Schweitzer Engineering Laboratories SEL-352-1, Instruction Manual

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4-12 Close Logic Date Code 20010731
SEL-352-1, -2 Instruction Manual
Synchronism Timer Dropout (SYNCdo)–Scheme 2
Range: 0–99999 cycles in 1/4-cycle steps
The SEL-352 Relay looks for synchronous conditions for a certain time after the CLOSE input is
received. Set SYNCdo to the time desired.
When determining the setting, consider the allowable slip and method of indicating a closed
breaker. The SYNCdo time needs to be long enough to allow the systems to slip past each other
one complete revolution. If the breaker does not close, the relay can generate a second close
pulse if the SYNCdo time has not expired.
Scheme 2 logic disables the synchronizing element once the breaker closes based on the
auxiliary inputs. Refer to the synchronism check logic diagram in
Section 5: Control Logic . If
auxiliary inputs are not available or are not reliable, you must consider another method for
disabling the synchronism check element to avoid getting two close pulses.
For systems expecting zero slip, set SYNCdo = 2 cycles.
Point-On-Wave Timer Pickup (PCApu, PCBpu, PCCpu)–Scheme 2
Range: 0.00–40.00 ms in 0.01-ms steps
Set these pickup timers based on the delay you want to accommodate breaker closing time in the
point-on-wave closing. The SEL-352 Relay output contact closes within 200
m
s if one of the fast
outputs is used. The contact closes at the point on the wave that the logic designates. Positive
and negative peak closing logic uses these timers.
The logic closes the output contact at a positive peak for logic detection of a positive trapped
charge, and it closes the output contact at a negative peak for a negative trapped charge. These
timers provide the delay for the breaker close time and any offset to move the closing point to
another point on the wave.
Zero-Crossing Timer Pickup (ZCApu, ZCBpu, ZCCpu)–Scheme 2
Range: 0.00–40.00 ms in 0.01-ms steps
Set these pickup timers based on the delay you want to accommodate breaker closing time in the
point-on-wave closing. The SEL-352 Relay output contact closes within 200
m
s if one of the fast
outputs is used. The contact closes at the point on the wave that the logic designates. The
positive and negative going zero-crossing closing logic uses these timers.
The default logic closes the output contact at a negative going zero crossing for failure of the
logic to detect any trapped charge. The positive going zero-crossing element is not used. These
timers provide the delay for the breaker close time and any offset to move the closing point to
another point on the wave.
Controlled Close Output Timers (CLSA, CLSB, and CLSC)–Scheme 2
Set CLSA, B, and C to the output contact that will provide the point-on-wave closing. It is
recommended that three of the fast, high current interrupting output contacts be used for point-