Simulation Analysis And Application Of Overvoltage Lightning For GuangZhou Area Typical Inlet Cable Of 110kV Transformer Substation

Once the overvoltage lightning on the line caused insulation breakdown,it easily lead to power system power outages,which has been widespread concerned.Presently,Guangzhou City 110 kV power grid has gradually adopted the cable terminal tower type from the overhead line conversion cable,which will lead that the over-voltage lightning of the overhead line have a chance to hit the cable system and substation.Traditionally,110 kV substation design adopted the method of the specification.This method mechanically calculate the general value of overvoltage lightning,which could not calculate the maximum of lightning overvoltage and assess its influences.In this paper,a simulation analysis method based on GuangZhou area topical 110 kV cable is proposed to analyse the dynamic characteristics of cable system in an inlet line of 110 kV cable and provide a protection strategy for the lightning protection of the 110 kV cable.The related work is to improve the safety of equipment and the reliability of power supply,Not only could the method reduce the frequency of failure,but also it protect the power system security and the reliable operation.Finally it improve equipment insulation life and engineering economic benefit is of great significance.This paper mainly completed the following main work:First of all,it briefly introduced the lightning damage in Guangzhou area and the characteristics of the 110 kV substation's incoming lines transmitted from the overhead line into short cable.Secondly,it focused on the theory of lightning wave process and the calculation method of overvoltage.PSCAD / EMTDC is selected as the core tool to build a simulation model for the analysis of overvoltage lightning in 110 kV cable sheath.Thirdly,based on PSCAD / EMTDC simulation model of lightning overvoltage,it analysed the maximum overvoltage lightning level of cable sheath and the different load of corresponding protector.The dynamic characteristics of overvoltage lightning are comprehensively grasped.Then it put forward the corresponding overvoltage protection design scheme.At last,the three-line defence scheme of 110 kV substation cable incoming lightning protection system is suggested to put forward.The insulation of earthing and returning line could be optimized after checking calculation.The research work in this paper lays the foundation for the study of overvoltage lightning in a typical incoming line system of 110 kV cable and provides a good reference value for the lightning protection of the corresponding wiring mode.