Research On Fault Location Method For Multi-parallel Transmission Lines On The Same Tower

Multi-parallel transmission lining on the same tower,as the backbone of China’s power system,takes the heavy responsibility for power transmission.When transmission breaks down,it is a prerequisite to locate and isolate the fault point in order to ensure the safe and stable operation of the power system.However,the structure of multi-parallel transmission lining on the same tower is not unique,the coupling of electrical parameters in different lines is also complex,as a result the previous decoupling analysis method and fault location technology are no longer fully applicable,and the research literature on fault location of some lines with asymmetric parameters is even rare.Therefore,this paper will focus on three different structures of multi-parallel transmission lining on the same tower,analyzing the respective characteristics of line parameters,and propose efficient and practical fault location method corresponding to each line type.(1)Aiming at the problem that it is difficult to solve the double-parallel line location algorithm considering the influence of line distribution parameters,a fault location method based on adaptive particle swarm optimization algorithm is proposed.The distributed parameter model is used in this method,and the fault location equation is constructed according to the voltage distribution along the line.By introducing adaptive particle swarm optimization algorithm,it is transformed into the optimization problem of univariate peak function,so as to locate the fault accurately.(2)This paper analyzes the electrical characteristics of asymmetric double-parallel transmission lines on the same tower.According to the principle that the voltage sequence components calculated from both ends to the fault point are equal after each parallel is decoupled,a fault location equation with multi-dimensional complex hyperbolic function is constructed,in which the fault distance is unknown.In order to overcome the shortcomings of the traditional method of solving the equation such as pseudo roots,the optimal solution is carried out according to the combination of the symmetrical parameter double loop and the adaptive particle swarm algorithm.By analyzing the different real number solutions of the ranging equation,the criterion of the fault point and its loop line is proposed,and the fault line selection function can be realized at the same time.(3)The parameter structure of the weak current and strong magnetic system of fourparallel lines on the same tower is complex,which seriously affects the fault analysis and diagnosis.Firstly,the six sequence component method is employed to decouple two subsystems with different voltage levels,then the incomplete decoupled zero sequence components are extracted to construct a new zero sequence matrix,and then the sequence network is established and the fault location equation is deduced by using the characteristics of the decoupled zero sequence paralleling current components in the lumped parameter model.(4)Three kinds of line models are built by using PSCAD/EMTDC simulation software,and the above fault location algorithms are simulated and verified respectively.A large number of simulation results show that the distance measurement algorithms proposed for each line type can accurately locate the fault point,and are not affected by factors such as transition resistance and system operation mode,and can better meet the corresponding line fault location requirements.