Section 26 Inverse Time Characteristics - ABB RES670 Technical Manual

1MRK 511 408-UUS A
Section 26
26.1
Phasor measurement unit RES670 2.2 ANSI
Technical manual
Inverse time characteristics
Application
In order to assure time selectivity between different overcurrent protections at different
points in the network different time delays for the different protections are normally
used. The simplest way to do this is to use definite time-lag. In more sophisticated
applications current dependent time characteristics are used. Both alternatives are
shown in a simple application with three overcurrent protections operating in series.
IPickup
ANSI05000129 V1 EN-US
Figure 342: Three overcurrent protections operating in series
Time
Stage 1
IEC05000130 V1 EN-US
Figure 343: Definite time overcurrent characteristics
Inverse time characteristics
IPickup
Stage 2
Stage 1
Section 26
IPickup
xx05000129_ansi.vsd
Stage 3
Stage 2
Stage 1
Fault point
position
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