Ashida ADR233B - CB Open Supervision (W1;W2) and CB Open Operation Alarm (W1;W2)

ADR233B
Doc ID : ADR233B/IM/01
Ref ID : ADR233B/IM/PS
Rev No. : 05
Page No. : 123 of 479
4.4.3 CB Open Supervision (W1/W2) and CB Open Operation Alarm (W1/W2)
Periodic maintenance of circuit breakers is necessary to ensure that the trip circuit and
mechanism operates correctly and also that the breaking capability has not been compromised
due to previous fault interruptions. Generally, such maintenance is based on a fixed time
interval. These methods of monitoring circuit breaker condition give a rough guide only and can
lead to excessive maintenance. The relays record various statistics related to each circuit
breaker trip operation, allowing a more accurate assessment of the circuit breaker condition to
be determined. For each circuit breaker trip operation the relay records statistics as shown in
the following
Record in
Measurement
Description
W1-BOT Winding1 “Breaker Opening Time” This is a circuit breaker opening
time in ms.
W1-BOC Winding 1“Breaker Opening Counter” This is counter indicating
numbers of CB operation.
W2-BOT Winding2 “Breaker Opening Time” This is a circuit breaker opening
time in ms.
W2-BOC Winding2“Breaker Opening Counter” This is counter indicating
numbers of CB operation.
TC “Trip Counter” This counter indicate numbers of protection trip.
The above counters in the CB condition monitoring function may be reset to zero, after
maintenance, inspection and overhaul.
4.4.3.1 CB Open Supervision (W1/W2):
Slow CB operation is also indicative of the need for mechanism maintenance. Therefore, an
alarm is provided and is settable in the range of 50ms to 1s. This time is set in relation to the
specified breaking time of the circuit breaker.
The diagram indicate operation CB open supervision logic
The relay starts internal timer as soon as any protection function is operated, and monitor CB
operation through W1CB (52B) / W2CB (52B) contact assign to any of binary input through
AProLogic.
If breaker opening time is more than set “CB Open Time” then relay generates CB Open
Supervision ALARM. An Alarm message is displayed on LCD display and the start LED is start
blinking & event is stored in Event Record. (Note that this time also include contact operating
time of relay and time between CB main contact and auxiliary contact if any).