Design - ABB RED650 Technical Manual

1MRK 505 394-UEN A
Normal voltage
IntBlkStVal1
IntBlkStVal2
IEC05000466 V1 EN-US
Figure 109: Blocking function
9.1.7.4
Line differential protection RED650 2.2 IEC
Technical manual
U Disconnection
U1<
U2<
Block step 1

Design

The voltage measuring elements continuously measure the three phase-to-neutral
voltages or the three phase-to-phase voltages. Recursive fourier filters or true RMS
filters of input voltage signals are used. The voltages are individually compared to
the set value, and the lowest 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 and 3
out of 3 criteria to fulfill the START condition. The design of Two step
undervoltage protection UV2PTUV is schematically shown in
tBlkUV1 <
t1,t1Min
tBlkUV2 <
t2,t2Min
Block step 2
Section 9
Voltage protection
Time
en05000466.vsd
M15326-35 v9
Figure 110.
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