Direct current system line fault positioning method

Abstract

The invention discloses a direct current system line fault positioning method. The method includes steps: firstly, deducing a voltage and current transient characteristic equation of lines with different fault types based on a VSC direct current system, and calculating a current differential initial value during the fault; performing fault discrimination by employing catastrophes of a positive electrode and a negative electrode in different fault types, and determining the fault type and the fault electrode after occurrence of the fault; then calculating a post-fault current and voltage characteristic equation, and calculating the transition resistance of a fault circuit; and finally deducing a fault positioning value by employing the current differential initial value during the fault, and realizing accuracy positioning of the line faults. According to the method, the fault positioning precision is high for a direct current system with high transition resistance and long distance, and the method can be applied to single-end radiation type direct current distribution networks, marine direct current distribution systems, and direct current systems whose transmission power is disperse, small, and random.

Description

technical field [0001] The invention relates to a fault location method for a direct current system line, belonging to the field of direct current line fault location. Background technique [0002] At present, the DC system fault location method is based on off-line technology, and the main methods are impedance method and traveling wave method. However, the impedance method is greatly affected by factors such as fault resistance, line load, transformer error and power supply parameters, and the actual application effect is not ideal. The traveling wave method is simple in principle and high in accuracy, so it is widely used in practice. The principle of the traveling wave method is to use the manual mode to detect the propagation time of the transient traveling wave on the fault line between the bus and the fault point to implement positioning. [0003] Traveling wave fault location relies on identifying the wave head and calibrating the initial time of the wave head to a...

AI Technical Summary

Problems solved by technology

The identification and calibration of the wave head has high requirements on the quality of personnel, and it is difficult to realize automation

When there is a transition resistance and the amplitude of the traveling wave head is limited, it is more difficult to accurately calibrate the starting point of the wave head, which seriously affects the accuracy and reliability of positioning

As the transition resistance continues to increase, the traveling wave fault location method will not be able to locate the fault because it has not started

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