Date Code 20020903 SEL-587Z Instruction Manual
Appendix C
Relay Word Bits
Software programs use variables as building blocks in realizing the relay
algorithms. Digital words are eight bits in length, each bit having a value of
either logical 1 or logical 0, depending on the status of the variable. The Relay
Word is a collection of selected program variables. Some of the Relay Word
bits are used in fixed logic that cannot be altered, but many are available to
create custom logic to satisfy a particular application. The Relay Word thus
contains placeholders, the Relay Word bits, for each of the protection
elements and logic conditions in the SEL-587Z Relay. Each Relay Word bit is
updated every eighth-cycle. For more information on using Relay Word bits to
progam the relay, see SEL
OGIC Control Equations on page 4.11 in Section 4:
Control Logic.
Note that the relay saves rows 1–13 of the Relay Word for the event reports.
Tab le C. 1 lists the SEL-587Z Relay Word. Ta b l e C .2 through Table C.10
define the Relay Word bits.
Table C.1 SEL-587Z Relay Word Bit Summary
Row Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7 Bit 8
0
EN 87 50 51 A B C G
1
51P1 51PT 51PR 51A 51AT 51AR 51B 51BT
2
51BR 51C 51CT 51CR 51G 51GT 51GR 51Q
3
51QT 51QR * 50P1 50P2 50P3 50A1 50A2
4
50B1 50B2 50C1 50C2 50G1 50G2 50Q1 50Q2
5
87A1 87A2 87B1 87B2 87C1 87C2 * *
6
* * * IN1 IN2 OC CC CF
7
LB1 LB2 LB3 LB4 LB5 LB6 LB7 LB8
8
RB1 RB2 RB3 RB4 RB5 RB6 RB7 RB8
9
SV1 SV2 SV3 SV4 SV5 SV6 SV7 SV8
10
SV9 SV10 SV11 SV12 SV13 SV14 * *
11
TRIP1 TRIP2 TRIP3 CLOSE * PDEM GDEM QDEM
12
SV5T SV6T SV7T SV8T SV9T SV10T SV11T SV12T
13
SV13T SV14T * ALARM OUT1 OUT2 OUT3 OUT4
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