Method for assessing probability of occurrence of back-arc electric breakdown of hot gas of SF6 breaker

A technology of occurrence probability and electrical breakdown, applied in the direction of instruments, electrical digital data processing, special data processing applications, etc., can solve the problem of electrical breakdown characteristics of hot gas without circuit breaker after arc

Active Publication Date: 2012-11-21
XI AN JIAOTONG UNIV +1
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  • Abstract
  • Description
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  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Although evaluating the dielectric breakdown characteristics of the high-voltage circuit breaker after arc is very important for the optimal design and performance improvement of the product, there is no SF 6 Effective evaluation method or means of electric breakdown characteristics of hot gas after circuit breaker

Method used

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  • Method for assessing probability of occurrence of back-arc electric breakdown of hot gas of SF6 breaker
  • Method for assessing probability of occurrence of back-arc electric breakdown of hot gas of SF6 breaker
  • Method for assessing probability of occurrence of back-arc electric breakdown of hot gas of SF6 breaker

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Embodiment Construction

[0021] The implementation process of the present invention will be described below in conjunction with the accompanying drawings.

[0022] The present invention to SF 6 The steps for evaluating the electrical breakdown characteristics of hot gas after the arc of a circuit breaker are as follows:

[0023] (1) By solving the Boltzmann equation, the electron energy distribution function (EEDF) is obtained, and then the SF at different temperatures and pressures is determined 6 The critical breakdown field strength E of the gas cr . figure 1 for SF 6 Gas reduced critical breakdown field strength (E / N) cr The calculation flow chart of is described in detail as follows:

[0024] The two-term approximation of the distribution function of electrons in 6-dimensional phase space in velocity space is used to solve the Boltzmann equation. According to the plasma dynamics theory, the distribution function f(r,v,t) of electrons in the 6-dimensional phase space satisfies the Boltzmann ...

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Abstract

The invention provides a method for assessing probability of occurrence of back-arc electric breakdown of hot gas of an SF6 breaker. The method is characterized by comprising the following steps: 1), obtaining an electron energy distribution function (EEDF) by solving a Boltzmann equation to further determine the critical breakdown field strength Ecr of the SF6 gas under different temperatures and pressures; 2), determining the back-arc distribution of temperature and pressure in an arc extinguishing chamber by means of MHD simulation analysis of the SF6 electric arc; and 3), comparing field strength Ea caused by recovery voltage of each point in the arc extinguishing chamber with the Ecr of the SF6 under the corresponding temperature and pressure, and assessing the probability of occurrence of electric breakdown of each point in the arc extinguishing chamber. The method is applicable to the assessment of back-arc electric breakdown features of all SF6 breakers, whether the SF6 breakers are made of polytetrafluoroethylene (PTFE) nozzle material or not; and therefore, an effective method is provided for assessing the back-arc electric breakdown features of the SF6 high-voltage breaker.

Description

Technical field: [0001] The invention relates to the field of power electronics, in particular to a method for evaluating SF 6 A method for the probability of occurrence of hot gas electrical breakdown after arcing in circuit breakers. Background technique: [0002] Sulfur hexafluoride (SF 6 ) gas has been widely used in high-voltage gas circuit breakers (GCB) due to its excellent insulation and arc extinguishing properties. in SF 6 In the development process of large capacity and miniaturization of circuit breakers, a prominent problem is how to improve the recovery strength of the back-arc medium and reduce the probability of restrike through the optimal design of the arc extinguishing chamber and its matching with the operating mechanism. [0003] In recent years, domestic and foreign attention to SF 6 Magnetohydrodynamics (MHD) simulation of switching arc has done a lot of work, which provides a very effective method for the design and optimization of high voltage ci...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F19/00
Inventor 李兴文贾申利赵虎姜旭
Owner XI AN JIAOTONG UNIV
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