ABB RET670 Commissioning Manual page 167

1MRK 504 154-UUS B
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
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
Aonly.
2. Check that function binary output signals PU_HOL_IDMT_A and PU_HOL 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 A, on the local HMI under Main menu/Test is
approximately
6. Check that service value for voltage across SCB in phase A, 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 B and phase C.
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 trip 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 magnitude of the injected current must be adjusted accordingly. The
following formula can be used to calculate required current RMS value in percent at the desired
injection frequency in order to archive voltage percentage value given in the above table:
[ ]
=×
I %
inj
EQUATION2274-ANSI V1 EN-US
Commissioning manual
Note that during testing the harmonic voltage overload feature the reactive power
overload feature or overcurrent feature may also give pickup and trip signals
depending on their actual settings. Therefore it is recommended to switch them
off during this test.
k_HOL_IDMT =1.0
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 trip for current signals with
varying frequency.
411A (that is, 0.822A · (500/1) = 411A).
f
[ ]
%
injected
.V
f
rated
1.2 1.3 1.4
300 60 15
Testing functionality by secondary injection
1.7 2.0 2.2
1 0.3 0.12
GUID-FECBCAD4-16CE-4EFC-9869-9F6D98E2F721 v2
(Equation 90)
Section 10
161