| 10kV power distribution system is directly related to the personal safety of users of power,Electromagnetic voltage transformer system as an important measurement,monitoring equipment,its safe and reliable operation for the economic operation of the system to provide a guarantee.Therefore,to achieve reliable protection of voltage transformers is particularly important.Currently,the 35 kV distribution system is usually taken in the primary side voltage transformer series fuses way to protect the voltage transformer internal fault or their fault line connected to the system.Fuse itself fast-acting characteristic is very good protection of voltage transformer so that fault current can be quickly removed to ensure that the voltage transformer itself and the system is not affected.However,according to the field operation experience,as the system capacity is increasing,the fuse for the protection of Electromagnetic Voltage Transformer often occurs without action or fuse blown abnormal phenomenon,serious lead to the voltage transformer burned,The system of reliable economic operation to bring a great threat.Although the fuse structure is simple,Fuse of a single fuse caused by the frequent replacement will cause varying degrees of power outages,and the fuse link replacement is very troublesome,most of the domestic fuses are expensive from foreign imports,Breaking process likely to affect the environment,and even serious explosion.Therefore,it is necessary to research and design a new device to achieve effective protection of voltage transformer,breaking several protection.First of all,this paper determines to use the circuit breaker vacuum interrupter as the open circuit voltage transformer primary side fault current of main equipment and design scheme of fast electromagnetic tripping mechanism of vacuum interrupter.The opening and closing of the vacuum interrupter with good opening performance canbreak current of a voltage transformer the secondary side of fault,and the breaking process has little effect on the environment.At the same time,design of supporting fast electromagnetic tripping mechanism in voltage transformer fault current can withstand time to achieve rapid vacuum interrupter contact open and closed.Secondly,based on the high voltage side voltage transformer fault current analysis and analysis of advantages and disadvantages of existing fuse protection,the fast electromagnetic tripping device operating characteristics,and the use of three-dimensional modeling software SOLIDWORKS to complete the overall modeling of a novel voltage transformer protection device.At the same time,the analysis of fast tripping device tripping characteristic analysis and electromagnetic theory.By using of the mechanical dynamics simulation software ADAMS and electromagnetic simulation software Ansoft Maxwell to establish the corresponding simulation model,achieved tripping action characteristic curve and the action needed electricity The magnetic force curve of protected device.By comparing the results of theoretical analysis shows that the new protection device can realize the preliminary fault current protection side a voltage transformer protection and fuse protection performance is significantly better than the conclusion.Finally,the completion of the design of novel protection device for processing and assembling an electromagnetic tripping mechanism prototype,and the protection of the pressure tripping test and electromagnetic breaking test,obtained the fast electromagnetic tripping mechanism in pressure spring force and brake spring force curve and release the required electromagnetic force curve,there are some difference between the experimental results and simulation results,but also can draw the conclusion: the new protective device is more reliable in protecting fuse protection,voltage transformer,current tuning action can be smaller and larger scope of protection,and the project has a certain practical value. |
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