Study On Fault Location Schemes For Power Grid By Coordinating The Distributed And Centralized Traveling Wave Measurements

Transmission lines are an important part of power grid and one of the components with the highest failure rate.The research shows that in the power transmission of the transmission network,compared with other lines,a few critical lines play a more important role.If these critical lines withdraw from operation due to failure,the power supply stability of the network will be greatly reduced,and even further develop into large-scale chain failure,which will eventually lead to the occurrence of the blackout.Therefore,these critical lines should be strengthened and monitored in priority,including determining the fault location more reliably and accurately after the fault occurs,so as to facilitate the maintenance personnel to eliminate the fault and repair the hidden trouble of partial insulation of the line in a timely manner,and to avoid the occurrence of chain fault or even power failure to the greatest extent.Based on this,from the identification of critical line in turn,the fault location of the critical lines and non-critical lines of three aspects,the trinity,distributed along the critical on a line by considering installing multiple popular electric wave measuring point and the entire network voltage traveling wave measuring point,partly on the substation centralized furnish with measuring the way of distribution and concentration of the grid line fault location,the gauge and measuring unit costs at the same time,can obtain precise positioning as a result,better adapt to the operation characteristics of the grid.For identification of the critical lines of the grid,the existing critical line identification approach is mostly single or running state from the grid topology degree of critical research lines,often one-sided critical line identification results,so this paper proposes a combination circuit state of structure importance and the importance of critical circuit identification method.From the perspective of structure,the power flow parameters of the line are adopted.In the view of state,two evaluation indexes are adopted.One is the improved entropy of power flow transfer based on the traditional entropy of power flow transfer,considering the transmission margin of the remaining lines in the system,and introducing the overload risk coefficient.The other is the total voltage deviation rate of the load nodes.Using the method of comprehensive integration based on game theory fusion of various subjective and objective weights of evaluation indexes,the synthesis weights,and finally will be after the normalization of the evaluation indexes weights according to the corresponding comprehensive weighted summation,the circuit of the index is used to identify the critical circuit,and carries on the simulation analysis in the IEEE30 node system,this paper is verified the effectiveness of the critical circuit identification method.For improving the critical circuit of the problem of the precision of traveling wave fault location method,considering the advantages of multiple measurements compared to the ordinary double end point measurement,by shortening the fault section to reduce wave signal attenuation and distortion,which benefits the accurate detection of Bob arriving time line and wave velocity of the advantages of online measurement,this paper puts forward the critical transmission line fault location algorithm based on distributed measurement,consists of the following three parts.Firstly,a distance setting method for measuring equipment based on the observability of traveling wave signals is proposed,which can ensure that weak traveling wave signals can be reliably detected at the set distance of measuring points.Then through the analysis of electricity popular wave in the process of spread along the first wave amplitude attenuation law of each frequency component in the head,found that for the same frequency component,the ends of the fault section and perfect section measuring point frequency component amplitude ratio difference,according to the characteristics of initial traveling wave frequency component is proposed based on multipoint the fault section judgement method of amplitude ratio.Finally,the distributed traveling wave fault location method based on three-terminal current flow is used to measure the traveling wave velocity and calculate the fault location.In IEEE30 node system of different critical circuit simulation of the different fault condition,based on a large number of simulation results validate the proposed distributed measurement of critical transmission line fault location algorithm has stronger adaptability,robustness and high positioning accuracy,especially for the critical to long lines,the positioning results compared with using the method of double side line length,has a higher precision,the advantage is more obvious.For the rest of the non-critical line fault location in the network,this article meter and the cost of measurement device,based on measuring device configuration optimization is proposed non-critical line fault location algorithm,first of all,on the basis of the principle of extended double side positioning to ensure that the entire network have requirement of observability for every non-critical lines,in the configuration of the power grid node voltage traveling wave number of measuring point as the goal,at least for measuring devices,the optimal configuration scheme.Based on the optimal configuration of measuring points,the fault lines are divided into two types: non-blind line and blind line.Finally,the effectiveness and reliability of the algorithm are simulated and verified in IEEE30 node system,and the results show that the proposed algorithm has high positioning accuracy,good fault tolerance and error resistance,and high reliability under the condition of optimal configuration.The paper contains 27 figures,28 tables and 89 references.