Power transmission line range finding method

Abstract

The invention discloses a power transmission line range finding method. The method is characterized by calculating an equivalent resistance by using the fault phase-to-phase voltage, the fault phase-to-phase current and the fault phase-to-phase negative-sequence current of a power transmission line protection installation position; using the equivalent resistance to multiply the fault phase-to-phase negative-sequence current so as to obtain a phase-to-phase short-circuit fault point voltage; calculating the real part of the ratio of the phase-to-phase short-circuit fault point voltage and a unit-length power transmission line voltage drop and acquiring an additional fault distance due to a transition resistor; and subtracting the additional fault distance from the real part of the ratio ofthe fault phase-to-phase voltage and the unit-length power transmission line voltage drop, and acquiring a fault distance from the power transmission line protection installation position to a phase-to-phase short-circuit fault point. In the invention, the influence of the transition resistor on the single-end range finding accuracy of a phase-to-phase short-circuit fault in a power transmissionline is overcome, high range finding precision is possessed, a range finding principle is simple, a program is easy to realize, a search algorithm does not need to be used and the fault distance can be directly calculated, a range finding speed is fast and real-time performance is high.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a distance measuring method for a power 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 a special wave recording device, and has high...

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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