Single-ended location method for line-to-phase faults based on amplitude characteristics of impedance location function

Abstract

The invention discloses a single-end distance measuring method for line phase-to-phase faults based on the amplitude characteristic of impedance positioning function. The method of the invention firstly measures the fault phase-to-phase voltage, fault phase-to-phase current and fault phase-to-phase negative sequence current at the protection installation of the transmission line, calculates the boundary impedance, uses a one-dimensional search method to sequentially calculate the comprehensive impedance at each point on the transmission line, and then sequentially calculates the transmission line The impedance positioning function value at each point above, and then select the distance between the point where the impedance positioning function value reaches the minimum on the transmission line and the transmission line protection installation as the fault distance. In principle, the method of the invention eliminates the influence of transition resistance, load current and power system operation mode, has high ranging accuracy, and is suitable for realizing the single-end ranging function of phase-to-phase short-circuit faults of 500kV, 220kV and 110kV transmission lines.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a method for single-terminal fault distance measurement between phases of a line based on the amplitude characteristic of an impedance positioning function. 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 and excessive resistance. However, it requires a high sampling rate, requires...

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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 location based on the characteristic that the line length is proportional to the impedance. It is simple and reliable, but the fault location accuracy is seriously affected by factors such as transition resistance and load current. Especially when the transition resistance is large, the result of the impedance method distance measurement will seriously deviate from the real fault distance, and even the fault distance measurement fails or the fault distance measurement result exceeds the entire length of the line, which cannot provide accurate fault location information, making it difficult to inspect the fault line. It is conducive to the rapid elimination of transmission line faults and the rapid restoration of line power supply

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