Verifying The Single-Phase Pickup From Winding Two Side - Hitachi RET670 Commissioning Manual

Section 11
Testing functionality by secondary injection
3. Check that the trip and alarm contacts operate according to the configuration logic.
4. Decrease the current slowly from the operate value and note the reset value.
5. Switch off the currents and connect an external timer to measure the operate time of the
function. Set the current in all three phases to twice the above measured pickup value.
6. Switch on the currents and note the operate time of the PSTPDIF function.
7. Check that the trip information is stored in the IED internal Event List and Disturbance
Recorder.
8. Check that the trip information is properly indicated on the LHMI LEDs.
11.3.5.7

Verifying the single-phase pickup from winding two side

1. Connect the test set for three-phase currents injection to the current terminals of the IED, which
are connected to the CTs on the winding two side of the power transformer.
2. Increase the current magnitude in phase L1 only until the protection function operates and note
the operating current. The secondary current at the moment of pickup will be greater for a
certain factor from the measured three-phase pickup value depending on the set value for the
parameter ZSCurrSubtrW2 and the actual phase angle shift across the protected power
transformer for which the test is conducted, as explained below:
•
•
100
The pickup current is independent of the actual phase angle shift across the
protected PST.
When ZSCurrSubtrW2 = Off, this factor will have a value between 1.00 and 1.50
depending on the actual phase angle shift as shown in
IEC18000247 V1 EN-US
Figure 23: Single-phase pickup factor when ZSCurrSubtrW2 = Off
For phase angle shifts greater than ±60 degrees, actual operation will happen
in one of other two phases where current has not been injected.
When ZSCurrSubtrW2 = On, this factor will have a value between 1.50 and 1.732
depending on the actual phase angle shift as shown in
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1MRK 504 165-UEN Rev. K
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Figure 23:
Figure 24:
Transformer protection RET670
Commissioning manual