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Busbar Tripping
For testing the distribution of the trip commands in the substation in the case of breaker failures it is important
to check that the trip commands to the adjacent circuit breakers are correct.
The adjacent circuit breakers are those of all feeders which must be tripped in order to ensure interruption of
the fault current should the local breaker fail. These are therefore the circuit breakers of all feeders which feed
the busbar or busbar section to which the feeder with the fault is connected.
A general detailed test guide cannot be specified because the layout of the adjacent circuit breakers largely
depends on the system topology.
In particular with multiple busbars, the trip distribution logic for the adjacent circuit breakers must be checked.
Here it should be checked for every busbar section that all circuit breakers which are connected to the same
busbar section as the feeder circuit breaker under observation are tripped, and no other breakers.
Termination
All temporary measures taken for testing must be undone, e.g. especially switching states, interrupted trip com-
mands, changes to setting values or individually switched off protection functions.
3.3.6
Testing User-Defined Functions
CFC Logic
The device has a vast capability for allowing functions to be defined by the user, especially with the CFC logic.
Any special function or logic added to the device must be checked.
Of course, general test procedures cannot be given. Configuration of these functions and the target conditions
must be actually known beforehand and tested. Possible interlocking conditions of switching devices (circuit
breakers, disconnectors, ground switch) are of particular importance. They must be observed and tested.
3.3.7
Current, Voltage, and Phase Rotation Testing
Preliminary Remark
Note
The voltage and phase rotation test is only relevant for devices with voltage transformers.
≥ 10 % of Load Current
The connections of the current and voltage transformers are tested using primary quantities. Secondary load
current of at least 10 % of the nominal current of the device is necessary. The line is energized and will remain
in this state during the measurements.
With proper connections of the measuring circuits, none of the measured-values supervision elements in the
device should pick up. If an element detects a problem, the causes which provoked it may be viewed in the
Event Log. If current or voltage summation errors occur, then check the matching factors.
Messages from the symmetry monitoring could occur because there actually are asymmetrical conditions in
the network. If these asymmetrical conditions are normal service conditions, the corresponding monitoring
functions should be made less sensitive.
SIPROTEC, 7SK80, Manual
E50417-G1140-C344-A5, Release date 11.2012
Mounting and Commissioning
3.3 Commissioning
337
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