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6.5.1.1
Overcurrent and undercurrent element OC1 to OC4, UC1, UC2 and CBF and Earth fault
element EF1 to EF4 and SEF1 to SEF4
The overcurrent element is checked on the operating current value and operating time for IDMT
curve.
Operating current check
Figure 6.5.1 shows a testing circuit. The operating current value is checked by increasing or
decreasing the magnitude of the current applied.
+
Single-phase
current
source
−
+
DC
power
−
supply
+
DC
voltmeter
0V
The output signal of testing element is assigned to the monitoring jack A.
The output signal numbers of the elements are as follows:
Element
OC1D-A
OC2D-A
OC3D-A
OC4D-A
• Enter the signal number to observe the operation at the monitoring jack A as shown in
Section 6.5.1.
• Apply a test current and change the magnitude of the current applied and measure the value
at which the element operates.
Check that the measured value is within 5% of the setting value.
A
Figure 6.5.1 Operating Current Value Test
Signal No.
Element
4
UC1-A
8
UC2-A
12
CBF-A
16
⎯
⎯
254
6 F 2 S 0 8 4 2
GRD150
TB1
-1
-2
Monitoring
jack
TB4
-18
-19
-20
(E)
Signal No.
164
168
112
A
0V
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