ABB RELION RET670, Applications Manual

Page: 420 / 1016

=
C
C
Line
X
K
X
EQUATION1895 V1 EN-US
(Equation 328)
A typical 500 km long 500 kV line is considered with source impedance
1
0
=
SA
Z
EQUATION1896 V1 EN-US
(Equation 329)
~
E
A
Z
SA1 Power line
A B
Seires
capacitor
Load
en06000585.vsd
IEC06000585 V1 EN-US
Figure 199: A simple radial power system
en06000586_ansi.vsd
0 200 400 600 800 1000 1200 1400 1600 1800
100
200
300
400
500
P[MW]
V
[k
V
]
V
limit
P
0
P
3
0
P
5
0
P
7
0
ANSI06000586 V1 EN-US
Figure 200: Voltage profile for a simple radial power line with 0, 30, 50 and 70% of
compensation
8.13.3.2 Increase in power transfer
GUID-C9163D4E-CC2B-4645-B2AC-2C8A3FE3D337 v3
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
201 .
The power transfer on the transmission line is given by the equation 330 :
( ) ( )
( )
A B A B
Line C Line C
V V sin V V sin
P
X X X 1 K
d d
× × × ×
= =
- × -
EQUATION1994-ANSI V1 EN-US
(Equation 330)
The compensation degree K
c
is defined as equation
Section 8
1MRK 504 163-UUS A
Impedance protection
414 Transformer protection RET670 2.2 ANSI
Application manual