基于安全性的接地阻抗校核的变电站接地网工程验收实践
|
摘要
作为接地网设计的最基本的参数,接地阻抗常成为接地网评价主要强调的单一指标。目前由于征地困难,新建变电站站址土壤条件不理想,导致地网接地阻抗越来越难以满足传统设计值(0.5Ω)的要求,接地阻抗取值合理性问题成为变电站接地网工程建设最为关注的问题之一。本文提出了一种基于安全性的接地阻抗校核方法,根据10 kV金属氧化物避雷器和电缆护层保护器在接地故障期间的能量吸收耐受,确定地电位升极限值,并将吸收的能量与通流容量进行比较,校核地电位升和接地阻抗是否满足要求。该方法较传统方法更科学,在确保安全性的前提下,适当放宽接地阻抗取值,对变电站接地网设计和验收工作具有较好的指导价值。
As the most basic parameter in the substation grounding grid design, the grounding impedance is usually the single index mainly emphasized in the substation grounding grid evaluation. Because of the difficulty of land expropriation at present, the soil condition of the new substation site is unsatisfactory. As a result, the grounding impedance of grounding grid is becoming more and more difficult to meet the requirement of the traditional design value(0.5 Ω). The rationality problem of the grounding impedance value has become one of the most concerned problems in substation grounding grid construction. A security based grounding impedance check method is proposed in this paper. The limit value of the ground potential rise is determined according to the energy absorption tolerance of the 10 kV metal oxide surge arrester and the cable sheath protector during the grounding fault and is compared with the flow capacity to check whether the ground potential rise and the grounding impedance meet the requirement or not. The method is more scientific than traditional methods. Under the premise of security, the proper relaxation of the range of the grounding impedance value has better guiding value to the design and the acceptance check of substation grounding grid.
As the most basic parameter in the substation grounding grid design, the grounding impedance is usually the single index mainly emphasized in the substation grounding grid evaluation. Because of the difficulty of land expropriation at present, the soil condition of the new substation site is unsatisfactory. As a result, the grounding impedance of grounding grid is becoming more and more difficult to meet the requirement of the traditional design value(0.5 Ω). The rationality problem of the grounding impedance value has become one of the most concerned problems in substation grounding grid construction. A security based grounding impedance check method is proposed in this paper. The limit value of the ground potential rise is determined according to the energy absorption tolerance of the 10 kV metal oxide surge arrester and the cable sheath protector during the grounding fault and is compared with the flow capacity to check whether the ground potential rise and the grounding impedance meet the requirement or not. The method is more scientific than traditional methods. Under the premise of security, the proper relaxation of the range of the grounding impedance value has better guiding value to the design and the acceptance check of substation grounding grid.
引文
[1]何金良,曾嵘.电力系统接地技术[M].北京:科学出版社,2007.
[2]张波,何金良,曾嵘.电力系统接地技术现状及展望[J].高电压技术,2015,41(8):2569-2582.
[3]李谦,饶章权,肖磊石.大型接地网多维度评价技术[M].北京:中国电力出版社,2016.
[4]李谦,张波.大型接地网多维度评价及指标校核[J].中国电机工程学报,2018,55(S1):129-136.
[5]李谦,文习山,肖磊石.土壤特性对接地网特性参数影响的数值分析[J].高电压技术,2013,39(11):2202-2209.
[6]谭波,杨建军,鲁海亮,等.接地网电位升对10 kV避雷器的反击仿真分析[J].高电压技术,2013,39(5):1265-1272.
[7]李谦,谭波,文豹,等.大型接地网地电位升控制值的校核[J].电网技术,2018,42(5):1675-1680.
[8]李谦,张波,蒋愉宽,等.变电站内短路电流暂态过程及其影响因素[J].高电压技术,2014,40(7):1986-1993.
[9]李谦,蒋愉宽,肖磊石.变电站内短路电流分流系数实测和分析[J].电网技术,2013,37(7):2060-2065.
[10]李谦,邵建康,张波.基于无线传输相位差比较的变电站接地网地线分流向量及接地阻抗准确测量[J].高电压技术,2014,40(8):2271-2278.
[11]DL/T 475-2017,接地装置特性参数测量导则[S].
[12]李谦.发电厂和变电站接地网安全性状态评估[M].北京:中国电力出版社,2013.
[2]张波,何金良,曾嵘.电力系统接地技术现状及展望[J].高电压技术,2015,41(8):2569-2582.
[3]李谦,饶章权,肖磊石.大型接地网多维度评价技术[M].北京:中国电力出版社,2016.
[4]李谦,张波.大型接地网多维度评价及指标校核[J].中国电机工程学报,2018,55(S1):129-136.
[5]李谦,文习山,肖磊石.土壤特性对接地网特性参数影响的数值分析[J].高电压技术,2013,39(11):2202-2209.
[6]谭波,杨建军,鲁海亮,等.接地网电位升对10 kV避雷器的反击仿真分析[J].高电压技术,2013,39(5):1265-1272.
[7]李谦,谭波,文豹,等.大型接地网地电位升控制值的校核[J].电网技术,2018,42(5):1675-1680.
[8]李谦,张波,蒋愉宽,等.变电站内短路电流暂态过程及其影响因素[J].高电压技术,2014,40(7):1986-1993.
[9]李谦,蒋愉宽,肖磊石.变电站内短路电流分流系数实测和分析[J].电网技术,2013,37(7):2060-2065.
[10]李谦,邵建康,张波.基于无线传输相位差比较的变电站接地网地线分流向量及接地阻抗准确测量[J].高电压技术,2014,40(8):2271-2278.
[11]DL/T 475-2017,接地装置特性参数测量导则[S].
[12]李谦.发电厂和变电站接地网安全性状态评估[M].北京:中国电力出版社,2013.