Method of achieving single-phase ground fault single-end distance measurement of line by means of voltage drop real part characteristics

Abstract

The invention discloses a method of achieving single-phase ground fault single-end distance measurement of a line by means of voltage drop real part characteristics. The method includes calculating a voltage phase angle of a single-phase ground fault point by means of fault phase negative-sequence voltage and positive-sequence impedance of a power transmission line per unit length, further calculating an additional fault distance caused by transition resistance, subtracting the additional fault distance caused by the transition resistance from a real part of a ratio between the fault phase voltage and voltage drop of the power transmission line per unit length, and obtaining a fault distance from a protective installation portion of the power transmission line to the single-phase ground fault point. The method solves the problem that precision of single-end fault distance measurement is influenced by the transition resistance and load currents. When a single-phase high-resistance ground fault occurs in the power transmission line, the method is high in distance measurement precision and simple in distance measurement principle, programs are easy to achieve, the fault distance can be directly calculated without a search algorithm, the distance measurement speed is high, and instantaneity is strong.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a single-end distance measuring method for a single-phase grounding fault of a line by using the characteristics of the real part of a voltage drop. Background technique [0002] The single-end fault location method of transmission lines 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 and excessive resistance. However, it requires a high sampling ra...

AI Technical Summary

Problems solved by technology

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 and excessive resistance. However, it requires a high sampling rate, requires a special wave recording device, and has high application costs.

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, due to the influence of the additional fault distance caused by the transition resistance, the measurement result of the fault distance will seriously deviate from the real fault distance, and even the fault distance measurement failure will occur.

Images