Pickup1
PICKUP
TRIP
tReset1
t1
ANSI10000038-2-en.vsd
ANSI10000038 V2 EN-US
Figure 337: Example for Definite Time Delay stage 1 operation
9.2.7.3 Blocking
M15330-20 v7
It is possible to block Two step overvoltage protection OV2PTOV, (59) partially or completely, by
binary input signals where:
BLOCK: blocks all outputs
BLKTR1: blocks all trip outputs of step 1
BLK1: blocks all pickup and trip outputs related to step 1
BLKTR2: blocks all trip outputs of step 2
BLK2: blocks all pickup and trip outputs related to step 2
9.2.7.4 Design
M15330-34 v7
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 figure
338.
1MRK 502 066-UUS B Section 9
Voltage protection
623
Technical manual
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