ABB RELION 670 SERIES REG670 - Voltage and Current Inversion

A B
-jX C
P
A
Q
A
P
B
Q
B
V
A
V
B
V
+jXL
V
A
V
B
en06000590_ansi.vsd
D
d
ANSI06000590 V1 EN-US
Figure 108: Transmission line with series capacitor
The effect on the power transfer when considering a constant angle difference (δ)
between the line ends is illustrated in figure
109. Practical compensation degree runs
from 20 to 70 percent. Transmission capability increases of more than two times can be
obtained in practice.
IEC06000592-2-en.vsd
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
1
1.5
2
2.5
3
3.5
Degree of series compensation [%]
Increase in power transfer
Power transfer with constant angle difference
Degree of
compensation
Multiple of power over
a non-compensated line
IEC06000592 V2 EN-US
Figure 109: Increase in power transfer over a transmission line depending on
degree of series compensation
8.3.3.3 Voltage and current inversion
GUID-CB215C0F-F4FA-4646-9235-AE6DB0255E80 v1
Series capacitors influence the magnitude and the direction of fault currents in series
compensated networks. They consequently influence phase angles of voltages
measured in different points of series compensated networks and this performances of
different protection functions, which have their operation based on properties of
measured voltage and current phasors.
Voltage inversion
GUID-E649A7CB-9877-48F7-8AB3-25D5E8695673 v1
Figure
110 presents a part of series compensated line with reactance X
L1
between the
IED point and the fault in point F of series compensated line. The voltage measurement
is supposed to be on the bus side, so that series capacitor appears between the IED
point and fault on the protected line. Figure 111 presents the corresponding phasor
diagrams for the cases with bypassed and fully inserted series capacitor.
1MRK 502 071-UUS A Section 8
Impedance protection
Generator protection REG670 2.2 ANSI and Injection equipment REX060, REX061, REX062 247
Application manual