarming for an abnormal open circuit in the trip circuit the TCMA bit provides 52A input verification It effectively compares the circuit breaker status input to 52ATC The TCMA bit can be used to alarm cancel reclosing or trigger event reports In Figure 2 4 a 52A contact is connected to relay input 52A You can connect a 52B...

Page 25: ...assign to IN3 only 0 TCP External Torque Control Phase and Negative Sequence Elements 1 TCP inverted sense of TCP 0 TCG External Torque Control Residual Overcurrent Elements 1 TCG inverted sense of TCG 0 52A Circuit Breaker Status 52A contact input N A 52A Circuit Breaker Status 52B contact input N A 52AR Circuit Breaker Status 52A contact input Reclose Initiate N A 52AR Circuit Breaker Status 52B...

Page 26: ...ain application needs see System Restoration After Underfrequency Load Shedding sub section in Section 5 Applications If this type of application is not needed then it is better to assign 52A or 52A to an input instead and avoid the 10 cycle time delay This time delay shows up in event reports and needs to be accounted for when making setting 52ADO The 10 cycle delay affects the circuit breaker mo...

Page 27: ...truction Manual Figure 2 6 SEL 251 Relay SELOGIC Control Equations Block Diagram Select Combinations of Relay Elements for Tripping and Other Purposes The 48 bit Relay Word contains relay elements intermediate logic results and programmable logic variables ...

Page 28: ...50NH Ground Residual instantaneous overcurrent element 51T Phase time overcurrent element 50LT Phase definite time overcurrent element 50C Phase instantaneous overcurrent element can override voltage control by 27 51QT Negative sequence time overcurrent element 50QT Negative sequence definite time overcurrent element 51NT Ground Residual time overcurrent element 50NLT Ground Residual definite time...

Page 29: ...any OR combination of elements in R3 and R4 J Select any OR combination of elements in R1 through R4 KT Output from timer TK driven by any selected OR combination of elements in R1 through R4 assigned to setting K L Output from an inverter driven by any selected OR combination of elements in R1 through R4 assigned to setting L V W X Y Select any AND combination of elements A through L ZT Output fr...

Page 30: ...MP3 the jumper has positions A4 and ALARM The CLOSE and ALARM functions have dedicated outputs CLOSE Asserts by recloser DC input or CLOSE command see Figure 2 25 for an illus tration of CLOSE output contact operations ALARM The ALARM output closes for the following conditions Three unsuccessful Level 1 access attempts 1 second pulse Any Level 2 attempt 1 second pulse Self test failures permanent ...

Page 31: ...INST target The phase current indicators A B C show which phases exceed the 51P pickup setting at the time of trip The negative sequence and residual current indicators Q N similarly show if these currents exceed the respective 51QP and 51NP pickup settings at the time of trip The last two indicators RS LO show the state of the reclosing relay reset or lockout Figure 2 9 SEL 251 Relay Front Panel ...

Page 32: ...input is deenergized RE 0 the relay goes to lockout 79LO 1 When the reclose enable input is deenergized the CLOSE output contact cannot automatically assert via the reclosing relay If no input is assigned to the RE input RE 1 internally reclosing is always enabled If a scheme is set up this way you can defeat automatic reclosing by setting the first open interval to zero 79OI1 0 One input must be ...

Page 33: ...sing SELOGIC Control Equations B 12 50NLT G 34 79SH X 56 B G TR 1246 51NT X effectively TR 1246 51NT 50NLT 79SH SEQ 1 50NL close TRIP output contacts TR 51NT 50NLT 79SH The M79SH setting selects for which shots 0 1 2 3 or 4 the 79SH bit is asserted 79SH 1 79SH supervises 50NLT for tripping 50NL is the pickup for 50NLT The SEQ 1 variable can be set to any OR combination of elements in Relay Word ro...

Page 34: ...using the relay shot counter to increment to shot 4 The line recloser then goes to lockout When the SEL 251 Relay reset interval timer expires shot 0 again Sequence coordination prevents the SEL 251 Relay from tripping for a fault beyond a line recloser However proper coordination was present between the line recloser fast curve and 50NLT in this example No phase overcurrent elements were enabled ...

Page 35: ...e of several global settings and is entered with the SET G command Active setting group changes via setting group selection inputs or GROUP command disable the relay for less than 0 5 seconds to allow loading of new active settings The ALARM output contacts close during this time and all timers and relay elements reset The DEMR setting allows you to specify whether or not demand values for current...

Page 36: ...nd currents If voltage is measured at the bus and there are current limiting reactors on the feeder the relay can derive the voltage on the load side of the reactors for metering and fault locating purposes see Figure 2 12 You can access and reset metering data using different METER commands See Section 3 Communications for more information SERIAL INTERFACES Port 1 and Port 2 are EIA 232 serial da...

Page 37: ...measures the offset voltage of each analog input channel and compares the value against fixed limits It issues a warning when offset is greater than 50 millivolts in any channel and declares a failure when offset exceeds 75 millivolts The offset levels of all channels appear in the STATUS command format Power Supply Power supply voltages are limit checked The table below summarizes voltage limits ...

Page 38: ...e is excessive or a conversion starts and never finishes There is no warning state for this test While an ADC failure disables protective functions control functions remain intact The relay transmits a STATUS message and closes the ALARM relay contacts Master Offset The master offset MOF test checks offset in the multiplexer analog to digital converter circuit A grounded input is selected and samp...

Page 39: ...gured to accept demodulated IRIG B input When JMP 13 and JMP 14 are bridged pins 6 and 4 will accept IRIG B and IRIG B respectively See Table 3 2 for port pinouts The IRIG B serial data format consists of a one second frame containing 100 pulses and divided into fields The relay decodes second minute hour month and day fields and sets the relay clock accordingly When IRIG B data acquisition is act...

Page 40: ...igure 2 20 for more information Phase overcurrent elements can be externally and internally torque controlled Negative sequence and ground residual overcurrent elements can only be externally torque controlled External Torque Control The ETC 1 setting selects overcurrent elements to be externally torque controlled Only over current elements in Relay Word row R1 can be selected As an example ETC 51...

Page 41: ... in this example If 27 asserts the selected phase overcurrent elements are enabled with respect to internal torque control If you set TCI equal to I the 50C element torque controls phase overcurrent elements selected in the ITC 1 setting 51P and 50H and consequently 51T in this example If 50C asserts the selected phase overcurrent elements are enabled with respect to internal torque control If you...

Page 42: ...he transformer bank is otherwise operating normally two of the phase to phase voltages presented to the relay drop to 0 58 per unit of nominal If two VT secondary fuses operate one phase to phase voltage measured by the relay goes to zero while the other two drop to 0 58 per unit With these facts in mind the logic described below is easy to understand How Does the SEL 251 Relay Detect Transformer ...

Page 43: ...f the SELOGIC Control Equations for tripping or pro grammable output contact operation DEMAND AMMETERS The SEL 251 Relay provides demand ammeters for phase negative sequence and zero sequence ground residual currents Peak demands are saved The demand ammeters behave much like low pass filters responding to gradual trends The demand ammeter time constant is used for all three demand ammeters The ti...

Page 44: ...for current limiting reactors to the load side of the PTs so the voltage VF can be derived and used for fault locating and metering Current limiting reactors are assumed to have zero mutual coupling between phases so the RS and XS settings represent the positive negative and zero sequence impedance values of the current limiting reactors The positive and zero sequence primary line impedance values...

Page 45: ...capacitor value Distribution line parameter errors Although the fault location computation takes several seconds the relay can handle several faults in quick succession The relay stores all fault data then processes each fault in turn For example suppose three faults occur within a few seconds The relay stores data from them as they occur The fault location computations begin with the first oldest...

Page 46: ...ts The relay encodes relay element states outputs and inputs using a simple process making the report compact and easy to interpret Use the EVENT command to access the eleven cycle event reports Use the HISTORY command to list summary event reports See Section 3 Communications for more information on these commands Event Report Triggering Set the variable ER 1246 to any OR combination of elements ...

Page 47: ...ectromechanical induction disc elements where the reset time depends on the time dial setting the percentage of disc travel and the amount of current between zero and pickup The time delay reset equations tr are given below tM curve operating time in seconds tr reset time in seconds for time delay reset TD time dial setting M multiples of pickup For curve operating time tM M 1 For reset time tr M ...

Page 48: ... 34 Specifications Date Code 20000421 SEL 251 2 3 Instruction Manual Figure 2 14 Moderately Inverse Curves Figure 2 15 Inverse Curves Figure 2 16 Very Inverse Curves Figure 2 17 Extremely Inverse Curves ...

Page 49: ...Date Code 20000421 Specifications 2 35 SEL 251 2 3 Instruction Manual Figure 2 18 SEL 251 Phase Overcurrent Logic Diagrams ...

Page 50: ...2 36 Specifications Date Code 20000421 SEL 251 2 3 Instruction Manual Figure 2 19 SEL 251 Negative Sequence Overcurrent Logic Diagrams ...

Page 51: ...Date Code 20000421 Specifications 2 37 SEL 251 2 3 Instruction Manual Figure 2 20 SEL 251 Ground Residual Overcurrent Logic Diagrams ...

Page 52: ...2 38 Specifications Date Code 20000421 SEL 251 2 3 Instruction Manual Figure 2 21 SEL 251 Overcurrent and Undervoltage Elements ...

Page 53: ...Date Code 20000421 Specifications 2 39 SEL 251 2 3 Instruction Manual Figure 2 22 SEL 251 Transformer Blown Fuse Detection Logic ...

Page 54: ...2 40 Specifications Date Code 20000421 SEL 251 2 3 Instruction Manual Figure 2 23 SEL 251 Demand Ammeters ...

Page 55: ...Date Code 20000421 Specifications 2 41 SEL 251 2 3 Instruction Manual Figure 2 24 SEL 251 Programmable Trip Logic Diagram Figure 2 25 SEL 251 Close Logic Diagram ...

Page 56: ......

Page 57: ...ons 3 6 Access Level 0 Command 3 6 ACCESS 3 6 Access Level 1 Commands 3 7 2ACCESS 3 7 BREAKER 3 7 BREAKER R 3 8 DATE mm dd yy 3 8 EVENT n 3 9 HISTORY 3 9 IRIG 3 11 METER n 3 12 METER D 3 13 METER RD 3 13 METER RP 3 14 QUIT 3 14 SHOWSET n 3 14 STATUS 3 16 TARGET n k 3 16 TARGET R 3 18 TIME hh mm ss 3 18 TRIGGER 3 18 Access Level 2 Commands 3 19 CLOSE 3 19 COPY m n 3 19 GROUP n 3 20 OPEN 3 20 PASSWO...

Page 58: ... 3 1 SEL 251 Conventional Terminal Block Model Relay Serial Port Connector Pin Assignments 3 2 Table 3 2 SEL 251 Plug In Connector Model Relay Serial Port Connector Pin Assignments 3 3 Table 3 3 Target LED Assignments 3 17 FIGURES Figure 3 1 9 Pin Connector Pin Number Convention 3 2 ...

Page 59: ...der Date 04 01 93 Time 01 01 01 SERIAL PORT CONNECTIONS AND CONFIGURATIONS Port 1 and Port 2 are EIA 232 serial data interfaces Port 1 is located on the rear panel and is generally used for remote communications via a modem an SEL PRTU or an SEL 2020 Port 2 has connectors on both the front and rear panels designated Port 2F and Port 2R respectively Port 2F has priority over Port 2R These ports are...

Page 60: ... Port 2R Port 2F Description 1 5 Vdc N C 5 Vdc available if JMP12 installed 2 RXD RXD Receive data input 3 TXD TXD Transmit data output 4 12 Vdc N C 12 Vdc available if JMP13 installed 5 GND GND 6 12 Vdc N C 12 Vdc available if JMP14 installed 7 RTS RTS The relay asserts this line under normal conditions When its received data buffer is full the line is deas serted and asserts again when the buffe...

Page 61: ... monitors CTS and transmits characters only if CTS is asserted 9 GND GND Ground for ground wires and shields COMMUNICATIONS PROTOCOL Communications protocol consists of hardware and software features Hardware protocol includes the control line functions described above The following software protocol is designed for manual and automatic communications 1 All commands received by the relay must be o...

Page 62: ...When the relay receives XOFF during transmission it pauses until it receives an XON character If there is no message in progress when the relay receives XOFF it blocks transmission of any message presented to its buffer Messages will be accepted after the relay receives XON The CAN character ASCII hex 18 aborts a pending transmission This is useful in terminating an unwanted transmission 5 Control...

Page 63: ...presents the Access Level 0 prompt The relays are shipped with Port 2 designated automatic you may use the SET command to change this designation see SET command AUTO setting This allows you to select Port 1 Port 2 or both ports to transmit automatic responses from the relay To enter Level 1 type the following on a terminal connected to Port 2 ACCESS ENTER ACCESS ENTER The response is Password Ent...

Page 64: ...y time after the terminal displays an appropriate prompt In this manual commands to type appear in bold upper case OTTER Keys to press appear in bold upper case brackets ENTER Some commands have optional parameters these appear after the command in bold lower case COMMAND DESCRIPTIONS Access Level 0 Command ACCESS ACCESS allows you to enter Access Level 1 The password is required unless you instal...

Page 65: ... Relay trips are determined by coinciding change in circuit breaker auxiliary contact input status 52A drops out or 52B asserts and relay TRIP output contact assertion Consideration should be given to the TDUR trip duration timer setting so TRIP output contact assertion always encompasses the status change of the circuit breaker auxiliary contact for a relay initiated trip See the note concerning ...

Page 66: ...rips and interrupted currents cannot be accumulated BREAKER R BREAKER R resets sets to zero the circuit breaker trip counters and interrupted current sums The relay also stores reset date and time BREAKER R ENTER BREAKER R ENTER Reset Trip Counters and Current Sums Are you sure Y N Y ENTER Y ENTER Example 21 6 kV distribution feeder Date 04 01 93 Time 09 10 30 Rly Trips 0 From 4 2 91 09 10 30 IA 0...

Page 67: ...clear the buffers All event data are lost when event buffers are cleared If an event buffer is empty when you request an event the relay returns an error message EVENT 12 ENTER EVENT 12 ENTER Invalid event Section 4 Event Reporting explains the generation and analysis of event reports HISTORY HISTORY displays the date time event type reclosing relay shot maximum phase current enabled setting group...

Page 68: ... from the following list Phase involvement is determined solely using uncompensated and load compensated current magnitudes The relay measures these magnitudes at the midpoint of the first continuous relay element pickup sequence in the event report for algorithmic details see the Fault Locator description in Section 2 Specifications AG For A phase to ground faults BG For B phase to ground faults ...

Page 69: ...dle of the fault in primary amperes This information can help you identify the row pair used by the relay for fault location calculations If the fault locator is not run for an event report the event report shows maximum phase current when the event report was triggered The GROUP column has the number of the setting group active at the time the report was triggered The TARGETS column lists the FAU...

Page 70: ...imary volts METER ENTER METER ENTER Example 21 6 kV distribution feeder Date 04 01 93 Time 09 12 49 MET IA 356 B 364 C 361 R 6 3I2 5 P 12 910 Q 1 130 VA 12021 VB 12015 VC 12043 3V0 20 AB 20827 BC 20839 CA 20836 3V2 17 P is positive when three phase real power flows out from the bus and into the line If P is negative three phase real power flows in the opposite direction Q is positive when three ph...

Page 71: ... METER D ENTER Example 21 6 kV distribution feeder Date 04 01 93 Time 09 13 33 DEM IA 347 B 349 C 349 R 4 3I2 3 P 12 897 Q 0 997 PK IA 412 B 410 C 414 R 15 3I2 13 P 14 701 Q 1 280 If control power to the relay is interrupted the demand and peak demand values reset to zero METER RD METER RD resets demand values to zero METER RD ENTER METER RD ENTER Reset Demand Meter Are you sure Y N Y ENTER Y ENTE...

Page 72: ... communicating with the relay to prevent unauthorized access Control returns to Access Level 0 automatically after a settable interval of no activity see the TIME1 and TIME2 settings of the SET command QUIT ENTER QUIT ENTER Example 21 6 kV distribution feeder Date 04 01 93 Time 01 45 40 SHOWSET n SHOWSET n displays the relay and logic settings for setting group n n 1 2 3 4 5 or 6 You cannot enter ...

Page 73: ... 99 50NLT 2 50NH 100 00 51NP 1 50 51NTD 2 00 51NC 3 51NRS N 50L 99 99 50LT 0 50H 40 00 51P 6 00 51TD 6 00 51C 3 51RS N 52APU 1200 52ADO 0 TSPU 0 TSDO 0 TKPU 0 TKDO 0 TZPU 0 TZDO 0 PRESS RETURN ENTER ENTER SELogic Equations S 123 A 12 B 12 50NLT C 12 50NL D 12 E 34 79RS 79CY 52AT F 34 IN6 G 34 H 34 J 1234 K 1234 L 1234 A1 1234 TF A2 1234 NDEM PRESS RETURN ENTER ENTER V 56 B E F W 56 C E F X 56 Y 56...

Page 74: ... failure following the displayed offset value The PS row indicates power supply voltages in volts for the three power supply outputs If a RAM or ROM test fails the IC socket code of the defective part replaces OK The A D self test checks analog to digital conversion time The MOF test checks dc offset in the MUX PGA A D circuit The SET self test calculates a checksum of the settings stored in nonvo...

Page 75: ...ies of ten target readings for Relay Word row R3 Target headings repeat every eight rows You cannot use parameter k without parameter n TARGET 3 10 ENTER TARGET 3 10 ENTER 79RS 79CY 79LO 79SH 52AT 52BT IN6 IN5 1 0 0 0 1 0 1 1 1 0 0 0 1 0 1 1 1 0 0 0 1 0 1 1 1 0 0 0 1 0 1 1 1 0 0 0 1 0 1 1 1 0 0 0 1 0 1 1 1 0 0 0 1 0 1 1 1 0 0 0 1 0 1 1 79RS 79CY 79LO 79SH 52AT 52BT IN6 IN5 1 0 0 0 1 0 1 1 1 0 0 0 ...

Page 76: ...ck type TIME and the desired setting then press ENTER Separate the hours minutes and seconds with colons semicolons spaces commas or slashes To set the clock to 23 30 00 enter TIME 23 30 00 ENTER TIME 23 30 00 ENTER 23 30 00 A quartz crystal oscillator provides the time base for the internal clock You can set the clock automatically through the relay time code input with a source of demodulated IR...

Page 77: ...put relay if the TRIP output and 52A input are not asserted The relay transmits the message Breaker CLOSED when the breaker closes or if it is already closed as determined by 52A input state Typing N ENTER after either of the above messages aborts the closing operation with the message Aborted CLOSE ENTER CLOSE ENTER Close BREAKER Y N Y ENTER Are you sure Y N Y ENTER Breaker CLOSED After CLOSE com...

Page 78: ...ROUP 3 ENTER GROUP 3 ENTER Change Group Variable Are you sure Y N Y ENTER Y ENTER Active Group 1 Group Variable 3 The above response to GROUP 3 command execution indicates that only Setting Group Selection input SS1 is energized see Table 2 3 because the active group did not change to Group 3 but remained Group 1 If you do not designate a setting group the relay displays present group information ...

Page 79: ...IKE ENTER PASSWORD 1 BIKE ENTER Set The relay sets the password pulses the ALARM relay closed and transmits the response Set After entering new passwords type PASSWORD ENTER to inspect them Make sure they are what you intended and record the new passwords Passwords can be any length up to six numbers letters or any other printable characters except delimiters space comma semicolon colon slash Uppe...

Page 80: ...50H The 50L and 50H phase overcurrent elements from Relay Word row 1 are selected for internal torque control The respective time delayed elements they control 50LT and 50HT are also internally torque controlled through this setting Note that AND logic variables V W X Y and ZT cannot select other AND variables from Relay Word rows 5 and 6 They can only select the OR logic variables A B C D E F H J...

Page 81: ...58 0 001 10000 Positive sequence line resistance X1 1 50 Positive sequence line reactance R0 1 44 Zero sequence line resistance X0 4 56 Zero sequence line reactance RS 0 00 Current limiting reactor resistance XS 0 00 Current limiting reactor reactance LL Line Len 2 42 0 001 10000 Line length unitless If LL 0 001 no fault location information DATC Dem 5 60 min 15 Demand ammeter time constant PDEM P...

Page 82: ...7H V l l sec 0 00 High set limit for undervoltage element 27 27C 2 3 Ph or 4 HS Blown Fuse 2 Select whether 27 is a phase to phase or three phase to phase element or select 4 to enable blown fuse detection TCI 0 none V 27 I 50C 3 both 0 Internal torque control conditions 50Q A sec 99 99 0 50 100 00 Pickup for negative sequence definite time overcurrent element 50QT The element responds to 3 I2 50Q...

Page 83: ...t 51NT 51NC Curve 1 2 3 or 4 2 Curve for ground residual time overcurrent element 51NT 1 moderately inverse 2 inverse 3 very inverse 4 extremely inverse 51NRS Dly Reset Y N N Time delay reset for ground residual time overcurrent element 51NT If N 51NT resets 1 cycle after 51NP drops out 50L A sec 99 99 0 50 100 00 Pickup for phase definite time overcurrent element 50LT 50LT Dly cyc 0 0 16000 Time ...

Page 84: ...Timer TZ time delay dropout timer TZ output is Relay Word bit ZT Set remaining settings equal to combinations of elements in the Relay Word via SELOGIC Control Equations You can clear logic settings by entering NA The following settings S 123 through A2 1234 can be set to equal any OR combination of elements in the Relay Word rows indicated in parentheses S 123 Input into timer TS TS output is Rel...

Page 85: ...his limit may overflow the relay input buffer and cause it to XOFF the terminal from which you are entering settings see Communications Protocol in this section The following settings specify overcurrent elements in Relay Word row R1 to be torque controlled e g ETC 1 51P 50NL ETC 1 Externally torque controlled elements ITC 1 Internally torque controlled phase overcurrent elements choose from 51P 5...

Page 86: ...g Group Selection inputs SS1 SS2 SS3 have to stabilize for time TGR before the relay changes setting groups ITT Inst Tar Time cyc 5 0 63 INST front panel target illuminates if TRIP occurs less than ITT time after any Relay Word row R1 overcurrent element picks up Setting ITT 0 defeats the INST target TIME1 Port 1 Timeout min 15 0 30 0 no timeout TIME2 Port 2 Timeout min 0 0 no timeout AUTO Autopor...

Page 87: ...assertion of the internal TRIP condition When the TRIP condition drops out and the circuit breaker is open per 52A or 52A the open interval starts timing 52AR or 52AR If 52AR or 52AR is assigned to an input not only does the input provide circuit breaker status information but it provides reclose initiation too The sensed transition of the circuit breaker status indicating that the circuit breaker...

Page 88: ...use of the 10 cycle time delay Refer to the Functional Specifications in Section 2 Specifications and be sure the global settings you choose result in relay performance appropriate to your application The AUTO setting selects Port 1 Port 2 or both serial ports for automatically transmitted messages If relay Port 2 is connected to an SEL RD or SEL PRTU the AUTO setting must direct automatic message...

Page 89: ... only enter DATE EVENT n Shows event record EVE or EVE 1 shows newest event EVE 12 shows oldest n 1 2 3 11 or 12 HISTORY Shows DATE TIME EVENT LOCAT location SHOT TARGETS and CURR maximum fault current for the last twelve events IRIG Forces immediate attempt to synchronize internal relay clock to time code input METER n Displays present phase residual and negative sequence current values present r...

Page 90: ... Opens circuit breaker if allowed by jumper setting PASSWORD Shows or sets passwords ALARM contacts pulse closed after password entry PAS 1 OTTER sets Level 1 password to OTTER PAS 2 TAIL sets Level 2 password to TAIL SET n p Initiates setting procedure for setting group n n 1 2 3 4 5 or 6 Option p directs the relay to begin the setting procedure for setting group n at setting p e g if p 51P the s...

Page 91: ...t Report 4 1 Long Event Report 4 2 Interpreting Voltage and Current Data 4 2 Relay Element Output Contact And Input Data 4 3 Example Event Reports 4 5 Externally Triggered Event Report 4 5 Fault Triggered Event Report 4 6 Example Event Report 1 4 7 Example Event Report 2 4 8 Firmware Identification 4 10 TABLES Table 4 1 Event Report Triggering Actions 4 1 ...

Page 92: ......

Page 93: ...ut for at least four cycles before they can initiate another event report This helps to eliminate multiple records for boundary faults Triggering is recorded to the nearest quarter cycle and referenced to the 16th row of data in the report All reports trigger at row 16 This system allows you to determine the total duration of a long fault which triggers two event reports Simply calculate the time ...

Page 94: ...and COPY command execution LONG EVENT REPORT The long event report contains 44 quarter cycles of prefault fault and post fault voltage and current information For each quarter cycle of information the relay also records the states of all fault measuring elements outputs and inputs The report also includes settings active during the event This information is useful in reviewing fault inception and ...

Page 95: ...tively By the above rules the phasor components are X Y 1 0 Now consider a cosine function Its samples taken at t 0 and t 90E are 1 and 0 its phasor representation is 0 1 The phasor 0 1 leads the phasor 1 0 by 90E This coincides with a 90E lead of the cosine function over the sine function To construct a phasor diagram of voltages and currents select a pair of adjacent rows from an area of interes...

Page 96: ...rent 51 51NP 51NT 0 0 0 1 1 1 0 p 1 1 T 50L 50NL 50NLT 0 0 0 1 not possible 1 0 p 1 1 T Event Report Column Elements Symbol 50H 50NH 0 1 p I Demand current thresholds DEM PDEM QDEM NDEM 0 0 0 0 0 1 N 0 1 0 Q 0 1 1 3 1 0 0 P 1 0 1 5 1 1 0 6 1 1 1 7 79 Reclosing relay states 79RS 79CY 79LO 0 0 0 no 52A or 52A 0 0 1 L 0 1 0 C 0 1 1 not possible 1 0 0 R 1 0 1 not possible 1 1 0 not possible 1 1 1 not ...

Page 97: ...er The report was generated with the TRIGGER command In this excerpt you can immediately see that load currents are balanced by the lack of significant current in the residual current column IR Also note that the line breaker is closed as signified by a B in the column labeled In 5 6 IN5 52A Event report data for the voltages and currents appears in rectangular format You can easily convert these ...

Page 98: ...report was triggered when the 50NL element picked up on an AG fault 50NL is set to trigger event reports via the programmable event report trigger variable ER 1246 50NL is not set to initiate tripping Tripping is initiated when 50NLT expires 2 cycles later setting 50NLT 2 50NLT is set to initiate tripping via the programmable tripping variable TR 1246 Comments to the right of the event report and ...

Page 99: ...229 E2 Currents Voltages P Q N I Out In A pri V pri 555T 55 555 D 7B T13A 135 IR IA IB IC VA VB VC 100C 10 100 E 9K L LHI LH M R C24R 246 1 310 171 141 12377 4872 7505 R 13B 3 16 262 276 1520 11479 9959 R 13B 1 310 171 141 12377 4872 7505 R 13B 3 16 262 276 1520 11479 9959 R 13B Event TRIG Location Shot 0 Targets Currents ABCQN amps primary 310 313 310 2 3 One cycle of data Event Summary ...

Page 100: ...13B 1540 1735 38 160 7147 132 8107 p p pT C T 3 13B 2272 2195 210 138 2213 11531 8388 p p pT C T 3 13B 1540 1737 36 160 7146 131 8109 p p pT C T 3 13B 2272 2193 210 138 2213 11530 8387 p p pT C T 3 13B 1540 1737 36 160 7146 130 8107 p p pT C T 3 136 2256 2183 210 138 2213 11529 8387 p p pT C T 3 136 1513 1703 36 160 7147 131 8119 p p pT C T 3 136 1754 1761 201 135 2411 11545 8379 p p p C T 3 136 5...

Page 101: ...6 G 34 H 34 J 1234 K 1234 L 1234 A1 1234 TF A2 1234 NDEM V 56 B E F W 56 C E F X 56 Y 56 Z 56 A3 1346 79CY A4 2346 TR 1246 50H 51T 51NT V RC 1246 50H TF ER 1246 51P 51QP 51NP TF W SEQ 1 ETC 1 ITC 1 Global settings DEMR Y CFT 60 TDUR 4 TFT 30 TGR 180 ITT 5 TIME1 15 TIME2 0 AUTO 2 RINGS 3 IN1 SS1 IN2 DT IN3 RE IN4 IN5 52A IN6 Group 1 is enabled because IN1 SS1 and is energized SS2 SS3 0 by default b...

Page 102: ...50 Hz 60 Hz Power System Frequency B 1 5 1 amp 5 amps Nominal Amps per Phase C 6 120 67 volts Nominal Volts Phase Phase D r radial Fault Locator type E p n positive negative Phase Sequence of Power System F 1 standard Recloser G r recloser Target LEDs H q standard Neg Seq OC Elements I y wye Voltage Connection J s e b standard extended Fast Meter Commands extended w fast operate EEPROM version spe...

Page 103: ...Overcurrent Elements 5 11 Negative Sequence Elements Protect for Phase Faults 5 11 Negative Sequence Overcurrent Elements and Delta Wye Transformers 5 13 Summary of Figure 5 8 5 13 Summary of Figure 5 9 5 16 Underfrequency Load Shedding Input 5 16 Undervoltage Load Shedding 5 17 Breaker Failure 5 17 Breaker Failure Implementation Notes 5 18 Qualify Trip Condition With Presence of Load Current 5 18...

Page 104: ...nd 52BT 5 7 Figure 5 7 Minimum Response Time Using Ground Residual Elements 5 11 Figure 5 8 Phase To Ground Fault on Delta Wye Transformer Secondary 5 14 Figure 5 9 Phase To Phase Fault on Delta Wye Transformer Secondary 5 15 Figure 5 10 Input IN5 Qualified by Time TKPU 5 16 Figure 5 11 Element 27 Qualified by Time TKPU 5 17 Figure 5 12 Underfrequency or Undervoltage Trip Condition Time Duration L...

Page 105: ...to save the fuse if the fault is transient If the fault is permanent the fuse will eventually operate on a subsequent shot where relay tripping is delayed The 50NL ground residual instantaneous overcurrent element in Figure 5 1 is incor porated in fuse saving schemes in the following examples Figure 5 1 Fuse Saving Using Ground Residual Elements At least two fuse saving scheme implementations are ...

Page 106: ...tting are pertinent shots 0 through 3 The shot counter increments when the reclosing relay issues an automatic reclosure CLOSE output contact assertion Shot 0 when the circuit breaker is closed and the reclosing relay is reset With the M79SH setting shown above 79SH remains set from the end of the preceding reset interval 79RST until the relay issues the second close shot 2 Figure 5 2 Reclosing Cy...

Page 107: ...eme Using the 52AT Bit The 52APU and 52ADO settings affect Relay Word bits 52AT and 52BT as follows Figure 5 3 Effect of 52APU and 52ADO Settings on Relay Word Bits 52AT and 52BT Note that the 52BT bit is the inverse of the 52AT bit The discussion involves only the 52AT bit If 50NL is supervised by 52AT 50NL continues to be disabled for 52APU time after circuit breaker closure 52A asserts when the...

Page 108: ...EL 251 Relay definite time overcurrent elements have total coordination with tap fuses near the substation No attempt is made to save the fuse in a fault situation For a fault to the load side of a tap fuse the fuse will clear the fault and the SEL 251 Relay will not operate at all A ground coordination example follows Using SELOGIC Control Equations TR 1246 50NLT TR is the programmable trip condi...

Page 109: ...ations required extra timers for the instantaneous relays to realize definite time overcurrent elements Definite time overcurrent elements are already available in the SEL 251 Relay eliminating the need for external timers BLOCKING SCHEMES FOR COLD LOAD INRUSH Overcurrent elements with low pickup and low time delay settings can operate unintentionally on cold load inrush These overcurrent elements...

Page 110: ...If the TSDO setting exceeds the longest reclosing relay open interval time setting 79OI1 79OI2 etc ST will not drop out during the reclose cycle Thus 50L remains enabled throughout the cycle ST drops out when TSDO expires after the recloser goes to lockout the circuit breaker is open and 50C 0 This may be desirable since typical open interval times are not long enough to warrant concern about cold...

Page 111: ...he 52AT Bit The 52APU and 52ADO settings affect Relay Word bits 52AT and 52BT as follows Figure 5 6 Effect of 52APU and 52ADO Settings on Relay Word Bits 52AT and 52BT Note that 52BT is the inverse of 52AT This discussion involves only 52AT If 52AT supervises 50L 50L continues to be disabled for 52APU time after circuit breaker closure Set 52APU slightly greater than the potential cold load inrush...

Page 112: ...isabled during distribution circuit paralleling operations This is done to avoid ground relay trips resulting from residual current unbalance This unbalance results from line switches not closing or opening all phases in unison when making or breaking parallel respectively Ground residual overcurrent elements in the SEL 251 Relay can be disabled by inputs functioning as permissive trip block trip ...

Page 113: ...pping When a block trip input is de energized selected overcurrent elements are enabled for tripping This function is the opposite of a permissive trip input Inputs IN5 and IN6 are available in the Relay Word and can be effectively used as block trip inputs Using SELOGIC Control Equations A 12 51NT ground residual time overcurrent element L 1234 IN5 input IN5 to function as a block trip input V 56...

Page 114: ... torque control input Using the SET G command global settings IN4 TCG external torque control input for ground residual elements Then externally torque control the ground residual time overcurrent element 51NT Using SELOGIC Control Equations TR 1246 51NT TR is the programmable trip condition ETC 1 51NP choose elements to be externally torque controlled close TRIP output contacts TR Setting ETC 1 l...

Page 115: ...s below To implement this scheme set 51NT and 50NLT with the same magnitude pickup setting 51NP 50NL Set the 50NLT setting with the desired minimum response time Using SELOGIC Control Equations A 12 51NT ground residual time overcurrent element B 12 50NLT ground residual definite time overcurrent element V 56 A B TR 1246 V TR is the programmable trip condition effectively TR 1246 51NT 50NLT close ...

Page 116: ... current For an LL fault current magnitudes only I x I xI x I x I P P P 2 2 3 3 3 3 173 Thus a negative sequence overcurrent element has the same sensitivity for LL faults as a phase overcurrent element if negative sequence overcurrent element pickup value is a factor of 1 73 times the phase overcurrent element pickup value The following negative sequence overcurrent elements with respective setti...

Page 117: ...es Ground time overcurrent relays also have shorter time dials than phase time overcurrent relays in their respective protection zones For an LG fault 51QT sees the same current magnitude as a ground time overcurrent relay I I for a LG fault x I x I 2 0 2 0 3 3 Negative Sequence Overcurrent Elements and Delta Wye Transformers Phase to ground and phase to phase faults on the secondary side of delta...

Page 118: ...5 14 Applications Date Code 20000421 SEL 251 2 3 Instruction Manual Figure 5 8 Phase To Ground Fault on Delta Wye Transformer Secondary ...

Page 119: ...Date Code 20000421 Applications 5 15 SEL 251 2 3 Instruction Manual Figure 5 9 Phase To Phase Fault on Delta Wye Transformer Secondary ...

Page 120: ...factor of 1 5 times the primary phase overcurrent element pickup value UNDERFREQUENCY LOAD SHEDDING INPUT Relay Word inputs IN5 and IN6 can be used as time qualified underfrequency load shedding inputs The output of an underfrequency relay is wired into IN5 or IN6 Using SELOGIC Control Equations K 1234 IN5 Figure 5 10 Input IN5 Qualified by Time TKPU Time TKPU qualifies the underfrequency input co...

Page 121: ...46 KT TR is the programmable trip condition close TRIP output contacts TR A system undervoltage condition is a three phase phenomenon so the 27 element should be set three phase sensitive setting 27C 3 Set high and low set limits for 27 27H and 27L according to system conditions BREAKER FAILURE Use the TF bit in the Relay Word to create a breaker failure scheme Using SELOGIC Control Equations A1 1...

Page 122: ... in duration Qualify Trip Condition With Presence of Load Current Phase instantaneous overcurrent element 50C is not used in the reclosing relay reset inhibit function and can be set below load levels 50C can assert with the presence of load current or deassert in its absence With this low setting 50C can indicate whether the circuit breaker is closed or open There is no 52A dependence Using SELOG...

Page 123: ... time constant DATC settable from 5 to 60 minutes BLOCK VOLTAGE REGULATING LOAD TAP CHANGER OPERATION Load tap changers should not operate when a reclosing cycle is in progress because fault current should not pass through a tap changer in motion Also if the voltage input to the load tap changer is on the load side of the feeder circuit breaker the load tap changer will see zero voltage during the...

Page 124: ... Conventional Terminal Block Relays all the output contacts can be configured as a or b contacts with soldered wire jumpers JMP4 through JMP11 each jumper has positions A and B ALARM output contacts are usually b contacts so soldered wire jumper JMP5 for A4 output contact should be in the B position for the A4 output contact to operate as an extra ALARM output contact This extra ALARM contact can ...

Page 125: ...upervising the SEL 251C Relay TRIP the SEL 251 Relay A4 output contact can function as an extra ALARM output contact by the placement of jumper JMP3 in the alarm position The A4 output contact is made a b contact by soldering wire jumper JMP5 in the B position This output contact can alarm a local annunciator or SCADA RTU for feeder relay failure Figure 5 13 Distribution Feeder Relay Backup Scheme...

Page 126: ...ion BUS TIE RELAY SETTING CHANGES In stations where bus tie breakers substitute for feeder breakers during maintenance the bus tie breaker relay can have a setting group for each feeder it protects Figure 5 14 Main Auxiliary Bus with Bus Tie Circuit Breaker CLOCK DRIVEN SETTING GROUP SELECTION Consider seasonal weekend weekday and daily system changes Develop optimum settings for various times and...

Page 127: ...de energized during the underfrequency condition There can be a possible contact race between the 52BF and AUX contacts in the feeder relay circuit breaker status input circuit If the 52BF contact closes before the AUX contact opens input IN6 will be energized and reclosing will be initiated for an underfrequency trip To avoid this problem the circuit breaker status function internal to the relay ...

Page 128: ...5 24 Applications Date Code 20000421 SEL 251 2 3 Instruction Manual Figure 5 15 Underfrequency Load Shedding and Reclose Initiate Supervision Figure 5 16 Timing for Reclose Initiation ...

Page 129: ...emand Ammeter Threshold A sec 0 25 12 00 QDEM Ground Residual Demand Ammeter Threshold A sec 0 25 12 00 NDEM Reclosing Relay Data Reclosing Relay Open Interval Time No 1 cycles 79OI1 0 defeats reclosing 0 16000 79OI1 Reclosing Relay Open Interval Time No 2 cycles 0 16000 79OI2 Reclosing Relay Open Interval Time No 3 cycles 0 16000 79OI3 Reclosing Relay Open Interval Time No 4 cycles 0 16000 79OI4 ...

Page 130: ...ent Pickup A sec 0 125 100 00 50NH Residual Ground Time Overcurrent Element Residual Ground Time Overcurrent Pickup A sec 0 25 12 00 51NP Residual Ground Time Overcurrent Time Dial 0 50 15 00 51NTD Residual Ground Time Overcurrent Curve 1 Moderately Inverse 2 Inverse 3 Very Inverse 4 Extremely Inverse 51NC Electromechanical Reset Y N 51NRS Phase Definite Time Instantaneous Overcurrent Elements Pha...

Page 131: ... cycles 0 16000 TZDO SELOGIC OR Variables OR combination of Relay Word rows in parentheses S 123 Input into Timer TS Output is Relay Word bit ST S 123 A 12 Relay Word bit A A 12 B 12 Relay Word bit B B 12 C 12 Relay Word bit C C 12 D 12 Relay Word bit D D 12 E 34 Relay Word bit E E 34 F 34 Relay Word bit F F 34 G 34 Relay Word bit G G 34 H 34 Relay Word bit H H 34 J 1234 Relay Word bit J J 1234 K ...

Page 132: ... Variables OR combination of Relay Word rows in parentheses A3 1346 Output Contact A3 A3 1346 A4 2346 Output Contact A4 A4 2346 TR 1246 Programmable Tripping Conditions TR 1246 RC 1246 Programmable Reclose Cancel Conditions RC 1246 ER 1246 Programmable Event Report Trigger Conditions ER 1246 SEQ 1 Sequence Coordination Overcurrent Elements SEQ 1 Torque Control Elements ETC 1 Externally Torque Cont...

Page 133: ... IN1 IN2 IN3 IN4 IN5 IN6 Input Setting Choices SS1 Setting Group Selection Input 1 assign to IN1 only SS2 Setting Group Selection Input 2 assign to IN2 only SS2 Setting Group Selection Input 3 assign to IN3 only TCP External Torque Control Phase and Negative Sequence Elements TCP inverted sense of TCP TCG External Torque Control Residual Overcurrent Elements TCG inverted sense of TCG 52A Circuit B...

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Page 135: ...ernal Power Jumpers 6 3 Jumper Installation Instructions 6 3 EIA 232 and IRIG B Installation 6 3 EIA 232 Cables 6 4 IRIG B Input Description 6 5 Installation Plug In Connector Model 6 6 Mounting 6 6 Frame Ground Connection 6 6 Power Connections 6 6 Secondary Circuits 6 6 Control Circuits 6 7 Communications Circuits 6 7 Jumper Selection 6 7 EIA 232 Jumpers 6 7 Password Protection Jumper 6 8 OPEN CL...

Page 136: ...ays with 1 amp nominal current inputs 6 16 Figure 6 6 Panel Cutout Diagram for Panel Mount Relays 6 17 Figure 6 7 SEL 251 Conventional Terminal Block Model DC External Connection Diagram Typical 6 17 Figure 6 8 SEL 251 Polarity Sensitive Plug In Connector Model DC External Connection Diagram Typical 6 18 Figure 6 9 Communications and Clock Connections One Unit at One Location 6 18 Figure 6 10 Remo...

Page 137: ...very low burden to the secondary potential and current circuits It requires three currents from the power system current transformer secondaries The four wire wye potential from potential transformer secondaries is optional It is used for fault locating voltage and MW MVAR metering and undervoltage torque control Control Circuits The control inputs are dry For example to assert the IN5 input you m...

Page 138: ...P3 and soldered wire jumpers JMP4 through JMP11 are toward the back of the main board and are accessed by removing the top cover EIA 232 Jumpers J6 provides EIA 232 baud rate selection Available baud rates are 300 600 1200 2400 4800 and 9600 To select a baud rate for a particular port place the jumper so it connects a pin labeled with the desired port to a pin labeled with the desired baud rate Ca...

Page 139: ... is available on either Port 1 or Port 2R Port 2F located on the front of the relay does NOT have power available To install jumpers for supplying power through the rear EIA 232 ports perform the following steps 1 Remove the relay top cover or withdraw the main circuit board 2 Locate jumpers JMP12 5 Vdc JMP13 12 Vdc and JMP14 12 Vdc near the AUX INPUT connector 3 Remove and install the needed jump...

Page 140: ...51 9 Pin DTE Device Cable 222 SEL 251 DCE Device Cable 231 SEL PRTU SEL 251 female chassis connector as viewed from outside panel GND 5 TXD 3 RXD 2 CTS 8 GND 5 TXD 3 RTS 7 RXD 2 CTS 8 GND 9 GND 1 TXD 2 RXD 4 CTS 5 12 7 GND 9 5 GND 2 RXD 3 TXD 7 RTS 8 CTS 1 DCD 4 DTR 6 DSR 7 GND 2 RXD 20 DTR 3 TXD 8 CD 1 GND 5 GND 2 RXD 3 TXD 7 RTS 8 CTS 9 GND Jumper ...

Page 141: ...IG B Input Description The port labeled J201 AUX INPUT receives demodulated IRIG B input Pin definitions appear in Table 6 1 Table 6 1 IRIG B Pin Definitions Pin Name Description 1 5 2 IRIGIN HI Positive IRIG B input 3 IRIGIN LOW Negative IRIG B input 4 12 6 12 5 9 GND Ground for ground wires and shields Consult the factory before using these power supply outputs RXD 2 TXD 3 GND 5 RTS 7 CTS 8 IRIG...

Page 142: ...LUG IN CONNECTOR MODEL Mounting The relay is designed for mounting by its front vertical flanges in a 19 vertical relay rack It may also be mounted semi flush in a switchboard panel Use four 10 screws for mounting This section includes front and rear panel drawings Frame Ground Connection Terminal 46 on the rear panel must be connected to frame ground for safety and performance These terminals con...

Page 143: ...ety grounding since their current carrying capacity is less than control power short circuit current and protection levels The communications circuits are protected by low energy low voltage MOVs and passive RC filters You can minimize communications circuit difficulties by keeping the length of the EIA 232 cables as short as possible Lengths of twelve feet or less are recommended and the cable le...

Page 144: ... Power Jumpers 5 Vdc power is available from Port 1 and Port 2R to energize external devices JMP12 must be bridged in order to route power to the rear ports Use caution to ensure the dc current require ment of the external equipment does not exceed the relay power supply specifications Route dc power to the rear ports only when required by your application EIA 232 and IRIG B Installation The follo...

Page 145: ...Cable 222 SEL 251 DCE Device Cable 231 SEL PRTU SEL 251 Cable 239 Data and IRIG B SEL 2020 SEL 251 GND 5 TXD 3 RTS 7 RXD 2 CTS 8 GND 9 GND 1 TXD 2 RXD 4 CTS 5 12 7 GND 9 RXD 2 TXD 3 GND 5 RTS 7 CTS 8 IRIG 4 IRIG 6 7 GND 2 RXD 20 DTR 3 TXD 8 CD 1 GND 5 GND 2 RXD 3 TXD 7 RTS 8 CTS 9 GND Port 2R J203 AUX Input J201 ...

Page 146: ...2R may be configured to accept demodulated IRIG B input When JMP13 and JMP14 are bridged pins 6 and 4 will accept IRIG B and IRIG B respectively See Table 3 2 for port pinouts The actual IRIG B input circuit is a 56 ohm resistor in series with an optocoupler input diode The input diode has a forward drop of about 1 5 volts Driver circuits should put approximately 10 mA through the diode when on Th...

Page 147: ... plug in connector model only 1 Apply control power and make sure the terminal displays the startup message If not set AUTO 2 with the SET G command in Access Level 2 Check the settings with the ACCESS and SHOWSET commands Use the TIME command to set the clock 2 Apply three phase voltages Execute the METER command and make sure the readings are accurate If they are not be sure the correct PT ratio...

Page 148: ...be assigned to an input for example IN6 52A With IN6 de energized circuit breaker open execute the CLOSE command The CLOSE contacts remain asserted for as long as the CFT close failure time setting unless the TRIP output contact is asserted or IN6 is energized circuit breaker apparently closed If CFT 0 CLOSE remains asserted indefinitely unless TRIP is asserted or IN6 is energized circuit breaker ...

Page 149: ...Date Code 20000421 Installation 6 13 SEL 251 2 3 Instruction Manual Figure 6 2 SEL 251 Conventional Terminal Block Model Relay Horizontal Front and Rear Panel Drawings ...

Page 150: ...6 14 Installation Date Code 20000421 SEL 251 2 3 Instruction Manual Figure 6 3 SEL 251 SLP Relay Dimensions and Drill Plan ...

Page 151: ...Date Code 20000421 Installation 6 15 SEL 251 2 3 Instruction Manual Figure 6 4 SEL 251 Plug In Connector Model Relay Horizontal Front and Rear Panel Drawings ...

Page 152: ...6 16 Installation Date Code 20000421 SEL 251 2 3 Instruction Manual Figure 6 5 SEL 251 LP Relay Dimensions and Drill Plan for relays with 1 amp nominal current inputs ...

Page 153: ...ode 20000421 Installation 6 17 SEL 251 2 3 Instruction Manual Figure 6 6 Panel Cutout Diagram for Panel Mount Relays Figure 6 7 SEL 251 Conventional Terminal Block Model DC External Connection Diagram Typical ...

Page 154: ...te Code 20000421 SEL 251 2 3 Instruction Manual Figure 6 8 SEL 251 Polarity Sensitive Plug In Connector Model DC External Connection Diagram Typical Figure 6 9 Communications and Clock Connections One Unit at One Location ...

Page 155: ...llation 6 19 SEL 251 2 3 Instruction Manual Figure 6 10 Remote Communications Local Display and Clock Connections Multiple Relay Units at One Location Figure 6 11 SEL Relay Communications Diagram for Connection to the SEL DTA ...

Page 156: ...6 20 Installation Date Code 20000421 SEL 251 2 3 Instruction Manual Figure 6 12 SEL 251 Relay Typical AC External Current and Voltage Connections ...

Page 157: ... SEEN ON SCREEN COMPANY NOTATION 1st LINE CHOSEN Y COMPONENT 2nd LINE CHOSEN X COMPONENT CALCULATED USE THE VALUES IN ROWS 1 AND 2 ABOVE TO DRAW PHASOR DIAGRAMS BELOW Ia Ib Ic Va Vb Vc I I I V V V MAGNITUDE X 2 Y 2 ANGLE IN DEGREES ARCTAN Y X R O W 1 R O W 2 TO VALUE OF Va DEGREES OBTAIN Va DEGREES 0 USED TO DRAW PHASOR DIAGRAM Va DEGREES 0 ANGLE 120 120 0 VOLTAGES 0 120 120 CURRENTS DWG A7 0446 ...

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Page 159: ... SEEN ON SCREEN COMPANY NOTATION 1st LINE CHOSEN Y COMPONENT 2nd LINE CHOSEN X COMPONENT CALCULATED USE THE VALUES IN ROWS 1 AND 2 ABOVE TO DRAW PHASOR DIAGRAMS BELOW Ia Ib Ic Va Vb Vc I I I V V V MAGNITUDE X 2 Y 2 ANGLE IN DEGREES ARCTAN Y X R O W 1 R O W 2 TO VALUE OF Va DEGREES OBTAIN Va DEGREES 0 USED TO DRAW PHASOR DIAGRAM Va DEGREES 0 ANGLE 120 120 0 VOLTAGES 0 120 120 CURRENTS DWG A7 0446 ...

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Page 161: ...ts 7 16 Reclosing Relay Tests Setup 7 17 Reclosing Relay Reset Interval Timer Test 7 19 Reclosing Relay Open Interval Timer Test 7 20 Reclosing Relay States Test 7 21 Reclosing Relay Shot Bit Test 7 22 Reclosing Relay Sequence Coordination Test 7 23 Close Failure Timer Test 7 25 Trip Failure Timer Test 7 26 Input Circuits Test 7 28 Serial Ports Test 7 28 IRIG B Time Code Input Test 7 28 Power Supp...

Page 162: ... 7 1 Low Level Test Interface for the Conventional Terminal Block Model 7 2 Figure 7 2 Communication Interface Setup 7 5 Figure 7 3 Three Phase Voltage and Current Source Test Connections 7 8 Figure 7 4 METER Test Connections 7 12 Figure 7 5 Nine Pin Connector Pin Number Convention 7 29 ...

Page 163: ... the pickup and dropout condition in much the same manner as an output contact See Section 3 Communications for more information about the TARGET command By employing the target LEDs for testing you need not change the relay settings for testing purposes Event Reporting The relay generates an eleven cycle event report in response to a trip condition or other user selected conditions Each event rep...

Page 164: ...he input module and the inputs to the processing module relay main board You can test the relay processing module using signals from the SEL RTS Low Level Relay Test System Never apply voltage signals greater than 20 volts peak peak to the low level test interface Figure 7 1 shows the signal scaling factors You can test the input module two different ways Measure the outputs from the input module ...

Page 165: ...the relay AUTO setting equal to the port which you intend to use Also set that port TIME setting equal to zero This prevents automatic message transmission to a port which may be timed out Remember to reset these settings and the target level before returning the relay to service following tests Testing Via Output Contact Assertion To test using this method set one programmable output contact to a...

Page 166: ...ble between terminal and relay 3 Source of control power 4 Source of three phase voltages and currents 5 Ohmmeter or contact opening closing sensing device 6 Plug in mating connectors wiring harness Plug In Connector model only Checkout Procedure In the procedure below you will use several relay commands Section 3 Communications provides a full explanation of all commands The following information...

Page 167: ...2 set to 2400 baud and Port 1 set to 300 baud Section 3 Communications provides additional details on port configura tion Baud rate selection is described under Jumper Selection in Section 6 Installation Figure 7 2 shows the typical communication interface setup for testing purposes Figure 7 2 Communication Interface Setup Step 4 Purpose Establish control power connections Method Connect a frame g...

Page 168: ... this section The prompt indicates that communications with the relay are at Access Level 0 the first of three levels The only command accepted at this level is ACCESS which opens communications on Access Level 1 Note If you are using a battery simulator be sure the simulator voltage level is stabilized before turning the relay on Step 6 Purpose Establish Access Level 1 communications Method Type ...

Page 169: ...0 99 79OI1 60 79OI2 600 79OI3 900 79OI4 0 79RST 1800 M79SH 00000 50C 99 99 27L 0 00 27H 0 00 27C 2 TCI 0 50Q 99 99 50QT 0 51QP 6 00 51QTD 15 00 51QC 3 51QRS N 50NL 19 99 50NLT 2 50NH 100 00 51NP 1 50 51NTD 2 00 51NC 3 51NRS N 50L 99 99 50LT 0 50H 40 00 51P 6 00 51TD 6 00 51C 3 51RS N 52APU 1200 52ADO 0 TSPU 0 TSDO 0 TKPU 0 TKDO 0 TZPU 0 TZDO 0 PRESS RETURN ENTER ENTER SELogic Equations S 123 A 12 ...

Page 170: ...oltage and current sources to the relay Method Turn power off and connect the sources of voltage and current to the rear panel terminals of the relay as shown in Figure 7 3 Apply 69 volts per phase line to neutral in positive sequence rotation Set the A phase current source to 2 amperes at the same angle as the A phase voltage Set the B phase current source to 2 amperes at the same angle as the B ...

Page 171: ...distribution feeder Date 04 01 93 Time 09 12 49 MET IA 240 B 239 C 242 R 6 3I2 5 P 8 942 Q 0 054 VA 12408 VB 12419 VC 12421 3V0 20 AB 21501 BC 21512 CA 21513 3V2 17 If you inadvertently switched a pair of voltages or currents the MW reading should be incorrect It is important to remember this when commissioning the relay using system voltages and currents Step 11 Purpose Establish Access Level 2 c...

Page 172: ...saves the twelve newest reports This checkout procedure demonstrates only a few relay features For a complete understanding of relay capabilities study Functional Description in Section 2 Specifications the Command Descriptions in Section 3 Communications and Section 4 Event Reporting For more test procedures see the Full Functional Test portion of this section FULL FUNCTIONAL TEST This procedure ...

Page 173: ...amperes secondary to 2 0 amperes secondary Type SET 1 51NP and press ENTER Following the 51NP prompt type 2 0 and press ENTER 3 To complete the setting procedure type END and press ENTER Type Y ENTER at the prompt OK Y or N The relay computes internal settings and compares them against fixed limits If all settings are within acceptable ranges the ALARM contact closes momentarily as the new setting...

Page 174: ...d equal the applied voltage times the potential transformer ratio setting With the Example 21 6 kV distribution feeder settings you should obtain VA VB VC 50 V 180 9000 V 0 5 Voltages VAB VBC and VCA should read less than 135 V primary Similarly currents IA IB and IC should equal the applied current times the current transformer ratio With the Example 21 6 kV distribution feeder settings you shoul...

Page 175: ... internal torque control on the overcurrent elements Using the SET command enter NA for the ETC 1 and ITC 1 settings These settings specify the overcurrent elements in Relay Word row R1 you want externally and internally torque controlled none in this case 3 Apply current to one phase and observe the pickup and dropout of each element Record the results Note With current applied to only one phase ...

Page 176: ...rcurrent elements in Relay Word row R1 you want externally and internally torque controlled respectively none in this case 2 Set a programmable output A1 A4 to follow a definite time overcurrent element pickup e g 50NL Use the assertion of this output open to close to start an external timer 3 Set another programmable output to follow definite time overcurrent element timeout via Relay Word bit 50...

Page 177: ...nally torque controlled respectively none in this case 2 Set a programmable output A1 A4 to follow a time overcurrent element pickup e g 51NP Use the assertion of this output open to close to start an external timer 3 Set another programmable output to follow time overcurrent element timeout via the 51NT bit in the Relay Word 51NP drives 51NT Use the assertion of this output to stop the external t...

Page 178: ... 1 3 345 0 0 0 240 0 0 120 345 0 0 120 0 120 115 0 Ð Ð Ð Ð Ð Ð Ð The negative sequence and ground residual overcurrent elements respond to 3xI2 and 3xI0 currents respectively Thus for this test all overcurrent elements see 3 45 A 6 Optional You may want to repeat this test with various multiples of pickup current e g M 3 5 and 7 and various time dial settings e g TD 1 5 and 10 for each of the four...

Page 179: ... e g IA 5 A IB IC 0 the following sequence currents result I I I I A A A A I I a I a I A B C A B C 0 1 3 1 3 2 1 3 2 5 0 0 0 0 0 167 0 Ð Ð Ð Ð Where a and a º Ð º Ð 1 120 1 240 2 I A A A A A A A 2 1 3 1 3 5 0 0 0 240 0 0 120 5 0 0 120 0 120 167 0 Ð Ð Ð Ð Ð Ð Ð The negative sequence and residual demand threshold elements respond to 3xI2 and 3xI0 currents respectively Thus for this test all demand t...

Page 180: ...open interval times cycles 79OI2 600 79OI3 900 79OI4 0 no fourth open interval 79RST 1800 reset interval time cycles M79SH 01010 50L 4 00 amps secondary A1 1234 79RS reset state A2 1234 79CY reclose cycle state A3 1346 79LO lockout state A4 2346 79SH shot bit asserts per M79SH setting TR 1246 50L programmable trip conditions RC 1246 NA no reclose cancel conditions SEQ 1 NA no sequence coordination...

Page 181: ...r the settings in the preceding Reclosing Relay Tests Setup if you haven t already 2 Open the circuit breaker simulator manually or via the OPEN command With the circuit breaker simulator open IN5 is de energized IN5 52A the front panel LO lockout LED is illuminated and the A3 output contact is asserted A3 79LO 3 Connect the circuit breaker simulator output to an external timer When the circuit br...

Page 182: ...ontact With the circuit breaker simulator closed IN5 is energized IN5 52A and the front panel RS reset LED illuminates after the reset interval timer expires 79RST 1800 cycles The A1 output contact asserts A1 79RS 3 If you just performed the preceding Reclosing Relay Reset Interval Timer Test The circuit breaker simulator is already closed and the reclosing relay is in the reset state The front pa...

Page 183: ...60 600 and 900 cycles The relay should go to lockout after the fourth trip Reclosing Relay States Test Purpose Verify reclosing relay states 79RS 79CY 79LO Method 1 Enter the settings in Reclosing Relay Tests Setup if you haven t already You can observe the reclosing relay states while performing the preceding Reclosing Relay Open Interval Timer Test 2 When you first trip the circuit breaker simul...

Page 184: ...emented and an automatic reclosure is initiated CLOSE output contact is asserted When the reclosing relay is in the reset state shot 0 The front panel RS reset LED is illuminated and the A1 output contact is asserted A1 79RS 79SH asserts according to the M79SH setting M79SH can be set for any combination of shots 0 1 2 3 and 4 As previously mentioned the number of shots depends on the number of se...

Page 185: ...ont panel LO lockout LED illuminates the A3 output contact asserts A3 79LO and the A2 output contact deasserts A2 79CY The shot counter remains at shot 3 last shot and the A4 output contact remains asserted A4 79SH Reclosing Relay Sequence Coordination Test Purpose Verify the operation of the reclosing relay sequence coordination feature Method 1 Enter the settings in Reclosing Relay Tests Setup i...

Page 186: ...utomatic reclosures depends on the number of set open interval times In this example there are three open intervals so there are three shots 79SH asserts according to the M79SH setting M79SH can be set for any com bination of shots 0 1 2 3 and 4 As previously mentioned the number of shots depends on the number of set open interval times this example uses three set open interval times M79SH is set ...

Page 187: ...A1 79RS The shot counter remains at shot 3 if you reapply current to the relay and remove it before the reset interval expires because shot 3 is the last shot The A4 output contact remains asserted A4 79SH The front panel RS reset LED remains illuminated and the A1 output contact remains asserted A1 79RS During this entire sequence coordination test the reclosing relay remained in the reset state ...

Page 188: ...timer when the A4 output contact asserts A4 contact assertion indicates that the relay failed to close the circuit breaker within the time allotted by the CFT setting CFT 120 cycles A4 CF close failure condition Assert the relay CLOSE output contact using the CLOSE Command or by ener gizing the IN4 input IN4 DC function The external and close failure timers start Input IN5 must remain de energized...

Page 189: ... assertion starts the external timer The trip failure timer in the relay also starts when the TRIP output contact asserts The TRIP output contact remains asserted until the trip duration timer TDUR expires and all programmable trip conditions TR go away Additionally all overcurrent element pickups have to drop out or TARGET RESET must be pushed to unlatch the TRIP output contact Connect the A4 out...

Page 190: ...t inputs and terminal numbers Table 7 3 Contact Inputs and Terminal Numbers IN1 IN2 IN3 IN4 IN5 IN6 17 18 19 20 21 22 23 24 25 26 27 28 Serial Ports Test Purpose Verify operation of serial Port 1 Method The initial checkout procedure assumes you connected a terminal to Port 2F on the relay front panel Set the baud rate of Port 1 to match that of Port 2 and switch your terminal from Port 2F to Port...

Page 191: ... Pin 6 12 Vdc Figure 7 5 Nine Pin Connector Pin Number Convention 3 Compare the 5 volt readings from the status report and voltmeter The voltage difference should be less than 50 mV and both readings should be within 0 15 volts of five volts The 12 volt supplies should be within 0 5 volts of their nominal values RELAY CALIBRATION The SEL 251 Relay is factory calibrated If you suspect that the rela...

Page 192: ...ns device not connected to system 2 Relay or communications device at incorrect baud rate or other communication parameter incompatibility including cabling error 3 System is processing event record Wait several seconds 4 System is attempting to transmit information but cannot due to handshake line conflict Check communications cabling 5 System is in the XOFF state halting communications Type CTRL...

Page 193: ...ith METER command and TRIGGER and EVENT sequence Terminal Displays Meaningless Characters 1 Baud rate set incorrectly Check terminal configuration See Section 3 Communications Self Test Failure 5 Volts 1 Power supply 5 volt output out of tolerance See STATUS command in Section 3 Communications 2 A D converter failure Self Test Failure 15 Volts 1 Power supply 15 volt output out of tolerance See STA...

Page 194: ... front panel pull out the drawout unit exchange several integrated circuit chips and reassemble the relay If you do not wish to perform the modifications yourself we can assist you Simply return the relay and integrated circuit chips to us We will install the new chips and return the unit to you within a few days Upgrade Instructions This procedure requires that you handle devices sensitive to Ele...

Page 195: ...mponents 6 Carefully place the new ICs in the appropriate sockets Check the orientation of the ICs ensuring each IC is in its corresponding socket Look for IC pins that bent under or did not enter a socket hole Verify proper orientation of the replaced ICs before reassembling the relay Energizing the relay with an IC reversed irrecoverably damages the IC If you mistakenly reenergize the relay with...

Page 196: ...satisfied If you have any questions please contact us at Schweitzer Engineering Laboratories Inc 2350 NE Hopkins Court Pullman WA USA 99163 5603 Tel 509 332 1890 Fax 509 332 7990 We guarantee prompt courteous and professional service We appreciate receiving any comments and suggestions about new products or product improvements that would help us make your job easier ...

Page 197: ...HOOTING TEST POINTS AND JUMPER LOCATIONS B 1 APPENDIX C ONEBUS PROGRAM TO COMPUTE TEST SET SETTINGS FOR TESTING DISTANCE RELAYS C 1 FIGURES Figure B 1 SEL 251 Conventional Terminal Block Model Main Board Troubleshooting Test Points and Jumper Locations B 1 Figure B 2 SEL 251 Plug In Connector Model Main Board Troubleshooting Test Points and Jumper Locations B 2 ...

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Page 199: ... 151 50 Hz 1 A SEL 151 R513 151 60 Hz 1 A SEL 151 R463 151 50 Hz 5 A SEL 151 R418 151 60 Hz 5 A The functionality of these versions is identical to previous versions SEL 251 3 R551 251 3 50 Hz 1 A ABC rotation extended fast meter fast operate SEL 251 3 R451 251 3 50 Hz 5 A ABC rotation extended fast meter fast operate SEL 151 R609 151 60 Hz 5 A ACB rotation SEL 251 2 R606 ACB rotation extended fas...

Page 200: ...5 A fast operate SEL 151 R560 151 50 Hz 1 A SEL 151 R510 151 60 Hz 1 A SEL 151 R461 151 50 Hz 5 A SEL 151 R415 151 60 Hz 5 A This firmware differs from previous versions as follows Added high side blown fuse logic with new 27C setting option Improved operation of fast meter Improved fast operate applies to SEL 251 3 only SEL 151 R607 151 60 Hz 5 A ACB rotation SEL 251 2 R604 ACB rotation extended ...

Page 201: ...1 60 Hz 1 A SEL 151 R456 151 50 Hz 5 A SEL 151 R410 151 60 Hz 5 A SEL 151 R602 151 60 Hz 5 A ACB rotation SEL 251 2 R402 251 2 60 Hz 5 A extended fast meter SEL 151 R554 151 50 Hz 1 A SEL 151 R504 151 60 Hz 1 A SEL 151 R455 151 50 Hz 5 A SEL 151 R409 151 60 Hz 5 A SEL 151 R601 151 60 Hz 5 A ACB rotation SEL 151 2 R401 251 2 60 Hz 5 A extended fast meter SEL 151 R553 151 50 Hz 1 A SEL 151 R503 151 ...

Page 202: ...f firmware in the table Firmware Part Revision No Description of Firmware SEL 251 Firmware Revision 4 Main Board Configuration added TRIP bit to Relay Word expanded DATC setting range 1 or 2 stop bit communications protocol options previously just 2 stop bits available SEL 151 R403 151 60 Hz 5 A SEL 151 R402 151 60 Hz 5 A SEL 151 R401 151 60 Hz 5 A SEL 151 R400 151 60 Hz 5 A To find the firmware r...

Page 203: ...UMPER LOCATIONS Figure B 1 SEL 251 Conventional Terminal Block Model Main Board Troubleshooting Test Points and Jumper Locations 5 amp nominal current input main board shown SLP chassis The 1 amp main board LP chassis has a similar layout but the test point positions and order are different Follow the labels on the board ...

Page 204: ...B 2 Appendix B Date Code 20000421 SEL 251 2 3 Instruction Manual Figure B 2 SEL 251 Plug In Connector Model Main Board Troubleshooting Test Points and Jumper Locations ...

Page 205: ...ngth of the protected line Next you may enter fault resistance which is used in the ground fault computations Enter source impedance as a per unit value with a base of the previously entered transmission line data For example if the radial system has a source impedance of about ten percent of the entered line impedance enter 0 1 for the per unit distance from the source to the bus Specify the dist...

Page 206: ...0 UA 67 VA 0 600 AR I AI J BR S R1 BI S S1 610 GOSUB 1000 620 AR RR AI RI BR 0 BI SQR 3 630 GOSUB 1000 635 TR RR TS RI 640 UB 67 0 5 TR 650 VB 67 SQR 3 2 TS 660 UC 67 0 5 TR 670 VC 67 0 5 SQR 3 TS 675 FF B C 680 GOSUB 4041 900 INPUT IMP BUS FAULT OR QUIT I B F Q A 910 IF A I THEN GOTO 50 920 IF A B THEN GOTO 75 930 IF A F THEN GOTO 120 ELSE GOTO 999 999 END 1000 REM MULT SUBROUTINE 1010 REM AR AI ...

Page 207: ... only enter DATE EVENT n Shows event record EVE or EVE 1 shows newest event EVE 12 shows oldest n 1 2 3 11 or 12 HISTORY Shows DATE TIME EVENT LOCAT location SHOT TARGETS and CURR maximum fault current for the last twelve events IRIG Forces immediate attempt to synchronize internal relay clock to time code input METER n Displays present phase residual and negative sequence current values present r...

Page 208: ... Opens circuit breaker if allowed by jumper setting PASSWORD Shows or sets passwords ALARM contacts pulse closed after password entry PAS 1 OTTER sets Level 1 password to OTTER PAS 2 TAIL sets Level 2 password to TAIL SET n p Initiates setting procedure for setting group n n 1 2 3 4 5 or 6 Option p directs the relay to begin the setting procedure for setting group n at setting p e g if p 51P the s...

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