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.
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]
1.15
1.2
1.3
1.4
1.7
2.0
2.2
Time [s]
1800
300
60
15
1
0.3
0.12
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.
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).
6.
Check that service value for voltage across SCB in phase L1, on the local HMI
under
Main menu/Test
is approximately 140%.
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.
10. Repeat above steps 1 - 8 to test different points from the above table.
Operation of this feature is based on internally calculated peak RMS voltage value.
That means that this feature is also able to operate for current signals with varying
frequency. Note that for the fundamental frequency injection, internally calculated
voltage in percent corresponds directly to the injected current value given in percent.
However if it is required to test IDMT characteristic with a varying frequency, the
1MRK 511 360-UEN A
Section 10
Testing functionality by secondary injection
Bay control REC670 2.1 IEC
113
Commissioning manual