Siemens SIPROTEC 4 Manual page 126

Functions
2.6 Voltage Protection 27, 59
[stoerfallverlauf-mit-stromkriterium-260602-kn, 1, en_US]
Figure 2-46
Upon the closing of the circuit breaker, current criterion is delayed for a short period of time. If the voltage
criterion 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 under-
stand, however, that if a low voltage condition exists on the load after the circuit breaker is closed (unlike
Figure 2-46), the desired pickup of the element will be delayed by 60 ms.
The following figure shows the logic diagram of the undervoltage protection function.
126
Typical fault profile for load side connection of the voltage transformers (with current supervi-
sion)
SIPROTEC 4, 7SJ80, Manual
E50417-G1140-C343-A8, Edition 12.2017