本质安全低压直流电路放电理论及数值研究综述

Review of discharge theory and numerical research on intrinsically safe low voltage DC circuits

分析了本质安全电阻性、电感性和电容性电路的放电特性,指出电感性、电容性电路放电能量较大,且放电波形较复杂,而电阻性电路放电特性相对简单。总结了本质安全电感性电路和电容性电路放电机理及其放电数学模型研究现状,给出了放电电流线性衰减模型、放电电流抛物线模型、静态伏安特性模型、动态伏安特性模型、电弧电阻指数模型等的数学表达式。介绍了宏观及微观气体放电数值模拟方法的优缺点:宏观方法计算量小,但只能仿真气体放电的外部特性;微观方法计算量大,但能精确仿真放电过程中各粒子的运动特性。探究了直流放电电路和放电电弧的微观机理,得出了不同电极材料、不同电极间距及不同初始电气参数下,不同表面发射机理如热场致电子发射、场致发射等对气体放电的影响。针对研究现状,提出了本质安全直流电路放电研究需进一步解决的问题:①宏观试验−数学模型表达式复杂、计算量大,部分模型适用范围单一,无法真正实现本质安全电路非爆炸评估。②本质安全电路放电的研究大部分还是基于IEC火花放电装置,影响特定电路参数放电的研究。③放电电弧的数值仿真研究无法定量研究两电极接触分断过程的电弧形成机理。④针对电感性电路、电容性电路的电感、电容对放电电弧特性的影响,还没有更具说服力的研究成果。⑤目前对于电路断路电弧或短路火花如何引爆危险气体的理论研究较少。

The discharge characteristics of intrinsically safe resistive,inductive and capacitive circuits are analyzed.It is pointed out that inductive and capacitive circuits have larger discharge energy and more complex discharge waveforms.The resistive circuits have relatively simple discharge characteristics.The discharge mechanism and mathematical models of the intrinsically safe inductive and capacitive circuits are summarized.The mathematical expressions of different models,such as linear decay model of discharge current,parabolic model of discharge current,static volt-ampere characteristic model,dynamic volt-ampere characteristic model and arc resistance index model,are given.The advantages and disadvantages of the numerical simulation method of macroscopic and microscopic gas discharge are introduced.The macroscopic methods have a small amount of calculation,but it can only simulate the external characteristics of gas discharge.The microscopic methods have a large amount of calculation,but it can accurately simulate the motion characteristics of particles in the discharge process.The microcosmic mechanism of the DC discharge circuit and discharge arc is studied.Under different electrode materials,different electrode distances and different initial electrical parameters,the influence of different surface emission mechanisms such as thermal field emission and field emission on gas discharge is obtained.According to the current research situation,the problems that need to be solved in the discharge research of intrinsically safe DC circuits are put forward.①The macro experiment-mathematical model has complex expression and a large amount of calculation.Some models have a single scope of application and cannot truly achieve the non-explosive evaluation of intrinsically safe circuits.②Most of the research on discharge in intrinsically safe circuits is based on IEC spark discharge devices,which affects the discharge of specific circuit parameters.③The numerical simulation of discharge arc cannot quantitatively study the arc formation mechanism during the contact breaking process of two electrodes.④There are no more convincing research results on the influence of inductance and capacitance of the inductive circuit and capacitive circuit on the characteristics of discharge arc.⑤At present,there are few theoretical studies on how to ignite dangerous gases by electric arc due to circuit break arc or short circuit spark.