增强序分量选相元件适应性的光伏并网逆变器序阻抗角重构方案

光伏电源的拓扑结构和控制方法与同步发电机有着显著差异,故其故障特性相较同步发电机产生了实质性的改变,恶化了传统序分量选相元件的动作性能。推导了将抑制负序电流作为控制目标时光伏电源的序阻抗表达式,详细分析了序分量选相元件受光伏电源影响的机理。提出了一种新型光伏电源控制方案,通过重构光伏并网逆变器的序阻抗角来模拟同步发电机的故障特性,从而辅助序分量选相元件正确判断故障类别。基于PSCAD/EMTDC平台的仿真结果验证了所提控制方案的有效性和可靠性。

Sequence impedance angle reconstruction scheme of photovoltaic grid-connected inverter to enhance adaptability of phase selector based on sequence component

The topology structure and control method of PV(PhotoVoltaic) power source are obviously different from synchronous generator, so its fault characteristics are substantially changed compared with synchronous generator, which deteriorates the operation performance of traditional phase selector. The expression of the sequence impedance of the PV power source is derived when the suppression of negative sequence current is taken as the control target, and the influence mechanism of PV power source on phase selector based on sequence component is analyzed in detail. A novel control scheme for PV power source is proposed, which simulates the fault characteristics of synchronous generators by reconstructing the sequence impedance angle of PV grid-connected inverters, so as to assist phase selector based on sequence component to correctly judge the fault types. Simulative results based on PSCAD/EMTDC platform validate the effectiveness and reliability of the proposed control scheme.