基于直流线路的低压配电网随机负荷转供方法

随着电动汽车的使用,配电网负荷随机性增加且负荷量增加,当前配电网结构可能无法与负荷的发展相适应。而分布式电源的接入使得部分用电需求较小的配电台区出现了电量剩余。对于地理位置上临近的配电台区,可通过互联线路减轻部分重载台区的负荷,降低随机负荷波动对单个台区的影响。交流互联线路往往存在负荷转功率低的缺陷,且易造成电磁环网,带来网络结构复杂、运行困难等问题。为此,文中提出一种利用直流互联线路实现低压配电台区负荷平衡的方法,采用功率解耦控制方法将负荷在台区之间按照配电变压器容量进行平衡,以降低部分台区的负荷率,同时实现分布式电源功率在低压配电台区的就地消纳。

An Approach for Random Load Transfer in Low-voltage Distribution Network Using DC Tie Lines

Along with the use of electric vehicles, load level increment as well as load of randomness incapacitates the distribution system from secure and reliable operation. Meanwhile, some distribution districts interfaced with distributed resources possess surplus power supply. Under the circumstances, tie lines can be used to relieve the burden of overloaded districts and mitigate the impact of soaring load on a single district, if these districts are adjacent geographically. When adopting AC tie lines, the rate of load transferred is limited, and electromagnetic looped network is likely to take place. An idea of load transfer by DC tie lines is proposed for achieving the goal of balanced load among different distribution districts, where inverters are adopted to interface different transformer districts with common DC system. Decoupled power control strategy is employed to determine the amount of transfer load in accordance with the corresponding capacity of the distribution transformer. The method proposed can reduce load rate while making it possible to locally accommodating the distributed energy resources. This work is supported by National Natural Science Foundation of China (No. 51407017) and National High Technology Research and Development Program of China (863 Program) (No. 2011AA05A107).