This paper examines various aspects of the design process and subsequent field test measurements of a large and complex substation grounding system. The study and measurements show that soil layering and lead interfer...This paper examines various aspects of the design process and subsequent field test measurements of a large and complex substation grounding system. The study and measurements show that soil layering and lead interference can have a significant impact on the appropriate test location that yields the exact substation ground impedance. Applying a specific percentage rule such as the 61.8% rule for uniform soils to obtain the true ground impedance may lead to unacceptable errors for large grounding systems. This poses significant problems when attempting to validate a design based on raw test data that are interpreted using approximate methods to evaluate substation ground impedance, and determine ground potential rise (GPR), touch and step voltages. Advanced measurement methodologies and modern software packages were used to obtain and effectively analyze fall of potential test data, compute fault current distribution, and evaluate touch and step voltages for this large substation. Fault current distribution between the grounding system and other metallic paths were computed to determine the portion of fault current discharged in the grounding system. The performance of the grounding system, including its GPR and touch and step voltages, has been accurately computed and measured, taking into account the impedance of the steel material used of the ground conductors and circulating currents within the substation grounding system.展开更多
The primary aim of the power system grounding is to safeguard the person and satisfying the performance of the power systemtomaintain reliable operation.With equal conductor spacing grounding grid design,the distribut...The primary aim of the power system grounding is to safeguard the person and satisfying the performance of the power systemtomaintain reliable operation.With equal conductor spacing grounding grid design,the distribution of the current in the grid is not uniform.Hence,unequal grid conductor span in which grid conductors are concentrated more at the periphery is safer to practice than equal spacing.This paper presents the comparative analysis of two novel techniques that create unequal spacing among the grid conductors:the least-square curve fitting technique and the compression ratio techniquewith equal grid configuration for both square and rectangular grids.Particle Swarm Optimization(PSO)is adopted for finding out one optimal feasible solution among many feasible solutions of equal grid configuration for both square and rectangular grids.Comparative analysis is also carried out between square and rectangular grids using the least square curve fitting technique as it results in only one unequal grid configuration.Simulation results are obtained by theMATLAB software developed.Percentage of improvement in ground potential rise,step voltage,touch voltage,and grid resistancewith variation in compression ratios are plotted.展开更多
地电位反击造成设备的损坏和人员生命安全是非常值得关注的问题。基于人工触发闪电,布置了共用地网的试验模型,通过引流杆注入真实雷电流,测量了共用接地情况下接地体的地电位升高电压,并对比分析了闪电回击和M分量放电过程引起地电位...地电位反击造成设备的损坏和人员生命安全是非常值得关注的问题。基于人工触发闪电,布置了共用地网的试验模型,通过引流杆注入真实雷电流,测量了共用接地情况下接地体的地电位升高电压,并对比分析了闪电回击和M分量放电过程引起地电位升高电压的波形特征。结果表明：获得触发闪电（T201514）7次回击和16次M分量上升沿10%～90%时间分别为0.4μs和279.7μs,半峰宽度的平均值分别为14.8μs和434.7μs。地电位升高电压波形的上升陡度和半峰宽度相对于回击都更大,将电压波形上升陡度和半峰宽度分别与电流波形的参数相比得到比值为14.0和2.7。M分量电压和电流波形相似,电压波形和电流波形对应参数的比值分别为0.8和1.1。触发闪电回击和M分量峰值的平均值分别为–19.1 k A和–1.3 k A,回击以及M分量的峰值和引起的地电位升高电压峰值有很好的线性拟合关系。将电压峰值和电流峰值相比得到等效接地电阻,雷电流的等效接地电阻明显小于回击。展开更多
文中测量了某500 k V GIS变电站断路器合闸操作及断路器分闸—合闸—分闸操作时智能组件端口骚扰电压和GIS外壳地电位升,研究了GIS设备断路器操作对智能组件端口的电磁骚扰特性。结果表明,该站内断路器合闸时地电位升幅值最大不超过2 30...文中测量了某500 k V GIS变电站断路器合闸操作及断路器分闸—合闸—分闸操作时智能组件端口骚扰电压和GIS外壳地电位升,研究了GIS设备断路器操作对智能组件端口的电磁骚扰特性。结果表明,该站内断路器合闸时地电位升幅值最大不超过2 300 V,但分合分操作时有接近5 000 V;汇控柜端口处的骚扰电压不超过250 V;智能组件端口骚扰电压微脉冲波形上升沿很陡,在3.2~6.8 ns之间,小于前期试验研究结果。该站智能组件端口骚扰电压主频幅值要高于前期实验结果。展开更多
文摘This paper examines various aspects of the design process and subsequent field test measurements of a large and complex substation grounding system. The study and measurements show that soil layering and lead interference can have a significant impact on the appropriate test location that yields the exact substation ground impedance. Applying a specific percentage rule such as the 61.8% rule for uniform soils to obtain the true ground impedance may lead to unacceptable errors for large grounding systems. This poses significant problems when attempting to validate a design based on raw test data that are interpreted using approximate methods to evaluate substation ground impedance, and determine ground potential rise (GPR), touch and step voltages. Advanced measurement methodologies and modern software packages were used to obtain and effectively analyze fall of potential test data, compute fault current distribution, and evaluate touch and step voltages for this large substation. Fault current distribution between the grounding system and other metallic paths were computed to determine the portion of fault current discharged in the grounding system. The performance of the grounding system, including its GPR and touch and step voltages, has been accurately computed and measured, taking into account the impedance of the steel material used of the ground conductors and circulating currents within the substation grounding system.
文摘The primary aim of the power system grounding is to safeguard the person and satisfying the performance of the power systemtomaintain reliable operation.With equal conductor spacing grounding grid design,the distribution of the current in the grid is not uniform.Hence,unequal grid conductor span in which grid conductors are concentrated more at the periphery is safer to practice than equal spacing.This paper presents the comparative analysis of two novel techniques that create unequal spacing among the grid conductors:the least-square curve fitting technique and the compression ratio techniquewith equal grid configuration for both square and rectangular grids.Particle Swarm Optimization(PSO)is adopted for finding out one optimal feasible solution among many feasible solutions of equal grid configuration for both square and rectangular grids.Comparative analysis is also carried out between square and rectangular grids using the least square curve fitting technique as it results in only one unequal grid configuration.Simulation results are obtained by theMATLAB software developed.Percentage of improvement in ground potential rise,step voltage,touch voltage,and grid resistancewith variation in compression ratios are plotted.
文摘地电位反击造成设备的损坏和人员生命安全是非常值得关注的问题。基于人工触发闪电,布置了共用地网的试验模型,通过引流杆注入真实雷电流,测量了共用接地情况下接地体的地电位升高电压,并对比分析了闪电回击和M分量放电过程引起地电位升高电压的波形特征。结果表明：获得触发闪电（T201514）7次回击和16次M分量上升沿10%～90%时间分别为0.4μs和279.7μs,半峰宽度的平均值分别为14.8μs和434.7μs。地电位升高电压波形的上升陡度和半峰宽度相对于回击都更大,将电压波形上升陡度和半峰宽度分别与电流波形的参数相比得到比值为14.0和2.7。M分量电压和电流波形相似,电压波形和电流波形对应参数的比值分别为0.8和1.1。触发闪电回击和M分量峰值的平均值分别为–19.1 k A和–1.3 k A,回击以及M分量的峰值和引起的地电位升高电压峰值有很好的线性拟合关系。将电压峰值和电流峰值相比得到等效接地电阻,雷电流的等效接地电阻明显小于回击。
文摘文中测量了某500 k V GIS变电站断路器合闸操作及断路器分闸—合闸—分闸操作时智能组件端口骚扰电压和GIS外壳地电位升,研究了GIS设备断路器操作对智能组件端口的电磁骚扰特性。结果表明,该站内断路器合闸时地电位升幅值最大不超过2 300 V,但分合分操作时有接近5 000 V;汇控柜端口处的骚扰电压不超过250 V;智能组件端口骚扰电压微脉冲波形上升沿很陡,在3.2~6.8 ns之间,小于前期试验研究结果。该站智能组件端口骚扰电压主频幅值要高于前期实验结果。
