Using Sequence Components to Realize the Single-end Distance Measurement Method for Single-phase-to-ground Fault

Abstract

The invention discloses a line single-phase earth fault single-terminal ranging method implemented by the aid of sequence components. The line single-phase earth fault single-terminal ranging method includes converting negative-sequence voltages of a power transmission line single-phase earth fault point into an equivalent zero-sequence voltage; accurately computing the fault distance according to a fault characteristic that a certain zero-sequence voltage of a power transmission line single-phase earth fault point is equal to the equivalent zero-sequence voltage so as to implement power transmission line single-phase earth fault single-terminal ranging. The line single-phase earth fault single-terminal ranging method has the advantages that the power transmission line single-phase earth fault single-terminal ranging is implemented according to distribution characteristics of the zero-sequence voltages along a power transmission line, influence of transition resistance on the ranging precision is eliminated in principle, influence of load currents and fault positions is prevented, and the ranging precision is high; a ranging principle of the method is simple, programs are easy to implement, the fault distance does not need to be directly computed by a search algorithm, and the method is high in ranging speed and instantaneity.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a single-end ranging method for single-phase grounding faults of lines by using sequence components. 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 need 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 the fault transient traveling wave to perform single-ended fault location. It has high precision and is not affected by the operation mode and transition resistance. However, it requires a high sampling rate, requires a special wave recording device, a...

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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 transition 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.

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