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Section 10
Testing functionality by secondary injection
setting IBase for this function is set to 289A (that is, setting for the base current corresponds to the
rated current of the protected SCB). It will be also assumed that all other settings have values as
shown in the setting example in the application manual for this SCB.
Test equipment
Connect the secondary test set to the CT inputs on the IED dedicated for the SCB currents. Single-
or three-phase test equipment can be used but it may be required to have facility to vary the
frequency of the injected current signal(s).
10.4.11.1
Verifying the settings and operation of the function
Reconnection inhibit feature
1.
Inject SCB rated current (that is, 0.587A at 50Hz for this SCB) in at least one phase (preferably
perform this test with three phase injection).
2.
After couple of seconds stop injection of all currents (that is, set all currents back to 0A).
3.
Check that function binary output signal RECNINH is set to logical 1 and that only resets after
the set time under parameter tReconnInhibit (for example 300s for this SCB) has expired.
4.
If this binary signal is used to prevent CB closing make sure that it is properly connected/wired
into the CB closing circuit.
Overcurrent feature
1.
Inject current 20% bigger than the set overcurrent pickup level under setting parameter IOC>
(for example, 1.2 · 1.35 · 0.587A = 0951A at 50Hz for this SCB) in phase L1 only.
2.
Check that function binary output signals STOCL1 and STOC are set to one.
3.
Check that function binary output signals TROC and TRIP are set to one after the set time
under parameter tOC (that is, 30s for this SCB) has expired.
4.
If any of these signals are used for tripping, signaling and/or local/remote indication check that
all relevant contacts and LEDs have operated and that all relevant GOOSE messages have
been sent.
5.
Check that service value from the function for current in phase L1, on the local HMI under Main
menu /Test is approximately 476A (that is, 0.951A · (500/1) = 476A).
6.
Stop injection of all currents (that is, set all currents back to 0A).
7.
Check that all above mentioned function binary output signals now have logical value zero.
8.
Repeat above steps 1-7 for phase L2 and phase L3.
Undercurrent feature
96
Note that during testing the overcurrent feature the harmonic voltage overload
feature or reactive power overload feature may also give start and operate signals
depending on their actual settings. Therefore it is best to switch them off during this
test.
Note that the operation of this feature is based on current peak value. That means
that this overcurrent function is also able to operate for the same current magnitude
but for different injected frequencies. If required repeat this injection procedure for
example for the 3rd harmonic by just simply injecting 3 · 50 = 150Hz currents with
the same magnitude. Obtain results shall be the same.
© 2017 - 2022 Hitachi Energy. All rights reserved
1MRK 505 372-UEN Rev. K
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Busbar protection REB670
Commissioning manual
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