光伏电站进孤岛后系统稳定性风险量化评估

光伏电站进入孤岛后可能导致系统的稳定性风险,特别是在电网故障导致光伏电站非计划进孤岛且孤岛检测装置未能及时动作的情况下。为了评估该风险,首先对功率差额、光伏渗透率和电机惯性影响光伏电站非计划进孤岛后系统短时间内稳定特性的机理进行了理论分析。随后,建立了光伏电站的电磁暂态模型,并据此在PSCAD/EMTDC上搭建了含光伏电站的大理电网模型,通过软件仿真验证了理论分析的结论。最后,提出了光伏电站进孤岛后系统稳定性风险量化评估指标和方法,为稳定性风险的评估提供了理论依据。

System Stability Risk Quantitative Analysis After PV Plants Drop Into Island Operation

There are stability risks after PV plants drop into island operation,especially in casa of unintentional islanding caused by grid faults and the islanding-state detection device fails.In order to estimate those risks,firstly,the paper theoretically analyzes the influence of three factors (power difference,PV permeability and motor inertia) on the stability characteristics of the island system in a short time after PV unintentionally dropped into island operation.Then the electromagnetic transient model of the PV station is established.According to that,the modified Dali Grid integrated with a PV station is modeled in PSCAD/EMTDC,verifying the theoretical analysis conclusions by simulation.Finally,quantitative stability risk index and method about PV station dropping into islanding are proposed according to the simulation results,which provide the theoretical basis for the stability risk estimation.