ABB
11
Motor Protection
REM615 ANSI
Product Version 2.0
1MAC251744 -PG Rev. A
Issued: 03.01.2010
11. Circuit-breaker
condition monitoring
For continuous knowledge of the operational
availability of the REM615 features, a comprehensive
set of monitoring functions to supervise the relay
health, the trip circuit and the circuit breaker health
is included. Th
e breaker monitoring can include
checking the wear and tear of the circuit breaker,
the spring charging time of the breaker operating
mechanism and the gas pressure of the breaker
chambers. Th
e relay also monitors the breaker
travel time and the number of circuit breaker (CB)
operations to provide basic information for scheduling
CB maintenance.
12. Trip-circuit
monitoring
Th
e trip-circuit monitoring continuously supervises
the availability and operability of the trip circuit.
It provides open-circuit monitoring both when the
circuit breaker is in its closed and in its open position.
It also detects loss of circuit-breaker control voltage.
Local and remote indication are programmable to
ensure immediate notifi cation so the necessary steps
can be established to correct before the next fault
event occurs.
13. Self-diagnostics
Th
e relay’s built-in self-diagnostics system
continuously monitors the state of the relay hardware
and the operation of the relay soft ware. Any fault
or malfunction detected will be used for alerting
the operator. A permanent relay fault will block the
protection functions of the relay to prevent incorrect
relay operation.
14. Fuse failure
protection
Depending on the chosen standard confi guration, the
IED includes fuse failure supervision functionality.
Th
e fuse failure supervision detects failures between
the voltage measurement circuit and the IED. Th
e
failures are detected by the negative sequence based
algorithm or by the delta voltage and delta current
algorithm. Upon the detection of a failure the fuse
failure supervision function activates an alarm and
blocks voltage-dependent protection functions from
unintended operation.
15. Current circuit
supervision
Depending on the chosen standard confi guration,
the IED includes current circuit supervision. Current
circuit supervision is used for detecting an open in the
current transformer secondary circuits. On detecting
an opening circuit, the current circuit supervision
function activates an alarm LED and blocks certain
protection functions to avoid unintended operation.
Th
e current circuit supervision function calculates
the sum of the phase currents from the protection
cores and compares the sum with the measured
single reference current from a core balance current
transformer or from separate cores in the phase current
transformers.