Characteristic Value
Start time , U
Fault
= 2 × set
Start
value
Minimum Typical Maximum
48 ms 51 ms 54 ms
Reset time Typically 40 ms
Reset ratio Typically 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,…
4.5.5.10 Technical revision history
Table 620: ROVPTOV Technical revision history
Technical revision Change
B Added a setting parameter for the "Meas-
ured Uo" or "Calculated Uo" selection
C Internal improvement
D Internal improvement
4.5.6 Negative-sequence overvoltage protection NSPTOV
4.5.6.1 Identification
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE
C37.2 device
number
Negative-sequence overvoltage
protection
NSPTOV U2> 47O-
4.5.6.2 Function block
Figure 345: Function block
4.5.6.3 Functionality
The negative-sequence overvoltage protection function NSPTOV is used to detect
negative sequence overvoltage conditions. NSPTOV is used for the protection of
machines.
The function starts when the negative sequence voltage exceeds the set limit.
NSPTOV operates with the definite time (DT) characteristics.
1
Residual voltage before fault = 0.0 × U
n
, f
n
= 50 Hz, residual voltage with nominal frequency in-
jected from random phase angle, results based on statistical distribution of 1000 measurements
2
Includes the delay of the signal output contact
Protection functions 1MRS757644 H
664 620 series
Technical Manual
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