Research On Protection And Fault Location Of Distribution Network Based On Sending Information On Distribution Terminal

With the large number of inverter distributed power sources are connected to the distribution network,the operation mode of the distribution network is flexible and changeable,which makes the three-stage current protection setting coordination based on the fixed value setting difficult.At the same time,due to the poor operating environment of the distribution network,distribution terminals and local area communication are easily affected.As a result,measurement data obtained by the protection based on local area communication may be missing or incorrect,which affects the protection to identify fault areas.In order to solve the above problems,this paper analyzes the short circuit current expression of distributed power supply,constructs the mapping curve family of short circuit current and node voltage,and then carries out the research on the adaptive protection and fault location method.The practical mapping relationship between fault current and node voltage is constructed.Based on the single machine mathematical model of inverter distributed power supply,the expression of short circuit current is analyzed,and the practical voltage and current mapping relationship is obtained by combining with the measured fault recording data for linearization.On this basis,the relationship between the output of distributed power supply and short circuit current is analyzed,and the practical voltage and current mapping curve family adapted to the different output of distributed power supply is obtained.An adaptive setting method for distribution network current protection considering missing and error of measurement data is proposed.By generating the associated impedance matrix containing the real-time topology information and adjusting the protection value adaptively after iterative calculation,the proposed protection can adapt to the dynamic change of the operation mode of the distribution network.The missing data reconstruction and abnormal data correction algorithm based on generative adversarial network are used to correct the missing and abnormal measurement data,which solves the problem of measurement data loss and error in the adaptive current protection based on local area communication,and realizes the correct and effective removal of fault lines.A regional protection method of distribution network based on switch morphology information is proposed.The redundant information in the region is used to construct the logical criteria for regional protection,and the corresponding protection criteria are configured for different switch forms in the region.The protection criteria can adapt to adjust the action time of local protection,improve the quickness and fault tolerance of the protection system,and strengthen the coordination between local protection.The test results show that the proposed area protection method can operate accurately under the abnormal conditions such as missing or false alarm of measuring device and local protection communication link failure.A fault location method of distribution network based on information fusion and verification is proposed.The electrical characteristics of measurement information are used to classify the reliability level of measuring equipment and reduce the dimension of solution space variables.Based on the Bayesian estimation model,the basic distribution probability of the fault hypothesis variables was obtained,the fault candidate set was established,and the consistency check algorithm of the location results of segment and port was proposed to improve the fault tolerance ability of the location method.The simulation results show that the proposed method has the advantages of convenient implementation and strong fault tolerance compared with the existing method in the operating environment where the measurement information is lost or distorted.