ABB REL670 2.2 IEC, Applications Manual

Page: 175 / 908

see figure 78 . This high apparent reactance will mainly be used for damping of
power oscillations.
en06000598.vsd
Imperatriz TCSC, Operating range
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3
3.2
0 300 600 900 1200 1500 1800 2100 2400 2700 3000
Line current (Arms)
X
tc
s
c
/X
c
(
p
u
)
Continuous
30 min. overload
10s overload
Bypass mode
Series5
Continuous 30 min 10s
B C D
E F
G
A
IEC06000598 V1 EN-US
Figure 78: 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.
8.1.2.9 Challenges in protection of series compensated and adjacent power
lines
SEMOD168320-10 v2
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.
1MRK 506 369-UEN B
Section 8
Impedance protection
Line distance protection REL670 2.2 IEC 169
Application manual