Areva MiCOM P441, Техническое руководство

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Application Notes P44x/EN AP/E33
MiCOM P441/P442 & P444 Page 59/220
2.12.1 Initiating TOR/SOTF Protection
SOTF/TOR Activated
2 signals are issued from the logic: TOR Enable - SOTF Enable (See DDB description in
appendix from that chapter). There is a difference between them due to the AR (internal or
external) which must be blocked in SOTF logic.
The detection of open pole is based on the activation of : Any Pole Dead (at least one pole
opened). It is a OR logic between the internal analog detection (level detectors) or the
external detection (given by CB status : 52A/52B, which is requested in case of VT Bus
side).
The Dead pole Level Detectors V< and I< per phase are settable as described belows:
−
V< is either a fixed threshold 20% Vn or equal to V Dead Line threshold of the check
synchro function if enabled, (default value for V< dead line = 20% V
N
)
−
I< is either a fixed threshold of 5% In or equal to the I< threshold of the Breaker
Failure protection (default value for I< CB fail = 5% I
N
).
TOR Enable logic is activated in 2 cases :
1. When internal AR is activated or when the reclaim signal from an external AR is
connected to a digital input (opto):
As soon as the reclaim time starts, the « TOR Enable » is activated . It will be reset at the
end of the internal or external reclaim time.
2. Without any reclaim time (internal AR disabled or external opto input Reclaim Time not
assigned in the PSL):
TOR Enable will be activated during a 200 ms time window, following the detection of pole
dead detection. The TOR logic will be reset (TOR Enable) ONLY 500 ms after the drop off of
any pole dead detection.
This behaviour has been designed to avoid any maloperation on a parallel line, in case of an
incorrect Any Pole Dead detection performed by the internal level detectors (Ex: Fault front
of Busbar on a parallel line and weak source on the other end of the line)
A delay of 200ms will allow the adjacent line to be tripped and the level detectors will then
reset the timer :
•
TOR protection logic is enabled any time that any circuit breaker pole has been open
longer than 200ms but not longer than 110s default value (ie. First shot autoreclosure
is in progress)- the timer is configurable from version A3.0 /allows variation of the
duration when dead pole is detected before the internal logic detects line dead and
activates the SOTF logic and also where the relay logic detects that further delayed
autoreclose shots are in progress.
Trip
Any Pole Dead
TOR Enable
200 ms
500 ms
P0532ENa
Reclosing
•
SOTF protection is enabled any time that the circuit breaker has been open 3 pole for
longer than 110s, that timer is configurable from version A3.0 /allows variation of the
duration when dead pole is detected before the internal logic detects line dead and
activates the SOTF logic and autoreclosure is not in progress. Thus, SOTF protection
is enabled for manual reclosures, not for autoreclosure.