sepam 20 user manual - Schneider Electric
sepam 20 user manual - Schneider Electric
sepam 20 user manual - Schneider Electric
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Protection functions Breaker failure<br />
ANSI code 50BF<br />
PCRED301005EN - 06/<strong>20</strong>08<br />
DE80108<br />
Setting example<br />
The example below shows how to determine the time delay setting for the breaker<br />
failure function:<br />
Overcurrent protection setting: T = inst.<br />
Circuit breaker operating time: 60 ms<br />
Auxiliary relay operating time to open the upstream circuit breaker(s): 10 ms<br />
The time delay for the breaker failure function is the sum of the following times:<br />
Rise time for the Sepam O1 output relay = 10 ms<br />
Circuit breaker opening time = 60 ms<br />
Overshoot time for the breaker failure function = 30 ms<br />
To avoid nuisance tripping by the upstream breakers, select a margin of<br />
approximately <strong>20</strong> ms.<br />
This gives a time delay of T = 1<strong>20</strong> ms.<br />
Characteristics<br />
30<br />
overshoot time<br />
Is set point<br />
Setting 0.2 In to 2 In<br />
Accuracy (1) ±5%<br />
Resolution 0.1 A<br />
Drop-out/pick-up ratio (87.5 ±10)%<br />
Time delay T<br />
Setting 0.05 to 300 s<br />
Accuracy (1) ±2%, or 0 ms to +15 ms<br />
Resolution 10 ms or 1 digit<br />
Characteristic times<br />
Overshoot time < 30 ms<br />
Taking into account of the circuit breaker position<br />
Setting With/without<br />
Choice of protection functions that activate the 50BF protection in the absence of circuit<br />
breaker control<br />
50/51-1A, 50/51-1B, 50/51-2A, 50/51-2B, 50N/51N-1A, 50N/51N-1B, 50N/51N-2A<br />
50N/51N-2B, 46<br />
(1) Under reference conditions (IEC 60255-6)<br />
30<br />
3/25<br />
3
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