微网的有限广域一体化保护

Limited Wide Area Integration Protection for Microgrid

相当规模的分布式电源渗透到配电网形成微网后,深刻地改变了原保护配置的机理。结合微网运行结构和特点,在微网继电保护中引入广域保护理念,提出了一种有限广域一体化的微网保护方案。该方案将多分布式电源以闭式环网的接线方式组成一个有限区域,并选取一个集中决策中心,根据故障分量幅值大小以及与负荷电流相位关系实现故障排查与定位。利用差动判据区内故障动作灵敏性与区外故障制动可靠性的特点,提出一种改进的新跳闸判据,实现故障隔离。最后,通过数字仿真,验证了保护方案的正确性与可行性。

With a variety of distributed generators penetrating, the distributed network is changed into a micro- grid. The existing principle of protection configuration should be profoundly adjusted. Considering the opera- tion structure and features of microgrid, the theory of wide area protection is introduced and a limited wide are- a integration scheme is proposed in the paper. In the scheme, the distributed generators form a limited areas in closed loop connection. First, a centralized decision center is selected, and the fault location is determined on the bases of fault component magnitude and phase angle relationship with load current. By using the current differential features of sensitivity in internal fault and reliability in external fault, an improved tripping criterion is proposed in order to isolate the fault segment. Finally, a digital simulation test is verified for the validity and feasibility of the protection scheme.