基于最低合理可行准则的接地网安全风险评估

摘要

目前我国的接地网安全设计要求依靠设计规范完成.规范中把人体电阻、土壤表层电阻率及接地短路存在的时间作为固定值来计算,实际上人体电阻、土壤表层电阻率及接地短路存在的时间随着各种因素在较大范围内变动,因此考虑影响的随机特性才能更加全面地评估接地网的安全风险.该文综合考虑接地网所处的环境、人员出现的概率等,计算人身安全事故的总概率.采用最低合理可行(ALARP)准则风险评价体系对接地网进行安全评价,对落入不同区域的风险概率进行相应的风险管理,能够降低接地网的改造费用.为电网运行和设计部门提供了一种新的接地网评价方法.%At present,the safety design of grounding grid in our country depends on the design specification.The resistance of the human body,the surface resistivity of the soil and the time of grounding short circuit are as fixed value in design specification.In fact,the resistance of the human body,the surface resistivity of the soil and the time of grounding short circuit change in a wide range with various factors.Therefore,it is necessary to consider the influence of random characteristics to evaluate the security risk of grounding grid.In this paper,consider the environment of the grounding grid and the probability of human appearance,so as to calculate the probability of the total personal safety accident.Evaluate the safety of the grounding grid using as low as reasonably practicable (ALARP) principle in the risk assessment system and carry out corresponding risk management for different regions of risk probability.It can reduce the cost of the grounding grid,and provide a new method for the evaluation of the grounding grid for the operation and design department of the power grid.