Research On Fault Location Of Distribution Network Based On PMU

Distribution network has the characteristics of complex structure,variable operation mode,few observation points and so on.It often occurs short circuit fault.Moreover,for a long time,the investment and construction of China's power industry is mainly concentrated in large generating units and transmission network,leading to the development of power distribution network fault location technology is severely restricted,so it is very difficult and urgent to realize accurate fault location.Although there are many theoretical methods of fault location in distribution networks,most of them are difficult to solve the fault ranging problem in distribution network with branches.In recent years,with the gradual development of distribution automation project and researches of synchronous Phasor Measurement Unit(PMU)applicable to distribution network,the high performance of PMU,such as high precision,high sampling rate,clock synchronization and phasor measurement,provide a new idea and solution for fault location in distribution network.It is of great significance to accurately locate the fault,reduce the outage time,reduce the economic losses and improve the reliability of power supply.Based on the idea of fault ranging after fault section location,the fault location strategy of distribution network based on PMU is proposed in this paper,and accurate fault location of distribution network with branches is realized.Firstly,an improved matrix algorithm is proposed to improve the tolerance of the algorithm under fault information omit,the fault section location of the non-single-phase ground short circuit is realized,and method based on zero sequence admittance of sections is applied to avoid the influence of neutral point operation mode on single phase to ground fault section location.Then,the double-ended synchronous and the inter-phase short circuit fault ranging algorithm are deduced by using the distributed parameter line model,and an improved single phase to ground fault ranging algorithm is proposed.Finally,equivalent model of distribution network is established on the basis of fault section location,the faulty branch is identified by the PMU configured at the head and the end of the main line,and the fault location is realized by the proposed hybrid fault ranging algorithm.Namely,the ranging of arbitrary short circuit fault type in main line is realized by applying the double-ended synchronous fault ranging algorithm based on PMU,and ranging of the branch line is realized by the improved single-phase grounding and inter-phase short circuit fault location algorithm.The simulation model of distribution network is established by MATLAB simulation platform to verify the improved single phase to ground fault ranging algorithm and hybrid fault ranging algorithm based on PMU.Different fault types,fault resistance and fault location are set up in the simulation.The simulation results show that the improved single phase to ground fault ranging algorithm has better stability and higher precision,the hybrid fault ranging algorithm is also feasible and effective.Hybrid fault ranging algorithm based on PMU combines the advantages and disadvantages of double-ended method and single-ended method.It is a simple and economical fault location method,which is easy to be popularized in the distribution network.