Increase In Power Transfer - ABB RELION 670 SERIES Applications Manual

Section 8
Impedance protection
8.13.3.2
402

Increase in power transfer

The increase in power transfer capability as a function of the degree of compensation for
a transmission line can be explained by studying the circuit shown in figure 73. The power
transfer on the transmission line is given by the equation 50:
( )
d
× ×
V V sin
= =
A B
P
-
X X
Line C
EQUATION1994-ANSI V1 EN
The compensation degree K
A
P
A
-jX
C
+jX
L
V
A
Q
A
ANSI06000590 V1 EN
Figure 199: 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 74. Practical compensation degree runs from 20 to 70
percent. Transmission capability increases of more than two times can be obtained in
practice.
Multiple of power over
a non-compensated line
Power transfer with constant angle difference
3.5
3
2.5
2
1.5
1
0 0.1 0.2
Degree of series compensation [%]
IEC06000592 V2 EN
Figure 200: Increase in power transfer over a transmission line depending on degree
of series compensation
( )
d
× ×
V V sin
A B
( )
× -
X 1 K
Line C
is defined as equation
c
D
V
V V
A B
B
P
B
d
V
B
Q
B
en06000590_ansi.vsd
0.3 0.4 0.5 0.6 0.7
Degree of
compensation
IEC06000592-2-en.vsd
1MRK 506 369-UUS -
48
Line distance protection REL670 2.2 ANSI
Application manual
(Equation 361)