Testing Of The Overcurrent Measuring Transformers; Testing Of The Overcurrent Stages - ABB REJ 525 Operator's Manual

1MRS 752137-MUM
5.3.1.
5.3.2.
Combined Overcurrent and Earth-Fault Relay
Operator's Manual
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When the test circuit has been completed and the switchgroups have been set, the
auxiliary voltage may be connected to the relay. The operation of the test circuit can
be verified using a multimeter.

Testing of the overcurrent measuring transformers

Test each used current transformer input separately. Apply a pure sinusoidal voltage
to the relay and compare the current value indicated on the display of the relay with
that shown by the ammeter. The measurements can be made at the rated current of
the relay, for instance. Note that the relay shows the measured current as a multiple
of the rated current, I , of the energizing input used.
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Testing of the overcurrent stages

The test is carried out as a single-phase test.
Before the test is started:
• Record the currently used SGR settings for later restoring.
∆I
• Check that stage is inhibited.
• Set the relay switchgroups as follows:
Table 5.3.2-1 Switchgroup settings
Setting SGR
I> to SO1 SGR1=4
t> to PO1 SGR2=1
I>> to SO2 SGR3=8
t>> to PO2 SGR4=2
∆I>
SGR9=0
t∆> SGR10=0
The setting values can be those currently in use.
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REJ 525
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