Method for recognizing single-phase permanent fault of single-ended electric transmission line with paralleling reactor

Abstract

The invention relates to a method for recognizing a single-phase permanent fault of a single-ended electric transmission line with a paralleling reactor. Existing fault property adjustment methods are different in application range and can be influenced by various factors. According to the method for recognizing the single-phase permanent fault of the single-ended electric transmission line with the paralleling reactor, the single-end sound-phase current and the current of the paralleling reactor are sampled firstly after fault-phase tripping, then the quantity of corresponding phases can be extracted with the full-wave Fourier algorithm, and thus the line voltage of the local-end and the current of the line in the flow direction can be represented according to the quantity of the corresponding phases; then, the voltage and current of a fault point relevant to the double-end voltage and current are calculated respectively according to a permanent fault distributed parameter model, it is deduced that the voltage to ground and current to ground of the fault point are only relevant to the single-end sound-phase current and the current of the paralleling reactor according to the boundary conditions which are met by the voltage and current of the fault point and the condition that the phase current of the opposite end is zero after fault tripping, and thus transition resistance can be calculated; the property of the fault can be recognized accurately through continuous calculation of the transition resistance. The method for recognizing the single-phase permanent fault of the single-ended electric transmission line with the paralleling reactor has the advantages that the fault property judgment is influenced by few factors, and the sensitivity is high.

Description

technical field [0001] The invention belongs to the technical field of power systems, and in particular relates to a method for identifying single-phase permanent faults of transmission lines with shunt reactors at single ends. Background technique [0002] At present, the automatic reclosing technology is basically adopted in the transmission lines at home and abroad, which plays a vital role in ensuring the stable operation of the power system. However, while automatic reclosing has brought huge economic benefits, it has also brought negative effects to the power system. Because the fault nature of the transmission line is divided into transient fault and permanent fault, if it overlaps with the permanent fault, it is equivalent to the power equipment being impacted by the fault current again, which will shorten the life of the power equipment. In order to reduce the loss of the power system, it is very important to judge the nature of the fault before reclosing. So far,...

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Problems solved by technology

Among them, the criterion based on the arc stage requires that the transformer can collect and transmit high-frequency signals (that is, a higher sampling rate is required), and the fault arc is highly nonlinear, which is difficult to simulate accurately. In addition, the shunt reactor speeds up the process of arc extinguishing; Criterions based on intelligent algorithms such as neural networks require a large amount of data to simulate different fault models, and their usability needs to be tested; criteria based on recovery voltage characteristics are easily affected by system oscillation and operation mode, and cannot judge the arc-off time. The shunt reactor also reduces the fault phase recovery voltage; the parameter identification method based on the transient fault model lacks the analysis of the permanent fault model, cannot reflect the severity of the permanent fault, and requires the use of double-terminal electrical quantities, including difficult to accurately Measured fault disconnection phase recovery voltage, practical application is difficult

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