scheider electric MiCOM P746 - Circuit Breaker Fail and Undercurrent Fonction; Supervision

Settings P746/EN ST/G31
MiCOM P746 (ST) 4-
13
ST
1.2.6 Circuit Breaker Fail and undercurrent fonction
This function consists of two-stage circuit breaker fail functions that can be initiated by:
• Internal protection element initiation.
• External protection element initiation.
For current-based protection, the reset condition is based on undercurrent operation to
determine that the CB has opened. For the non-current based protection, the reset criteria
may be selected by means of a setting for determining a CB Failure condition.
It is common practice to use low set undercurrent elements in protection relays to indicate
that circuit breaker poles have interrupted the fault or load current, as required.
Setting Range
Menu Text Default Setting
Min. Max.
Step Size
CB FAIL & I<
BREAKER FAIL
CBF Control by I< and 52a 52a / I< / I< and 52a
Setting which determines the elements that will reset the circuit breaker fail time protection
function.
Both means that 52a and current criteria have to indicate open to reset the CB fail.
I< Current Set 5.000 % 5.000 % 400.0 % 1.000 %
If “CBF Control by” “I<” or “I> and 52a”: setting that determines the circuit breaker fail timer
reset current for overcurrent based protection circuit breaker fail initiation
CB Fail 1 Timer 50.00 ms 0.000 s 10.00 s 10.00 ms
Setting for the circuit breaker fail timer stage 1 for which the initiating condition must be
valid.
CB Fail 2 Timer 200.0 ms 40.00 ms 10.00 s 10.00 ms
Setting to enable or disable the second stage of the circuit breaker function.
CB Fail 3 Timer 50.00 ms 0.000 s 10.00 s 10.00 ms
Setting to enable or disable the third stage of the circuit breaker function.
CB Fail 4 Timer 200.0 ms 40.00 ms 10.00 s 10.00 ms
Setting to enable or disable the fourth stage of the circuit breaker function.
I> Status Disabled Disabled / Enabled
To enable (activate) or disable (turn off) the overcurrent check
I> Current Set 120.0 % 5.000 % 400.0 % 1.000 %
If “I> Status” is enabled, pick-up setting for overcurrent element
1.2.7 Supervision
Setting Range
Menu Text Default Setting
Min. Max.
Step Size
SUPERVISION
VT SUPERVISION
VTS Status Blocking Blocking / indication
Sets Voltage Transformer Supervision (VTS) operation.
The relay respond as follows, on operation of any VTS element: VTS set to provide alarm
indication only or blocking of voltage dependent protection elements.