Prediction method for electrode air gap breakdown voltage

Abstract

The invention discloses a prediction method for electrode air gap breakdown voltage. The prediction method comprises the steps of firstly measuring breakdown voltage of typical electrode air gaps in different structures, and defining a withstand voltage interval and a breakdown voltage interval; then performing electric field calculation to the typical electrode air gasp in different structures, extracting electric field characteristic quantity and establishing a training sample set; establishing a breakdown voltage prediction model based on the training sample set, wherein the breakdown voltage prediction model takes the electric field characteristic quantity as input and the withstand voltage interval and the breakdown voltage interval as output; finally, predicting the breakdown voltage of an electrode air gap by adopting the breakdown voltage prediction model. The prediction method for the electrode air gap breakdown voltage has the advantages that the operation process is simple, the prediction accuracy is high, the period is short, the cost is low, the prediction method is suitable for engineering application and the prediction result can be used for guiding power transmission and transformation engineering design.

Description

technical field [0001] The invention relates to the field of external insulation of power transmission and transformation engineering, in particular to a method for predicting the breakdown voltage of an electrode air gap. Background technique [0002] The discharge characteristic of the air gap is an important basis for the external insulation design of high-voltage power transmission and transformation projects. Aiming at the discharge characteristics of air gaps, researchers mainly carried out a large number of experimental studies on two types of gaps: typical electrode air gaps and actual power transmission and transformation engineering air gaps. For the electrode air gap, the basic characteristics of the air gap breakdown are generally obtained through discharge tests on typical electrodes, and the gap coefficient is used to predict the breakdown characteristics of the engineering air gap, so as to guide the design of power transmission and transformation projects. O...

AI Technical Summary

Problems solved by technology

However, there are still many key physical parameters that cannot be accurately described and measured. For example, there is a lack of deep understanding of the space charge distribution in the streamer region, and there are large errors in calculating the space charge distribution by assuming that the streamer geometry and the regional electric field are constant.

Lack of understanding of the characteristic parameters of the leader channel. At present, it is assumed that the leader channel has characteristics similar to those of the arc, and the leader charge density per unit length is constant, which cannot accurately reflect the relationship between the leader characteristic parameters and the degree of thermal ionization.

In addition, the partial discharge mechanism is not yet perfect. For example, the main mechanism of streamer to leader conversion is thermal ionization. It is currently assumed that the critical temperature of leader initiation is equal to the critical temperature of negative ion desorption, which has not been confirmed by experimental measurements.

The above problems make it difficult for the current mathematical simulation model to accurately predict the breakdown voltage of the air gap

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