一种基于电压源型多端直流输电的供电系统

针对目前单个电压源型FACTS装置只能抑制和消除某一种特定的电能质量问题,提出了一种能综合控制电能质量的新供电方案,其核心是将电压源型多端直流输电系统应用于向重要负荷供电的方案设计。介绍了该供电方案的系统结构,并设计了相关的控制器。一电压源型五端供电系统在几种典型异常运行工况下对重要负荷供电影响的数字仿真表明,电压源型多端直流输电系统是实现电能质量综合控制的有效供电方案。

Supply System Based on VSC-MTDC System

With the development of control techniques,power electronic techniques and energy storage techniques,a wide diversity of solutions to power quality problems is available.At present,many FACTS devices are used to improve power quality.For example,active power filters can be used to reduce harmonics while D-STATCOM,dynamic voltage restorers and UPS are all used to depress voltage fluctuation,flicker,voltage swell and interruption etc.However,a single FACTS device illustrated above can be dedicated to suppress or eliminate only one kind of special problem on the power quality.Aiming at this situation,a new power supply scheme to realize the integrated control of the power quality is proposed in this paper.The kernel of this scheme is that the VSC based multi-terminal HVDC system is used to supply important loads.The system configuration of the scheme is introduced and the related controllers are designed.The current decoupled compensation and the voltage feed-forward compensation are adopted for the controller of the converter.At the same time,multi-point DC voltage control strategy is proposed for stability control of the multi-terminal HVDC system,which is able to improve power balancing ability of the MTDC system and enhance reliability of system operation.Based on a VSC five-terminal power supply system,digital simulations are implemented to study the effects of the system on the supply to the important loads in several typical abnormal operating conditions.The results show that the VSC based multi-terminal HVDC system is effective to realize the integrated control of the power quality.