Study On Abnormal Fuse Mechanism Of 10kV Distribution Network V/V Wiring High-voltage Fuse

The high-voltage electric energy measurement device is an important part of the power grid as a whole of measuring instruments and auxiliary equipment necessary for measuring electric energy.It is also an important basis for electric energy trade settlement.Whether reliable and stable operation directly affects power supply reliability and electric energy trade settlement Fairness.However,during the operation of the high-voltage electric energy measurement device,problems such as measurement abnormalities and device failures often occur,which affect the fairness of the electric energy trade,and even the safety of the power grid in severe cases.According to the statistical data of Zhongshan Power Supply Bureau of Guangdong Power Grid Company,the abnormal fuse failure of the fuse is the most frequent in the highvoltage electrical energy measurement device.More than 6000 sets of high-voltage electrical energy measurement device installed on the site have about 100 failures per year and the failure rate reaches 1.7% Among them,abnormal failures of high-voltage fuses account for more than 50%.In order to ensure the reliability of power metering,this paper has carried out a study on the abnormal fusing mechanism of high-voltage fuses.This paper takes the distribution network system of Zhongshan Power Supply Bureau as a research case,and establishes a 10 k V distribution network simulation model.It sequentially analyzes the electromagnetic type of V / V wiring in transient processes such as short-circuit faults,switch transient processes,and non-simultaneous closing.The voltage at both ends of the voltage transformer branch and the current through the high-voltage fuse.The results show that under the traditional voltage transformer model,there is no serious overcurrent in the transient process of the power system,and it is impossible to analyze the abnormal fusing of the high-voltage fuse.The reason of the mechanism shows that the traditional transformer model has limitations in the transient process.Based on the above research,this paper proposes a distributed parameter model of the electromagnetic voltage transformer that takes into account the capacitive branch of the shielding layer: taking into account the impact of the high-frequency signal in the transient process,the physical segmentation of the transformer is used.Method to establish its distributed equivalent model;starting from the structure of the transformer,considering the influence of the distributed parameters on the characteristics of the transformer,the calculation of the spurious parameters is carried out by means of finite element analysis.After that,the distributed parameter model was used for simulation analysis,and the results showed that the presence of distributed parameters caused a temporary overcurrent condition of the transformer branch at high frequency,which caused abnormal fusing of the fuse.Finally,the improvement measures to replace the traditional ferromagnetic voltage transformer with the resistance voltage divider type electronic transformer are proposed.The principle and structure of the resistance voltage divider transformer are analyzed in detail,and the electronic voltage transformer is built.The simulation model of the transformer was analyzed,and it can be obtained from the simulation results that the resistance voltage divider type voltage transformer can suppress the overcurrent at high frequency,thereby avoiding abnormal operation of the high-voltage fuse and effectively improving the reliability of the high-voltage electric energy measurement device.