Characteristic Value
Start time
1, 2
Typically 40 ms
Reset time Based on maximum value of
Recovery time
setting
Operate time accuracy ±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,…
4.5.9 Voltage vector shift protection VVSPPAM (ANSI 78VS)
4.5.9.1 Identification
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Voltage vector shift protection VVSPPAM VS 78VS
4.5.9.2 Function block
Figure 508: Function block
4.5.9.3 Functionality
The voltage vector shift protection function VVSPPAM, also known as vector surge
or delta phi function, measures continuously the duration of a voltage cycle. At the
instance of islanding, the duration of measured voltage cycle becomes shorter or
longer than the previous one, that is, the measured voltage cycle shifts with time.
This shifting of voltage is measured in terms of phase angle. VVSPPAM issues an
instantaneous trip when the shift in voltage vector exceeds the set value.
VVSPPAM can be blocked with BLOCK input. Blocking resets timers and outputs.
4.5.9.4 Analog channel configuration
VVSPPAM has one analog group input which must be properly configured.
Table 860: Analog inputs
Input Description
U3P Three-phase voltages
1
Tested for
Number of Start phases
= 1 out of 3, results based on statistical distribution of 1000
measurements
2
Includes the delay of the signal output contact
Protection functions 1MRS759142 F
908 REX640
Technical Manual
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