Toshiba GRT100 Series Instruction Manual page 124

Theoretical operating value = (CT secondary rated current) × (1ik setting)
Percentage restraining characteristics
The percentage restraining characteristic is tested on the outflow current (l
(l ) plane as shown in Figure 6.5.8. The characteristic shown in Figure 6.5.8 is equivalent to the
in
one on the differential current (ld) and restraining current (lr) plane shown in Figure 2.11.2.
I out
0
Figure 6.5.8 Restricted Earth Fault Element (I out - I in Plane)
Figure 6.5.9 shows a testing circuit simulating infeed from a neutral circuit and outflow from a
primary winding.

A
Single-phase
current

source

A
Single-phase
current
source


DC
power

supply

DC
voltmeter

Figure 6.5.9 Testing Restricted Earth Fault Element (Model 100s, 200s)
 Enter a signal number 71 to observe the 1REF output at monitoring jack A and press the
DF1
[kp･p2 + (1- p1)ik]/(p2 – p1)
ik

 123 
) and infeed current
out
DF2
I in
GRT100
TB 1
-1
I
in
-2
Monitoring
jack
-7
I
out
-8
TB 4
- A16
- A17
E
6 F 2 S 0 7 8 9
A
0V