Table of Contents
Advertisement
ABB Substation Automation
Products and Systems
4.1.3
4.1.3.1
1MRS750940-MUM
Technical Reference Manual
Protection
Block diagram
IL 1
I>
IL 2
IL 3
SGB1/5
0.12 * I>
1.5 * I>
1.25 * I>
SGB1/6
BI
SGB1/4
SETTINGS (Group 1 / Group 2)
SGB1/1
RESET INDICATORS
SGB1/2
RESET INDICATORS AND LATCHED OUTPUT RELAYS
SGB1/3
RESET INDICATORS, LATCHED OUTPUT RELAYS AND REGISTERS
Figure 4.1.3-1 Block diagram of the overcurrent relay
Overcurrent unit
When the phase currents exceed the set start current of the low-set stage I>, the
overcurrent unit starts delivering a start signal after a preset ~ 55 ms start time. When
the set operate time at definite-time operation or the calculated operate time at
inverse-time operation elapses, the overcurrent unit operates. In the same way, the
high-set stage I>> of the overcurrent unit starts delivering a start signal after a preset
~ 30 ms start time when the set start current is exceeded. When the set operate time
elapses, the overcurrent unit operates.
The low-set stage of the overcurrent unit may be given a definite-time or an inverse
definite minimum time (IDMT) characteristic. When the IDMT characteristic is
55 ms
t> , k
SGF3/1...6
I>>
30 ms
SGF2/3
t>>
SGF2/1
2 * I>>
&
4
40/80 ms
SGR1/x
3
40/80 ms
SGR2/x
C
SGF1/3
SGF1/2
SGR3/x
1
2
40/80 ms
SGR4/x
SGF1/5
0.1 ... 1 s
SGF1/1
1
1
40/80 ms
SGF1/4
I>
1
I>>
C
SGF2/4, 5
t>
1
t>>
C
REJ 523
SO2
SO1
5 s
PO2
1
5 s
C
PO1
START
TRIP
13
Advertisement
Table of Contents
