Functions
2.5 Voltage Protection 27, 59
SIPROTEC, 7SK80, Manual
E50417-G1140-C344-A5, Release date 11.2012
113
Figure 2-31 Typical fault profile for load side connection of the voltage transformers (with current supervi-
sion)
Upon the closing of the circuit breaker, current criterion is delayed for a short period of time. If the voltage cri-
terion drops out during this time period (about 60 ms), the protection function does not pick up. Therefore no
fault record is created when voltage protection is activated in a healthy system. It is important to understand,
however, that if a low voltage condition exists on the load after the circuit breaker is closed (unlike Figure 2-31),
the desired pickup of the element will be delayed by 60 ms.
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