Table 47. Negative-sequence overvoltage protection (NSPTOV)
Characteristic Value
Operation accuracy Depending on the frequency of the voltage measured: f
n
±2 Hz
±1.5% of the set value or ±0.002 × U
n
Start time
1)2)
Minimum Typical Maximum
U
Fault
= 1.1 × set
Start value
U
Fault
= 2.0 × set
Start value
33 ms
24 ms
35 ms
26 ms
37 ms
28 ms
Reset time < 40 ms
Reset ratio Typical 0.96
Retardation time < 35 ms
Operate time accuracy in definite time mode ±1.0% of the set value or ±20 ms
Suppression of harmonics DFT: -50 dB at f = n × f
n
, where n = 2, 3, 4, 5,…
1) Negative-sequence voltage before fault = 0.0 × U
n
, f
n
= 50 Hz, negative-sequence overvoltage with nominal frequency injected from random phase angle, results based on statistical
distribution of 1000 measurements
2) Includes the delay of the signal output contact
Table 48. Negative-sequence overvoltage protection (NSPTOV) main settings
Parameter
Function Value (Range) Step
Start value NSPTOV 0.010...1.000 x U
n
0.001
Operate delay time NSPTOV 40...120000 ms 1
Table 49. Overexcitation protection (OEPVPH)
Characteristic
Value
Operation accuracy Depending on the frequency of the voltage measured: fn ±2 Hz
±2.5% of the set value or 0.01 x Ub/f
Start time
1)2)
Frequency change Typical 200 ms (±20 ms)
Voltage change Typical 100 ms (±20 ms)
Reset time < 60 ms
Reset ratio Typical 0.96
Retardation time < 45 ms
Operate time accuracy in definite-time mode ±1.0% of the set value or ±20 ms
Operate time accuracy in inverse-time mode ±5.0% of the theoretical value or ±50 ms
1) Results based on statistical distribution of 1000 measurements
2) Includes the delay of the signal output contact
Table 50. Overexcitation protection (OEPVPH) main settings
Parameter
Function Value (Range) Step
Start value OEPVPH 100...200 % 1
Time multiplier OEPVPH 0.1...100.0 0.1
Operate delay time OEPVPH 200...200000 ms 10
Cooling time OEPVPH 5...10000 s 1
Operating curve type OEPVPH Definite or inverse time
Curve type: 5, 15, 17, 18, 19, 20
Transformer Protection and Control 1MRS757846 A
RET620
Product version: 2.0
ABB 35
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