具有低电压穿越能力的光伏电源接入配电网方向元件新判据

具有低电压穿越能力的光伏电源与传统电源故障输出特性不同,其接入将影响配电网中传统功率方向元件的动作特性,使得传统功率方向元件不能正确判断故障方向。在研究具有低电压穿越能力的光伏电源接入配电网故障特性的基础上,得出了配电网保护正方向及反方向故障时流过保护的正序电流和保护安装处故障前电压的相位关系,以此为基础提出了一种基于正序故障电流和故障前电压相位信息的方向元件新原理。该原理保证了不同故障类型和故障位置条件下含光伏电源的配电网中方向元件动作的可靠性,同时避免了传统功率方向元件电压死区的问题。经仿真验证了该方向元件原理的有效性。

New Criteria of Directional Component in Distribution Network with Photovoltaic Generator of Low Voltage Ride Through Capability

Different from fault characteristics of the traditional generator, photovoltaic (PV) generator will affect the action of conventional power directional components of a distribution system, making the components unable to judge the fault direction correctly. This paper studies the fault characteristics of the PV generator by deriving the relationship between positive fault current phase and normal voltage phase during forward direction and negative direction fault. A new directional component theory is proposed as a result, which guarantees the action reliability of the directional component during various types of fault at different places of the distribution system while avoiding the voltage dead zone of traditional power directional components. The theory is verified by simulation.