| The lightning protection of substations is generally designed in accordance with engineering specifications.In the management of substation operation,the power grid company seldom makes periodic quantitative evaluation of lightning protection level of substation.The management level of substation lightning protection facilities is relatively traditional,and there are still cases of lightning damage to substation equipment.EMTP(Electro-Magnetic Transient Program)is a widely used electromagnetic transient simulation software,which is widely used in academic,scientific research,design and simulation fields,but it is not often used in power grid company's substation operation.At present,there are few studies on quantitatively evaluating lightning protection level of substation by using EMTP simulation software to construct substation simulation model.Based on the 220 kV Huilan Substation in Qingyuan City and according to the actual situation of the Substation,the whole substation model is constructed by EMTP simulation software,and the lightning protection capability of substation and the improvement effect of three lightning protection measures are quantitatively evaluated in this paper.The research provides a replicable and referential solution for improving the lightning protection capability of substation.Firstly,three types of lightning strike on substation are analyzed,including lightning wave directly hitting substation,overvoltage caused by induced lightning in substation and lightning wave invading along transmission line.Through the calculation and analysis of three types of overvoltage,the intrusion forms of lightning wave which need to be simulated are determined.Then,according to the actual situation of 220 kV Huilan Substation in Qingyuan City,EMTP simulation models of transmission tower,transmission line andequipment in power station are established.And the overall EMTP simulation model of 220 kV Huilan Substation is built.It provides a complete solution for building EMTP simulation model of other substations.Two improved methods,EMTP simulation model of lightning arrester aging with time and EMTP simulation model of insulator flashover considering rainwater factor,are proposed in this paper,.Finally,based on the setting of simulation parameters such as lightning stroke mode and power frequency phase angle,The lightning protection capability of 220 kV Huilan substation under normal operation mode and extreme conditions is analyzed.The effects of three lightning protection enhancement measures such as reducing tower grounding resistance,erecting coupling ground wire and increasing arrester array are compared.The lightning protection capability of 220 kV Huilan substation is simulated after taking three kinds of lightning protection enhancement measures.The simulation results show that the 220 kV Huilan substation can defend against lightning attack in extreme conditions after three kinds of lightning protection measures are adopted. |
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