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Section 11
Testing functionality by secondary injection
6.
Check that service value from the function for reactive power in phase L1, on the local HMI
under Main menu /Test is approximately 169% (that is, 1.3 · 1.3 = 1,69pu = 169%).
7.
Stop injection of all currents (that is, set all currents back to 0A).
8.
Check that all above mentioned function binary output signals now have logical value zero.
9.
Repeat above steps 1 - 8 for phase L2 and phase L3.
The following formula can be used to calculate SCB reactive power in per-unit system when current
with different frequency from the rated frequency is injected.
[ ]
Q pu
EQUATION2273 V1 EN-US
Harmonic voltage overload feature
Procedure to test inverse time delayed step:
The following points on the inverse curve are defined per relevant IEC/ANSI standards for time
multiplier value set to kHOLIDMT=1.0
UpeakRMS [pu]
Time [s]
Here will be shown how to test the fourth point from the above table. Other points can be tested in
the similar way:
1.
Inject 140% of the base current (that is, 1.4 · 0.587A = 0.822A at 50Hz for this SCB) in phase
L1only.
2.
Check that function binary output signals STHIDML1 and STHOL are set to one.
3.
Check that function binary output signals TRHOL and TRIP are set to one after the expected
time (for example, 15s for this voltage level in accordance with the above table) 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 for current in phase L1, on the local HMI under Main menu /Test is
approximately 411A (that is, 0.822A · (500/1) = 411A).
184
Note that operation of this feature is based on injected current and internally
calculated true RMS values. That means that this feature is also able to operate for
current signals with varying frequency. However due to relatively complex calculation
procedure it is recommended to do secondary tests only with fundamental frequency
current signals.
f
[ ]
=
×
2
rated
I
pu
f
injected
Note that during testing the harmonic voltage overload feature the reactive power
overload feature or overcurrent feature may also give start and operate signals
depending on their actual settings. Therefore it is recommended to switch them off
during this test.
1.15
1800
Note that operation of this feature is based on internally calculated voltage peak
RMS value. That means that this feature is also able to operate for current signals
with varying frequency.
© 2017 - 2022 Hitachi Energy. All rights reserved
1.2
1.3
1.4
300
60
15
1MRK 504 165-UEN Rev. K
(Equation 93)
GUID-3C6B2C73-026D-4173-BD4D-1E7E9ADAE160 v3
1.7
2.0
2.2
1
0.3
0.12
GUID-FECBCAD4-16CE-4EFC-9869-9F6D98E2F721 v2
Transformer protection RET670
Commissioning manual
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