逆变式电源接入下的配电网自适应距离保护方案

Adaptive distance protection scheme for a distribution network given access of inverter power supply

以光伏、储能为代表的逆变式电源(inverter interfaced distributed generator,IIDG)大量接入配电网,使得传统距离保护受到巨大干扰,同时存在拒动或误动的风险。针对此问题,分析了含IIDG配电网不同类型故障下的复合序网,利用IIDG侧正序故障分量求取不同故障下的附加阻抗角。结合故障下阻抗的复平面关系,计算线路故障位置对应的短路阻抗,得到了一种真实短路阻抗求解办法。提出了一种适用于逆变式电源接入下的自适应距离保护方案。该方案求解过程利用IIDG侧单端电气量,解决了距离保护受IIDG故障输出受控特性和过渡电阻影响的问题,在有效降低配网通信成本的同时不受故障位置变化的影响。通过实时数字仿真器(real time digital simulator,RTDS)对该保护方案进行了验证,结果表明其在不同类型故障下都有较好的选择性和可靠性。

A large number of inverter-interfaced distributed generators(IIDG)represented by photovoltaics and energy storage is connected to the distribution network.This greatly disturbs traditional distance protection,and at the same time there is the risk of refusal or misoperation.Thus this paper analyzes the composite sequence network under different types of faults in the IIDG distribution network,and uses the positive sequence fault component on the IIDG side to obtain the additional impedance angle under different faults.Combined with the complex plane relationship of impedance under fault,the short-circuit impedance corresponding to the fault position of the line is calculated,and a real short-circuit impedance solution method is obtained.An adaptive distance protection scheme suitable for the connection of inverter power supply is also proposed.The solution process uses the single-ended electrical quantity on the IIDG side to solve the problem that the distance protection is affected by the controlled characteristics of the IIDG fault output and the transition resistance.It is not affected by the change of the fault location while effectively reduces the communication cost of the network.The protection scheme is verified by a real time digital simulator(RTDS),and the results show that it has good selectivity and reliability under different types of faults.