Negative Sequence Overcurrent Element Nps1 And Nps2; Testing Nps Elements - Toshiba GRE110 Instruction Manual

The output signal numbers of the elements are as follows:
To test easily the thermal overload element, the scheme switch [THMRST] in the "Switch" screen
on the "Test" menu is used.
• Set the scheme switch [THMRST] to "ON".
• Enter the signal number to observe the operation at the LED as shown in Section 6.5.1 and
press the ENTER key.
• Apply a test current and measure the operating time. The magnitude of the test current
should be between 1.2 × I s to 10 × I s , where I s is the current setting.
CAUTION
After the setting of a test current, apply the test current after checking that the THM% has
become 0 on the "Metering" screen.
• Calculate the theoretical operating time using the characteristic equations shown in Section
2.5. Check that the measured operating time is within 5%.
6.5.1.4

Negative sequence overcurrent element NPS1 and NPS2

The testing circuit is shown in Figure 6.5.5.
I a
A
Three-phase
I b
A
Current
source
I c
A
+
power
supply
−
The output signal of testing element is assigned a configurable LED.
The output signal numbers of the elements are as follows:
Element Signal No.
THMA 77
78
THMT
Figure 6.5.5 Testing NPS elements
Element Signal No.
NPS1 79
80
NPS2
 170 
6 F 2 T 0 1 7 2
GRE110
TB1
-1
-2
-3
-4
-5
-6
TB1
-13
-14
-12