基于耦合负压原理的10kV直流负荷开关设计

Design of 10 kV DC Load Switch Based on Coupled Negative Voltage Principle

为满足柔性直流配电系统负荷电流频繁投切对开关操作寿命的高要求,解决直接采用直流断路器方案成本高、体积大的难题,文中研究了一种基于耦合负压原理的直流负荷开关方案。首先对其拓扑和工作原理进行了介绍,然后设计了基于双动结构和电磁斥力机构的主支路快速机械开关、基于耦合负压装置的换流单元和采用反串联拓扑的电力电子开关阀单元,最后,根据苏州某换流站工程需求,研制出10 kV耦合负压型直流负荷开关样机并进行试验验证。结果表明:所研制的10 kV直流负荷开关可在3 ms内开断额定电流和最大开断电流,且能连续动作,体积为目前国内同等参数最小,并具有低损耗、高机械寿命和高可靠性的优点,完全满足工程要求,同时为后续直流负荷开关产品的开发提供了参考。

For meeting the requirements of frequent switching of load current of flexible DC power distribution system to the operation life of switchgear and solving the difficulty of high cost and large volume due to the direct use of DC circuit breaker,a kind of DC load switch scheme based on couple negative voltage principle is studied in this paper.Firstly,its topology and working principle are introduced.Then,the fast mechanical switch in the main branch based on double-acting structure and electromagnetic repulsion mechanism,the converter unit based on the coupled negative voltage device and the power electronic valve unit using the anti-series topology,are designed respectively.Finally,according to the engineering requirements of a converter station in Suzhou,a 10 kV coupled negative voltage DC load switch prototype is developed and verified by tests.The result shows that the developed 10 kV DC load switch can frequently interrupt the rated current and the maximum breaking current within 3 ms,the volume at present is the smallest with the same parameters in China,and it has the advantages of low loss,high mechanical life and reliability.It fully satisfies the engineering requirements and,at the same time,provides a reference for the development of subsequent DC load switch products.