Functions
2.6 Voltage Protection 27, 59
SIPROTEC, 7SJ62/64, Manual
C53000-G1140-C207-2, Release date 01.2008
142
2.6.2 Overvoltage Protection 59
Function
The overvoltage protection has two elements. In case of a high overvoltage, tripping switchoff is performed with
a short-time delay, whereas in case of less severe overvoltages, the switchoff is performed with a longer time
delay. When one of the adjustable settings is exceeded, the 59 element picks up and trips after an adjustable
time delay has elapsed. The time delay is not dependent on the magnitude of the overvoltage.
The dropout ratio for the two overvoltage elements (= V
dropout value
/V
pickup value
) can be set.
The following figure shows the logic diagram of the overcurrent protection function.
Figure 2-45 Logic diagram of the overvoltage protection
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