Overvoltage Protection 59; Undervoltage Protection 27 - Siemens 7SC80 Manual

Overvoltage Protection 59

2.6.2
Function
The overvoltage protection has two elements. In case of a high overvoltage, tripping switch off is performed
with a short-time delay, whereas in case of less severe overvoltages, the tripping is performed with a longer
time delay. When one of the adjustable settings is exceeded, the 59 element picks up and trips after an adjust-
able 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
The pickup voltages and time delays can also be set phase-specifically.
The following figure shows the logic diagram of the overvoltage protection function.
The logic diagram also applies to setting the phase-specific overvoltage protection (Vphph selective or
Vph-n selective). The threshold values and time delays have to be replaced with the phase-specific
values.
[7sc80-ueberspgs-schutz-20130115, 1, en_US]
Figure 2-48
2.6.3

Undervoltage Protection 27

Function
Undervoltage protection consists of two definite time elements (27-1 PICKUP and 27-2 PICKUP). There-
fore, tripping can be time-coordinated depending on how severe voltage collapses are. Voltage thresholds and
time delays can be set individually for both elements.
The pickup voltages and time delays can also be set phase-specifically.
SIPROTEC Compact, 7SC80, Manual
E50417-G1140-C486-A8, Edition 07.2017
Logic Diagram of the Overvoltage Protection
/V ) can be set.
dropout value pickup value
Functions
2.6 Voltage Protection 27, 59
189