TSINGHUA SCIENCE AND TECHNOLOGY
I S S N 1 0 0 7 - 0 2 1 4
V o l u m e 10, N u m b e r
Application of Six-Sequence Fault Components in Fault
Location for Joint Parallel Transmission Line
FAN Chunju CAI Huarong YU Weiyong (#'HMt)
Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China
Abstract: A new fault location method based on six-sequence fault components was developed for parallel
lines based on the fault analysis of a joint parallel transmission line. In the six-sequence fault network, the
ratio of the root-mean square value of the fault current from two terminals is the function of the line imped-
ance, the system impedance, and the fault distance away from the buses. A fault location equation is given
to relate these factors. For extremely long transmission lines, the distributed capacitance is divided by the
fault point and allocated to the two terminals of the transmission line in a lumped parameter to eliminate the
influence of the distributed capacitance on the location accuracy. There is no limit on fault type and syn-
chronization of the sampling data. Simulation results show that the location accuracy is high with an average
error about 2%, and it is not influenced by factors such as the load current, the operating mode of the power
system, or the fault resistance.
Key words: fault location; joint parallel line; six-sequence components; two-terminal
Fault location for transmission line can be classified
into one-terminal method
The location method that uses one-terminal informa-
tion is very difficult to overcome the influence of the
change of the remote-terminal system impedance and
the fault resistance on location accuracy. Suonan et
sound line of the joint parallel line to obtain the infor-
mation of the remote terminal. This method is effective
for single line faults, but not so effective for overline
(one line to another line) faults.
The fault location method that uses two-terminal in-
formation is not influenced by these factors and is ac-
curate in theory, but the asynchronous problem of the
data in these two terminals is difficult to be solved. Ji-
ang et al.
[1_6] and two-terminal method
[ 5 ] proposed a method that makes full use of the
[ 9 ] proposes a new method for fault location in
* * To whom correspondence should be addressed.
E-mail: email@example.com; Tel: 86-21-62932278
parallel double-circuit multi-terminal transmission
lines. Although one equation can be used for all types
of faults, and classification of faults and selection of
fault phase are not required, the proposed methods do
not have enough accuracy when the fault occurs across
both circuits of a parallel double-circuit line. Saha et
measurement unit device. However, this method is not
economic and the accuracy of fault location is not very
A power system is generally a symmetrical three-
phase system. If the symmetrical component method is
used to decompose the asymmetrical phase measure-
ment, all the calculations can be carried out according
to single-phase condition for the asymmetry caused by
asymmetrical fault and asymmetrical load. For the ex-
tremely long transmission line, especially for the joint
parallel lines, there is zero sequence mutual reactance,
as well as positive and negative sequence mutual reac-
tance between phases
symmetrical component method is difficult, so the
[ 1 0 ] and Ge
[ 1 1 ] proposed a method based on the phase
. Application of the traditional
FAN Chunju ot al: Application of Six-Sequence Fault Components
parallel lines. In the additional six-sequence fault net-
work, the ratio of the two terminals' root-mean square
currents is the function of the line impedance, the sys-
tem impedance, and the fault distance. Thus, a simpli-
fied equation is deduced to obtain the distance of the
fault point from the bus.
For various grounded faults, the greatest fault resis-
tance is 300 Ω . The sudden-changing six-sequence
fault components are used to solve the system reac-
tance of the two terminals of the transmission line and
the fault distance away from the bus. Even if the fault
resistance is very large and the fault current direction
of the receiving terminal is from the transmission line
to the bus, the proposed method still has a high fault
location accuracy with an error of about 2%. The
simulation results of various types of faults for joint
parallel lines indicate that the proposed method can
accurately predict fault locations, and is not influenced
by factors, such as fault type, the operating mode of
the power system the fault resistance at the fault point.
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