| Distribution network plays a crucial role in power distribution network as a link the transmission network and demand side.However,the traditional fault location method is not applicable because of the distribution of distribution network,the complexity of the topology,the wider coverage area,and the access of distributed generation(DG)in recent years.Distribution lines are widely used in urban areas,rural areas,its operation directly affect the end-user power quality.If the distribution network failure,especially with the branch of the distribution network single-phase ground fault for rapid and effective positioning,which the entire power system stability and safety and economic operation are of great significance.However,most of the distribution network fault location at this stage relies on the need for precise time-finding system,the requirements of the communication equipment is more stringent,the cost is bigger,the majority of rural distribution network adaptability is poor.Single-phase ground fault is the most frequency fault.In the event of a single-phase earth fault,the non-fault phase voltage rises to line voltage,and the resulting overvoltage is likely to cause the device to burn down and cause an arc to cause a short circuit between phases.For many years,domestic and foreign scholars have paid much attention to the problem of single-phase earth fault,and proposed different fault location methods.However,due to the complexity of the distribution network itself and other reasons,the accuracy of fault location has been not high.In practical application,the effective way is still using the pull line selection line with artificial inspection line to find the point of failure,this approach is not only time-consuming and labor-saving power to reduce the reliability of the grid,nor fit the contemporary distribution network to the development trend of automation.Based on the above discussions,this paper presents a multi-branch fault location method for distribution network based on dual frequency signal injection.In this method,in order to avoid the interference of the harmonic,choose to use the signal source to the branch distribution network with two different frequency of high frequency signal,through the extraction of voltage and current signals,and according to the transmission Equation,traverse the line length,and finally use the diagnostic letter to solve the fault distance.In this paper,the single-phase-to-ground fault location of the distribution line with the straight line and the branch structure is modeled and simulated.Based on the frequency of the true fault,the true fault value is constant and the value of the false fault is different Criterion,effectively measure the true fault distance,remove the equivalent fault.The simulation results show that the proposed method can quickly and accurately realize the effective identification and fault distance measurement of straight line and branch distribution line fault,which is a more effective method of distance measurement. |
