ABB REJ 527 Technical Reference Manual page 14

REJ 527
14
Technical Reference Manual
When an earth-fault stage starts, a starting signal is generated and simultaneously the
display on the front panel indicates starting. If the above mentioned criteria are
fulfilled long enough to exceed the set operate time, the stage that started initiates a
tripping signal. At the same time the operation indicator on the front panel is lit. The
red operation indicator remains lit although the protection stage resets. The direction
towards the fault spot is determined by means of the angle between the voltage and
current. The basic angle ϕ
is 0°, the negative quadrant of the operation sector can be extended with ϕ
4.1.3.2.-1) The wider operation sector ϕ
In Fig. 4.1.3.2.-1 ... Fig. 4.1.3.2.-3 examples of the operation characteristic with the
basic angle.
ϕa=40°
OPERATION
AREA
Negative
quadrant
-140° -120° -100° -80° -60° -40° -20°
Fig. 4.1.3.2.-1 Operation characteristic of the directional earth-fault protection
unit when the basic angle ϕ
the wider operation sector ϕ
LEAD LAG
Uo
ϕ
∆ϕ
Io>
ϕa=40°
Fig. 4.1.3.2.-2 Operation characteristics when the basic angle ϕ
sector ∆ϕ=±80° and the wider operation sector ϕ
can be set between -90° and 0°. When the basic angle ϕ
b
is settable to 0...90°.
a
Io
In ϕb=0°
∆ϕ=80°
6
5
OPERATION
AREA
4
Positive
quadrant
3
2
1
Io>
0° 20° 40°
NON-OPERATION AREA
= 0°, operation sector ∆ϕ=±80° and
b
=40°
a
Io
OPERATION SECTOR
ϕ
b=0°
∆ϕ
=80°
ABB Substation Automation
Products and Systems
. (See Fig.
a
60° 80° 100°
= 0°, operation
b
=40°.
a
1MRS750616-MUM
b