Impedance protection
SEMOD173242-2 v14
Table 44. Full-scheme distance protection, Mho characteristic ZMHPDIS
Function Range or value Accuracy
Number of zones, Ph-E Max 4 with selectable
direction
-
Minimum operate current (10–30)% of IBase -
Positive sequence impedance,
Ph-E loop
(0.005–3000.000) W/phase
±2.0% static accuracy
Conditions:
Voltage range: (0.1-1.1) x U
r
Current range: (0.5-30) x I
r
Angle: 85 degrees
Positive sequence impedance
angle, Ph-E loop
(10–90) degrees
Reverse reach, Ph-E loop
(Magnitude)
(0.005–3000.000) Ω/phase
Magnitude of earth return
compensation factor KN
(0.00–3.00)
Angle for earth compensation
factor KN
(-180–180) degrees
Dynamic overreach <5% at 85 degrees
measured with CVT’s and
0.5<SIR<30
-
Definite time delay Ph-Ph and
Ph-E operation
(0.000-60.000) s ±0.2% or ±60 ms whichever is greater
Operate time 22 ms typically IEC 60255-121
Reset ratio 105% typically -
Reset time at 0.5 x Zreach to
1.5 x Zreach
Min. = 30 ms
Max. = 50 ms
-
Generator protection REG670
1MRK 502 074-BEN M
Hitachi Power Grids 73
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