Direct current power distribution network line single-pole ground fault locating method

Abstract

The invention discloses a direct current power distribution network line single-pole ground fault locating method. The method comprises the steps that 1, a fault current differential initial value expression is obtained according to a transient characteristic equation of a fault current; 2, a fault current differential initial value is replaced through an interpolation algorithm; 3, a fault location value expression containing the fault current differential initial value is obtained; 4, the fault location value expression is combined with a loop current equation, and a fault-based location equation is obtained; 5, voltage and current value information before and after a single-pole ground fault happens is obtained, the fault current differential initial value obtained in the step 2 and the fault location equation obtained in the step 4 are combined, and a fault location value is obtained. According to the direct current power distribution network line single-pole ground fault locating method, calculation is easy, the application range is wide, the method is free of influence of factors such as transition resistance, the calculation result can be used for offline maintenance, automatic operation can be achieved, high resistance to transition resistance is achieved, and when the transition resistance is increased, the high location precision is still achieved.

Description

technical field [0001] The invention relates to the field of unipolar grounding fault location of a DC distribution network line, in particular to a single-pole of a DC distribution network line suitable for a two-level voltage source converter (Voltage Source Converter, VSC) based on an analytical method Earth fault location method. Background technique [0002] Due to line aging, damage and other reasons, the probability of line failure is the highest compared with other parts of the DC power distribution system. At present, there are few researches on fault location of DC power distribution system, and they mainly refer to DC transmission system with relatively mature fault location technology. The fault location methods of DC transmission system mainly include impedance method, traveling wave method and fault analysis method. The impedance method is not ideally applied in practical engineering because it is greatly affected by factors such as grounding resistance, line...

AI Technical Summary

Problems solved by technology

Impedance method is not ideal in practical engineering due to the influence of grounding resistance, line type, system parameters and other factors.

The principle of the traveling wave method is simple, the accuracy is high, and it is not affected by the type of line or the type of fault. Accurate calibration will seriously affect 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 is not activated.

The fault analysis method mainly uses the wave recording data of the fault recorder for analysis and calculation, so as to achieve the purpose of distance measurement and positioning. The fault analysis method can directly use the wave recording data of the fault recorder to realize fault location, which requires low equipment sampling rate and is reliable. The reliability is high, but this method is based on the accurate line parameter model. When the line parameter model is inaccurate or the frequency variation characteristics change, the accuracy of fault location will be affected.

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