Over-voltage Analysis And Protection Study Of Lightning Intrusion Wave In The 35kV Substation

With the progress of social science and technology and the rapid development of economy,the importance of electric energy is more and more obvious.The increasing of electricity consumption has made people more and more demanding for power supply reliability.As the terminal part of power system,The 35 kV substation,is responsible for the distribution of power to customers,and its operational reliability will directly affect the users' reliable electricity consumption.According to the operation statistics,lightning stroke has become an important factor causing the power failure of distribution network,and the damage of electrical equipment is caused by the lightning overvoltage.In severe cases,it will destroy the stable operation of the system,cause large scale blackouts,and produce incalculable economic losses.Among them,the main source of lightning strike in substation is the lightning wave which is invaded by overhead lines.Based on 35 kV substation as the research object,this paper in the ATP-EMTP simulation environment based substation into line 2 km overhead line and substation lightning invasion wave overvoltage model,to carry out the relevant simulation analysis,the main research contents are as follows:First of all,it introduces the current research status of lightning circumvention overhead lines and counter-attack overhead lines and lightning intrusion waves.Secondly,the lightning current model,overhead line model,tower model,insulator flashover model,time-varying resistance model,electrical equipment model in substation are established.Then,the lightning protection simulation calculation is carried out,and the reasonable parameters are set.The impact of lightning strike position,lightning current amplitude,lightning arrester and main transformer on the lightning intruding wave is analyzed,and the specific overvoltage formed on the main equipment in the substation is obtained.At the same time,the effects of lightning line,different types of wire type,line arresters on the lightning resistance level of the line and the overvoltage amplitude of the main equipment in the substation were analyzed.Finally,according to the actual operation of the 35 kV substation,the initial lightning protection measures of the substation have been improved.It is proposed that if only the influence of lightning intruding waves on the main equipment in the substation is considered,the arrester can be placed within 4m from the main transformer.Install a lightning arrester at the entrance of the incoming section;on the basis of comprehensive consideration of the lightning-resistant level of the line and the lightning intruding wave,the arrester can be placed within 4m from the main transformer,and the arrester is installed at the entrance of the incoming section,and at the same time in the 1# pole and hit the 7# pole to install a lightning arrester.