Design - ABB REL650 series Technical Manual

1MRK 506 335-UUS A
8.2.7.4
Technical manual
BLOCK:
BLK1:
BLK2:

Design

The voltage measuring elements continuously measure the three phase-to-ground
voltages or the three phase-to-phase voltages. Recursive Fourier filters or true RMS filters
of input voltage signals are used. The phase voltages are individually compared to the set
value, and the highest voltage is used for the inverse time characteristic integration. A
special logic is included to achieve the 1 out of 3, 2 out of 3 or 3 out of 3 criteria to fulfill the
PICKUP condition. The design of Two step overvoltage protection (OV2PTOV, 59) is
schematically described in
blocks all outputs
blocks all pickup and trip outputs related to step 1
blocks all pickup and trip outputs related to step 2
Figure 141.
Section 8
Voltage protection
305