Design - ABB REG650 Technical Manual

1MRK 502 043-UUS B
9.2.7.4
Technical Manual

Design

The voltage measuring elements continuously measure the three phase-to-ground
voltages or the three phase-to-phase voltages. Recursive Fourier filters filter the input
voltage signals. 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 Figure 122.
Section 9
Voltage protection
263