Electric Loss Of 500 KV Overhead Ground Wire Of 500 Common-Tower Double-Transmission Lines

With the rapid development of China's power grid,transmission line level also increased gradually,to ensure transmission lines can work safely and stably,HV and UHV transmission lines usually use two wires.The appearance of double overhead ground wires greatly improved the stability of transmission line operation undoubtedly.But at the same time,the power loss generated by overhead ground line is becoming more and more significant,which brings new problems to the energy saving work of power grid.When the overhead ground line of the transmission line is grounded by tower,induced current will be generated between the overhead ground line and the overhead ground line and the ground,resulting in power loss.Therefore,attention to the application of double overhead ground line has also become a very important issue in the construction of high voltage power grid.This paper aims at the problems of overhead ground lines in different operating conditions of transmission lines,a new simulation model is set up to study and analyze the induced current,induced voltage and power loss of overhead ground line,and a new grounding method is proposed to reduce the power loss generated by overhead ground lines.Firstly,this paper analyzes the protection scope and lightning protection of overhead ground lines.It is clear that transmission lines above 500 kV must be erected along two ground lines.In practical engineering,it is usually chosen to use optical fiber composite overhead ground wire fiber composite ground line and common ground line.Secondly,ATP-EMTP electromagnetic simulation software is used to build a 500 kV twin transmission line for simulation,in the same tower double back transmission line,when the transmission line is runningnormally and the transmission line is running normally,the different operating conditions of the power outage are analyzed theoretically;using EMTP program studies the induction voltage and induction circulation of overhead ground line on the maintenance line.This paper mainly analyzes the factors that affect the inductive voltage and inductive circulation of the ground line of the twin transmission line of the same tower: the wire arrangement,the length of the line,the distance between the wire circuits,and the soil resistivity,so as to obtain the general rules of the overhead inductive voltage and inductive circulation of the twin transmission line of the same tower.Finally,aiming at the existing problems of overhead ground line grounding,this paper proposes the grounding method of odd section grounding and even section transposition method was proposed in this paper.Using the characteristics of 500 kV double overhead ground line induction voltage,the voltage before and after the transposition of the same segment of the ground line is neutralized by the odd-numbered segment transposition of the overhead ground line.The results show that the proposed method can effectively reduce the induction voltage,induction circulation and power loss of overhead ground line.