Setting - Toshiba GRT100 Series Instruction Manual

2.3.4 Setting

The following shows the setting elements necessary for the current differential protection and
their setting ranges. The setting can be performed on the LCD screen or PC screen.
Element
DIFT
DIF
HOC
CT matching
CT ratio
Phase angle
Scheme switch
[DIFTPMD]
[2F – LOCK]
[5F - LOCK]
[DIF1] to [DIF5]
(): Multiplier of CT secondary rated current including CT ratio sorrection.
(**): Default settings are dependent on the models. See Appendix H.
Setting of ik
ik determines minimum operation sensitivity of DIF element. ik is set as a ratio to the CT
secondary rated current.
Minimum setting of ik is determined from the maximum erroneous differential current under
normal operating conditions.
Setting of p1, p2 and kp
Percentage restraining factor (% slope)
= (Differential current) / (Through current)
= (Differential current) / [{(Incoming current) + (Outgoing current)} /2]
p1 is the percentage restraining factor which defines the DIF restraining characteristic in the
small current region. The setting is determined by the sum of:
Range
(  )
0.10  1.00
i k
10  100%
p1
10  200%
p2
1.00  20.00(*)
kp
10  50%
k2f
10  100%
k5f
2.00  20.00(*)
kh
0.05  50.00
kct1
0.05  50.00
kct2
kct3 0.05  50.00
0  11
d1
0  11
d2
d3 0  11
3POR / 2PAND
Off / On
Off / On
Off / On
 16 
Step Default Remarks
0.01 0.30 Minimum operating current
1% 100% % slope of small current region
1% 200% % slope of large current region
0.01 1.00 Break point of dual characteristics
1% 15% Second harmonic detection
1% 30% Fifth harmonic detection
0.01 2.00 High-set overcurrent protection
0.01 1.00 Primary winding
0.01 1.00 Secondary winding
0.01 1.00 Tertiary winding
1 0 Primary winding
1 0 Secondary winding
1 0 Tertiary winding
Enable or disable to
3POR Trip mode
On block by second harmonic
On block by fifth harmonic
(**) output tripping signal
6 F 2 S 0 7 8 9