ABB RET670 Commissioning Manual page 216

Section 11
Testing functionality by secondary injection
210
Check of U1Low
Procedure
1. Connect voltages to the IED according to valid connection diagram and figure
48.
2. Apply voltage higher than the highest set value of UDTrip, U1Low and
U2Low to the U1 three-phase inputs and to one phase of the U2 inputs
according to figure 48.
The voltage differential START signal is set.
UL1
UL2
UL3
UN
IEC07000106 V2 EN-US
Figure 48: Connection of the test set to the IED for test of U1 block level
where:
1 is three-phase voltage group1 (U1)
2 is three-phase voltage group2 (U2)
3. Decrease slowly the voltage in phase UL1 of the test set until the START
signal resets.
4. Check U1 blocking level by comparing the voltage level at reset with the set
undervoltage blocking U1Low.
5. Repeat steps 2 to 4
The connections to U1 must be shifted to test another phase.
(UL1 to UL2, UL2 to UL3, UL3 to UL1)
to check U1Low for the other phases.
1MRK 504 165-UEN A
SEMOD175258-75 v3
UL1
UL2
1
UL3
UN
UL1
2
UL2
UL3
IEC07000106-1-en.vsd
Transformer protection RET670 2.2 IEC
Commissioning manual