Section 19 Time Inverse Characteristics - ABB REC650 Technical Manual

1MRK 511 287-UEN A
Section 19
19.1
Technical manual
Time inverse characteristics
Application
In order to assure time selectivity between different overcurrent protections in
different points in the network different time delays for the different relays are
normally used. The simplest way to do this is to use definite time delay. In more
sophisticated applications current dependent time characteristics are used. Both
alternatives are shown in a simple application with three overcurrent protections
connected in series.
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Figure 281: Three overcurrent protections connected in series
Time
Stage 1
IEC05000130 V1 EN
Figure 282: Definite time overcurrent characteristics
Time inverse characteristics
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Stage 2
Stage 1
Section 19
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Stage 2
Stage 1
Fault point
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