| According to statistics,after the transformation of urban and rural power grids,the main network fault accounts for only 10%,while branch network and client fault accounts for 90%.The best way to solve the safety of distribution network operation is to install fast-switching device,remove the fault equipment from the system quickly,and send power to the fault circuit quickly,so as to improve the security and reliability of power supply.Therefore,in the process of building an international first-class distribution network,before realizing the time synchronization of wide-area operation parameters and wireless communication secrecy technology to meet the remote control technology of distribution network,it is necessary to minimize the short-term blackouts and electrical damage caused by power cut-off.It is urgent to carry out senseless blackouts in low-voltage distribution network.Breakthrough in power regulation technology will improve the level of safe and reliable power supply in distribution network.This paper studies the application of sensorless power regulation technology in 400V voltage level.In view of the long power cut-off time in the process of switching power supply,it focuses on improving the function of automatic switching device,integrating circuit breaker and arc extinguishing device,and using single chip computer to program and control switch to achieve the goal of sensorless switching power supply customers.In the future,the upgrading of distribution maintenance mode and the adjustment of distribution mode among different power supply lines will lay a solid foundation.Firstly,this paper describes the development status of sensorless automatic switching devices at home and abroad,and points out the problems to be solved in this paper,combining with the statistical analysis of low-voltage faults in the work,and puts forward the requirement analysis of sensorless switching devices.Based on the functional analysis of the automatic switching device of”first closing then closing,and "first closing and then closing",the dual-voltage automatic switching device of "first closing and then closing" is established,and the requirements of functional modules are decomposed in turn,the equipment that meets the functional requirements is selected,and the best scheme of functional realization is determined,so as to shorten the automatic switching time of dual power supply.The purpose is less than 60 ms.Secondly,in practical engineering applications,through theoretical analysis and combined with practical application scenarios,I/O port functions of monostable permanent magnet mechanism,vacuum interrupter and PIC MCU are studied and designed,and program development is completed by C language programming.Finally,the circuit and control strategy are calibrated through debugging experiments,and the field test of the automatic switching device of double power supply without sensing in low-voltage station area proves that it can realize the non-sensing power regulation for industrial and office loads,and achieves the original design purpose.At the beginning of 2019,the first 10 kV intelligent distribution room in Shandong Province,400 V bus side of Chunjiang Yuan distribution room in Zhangdian District,Zibo City,was equipped with low-voltage station area non-perceptual dual-power automatic switching device,which was applied in the process of equipment overhaul and fault treatment in the station area.During the process of power switching,industrial and residential customers did not know the whole process of inductance stopping.It has produced enormous social,safety and economic benefits. |
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