新型直流断路器拓扑及在多端柔直工程中的仿真研究

Research on A Novel Topology of DC Breaker and Its Application in Simulation of Multi-terminal VSC-HVDC Project

直流断路器作为发展柔性直流输、配电网的关键设备仍然存在诸多技术挑战:在设备层面,要求直流断路器的拓扑满足强关断能力、高可靠性和低成本等要求;在系统层面,要求直流断路器结合系统故障特性,具备合理的参数配置和控制保护方案。为此,提出一种新型直流断路器拓扑,阐述其结构、工作模式并设计开关器件的均压电路参数;结合实际工程建立仿真模型,基于直流故障电流特性,为直流断路器设计相应的参数与运行控制方法。结果表明,该拓扑及其控制保护策略在显著降低设备成本的同时,能够有效清除系统故障,同时保证直流断路器各部分元件的安全运行。

It still has many challenges for DC breaker operating as a critical equipment for the development of flexible DC transmission and distribution power grid. In terms of equipment, it requires that the topology of the DC breaker should have strong breaking ability, high reliability and low cost. In terms of power system, the DC breaker should have reliable and effective parameter design as well as control and protect strategies based on the system fault characteristics. Therefore, this paper propose a new topology of the DC breaker to solve above problems, introducing the structure, working modes and design methods of equalization circuit parameters in detail. On this basis, the paper establishes a simulation model according to the parameters of a real project, and investigates the fault current characteristics of the three-terminal VSC-HVDC system, in order to design the parameters as well as the operating and control methods for the DC breaker. The results show that the proposed topology can not only decrease the cost, but also eliminate the fault reliably and ensure the stable operation of each element in the DC breaker.