Fault range finding method of power distribution network based on equivalent positive and negative sequence impedance principle

Abstract

The invention discloses a fault range finding method of a power distribution network based on an equivalent positive and negative sequence impedance principle. According to the method, a PMU is used to obtain line state information in real time, and a fault line is determined by calculating and comparing the head-end line voltages in the same branch point; normal line information is used to calculate the head-end voltage and current of the fault line; and on the basis that electrical quantity of the two ends of the fault line is known, accurate fault locating is realized on the basis of the equivalent positive and negative sequence impedance principle. The difficulty that too many branch lines are included in fault location in the power distribution network via the limited PMU, and accurate fault locating is realized; fault range finding is realized by measurement in the two ends, it is not required to determine the fault type, the method is avoided from influence of transitional resistors or opposite-end feed-in current, and it is not required to consider the change of fault boundary condition or system operation manner, and compared with the single-end measurement method, the range finding precision is higher, fault range finding can be realized rapidly and accurately, the operational reliability, safety and flexibility of the system are improved greatly, and the applicationprospects are better.

Description

technical field [0001] The invention belongs to the application field of distribution network fault location, and in particular relates to a distribution network fault location method based on the principle of equal positive and negative sequence impedances. Background technique [0002] With the continuous development of society, power users have higher and higher requirements for power quality and power supply reliability. When a fault occurs in the distribution network, the fault location function can be used to quickly find out the area where the fault occurred, isolate the fault and restore it to the user as soon as possible. power supply. The rapid and accurate positioning of distribution line faults can not only repair the line as soon as possible to ensure reliable power supply, but also play a very important role in ensuring the safe, stable and economical operation of the entire power system. The distribution network has the characteristics of wide area coverage, ...

AI Technical Summary

Problems solved by technology

[0004] With the application of PMU in power system positioning, it is possible to collect synchronized phasors at both ends of the line for fault location. The fault location algorithm based on the measurement results of PMUs at both ends of the line has strong self-adaptability, high positioning accuracy, and small algorithm calculation. advantages, but the structure of the distribution network has multiple branches. In practice, considering factors such as line investment cost and technology, it is impossible to install PMUs at both ends of each feeder line. However, the fault location using single-ended electrical quantity information, the algorithm Only the information on the local side can be used, and the change of the operation mode of the opposite side system and the influence of the transition resistance of the fault point cannot be eliminated, resulting in a large error in the fault location measurement result, or even failure

[0005] According to the above analysis, in view of the large number of feeders and the wide range of power supply in the distribution network, the existing fault location algorithm has the problem of inaccurate location results, which affects the reliability of the power system.

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