Toshiba GRL150-100 Series Instruction Manual page 134

6.5.1.1 Phase current differential element DIF
The phase current differential element is checked for the following items.
Operating current value
Percentage restraining characteristic
The top two items are tested locally or under an end-to-end setup of each terminal relay.
The last item is tested only under an end-to-end setup of each terminal relay.
Operating current value
Figure 6.5.1.1 shows the circuit to test the element locally.
Single-phase
current
source
+
DC
power
−
supply
DC
voltmeter
Figure 6.5.1.1 Testing Phase Current Differential Element
The output signal numbers of the DIF element are as follows.
• Set the [L.test] to "1" (= On) on the "Switch" screen of the "Test" sub-menu. See Section 4.2.7.
• Select the "Logic circuit" on the "Test" sub-menu screen to display the "Logic circuit" screen.
• Enter a signal number 48 for Term A line to observe the DIF-A operation at monitoring jack A
and press the ENTER key.
• 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 7% of the setting DIFI1.
A
Element Signal number
DIF-A 48
DIF-B 49
DIF-C 50
⎯ ⎯
133
GRL150
TB1 -1
TX
I a
RX
-2
Monitoring
jack
TB2 -A9
-B9
E
6 F 2 S 0 8 2 8
A
0V