ABB RET670 Applications Manual page 219

1MRK504116-UUS C
Application manual
3.2
B
3
2.8
2.6
2.4
2.2
Continuous
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
-0.2
-0.4
0 300 600
IEC06000598 V1 EN
Figure 83: Operating range of a TCSC installed for damping of power oscillations
(example)
During continuous valve bypass the TCSC represents an inductive impedance of about
20% of the capacitor impedance. Both operation in capacitive boost mode and valve
bypass mode can be used for damping of power swings. The utilization of valve bypass
increases the dynamic range of the TCSC and improves the TCSC effectiveness in
power oscillation damping.
Challenges in protection of series compensated and adjacent power lines
System planning does not consider any more possible protection issues and difficulties,
when deciding for a particular, non conventional solution of certain operation and
stability problems. It is supposed that modern communication and state of the art
computer technologies provides good basis for the required solution. This applies also
to protection issues in series compensated networks. Different physical phenomena,
which influence conventional principles of IED protection, like distance protection,
phase comparison protection, are well known and accordingly considered in IED
design. Some other issues, like influence of controlled thyristors in series capacitor
banks are getting increased importance, although not as high as they would deserve.
The most important challenges, which influence the operation of different protection
functions in the greatest extent, are described in this chapter.
Imperatriz TCSC, Operating range
C D
10s
30 min
A
E
900 1200 1500 1800
Line current (Arms)
Section 3
IED application
G
F
2100 2400 2700 3000
en06000598.vsd
Continuous
30 min. overload
10s overload
Bypass mode
Series5
213