Research On Fault Location Algorithm For Double-circuit Transmission Lines Based On Six-sequence Component Method

Because the economy of modern society is constantly developing,higher requirements are placed on energy.The increasing power load requires modern power systems to have sufficient transmission capacity to deliver sufficient power to the load center.However,as the size of the transmission line increases,it will occupy more transmission line corridors,resulting in a decline in economy.Two transmission lines share the same tower,which can save transmission line corridors,save investment,improve economic efficiency,increase transmission capacity,help improve the stability of power system,meet the needs of modern power systems,and therefore in transmission systems widely used.However,the double-circuit transmission line has a long transmission distance.If the fault location can be found accurately and timely after the fault,it can not only reduce the workload of the line-punching workers,reduce the labor cost,but also help to quickly repair the faulty line and ensure the reliability of the power supply.However,the structure and fault type of the double-circuit transmission line on the same pole are relatively complicated.Because of the small distance between the two return lines,the electromagnetic influence is intensified,and the coupling capacitance between the phases and the line increases,ignoring the coupling capacitance between the phases and the line will cause the accuracy of the fault location results is degraded,and complex fault types make fault location more difficult.This paper introduces the six-sequence component method as an analysis method for fault characteristics of double-circuit transmission lines on the same pole.The six-sequence component method can transform the voltage and current after the line fault into six symmetric sequence components,which can simplify the complex fault analysis problem and facilitate the analysis of fault characteristics of various types of faults.Therefore,based on the six-sequence component method,this paper analyzes the fault characteristics of different fault types,and hopes to obtain a fault feature that exists in any fault type,and analyzes the characteristics of the fault and the transmission line distribution parameter equation.In the case of using the least amount of peer data,the fault location function is constructed with general fault characteristics,so that it can be used in any fault type and do not need to distinguish fault types.Accurate fault location can be achieved and the work pressure of communication system after the fault can be mitigated.Firstly,the distributed parameter model of the double-circuit transmission line is established.The voltage and current after the fault of the double-circuit transmission line are decoupled according to the six-sequence component method.The fault characteristics of the double-circuit transmission line are analyzed,and the fault sequence network diagram is constructed for the next constructing faults location equation.Secondly,according to the fault characteristics and complex series network chart of different fault types,Explain that there are common positive sequence in any fault type,which means that the fault location function is constructed by common positive sequence can be used in any fault type.Next,based on the distribution parameter equation of the transmission line,the fault location equation is constructed,and the fault data of the fault location equation is simplified by analyzing the characteristic of fault location equation.After that,the simulation model of the double-circuit transmission line system is built,and the voltage and current after fault at both ends of the line are obtained,which are decomposed into six-sequence components,and the data required for ranging is substituted into the fault location equation to study the change trend of the fault location function.The trend is to find a solution to reduce the number of iterations while satisfying the accuracy.Finally,verify the accuracy and effectiveness of the fault location method proposed in this paper under different fault locations,different fault types and different transition resistances by simulation.