High voltage cable-overhead line hybrid line fault phase ranging method

Abstract

The invention discloses a method for realizing high voltage cable-overhead line hybrid line fault ranging by using the phase characteristic of a positioning function, which belongs to the technical field of relay protection of power systems. The method comprises: firstly, acquiring positive sequence electrical data at two ends of a failed hybrid line system and equaling the entire hybrid line to a line of the same length; secondly, deducing the positioning function by using the positive electrical data at the two ends of the hybrid line system, and determining a minimum fault partition having a fault point according to the size of the phase of the positioning function; and finally, accurately finding the fault range of the hybrid line in the fault partition by using the size of the phase angle of the positioning function. The method can accurately find the position of a fault, reduce troubleshooting time and accelerate power supply restoration and has a great significance for the safe and economic operation of the power system.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a method for realizing fault distance measurement of a high-voltage cable-overhead line hybrid line by using the phase characteristic of a positioning function. Background technique [0002] With the rapid development of large and medium-sized cities in my country and the requirements of urban planning, power cables have been widely used due to their advantages of small footprint, personal safety, high power supply reliability, and small maintenance workload. On the basis of overhead lines, cable-overhead hybrid lines are developed and applied more and more widely, such as Shanghai Xiaoyangshan cable-overhead hybrid line, railway self-closing through cable-overhead line and electrified railway cable-overhead hybrid line. After the high-voltage cable-overhead line hybrid line fails, it can accurately measure the distance, which can shorten the trouble...

AI Technical Summary

Problems solved by technology

Yu Yuze, Qin Jian, and Li Gongxin published "A Review of Fault Location Methods for Cable-Overhead Line Hybrid Lines", which proposed injecting pulse currents into fault phases and non-fault phases at the same time for cable-overhead line fault location. The faulty phase and non-faulty phase traveling wave signals first determine the location of the connection point and the fault point, and then go to the method of precise distance measurement, but the pulse transmitter and its synchronization are difficult to achieve in practical applications

Cai Yumei's "Research on Fault Location Method for Railway Self-closing Through Lines" aims at the problem of fault location of railway self-closing through cables-overhead lines, and proposes a method of comparing the polarity of the zero-mode component of the current traveling wave line to accurately locate the section method, but does not consider the influence of line zero-mode component coupling at the fault point

Wu Chengen, Tai Nengling and Yu Weiyong published the "Extra-high Voltage Cable-Overhead Line Hybrid Line Fault Finding Method", aiming at the fault location of EHV cable-overhead line hybrid line, it is proposed to use the fault point in the additional negative sequence network to maximize the negative sequence voltage amplitude of the fault point. This feature constructs the criterion to first identify the cable line or overhead line where the fault point is located, and then calculates the fault point by using the voltage and current mutations at the beginning and end of the fault area. The magnitude of the negative sequence voltage at the connection point is basically the same, and the impact of the fault transient process may not be able to correctly judge the fault section near the connection point, resulting in the failure of ranging

Shu Hongchun and Sun Tao published "A New Method for Fault Traveling Wave Location of Cable-Overhead Line Mixed Lines", aiming at cable-overhead line fault location. The size of the distributed current at the connection point of the overhead line judges the fault area, and then uses the single-ended traveling wave distance measuring device to perform accurate fault location. The magnitude of the distributed current at the connection point of the cable overhead line is basically the same, plus the influence of the fault transient process, there will be a ranging dead zone near the connection point, and it is not suitable for symmetrical faults

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