Electric transmission line phase fault single-ended distance measuring method

Abstract

The invention discloses an electric transmission line phase fault single-ended distance measuring method. The electric transmission line phase fault single-ended distance measuring method includes the following steps of working out equivalent resistance through the voltage between fault phases, the current between the fault phases, and the negative-sequence current between the fault phases at the electric transmission line relay location, obtaining the voltage of a phase fault point through the fact that the equivalent resistance is multiplied by the negative-sequence current between the fault phases, working out the real part of a ratio between the voltage of the phase fault point and the voltage drop of an electric transmission line of per unit length, obtaining the additional fault distance caused by a transition resistor, and obtaining the fault distance from the electric transmission line relay location to the phase fault point through the difference between the real part of the ratio between the voltage between fault phases and the voltage drop of the electric transmission line of per unit length and the additional fault distance. The electric transmission line phase fault single-ended distance measuring method solves the problem that the transition resistor influences the precision of electric transmission line phase fault single-ended distance measuring, has high distance measuring precision and is simple in distance measuring principle. In addition, according to the electric transmission line phase fault single-ended distance measuring method, a program is easy to achieve, the fault distance is directly worked out without the need for application of search algorithms, distance measuring is fast, and the 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 short-circuit fault between phases of a transmission line. 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. [0003] Single-ended fault location methods for transmission lines 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 rate, requires ...

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 the transition resistance, especially when the transition resistance is large In this case, the single-ended fault location results will seriously deviate from the real fault distance, and even exceed the total length of the transmission line, so that the single-ended fault location results lose their reference value and cannot provide accurate and effective fault location information for power system fault line inspectors. Facilitate rapid fault location finding and troubleshooting

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