Measurement Principle; Time Delay; Blocking; Design - ABB RET650 Technical Manual

1MRK 504 135-UEN A
9.3.7.1
9.3.7.2
9.3.7.3
9.3.7.4
Technical manual

Measurement principle

The residual voltage is measured continuously, and compared with the set values,
U1> and U2>.
To avoid oscillations of the output START signal, a hysteresis has been included.

Time delay

Blocking

It is possible to block two step residual overvoltage protection (ROV2PTOV) partially
or completely, by binary input signals where:
BLOCK:
BLKST1:
BLKST2:

Design

The voltage measuring elements continuously measure the residual voltage.
Recursive Fourier filters filter the input voltage signal. The single input voltage is
compared to the set value, and is also used for the inverse time characteristic
integration. The design of Two step residual overvoltage protection (ROV2PTOV) is
schematically described in
blocks all outputs
blocks all startand trip outputs related to step 1
blocks all start and trip inputs related to step 2
Figure 97.
Section 9
Voltage protection
219