ABB REL670 2.2 IEC - Increase in Power Transfer

~
E
A
Z
SA1
Power line
A B
Seires
capacitor
Load
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IEC06000585 V1 EN-US
Figure 195: A simple radial power system
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0 200 400 600 800 1000 1200 1400 1600 1800
100
200
300
400
500
P[MW]
U
[
k
V
]
U
limit
P
0
P
3
0
P
5
0
P
7
0
IEC06000586 V1 EN-US
Figure 196: 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 197. The power transfer on the transmission line is given by the
equation 360:
( ) ( )
( )
sin sin
1
d d × × × ×
= =
- × -
A B A B
Line C Line C
U U U U
P
X X X K
EQUATION1897 V1 EN-US (Equation 360)
The compensation degree K
c
is defined as equation
A B
-jX C
P
A
Q
A
P
B
Q
B
U
A
U
B
U
+jXL
U
A
U
B
d
D
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IEC06000590 V1 EN-US
Figure 197: 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
198. Practical compensation degree
runs from 20 to 70 percent. Transmission capability increases of more than two
times can be obtained in practice.
1MRK 506 369-UEN B Section 8
Impedance protection
Line distance protection REL670 2.2 IEC 375
Application manual