Seg WIC1-W3 - Special Features for Earth Current Tests; Switching Points for the Earth Current Step

Technical Manual WIC1 SEG Electronics GmbH
DOK-TD-WIC1E, Rev. M 49
6.8 Special features for earth current tests
Functional description:
In the WIC1 the earth current is calculated and cannot be measured. It is established from the geometrical amount
of the three phase current values, more or less a numerical Holmgreen. If, for instant, a single-phase test current is
impressed, the measuring value (tripping value) in the earth current path equals the current in the tested phase. If,
with a phase shift of 120° a three-phase test current is impressed, the measuring value in the earth current path
equals zero.
Requirement on the test system:
The WIC1 is powered by the instrument transformer. In order to guarantee reliable tripping a minimal current of
0.9 x lowest nominal CT current (0.9 x lowest I> setting) has to flow in one of the phases. If the setting of the earth
current IE> is lower than the smallest possible switching point for the phase current, then the switching point for
earth current tripping can only be tested by a three-phase power source. In case the set switching point for earth
current is higher than the smallest possible switching point for overcurrent tripping (Is x I>, then the test can be per-
formed with a single-phase power source.
6.8.1 Switching points for the earth current step
DIP 1-1
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
DIP 1-2
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
DIP 1-3
OFF
OFF
OFF
OFF
ON
ON
ON
ON
OFF
OFF
OFF
OFF
ON
ON
ON
ON
DIP 1-4
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
ON
ON
ON
ON
ON
ON
ON
ON
HEX switch
IE>
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
Setting IE>
0.2**
0.3**
0.4**
0.5**
0.6**
0.7**
0.8**
0.9
1
1.2
1.4
1.6
1.8
2.0
2.5
EXIT
Is = Hex „0“
0,064
0,096
0,128
0,160
0,192
0,224
0,256
0,288
0,320
0,384
0,448
0,512
0,576
0,640
0,800
-
Is = Hex „1“
0,072
0,108
0,144
0,180
0,216
0,252
0,288
0,324
0,360
0,432
0,504
0,576
0,648
0,720
0,900
-
Is = Hex „2“
0,080
0,120
0,160
0,200
0,240
0,280
0,320
0,360
0,400
0,480
0,560
0,640
0,720
0,800
1,000
-
Is = Hex „3“
0,088
0,132
0,176
0,220
0,264
0,308
0,352
0,396
0,440
0,528
0,616
0,704
0,792
0,880
1,100
-
Is = Hex „4“
0,096
0,144
0,192
0,240
0,288
0,336
0,384
0,432
0,480
0,576
0,672
0,768
0,864
0,960
1,200
-
Is = Hex „5“
0,104
0,156
0,208
0,260
0,312
0,364
0,416
0,468
0,520
0,624
0,728
0,832
0,936
1,040
1,300
-
Is = Hex „6“
0,112
0,168
0,224
0,280
0,336
0,392
0,448
0,504
0,560
0,672
0,784
0,896
1,008
1,120
1,400
-
Is = Hex „7“
0,120
0,180
0,240
0,300
0,360
0,420
0,480
0,540
0,600
0,720
0,840
0,960
1,080
1,200
1,500
-
Is = Hex „8“
0,128
0,192
0,256
0,320
0,384
0,448
0,512
0,576
0,640
0,768
0,896
1,024
1,152
1,280
1,600
-
Is = Hex „9“
0,136
0,204
0,272
0,340
0,408
0,476
0,544
0,612
0,680
0,816
0,952
1,088
1,224
1,360
1,700
-
Is = Hex „A“
0,144
0,216
0,288
0,360
0,432
0,504
0,576
0,648
0,720
0,864
1,008
1,152
1,296
1,440
1,800
-
Is = Hex „B“
0,160
0,240
0,320
0,400
0,480
0,560
0,640
0,720
0,800
0,960
1,120
1,280
1,440
1,600
2,000
-
Is = Hex „C“
0,176
0,264
0,352
0,440
0,528
0,616
0,704
0,792
0,880
1,056
1,232
1,408
1,584
1,760
2,200
-
Is = Hex „D“
0,192
0,288
0,384
0,480
0,576
0,672
0,768
0,864
0,960
1,152
1,344
1,536
1,728
1,920
2,400
-
Is = Hex „E“
0,208
0,312
0,416
0,520
0,624
0,728
0,832
0,936
1,040
1,248
1,456
1,664
1,872
2,080
2,600
-
Is = Hex „F“
0,224
0,336
0,448
0,560
0,672
0,784
0,896
1,008
1,120
1,344
1,568
1,792
2,016
2,240
2,800
-
Table 6.5: Test current via the CD winding with the IE> step and the different Is setting values
** When the earth current setting is <0.9 x Is a three-phase test system has to be used for correct testing. With a
single-phase test the trip is only triggered from 0.9 x Is on.