Protection; Block Diagram; Directional Or Non-Directional Earth-Fault Current Unit - ABB REJ 527 Technical Reference Manual

ABB Substation Automation
Products and Systems
4.1.3.
4.1.3.1.
4.1.3.2.
1MRS750616-MUM
Technical Reference Manual

Protection

Block diagram

Uob
0.50% x Un
ϕ /Ιϕ
&
b
0.48% x In
ϕ
Io
BI
SGB1/1
RESET INDICATORS
SGB1/2
RESET INDICATORS AND LATCHED OUTPUT RELAYS
SGB1/3
RESET INDICATORS, LATCHED OUTPUT RELAYS AND REGISTERS
SGB1/4
SETTINGS (Group 1 / Group 2)
SGB1/8
BASIC ANGLE CONTROL or Iϕ characteristica (sin(ϕ) or cos(ϕ))
Fig. 4.1.3.1.-1 Block diagram of the directional earth-fault relay REJ 527

Directional or non-directional earth-fault current unit

The directional earth-fault current unit of the relay REJ 527 comprises two earth-
fault current stages, a low-set stage I
configured as either directional or non-directional. For the directional stages there
are two alternative operation characteristics: 1) directional earth-fault with basic
angle and 2) directional earth-fault with sin(ϕ) or cos(ϕ) characteristics.
1) The operation of the directional earth-fault unit with basic angle is based on
measuring the earth-fault current I
phase angle ϕ between the voltage and current. The earth-fault stage starts if the
following three criteria are fulfilled at the same time:
• The earth-fault current I
The earth-fault unit has two earth-fault current stages I
• The zero-sequence voltage U
starting level, U >, serving both stages in deblocking mode.
0b
• The phase angle ϕ between the voltage and current falls within the operation
sector ϕ ±∆ϕ.
The basic angle ϕ of the network is -90° for isolated neutral networks and 0° for
resonant earthed networks, earthed over an arc suppression coil (Petersen coil) with
or without a parallel resistor. The operation sector is selectable to ∆ϕ = ±80° or ±88°,
both with the addition of a wider operation sector.
Uob>
SGF2/8
Uo>
SGB1/5
SGF3/1 &
Io>
SGB1/6
Uo>>
&
SGF3/3 SGF2/3
SGB1/7
Io>>
SGF2/1
0.12 * Io>
2 * Io>>
60 ms
&
1.5 * Io>
1.25 * Io>
> and a high-set stage I
0
and the zero-sequence voltage U
0
exceeds the set starting level of the earth-fault stage.
0
exceeds the set starting level. The unit has one
0
REJ 527
5 s
C
SGR1/x
SGF1/1
70 ms
tb>
PO1
1
SGR2/x
1
SGR3/x
70 ms
SGF1/5
0.1 ... 1s
to>,k
SGR4/x
C
5 s
SGF1/2
PO2
1
SGR5/x
2
1
60 ms
to>>
SO1
3
SGR6/x
SO2
4
Uob> START
1
Io>
Io>>
C
tb>
1
to>
to>>
C
>> that can be
0
and further the
0
> and I >>.
0 0
TRIP
13