Hitachi Relion 670 Series Applications Manual page 328

Section 15
Monitoring
15.4 Breaker monitoring SSCBR
15.4.1 Identification
Function description
Breaker monitoring
15.4.2 Application
The circuit breaker maintenance is usually based on regular time intervals or the number of
operations performed. This has some disadvantages because there could be a number of abnormal
operations or few operations with high-level currents within the predetermined maintenance interval.
Hence, condition-based maintenance scheduling is an optimum solution in assessing the condition of
circuit breakers.
Circuit breaker contact operation time
Auxiliary contacts provide information about the mechanical operation, opening time and closing time
of a breaker. Detecting an excessive operation time is essential to indicate the need for maintenance
of the circuit breaker mechanism. The excessive operation time can be due to problems in the driving
mechanism or failures of the contacts.
Circuit breaker status
Monitoring the breaker status ensures proper functioning of the features within the protection relay
such as breaker control, breaker failure and autoreclosing. The breaker status is monitored using
breaker auxiliary contacts. The breaker status is indicated by the binary outputs. These signals
indicate whether the circuit breaker is in an open, closed or error state.
Remaining life of circuit breaker
Every time the breaker operates, the circuit breaker life reduces due to wear. The wear in a breaker
depends on the interrupted current. For breaker maintenance or replacement at the right time, the
remaining life of the breaker must be estimated. The remaining life of a breaker can be estimated
using the maintenance curve provided by the circuit breaker manufacturer.
Circuit breaker manufacturers provide the number of make-break operations possible at various
interrupted currents. An example is shown in figure 160.
322
IEC 61850
identification
SSCBR
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GUID-0FC081B2-0BC8-4EB8-9529-B941E51F18EE v7
IEC 60617 ANSI/IEEE C37.2
identification device number
- -
GUID-45572680-3A39-4B3C-8639-4E4C5A95AA26 v11
Railway application RER670
1MRK506375-UEN Rev. N
Application manual