Connect The Test Circuit - GE P741 Technical Manual

Commissioning
MiCOM P741, P742, P743
Fail & I<] are all set to "Disabled". Make a note of which elements need to be re-enabled
after testing.
6.3.1.1

Connect the test circuit

The following tests require an injection test set, able to feed the relays with one or two
currents variable in phase and magnitude.
If only one current is available:
As shown in Figure 7, this method will be used for a distributed solution when only one
peripheral unit is available.
P741
FO
Central
Unit
FIGURE 7: CONNECTION FOR BIAS CHARACTERISTIC TESTING
An increasing current I
differential and bias current.
I = I = I
diff bias 2
K2 : Zone percentage bias, Characteristic limit: I
KCZ : Check Zone percentage bias, Characteristic limit: I
In this case, we increase I
KCZ : Check Zone percentage bias, Characteristic limit: I
K2 : Zone percentage bias, Characteristic limit: I
I 2
P742/3
Peripheral
Unit 1
is injected into a phase (and neutral) of the PU1 which is used as
2
from 0 to A then B point until the differential element operates:
2
P74x/EN CM/Na7
A
= ID>2
diff
= IDCZ>2
diff
= IDCZ>2, point A
diff
= ID>2, point B
diff
(CM) 10-27
Test
Box
P3749ENa
CM