ABB REG650 User Manual

Section 21 Time inverse characteristics
21.1 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.
xx05000129.vsd
I> I> I>
IEC05000129 V1 EN
Figure 315: Three overcurrent protections connected in series
en05000130.vsd
Time
Fault point
position
Stage 1
Stage 2
Stage 3
Stage 1
Stage 2
Stage 1
IEC05000130 V1 EN
Figure 316: Definite time overcurrent characteristics
1MRK 502 048-UEN A Section 21
Time inverse characteristics
683
Technical manual

ABB REG650 Specifications

General

Brand	ABB
Model	REG650
Category	Protection Device
Language	English