ABB RET670 Commissioning Manual page 203

1MRK 504 165-UEN A
Transformer protection RET670 2.2 IEC
Commissioning manual
Testing functionality by secondary injection
Reactive power overload feature
Note that during testing the reactive power overload feature the
harmonic voltage 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. Inject current equal to the set reactive power overload pickup level under
setting parameter QOL> (that is, 1.3 · 0.587A = 0.763A at 50Hz for this
SCB) in phase L1 only.
2. Check that function binary output signals STQOLL1 and STQOL are set to
one.
3. Check that function binary output signals TRQOL and TRIP are set to one
after the set time under parameter tQOL (for example, 60s 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 382A (that is, 0.763A ·
(500/1) = 382A).
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.
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.
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.
f
[ ] [ ]
= ×
2
Q pu rated I pu
f
injected
EQUATION2273 V1 EN-US
Section 11
GUID-6DA88E90-366A-494F-B3A4-F8B5A3FD6396 v3
(Equation 89)
197