GE Industrial Solutions Entellisys 5.0 User Manual - Manual (Page 103)

Advanced Protection Relays 103
5
5.3.5 Redundant Trip Coil
Each electrically operated EntelliGuard circuit breaker has two means to actuate the breaker:
the Trip and the Open coil. Manually operated breakers only have a Trip coil.
Normally, in an overcurrent condition, the Trip coil will open the breaker, whereas the Open and
Close coils are used to electrically actuate the breaker without engaging the network interlock
or bell alarm (if equipped).
The Redundant Trip Coil feature will utilize the Open coil as a redundant trip mechanism to open
an electrically operated breaker in the event of a trip signal. When a trip event occurs, the CPU
will send a command to both the Trip and Open coils simultaneously.
5.3.5.1 Operation
To maintain UPS control power stability, the Open coil command will only be issued to three
breakers at any instance in time. In an event which involves more than 3 breakers
simultaneously, the CPU will issue trip commands to all relevant breakers and will que Open coil
commands as necessary in order of breaker number. Lower breaker numbers have first priority
since, in Entellisys, Main and Tie breakers are always numbered starting with 1.
In the event of a high IOC fault condition, the Messenger will actuate the Trip coil first. The Trip
and Open commands from the CPU will occur shortly after.
5.3.5.2 Event Logging
There are no events which are specifically related to the Redundant Trip Coil, however, operation
of the Redundant Trip Coil can be validated in the event log. In the event of a Trip signal from
either a protection relay or a manual HMI trip command, both Open and Trip command events
will be seen in the event log as shown in figure 5-19.
Figure 5-19 Redundant Trip Coil events
NOTE: Electric operated breakers are required as the open coil is actuated in unison with the
Trip coil.