Protection Engineering Basics and Schemes Protection Engineering | Page 71

We used Resistor in trip supervision circuit relay to
prevent it from mal operation, due to this if there is any
fault in lamp it is not count as circuit fault.
2.4.2 H5 Circuit Scheme:
H4 scheme is ok, but we include breaker and Relay in H5
protection
scheme, so we
need to put check
not only on
protection relay
but also circuit breakers. We keep one extra resistor-
break contact circuit across auxiliary make switch 52a of
breaker.
Operation: Both circuits check the healthiness of
Protection
circuit and
circuit breaker
circuit
respectively.
Both circuits hold minimum amount of current from
Protection scheme circuit during normal condition.
pg. 71