不对称电压跌落下考虑场景区分的逆变型分布式电源控制策略研究

Control strategy for inverter-interfaced distributed generation during unbalanced voltage sag considering scenario classification

逆变型分布式电源(Inverter-Interfaced Distributed Generation,IIDG)在电网电压跌落时可能存在电流越限、切机等风险,进而影响其自身和系统的安全稳定运行。对此,提出一种考虑不同运行场景的IIDG控制策略。首先,以相电压幅值为约束条件,构建了基于正序分量的电压支撑方程,实现了正序电压的最大化支撑。其次,为保证逆变器在安全的前提下充分利用自身容量,提出一种考虑电压跌落程度和IIDG有功出力大小的场景区分方法。然后,根据不同场景下的电流注入模式和控制目标推导参考电流,使IIDG兼具电压支撑、电流限幅能力。同时,通过输出有功功率和负序无功功率,提升了系统稳定性,降低了电压不平衡度。最后,基于Matlab/Simulink搭建了含IIDG的仿真模型,算例结果验证了所提策略的有效性。

During voltage sag,the Inverter-Interfaced Distributed Generation(IIDG)may suffer from overcurrent and disconnection,which affect the safe and stable operation of IIDG and the power system.Thus,a new IIDG control strategy considering different operation scenarios is proposed.First,by considering the phase voltage amplitude constraint,a positive sequence components-based voltage support method is established.This maximizes the voltage support capability.To fully use the inverter capacity and ensure its safety,a scenario classification method considering the severity of voltage sag and the active power of the IIDG is presented.Based on the current injection mode of each scenario and the control objectives,the reference currents are calculated to ensure voltage support and current limitation.By delivering the active power and negative sequence reactive power,both system stability and voltage imbalance are improved.Finally,a simulation model with IIDG is established based on Matlab/Simulink.The simulation results verify the effectiveness of the proposed strategy.