Figure. 7.3. - 171. IED trip contact used to open the circuit breaker has to be non-latched.
Non-latched trip output contact is a mandatory to have if Autorecloser is used in feeder applications.
TCS is generally easier and more reliable to build with non-latched output.
The open coil is energized only as long as the circuit breaker is opened and IED output releases. This
takes approximately 100ms depending of the size and type of the breaker. When the breaker opens the
auxiliary contacts will open the inductive circuit but the IED trip contact won’t open at the same time.
IEDs output relay contact will open in <50ms or after con gured release delay due the breaker is open.
This means that the open coil is energized for a short moment even the breaker is already open. Coil
could be energized even moment longer if circuit breaker failure protection has to be used and incomer
is performing the tripping.
Trip circuit open coil supervision with one digital input and connected and latched trip
output
The main difference between non-lathed and latched control in trip circuit supervision is that when
latched control is used it is not possible to monitor the trip circuit in open state due the digital input is
shorted by the trip output of the IED.
Figure. 7.3. - 172. Trip circuit supervision by using one DI and latched output contact.
AQ-T257
Instruction manual
Version: 2.00
© Arcteq Relays Ltd
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