Schweitzer Engineering Laboratories SEL-311C - Figure 6.4 SEL-311 C Relays Installed at both Ends of a Transmission Line in a High-Speed Reclose Scheme

6.9
Date Code 20060320 Instruction Manual SEL-311C Relay
Close and Reclose Logic
Reclose Supervision Logic
Figure 6.4 SEL-311C Relays Installed at Both Ends of
a Transmission Line in a High-Speed Reclose Scheme
SEL-311C(1) Relay
Before allowing circuit breaker 52/1 to be reclosed after an open interval time-
out, the SEL-311C(1) Relay verifies that Bus 1 voltage is hot and the
transmission line voltage is dead. This requires reclose supervision settings:
79CLSD = 0.00 cycles (only one check)
79CLS = 3P59 * 27S
SEL-311C(2) Relay
The SEL-311C(2) Relay verifies that Bus 2 voltage is hot, the transmission
line voltage is hot, and in synchronism after the reclosing relay open interval
times out, before allowing circuit breaker 52/2 to be reclosed. This requires
reclose supervision settings:
79CLSD = 0.00 cycles (only one check)
79CLS = 25A1
Other Setting Considerations for SEL-311C(1) and SEL-311C(2) Relays
Refer to Skip Shot and Stall Open Interval Timing Settings (79SKP and
79STL, Respectively) on page 6.21.
SEL
OGIC control equation setting 79STL stalls open interval timing if it
asserts to logical 1. If setting 79STL is deasserted to logical 0, open interval
timing can continue.
The SEL-311C(1) Relay has no intentional open interval timing stall
condition (circuit breaker 52/1 closes first after a transmission line fault):
79STL = 0 (numeral 0)
The SEL-311C(2) starts open interval timing after circuit breaker 52/1 at the
remote end has reenergized the line. The SEL-311C(2) has to see Bus 2 hot,
transmission line hot, and in synchronism across open circuit breaker 52/2 for
SEL-311C (1)
Bus 1 Bus 2
52
1
52
2
IA, IB, IC
VA, VB, VC
VS
SEL-311C (2)
IA, IB, IC
VA, VB, VC
VS
3-Phase 3-Phase
1-Phase
where:
3P59 = all three Bus 1 phase voltages (VA, VB, and VC) are hot
27S = monitored single-phase transmission line voltage (channel VS)
is dead
where:
25A1 = selected Bus 2 phase voltage (VA, VB, VC, VAB, VBC, or
VCA) is in synchronism with monitored single-phase
transmission line voltage (channel VS) and both are hot