Technical description
9 Technical data
9.3 Protection stages
VM55.EN005
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171
Positive sequence undervoltage stages U
1
<, U
1
<< (27P)
Setting range
20 – 120% x U
N
Definite time function:
- Operating time
0.08
*)
– 300.00 s
Undervoltage blocking
2 – 100% x U
N
(common for both stages)
Start time
Typically 60 ms
Reset time
<95 ms
Retardation time
<50 ms
Reset ratio
1.05
Inaccuracy:
- Starting
±3% of set value
- Operating time
±1% or ±30 ms
*) This is the total operational time including the fault detection time and operation time of the
trip contacts.
NOTE! To make the relay trip after low voltage blocking, the positive sequence
voltage has to go above the pick-up setting.
Undervoltage stages U<, U<< and U<<< (27)
Setting range
20 – 120%xU
N
Definite time function:
- Operating time U<
- Operating time U<< and U<<<
0.08
*)
– 300.00 s (step 0.02 s)
0.06
*)
– 300.00 s (step 0.02 s)
Undervoltage blocking
0 – 80% x U
N
Start time
Typically 60 ms
Reset time for U<
0.06 – 300.00 s (step 0.02 s)
Reset time for U<< and U<<<
<95 ms
Retardation time
<50 ms
Reset ratio (hysteresis)
Reset ratio (Block limit)
1.001 – 1.200 (0.1
20.0 %, step 0.1 %)
0.5 V or 1.03 (3 %)
Inaccuracy:
- starting
±3% of set value
- blocking
±3% of set value or ±0.5 V
- time
±1% or ±30 ms
*) This is the instantaneous time i.e. the minimum total operational time including the fault
detection time and operation time of the trip contacts.
VS_Uo_Over Uo_Over1
Zero sequence voltage stages U
0
> and U
0
>> (59N)
Zero sequence voltage setting range
1 – 60 %U
0N
Definite time function:
- Operating time
0.3 – 300.0 s (step 0.1 s)
Start time
Typically 200 ms
Reset time
<450 ms
Reset ratio
0.97
Inaccuracy:
- Starting
±2% of the set value or ±0.3% of the rated
value
- Starting UoCalc (3LN mode)
±1 V
- Operate time
±1% or ±150 ms
