ABB Relion REG670, Technical Manual

Page: 272 / 1298

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Real part (R) of Z in Ohms
Im
ag
ina
ry
pa
rt
(X
) o
f Z
in
O
hm
s
^ ^ ^ ^ ^ ^ ^ ^
^ ^ ^ ^ ^ ^ ^ ^
^ ^
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Ztr
Ze
Zgen
SE
RE
Z(R,X)
R
Zline
Zone 2
relay
← Z-line
120°
←
Lens is the locus
of constant rotor (power)
angle, e.g. 120°.
Lens' width determined
by the setting StartAngle
X
Position of the OOS
relay is the origin of
the R - X plane
Zone 1
limit-of-reach →
circle depends on
the position of the
points SE and RE
X-line
determined
by the →
setting
ReachZ1
IEC10000112-1-en.vsd
IEC10000112 V1 EN
Figure 114: Construction of the lens characteristic for a power system
IEC10000113-2-en.vsd
d
Y
G
Generator
13.8 kV
13.8 kV
Power line
220 kV
Infinite power
system
Out-Of-Step
protection
OOSPPAM
Transformer
13.8 / 220 kV
System
equivalent
REG
Zgen(Rgen , Xgen ) Ztr(Rtr, Xtr) Zline(Rline, Xline) Zeq(Req, Xeq)
ReverseZ ForwardZ(ForwardR, ForwardX)
ReverseR = Rg ForwardR = Rtr + Rline + Req
ReverseX = Xd’ ForwardX = Xtr + Xline + Xeq
All impedances must be referred to the generator voltage 13.8 kV
SE RE
d
Y
G
Generator
13.8 kV
13.8 kV
Power line
220 kV
Infinite power
system
Out-Of-Step
protection
OOSPPAM
Transformer
13.8 / 220 kV
System
equivalent
REG
Zgen(Rgen , Xgen ) Ztr(Rtr, Xtr) Zline(Rline, Xline) Zeq(Req, Xeq)
ReverseZ(ReverseR, ReverseX)) ForwardZ(ForwardR, ForwardX)
ReverseR = Rg ForwardR = Rtr + Rline + Req
ReverseX = Xd’ ForwardX = Xtr + Xline + Xeq
All impedances must be referred to the generator voltage 13.8 kV
SE RE
IEC10000113 V2 EN
Figure 115: Example of an actual power system
To be able to automatically construct the lens characteristic for a system shown in
Figure
115 , the actual power system must be modeled as a two-machine equivalent
system, or as a single machine – infinite bus equivalent system, the following
information is necessary: Zgen(Rgen, Xgen), Ztr(Rtr, Xtr), Zline(Rline, Xline),
Zeq(Req, Xeq), and the setting
StartAngle , for example 120 degrees. All impedances
must be referred to the voltage level where the out-of-step protection relay is placed;
in the case shown in Figure
115 the relay is connected to the terminals of the generator
and, therefore, the previous quantities shall be referred to the generator nominal
Section 7
1MRK502052-UEN B
Impedance protection
266
Technical manual