Study On Operating Mechanism And Controller Of Fast Switch

In recent years,our power grid system is gradually becoming a smart grid with strong economy and high compatibility.Circuit breaker,as the most important protection equipment in power system,is the basic condition and key node of smart grid.The improvement of its reliability,intelligence and other performance indicators can better meet the needs of smart grid.Traditional circuit breakers are difficult to adapt to the coordination and unification of power systems at all levels in smart grid because of their slow operation time,low automation and intelligence.The thesis mainly focuses on the operation mechanism and controller of fast switch.In the aspect of fast switching mechanism,firstly,the permanent magnet mechanism is studied,the structure model and working principle of monostable permanent magnet mechanism are analyzed,and the mathematical model is constructed to study the dynamic characteristics.Compared with bistable permanent magnet mechanism,it can effectively alleviate the impact between contacts and has more advantages in closing performance.Secondly,the repulsion force is studied.In order to solve the problem that the traditional eddy current repulsion mechanism has weak backhaul and may fail to open,a method of constructing the double coil disk repulsion mechanism by using the same material parameters of the dynamic and static coils is proposed,which guarantees the synchronization of the force,generates a larger electric repulsion force,and the opening operation is very fast.Finally,combining the characteristics of the two,the structure model of hybrid actuator is designed,which has excellent performance in both switching and closing operation,and can achieve the purpose of fast switching.Combining information technology and modern power electronics technology,an intelligent controller with functions of communication,control and protection is designed.CPLD is used as the core chip in hardware circuit design.According to the overall structure of the system,capacitor charging and discharging,main circuit of switch-off,power conversion and state information monitoring module are designed.The design idea and function of hardware module are studied.According to the functional requirements of hardware circuit,the software design adopts the hardware description language with high standardization and portability.According to the overall functional requirements,the sub-programs of closing,opening and failure state are designed.Combining information technology and modern power electronics technology,an intelligent controller with functions of communication,control and protection is designed.CPLD is used as the core chip in the hardware circuit design.According to the overall structure block diagram of the system,the main circuit of capacitor charging and discharging,the main circuit of switching on and off,the power conversion and the monitoring module of state information are designed.The design idea and function of the hardware module are studied.Now.In view of the functional requirements of hardware circuits,VHDL,a highly standardized and portable hardware description language,is used in software design.According to the overall functional requirements,the sub-programs of closing,opening and failure state are designed.The accurate finite element model of hybrid fast switching actuator is established,and the key influencing factors such as coil turns,external capacitance capacity and voltage in permanent magnet actuator and repulsion mechanism are determined by simulation analysis according to the influencing factors determined by theoretical research.Finally,the experimental verification is carried out on the experimental platform.The measured opening time is less than 3 ms and the closing time is less than 10 ms.The simulation and experimental results show that the performance of the fast switch operating mechanism and its controller studied in this paper is in line with the requirements.