Arcteq AQ-S215, Instruction Manual

Page: 247 / 289

When the trip relay is controlled and the circuit breaker is opening, the digital input is shorted by the
trip contact as long as the breaker opens. Normally, this takes about 100 ms if the relay is non-latched.
A one second activation delay should, therefore, be added to the digital input. An activation delay that
is slightly longer than the circuit breaker's operations time should be enough. When circuit breaker
failure protection (CBFP) is used, adding its operation time to the digital input activation time is useful.
The whole digital input activation time is, therefore, t
DI
= t
CB
+ t
IEDrelease
+ t
CBFP
.
The image below presents the necessary settings when using a digital input for trip circuit supervision.
The input's polarity must be NC (normally closed) and a one second delay is needed to avoid nuisance
alarm while the circuit breaker is controlled open.
Figure. 7.4 - 148. Settings for a digital input used for trip circuit supervision.
Non-latched outputs are seen as hollow circles in the output matrix, whereas latched contacts are
painted. See the image below of an output matrix where a non-latched trip contact is used to open the
circuit breaker.
Figure. 7.4 - 149. Non-latched trip contact.
When the auto-reclosing function is used in feeder applications, the trip output contacts must be non-
latched. Trip circuit supervision is generally easier and more reliable to build with non-latched outputs.
The open coil remains energized only as long as the circuit breaker is opened and the IED output
releases. This takes approximately 100 ms depending on the size and type of the breaker. When the
breaker opens, the auxiliary contacts open the inductive circuit; however, the trip contact does
not open at the same time. The IED's output relay contact opens in under 50 ms or after a set release
delay that takes place after the breaker is opened. This means that the open coil is energized for a
while after the breaker has already opened. The coil could even be energized a moment longer if the
circuit breaker failure protection has to be used and the incomer performs the trip.
A AQ Q-S215 -S215
Instruction manual
Version: 2.04
246