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GE P50 Agile P253 User Manual

GE P50 Agile P253
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P50 Agile P253
8 Monitoring & Control
P253/EN M/C
8-15
Breaker opening time is displayed on the LCD display under MEASUREMENTS menu.
The CB Open Supervision logic is explained in following diagram:
Figure 6: CB open supervision logic
2.9.2 CB Open Operation Alarm
Every circuit breaker operation results in some degree of wear for its components. Therefore routine
maintenance, such as oiling of mechanisms, may be based on the number of operations. Suitable
setting of the maintenance threshold will allow an alarm to be raised, indicating when preventative
maintenance is due.
Some circuit breakers, such as oil circuit breakers (OCBs) can only perform a certain number of fault
interruptions before requiring maintenance attention. This is because each fault interruption causes
carbonising of the oil, degrading its dielectric properties. The maintenance alarm threshold (setting
CB Open operations) may be set to indicate the requirement for oil dielectric testing or for more
comprehensive maintenance.
The relay records statistics for each circuit breaker trip operation. The relay monitors the number of
circuit breaker operation by maintaining two types of counter. (1) Breaker Trip counter is based on the
number of trips issued by the relay. (2) Breaker Operation counter, which is the count of total breaker
operations, is based on the status change of CB auxiliary contact wired to one of the relay opto inputs.
The relay compares the Breaker Operation Counter (BOC) with CB Open Operations (CB Open
Oper) setting and generates a CB Open Operation alarm. Therefore, when the counter exceeds the
set value it shows that the preventative maintenance is due. The alarm message is displayed on the
LCD display and the START LED starts blinking. The associated event is stored in Event Record.
2.10 CB Control
There are several types of circuit breaker;
CBs with no auxiliary contacts
CBs with 52A contacts (where the auxiliary contact follows the state of the CB)
CBs with 52B contacts (where the auxiliary contact is in the opposite state the state of the CB)
CBs with both 52A and 52B contacts
Circuit Breaker control is only possible if the circuit breaker in question provides auxiliary contacts.
For local control the CB control by cell should be set accordingly.
The length of the trip and close control pulses can be set via the Open Pulse Time and Close Pulse
Time settings respectively. These should be set long enough to ensure the breaker has completed its
open or close cycle before the pulse has elapsed.
If an attempt to close the breaker is being made, and a protection trip signal is generated, the
protection trip command overrides the close command.
If the CB fails to respond to the control command (indicated by no change in the state of CB Status
inputs) an Open Fail alarm or Close Fail alarm is generated after the relevant trip or close pulses
have expired. These alarms can be viewed on the LCD display, remotely, or can be assigned to output
contacts.

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GE P50 Agile P253 Specifications

General IconGeneral
BrandGE
ModelP50 Agile P253
CategoryRelays
LanguageEnglish

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