Research On Fault Location Algorithm For Four-Parallel Transmission Lines On Same Tower

In terms of power grid construction,the planning and construction of overhead transmission lines is becoming more and more difficult for some cities with rapid economic development is lack of land resource,four-parallel transmission lines on the same tower(FPTL)and teed structure consisting of four-parallel transmission lines on the same tower(teed structure consisting of FPTL)can effectively save the occupancy rate of land construction,so that two overhead transmission lines get great promotion.But the new problem comes along,the complicated circuit electromagnetic coupling makes the fault analysis and fault location of transmission line become more difficult.This dissertation researches on fault location algorithm of FPTL and the teed structure consisting of FPTL.The research and summary of this paper are as follows:1.According to the structure of the four circuit transmission lines on the same tower,this paper studys and analysises of the electrical characteristics of transmission line parameters,using the mind which derives the symmetrical component method and the six sequence component method to derives the 12 sequence component method,and the fault sequence network as well,as a result,in order to lay a theoretical foundation for the fault analysis and fault location research of the FPTL and the teed structure consisting of FPTL in this paper.2.According to the current and voltage components of each phase of the FPTL,fault location algorithms based on e sequence of positive sequence fault components and f sequence of positive sequence fault components are proposed through extracting the corresponding sequence fault component,by comparing the advantages and disadvantages of the two algorithms,it is clear that these two different fault location algorithms are suitable for what kind of fault.3.A practical algorithm for fault location of transmission lines is proposed,which is based on distribution parameter model of transmission line and using the 12 sequence component method then equivalenting to a two port(47)equivalent circuit for the FPTL,for the theory of two port network,the fault location function of complex coefficient is established.The proposed algorithm is simulated by PSCAD/EMTDC model,and the simulation results verify the feasibility and accuracy of the proposed algorithm.4.For the FPTL parameter decoupled after the establishment of the long linetransmission line equation is very difficult to solve problems.In this paper,the optimization of transmission line fault location equation,then introduce improved ant colony algorithm,the fault location problem is transformed into a suitable for ant colony algorithm for function optimization problems.5.A new fault location algorithm is proposed for the teed structure consisting of FPTL,which is based on the characteristics of fault transition resistance is purely resistive,researched and analysised of the single-phase grounding,two phase grounding,relationship between sequence components phase to phase short circuit and three-phase short circuit fault,the fault location algorithms don't need determine the fault branch can be fault location,is not affected by the T node position and high resistance fault,the fault location accuracy is high.