VAMP Ltd
Generator protection relay
Technical description
VAMP 210
VM210.EN004
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41
3.4.
Trip circuit supervision
Trip circuit supervision is used to ensure that the wiring from
the protective relay to the circuit breaker is in order. This
circuit is most of the time unused, but when the protection
relay detects a fault in the network it is too late to notice that
the circuit breaker cannot be tripped because of a broken trip
circuitry.
A digital input of the relay can be used for trip circuit
monitoring.
•
The digital input is connected to an auxiliary
miniature relay, which is connected parallel with the
trip contacts (Figure 3.4-1).
•
A resistor module VR11CB enables supervision also
when the circuit breaker is open. The module consists
of a resistor for 110 Vdc and is connected according the
auxiliary voltage.
•
The digital input is configured as Normal Closed (NC).
•
The digital input delay is configured longer than
maximum fault time to inhibit any superfluous trip
circuit fault alarm when the trip contact is closed.
•
The trip relay should be configured as non-latched.
Otherwise a superfluous trip circuit fault alarm will
follow after the trip contact operates and remains
closed because of latching.