Section 19 Time Inverse Characteristics - ABB REB650 Technical Manual

1MRK 505 277-UUS C
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.
IPickup
ANSI05000129 V1 EN
Figure 175: Three overcurrent protections connected in series
Time
Stage 1
IEC05000130 V1 EN
Figure 176: Definite time overcurrent characteristics
Time inverse characteristics
IPickup
Stage 2
Stage 1
Section 19
IPickup
xx05000129_ansi.vsd
Stage 3
Stage 2
Stage 1
Fault point
position
en05000130.vsd
459