Different types of lightning air terminals have been designed over the years.Concern regarding the effect of different types of air terminals,especially the early streamer emission(ESE)-type,remains controversial.This...Different types of lightning air terminals have been designed over the years.Concern regarding the effect of different types of air terminals,especially the early streamer emission(ESE)-type,remains controversial.This paper describes the discharge characteristics of different types of air terminals,two of which are quite similar to the ESE-type dynasphere,and concludes that the tested non-standard air terminals have discharge characteristics similar to those of Franklin rods and that their lightning protection performance should be similar.展开更多
Mutual influence may be driven by different models and operating mechanisms of grounding systems in multi-in-one substations.Even equipment damage and personal injury will occur in the event of a short-circuit or ligh...Mutual influence may be driven by different models and operating mechanisms of grounding systems in multi-in-one substations.Even equipment damage and personal injury will occur in the event of a short-circuit or lightning strike.To meet the construction requirements of different multi-in-one substations,two typical application modes of grounding systems in multi-in-one substations are analyzed in this paper:plane and longitudinal layout schemes.First,the safety index and withstand voltage of secondary equipment in multi-in-one substations are introduced.Second,the plane layout scheme of grounding grids is examined.Based on a 35-kV multi-in-one substations in Shanghai,it was verified that the overall grounding grid needs to be laid to meet the safety of secondary equipment in the station.Finally,considering that it is feasible to rebuild the upper layer of a substation,the longitudinal layout scheme of the grounding grid in multi-in-one substations is also examined.Safety assessment is carried out in terms of aspects such as short-circuits and lightning strikes,and relevant optimization construction methods are analyzed.In this study,a real 35-kV substation in Shanghai was selected as an example.Simulation and field tests based on Current Distribution,Electromagnetic Fields,Grounding and Soil Structure Analysis(CDEGS)software verified that the proposed construction scheme can achieve safe operation of multi-in-one substations.This construction idea can also serve as a reference for the future construction of multi-in-one substations.展开更多
The modelling of the distribution transformer winding is the starting point and serves as important basis for the transformer characteristics analysis and the lightning pulse response prediction.A distributed paramete...The modelling of the distribution transformer winding is the starting point and serves as important basis for the transformer characteristics analysis and the lightning pulse response prediction.A distributed parameters model can depict the winding characteristics accurately,but it requires complex calculations.Lumped parameter model requires less calculations,but its applicable frequency range is not wide.This paper studies the amplitude-frequency characteristics of the lightning wave,compares the transformer modelling methods and finally proposes a modified lumped parameter model,based on the above comparison.The proposed model minimizes the errors provoked by the lumped parameter approximation,and the hyperbolic functions of the distributed parameter model.By this modification it becomes possible to accurately describe the winding characteristics and rapidly obtain the node voltage response.The proposed model can provide theoretical and experimental support to lightning protection of the distribution transformer.展开更多
基金partly supported by National Natural Science Foundation of China(No.51577098)the State Grid Corporation of China,and China Southern Power Grid
文摘Different types of lightning air terminals have been designed over the years.Concern regarding the effect of different types of air terminals,especially the early streamer emission(ESE)-type,remains controversial.This paper describes the discharge characteristics of different types of air terminals,two of which are quite similar to the ESE-type dynasphere,and concludes that the tested non-standard air terminals have discharge characteristics similar to those of Franklin rods and that their lightning protection performance should be similar.
基金supported by National Natural Science Foundation of China(No.92067105)the science and technology project of State Grid Shanghai Municipal Electric Power Company(No.5209211900VD).
文摘Mutual influence may be driven by different models and operating mechanisms of grounding systems in multi-in-one substations.Even equipment damage and personal injury will occur in the event of a short-circuit or lightning strike.To meet the construction requirements of different multi-in-one substations,two typical application modes of grounding systems in multi-in-one substations are analyzed in this paper:plane and longitudinal layout schemes.First,the safety index and withstand voltage of secondary equipment in multi-in-one substations are introduced.Second,the plane layout scheme of grounding grids is examined.Based on a 35-kV multi-in-one substations in Shanghai,it was verified that the overall grounding grid needs to be laid to meet the safety of secondary equipment in the station.Finally,considering that it is feasible to rebuild the upper layer of a substation,the longitudinal layout scheme of the grounding grid in multi-in-one substations is also examined.Safety assessment is carried out in terms of aspects such as short-circuits and lightning strikes,and relevant optimization construction methods are analyzed.In this study,a real 35-kV substation in Shanghai was selected as an example.Simulation and field tests based on Current Distribution,Electromagnetic Fields,Grounding and Soil Structure Analysis(CDEGS)software verified that the proposed construction scheme can achieve safe operation of multi-in-one substations.This construction idea can also serve as a reference for the future construction of multi-in-one substations.
基金supported by the National Key Research and Development Plan of China under Grant(2016YFB0900600XXX)
文摘The modelling of the distribution transformer winding is the starting point and serves as important basis for the transformer characteristics analysis and the lightning pulse response prediction.A distributed parameters model can depict the winding characteristics accurately,but it requires complex calculations.Lumped parameter model requires less calculations,but its applicable frequency range is not wide.This paper studies the amplitude-frequency characteristics of the lightning wave,compares the transformer modelling methods and finally proposes a modified lumped parameter model,based on the above comparison.The proposed model minimizes the errors provoked by the lumped parameter approximation,and the hyperbolic functions of the distributed parameter model.By this modification it becomes possible to accurately describe the winding characteristics and rapidly obtain the node voltage response.The proposed model can provide theoretical and experimental support to lightning protection of the distribution transformer.
