Design And Research On The New Type Of12kV Inflatable Vacuum Circuit Breaker

With the construction and development of the smart power grid, it has higher requirements on the control and protection devices in power system, and the intelligent switchgear becomes the development trend. In recent years, with the inspiration of the national policy of vigorously developing the urban and rural economy, the development of urban and rural areas’ economy enjoys a rapid growth. Consequently, the electricity consumption becomes higher and the request for the reliability of power switchgear becomes stricter. Based on the Water pressure up Case Configuration of12kV load switch, the thesis describes a new type12kV vacuum circuit breaker (VCB) in this paper. The configuration is fully-enclosed, moisture-proof, condensation-proof, and it is applicable to those high temperature and humid areas. In addition, there are some other advantages, such as stable performance, compact structure, small size, light-weight, etc. The permanent magnetic force (PMA), which can not only achieve manual or electric opening and closing operation but also carry out the remote control, is adopted to be operating mechanism of the new type VCB. What’s more, with a suitable controller, power distribution automation can come true.In order to study the PMA’s characteristics, the paper adopts the electromagnetic analysis software ANSOFT to conduct simulation researches on static and dynamic characteristics, which can optimize the model size to meet the CB’s technical requirements. In this part, it does some analyses about the influence on the opening characteristics with different capacitor voltage and on the closing characteristics with different capacitor voltage and coil turns. Moreover, it builds an automatic reclosing system to measure the reliable performance of PMA and its control circuit. According to the results, a prototype is produced and present in the paper. The control system of PMA, which takes ATmegal6as the main control unit and adopts IGBT bridge circuit as discharge circuit, completes the type test of mechanical properties of PMA. The results show that the performance of PMA is good, and it can drive the circuit breaker to open, close and automatic reclose very well.Furthermore, with the new type of small Water pressure up Case Construction and compact structure, the compact structure enables the distance among three phases closer. In order to analyze its insulting property, ANSOFT electric field solver is adopted to conduct simulation analysis. It conducts lmin power frequency withstand voltage simulation analysis with adding42kV to the movable and static ends of three phases and lightning impulse voltage simulation analysis with adding75kV to the movable and static ends of AB phases at the closed position. Moreover, it conducts lighting impulse voltage simulation analysis with adding75kV to the movable ends of AB phases at the open position. The results present that the new type construction with pre-pressure0.12MPa SF6(20℃) has good insulating properties. In order to further assess its insulation capability, it conducts the type test of insulating property in a national test station. The results show that the new type circuit breaker has a good frequency withstand voltage level and the ability to withstand lighting impulse voltage.