Single-end distance measurement method for line single-phase ground faults against the influence of transition resistance and load current

Abstract

The invention discloses a line single-phase ground fault single-terminal location method capable of preventing influences of both transitional resistance and load current. According to the method, the voltage phase angle of a single-phase ground fault point is calculated by utilizing the fault-phase negative sequence voltage of the relay location of a transmission line and the positive sequence impedance of the transmission line per unit length; the imaginary part of the voltage drop from the relay location of the transmission line to the single-phase ground fault point is calculated according to the characteristic that the voltage along the transmission line is in linear monotone decreasing; and the imaginary part of the voltage drop from the relay location of the transmission line to the single-phase ground fault point is divided by the imaginary part of the voltage drop of the transmission line per unit length to obtain the fault location. The line single-phase ground fault single-terminal location method solves the problem that the transitional resistance and the load current influence the single-terminal fault location precision, is high in single-terminal location precision, simple in location principle and easy in program implementation, and does not need to adopt the search algorithm, so that direct calculation of the fault location is realized, location speed is quick and the real-time performance is strong.

Description

technical field [0001] The invention relates to the technical field of single-end fault distance measurement in power systems, in particular to a method for single-terminal single-terminal fault distance measurement of line single-phase ground faults that is resistant to the influence of transition resistance and load current. Background technique [0002] The single-ended fault location method only uses the electrical quantity at one end of the transmission line for fault location, does not require communication and data synchronization equipment, has low operating costs and stable algorithms, and has been widely used in transmission lines. Single-ended fault location methods are mainly divided into traveling wave method and impedance method. The traveling wave method utilizes the transmission properties of fault transient traveling waves to perform single-ended fault location. It has high precision and is not affected by the operation mode of the power system and excessive...

AI Technical Summary

Problems solved by technology

The traveling wave method utilizes the transmission properties of the fault transient traveling wave to perform single-ended fault location. It has high precision and is not affected by the operation mode of the power system and excessive resistance. However, it requires a high sampling rate and requires a special wave recording device. high cost

The impedance method uses the voltage and current after the fault to calculate the fault loop impedance, and performs single-ended fault distance measurement according to the characteristic that the line length is proportional to the impedance. It is simple and reliable, but the distance measurement accuracy is seriously affected by factors such as transition resistance and load current, especially When the transition resistance is large, the ranging result of the impedance method will seriously deviate from the real fault distance, and even the ranging failure will occur.

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