Checking Through-Fault Stability With De-Energized Busbars - ABB RELION REB500 Commissioning Manual

1MRK 505 401-UEN B
I
II
Primary
injection
test set
IEC18000344 V1 EN-US
Figure 3:
The feeder currents and the differential current can be read using HMI500.
3.2.8.2

Checking through-fault stability with de-energized busbars

Where protection stability cannot be tested before the busbar is energized or in the case of an
extension to an existing system, it has to be tested using load current.
In order to carry out the test, all the amplitudes and directions of the primary currents must be
known. Perform one of the following:
• Short-circuit the CTs and isolate them from the protection.
• Use the test mode to simulate that all the isolators are open (this is the simpler method).
In the first case, connect the infeeds one by one, or in the second case, simulate the closure of
the isolators one by one. Whichever method is chosen, check that the differential current
increases as each infeed is connected (either HMI500 or the local HMI in the central unit).
Repeat this procedure with the loads and the differential current must reduce as each feeder is
connected.
Distributed busbar protection REB500
Commissioning manual
Reference feeder
Through-fault stability by primary injection (bus-tie breaker)
The comparison with the reference feeder has to be conducted for phase and
neutral currents for protection schemes that evaluate the neutral current.
For this test, either tripping by the protection has to be blocked or the tripping
circuits have to be interrupted before the currents are applied to the
protection.
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Short‐ circuit CTs
14000044-IEC18000344-1-en.vsd
Section 3
Commissioning
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