主动配电网保护方案的研究

Study on Solutions for Active Distribution Grid Protection

主动配电网中含有分布式电源,故障电流的方向和幅值发生变化,传统配电网保护会因此发生误动或拒动。目前提出的解决方案大多需要引入电压信息,而配电网一般不具备此条件。文章研究了适用于主动配电网的保护技术,提出不需电压信息的方向元件,该方向元件利用母线上3条以上线路的故障分量电流相位来判断故障方向,灵敏度高。提出4种不需电压信息的保护方案,包括方向过流保护、纵联方向保护、母线保护和广域保护方案,可以为主动式配电网提供比较全面的保护,灵敏度高,动作速度快,有利于提高主动配电网对分布式电源的容纳能力。Simulink仿真验证了方案的有效性。

Traditional protection relays might mal-operate or fail to operate in active distribution grids, in which the direction and magnitude of fault currents will be affected by the distributed generation resources. The existed ways solving above problems need voltage unavailable in the distribution information, which is always network. This paper aimed to design the protection solutions for active distribution grid. A voltage independent directional element with higher sensitivity was designed firstly, and it used the phase information of fault currents from at least three feeders connecting to the bus bar to identify fault direction. Then, based on different principles including directional current protection, pilot line protection, bus-bar protection and wide-area protection, four protection solutions were proposed to provide high protection performance for active distribution grid in terms of reliability, sensitivity and fast operation speed, so as to improve receptive capability for distributed generation resources. The simulations based on Simulink demonstrate the effectiveness of the proposed solutions.