An online dynamic equivalent method for large scale photovoltaic plant electromechanical transient simulation

In order to improve the modeling accuracy of the interconnected large-scale photovoltaic power plant for electromechanical transient simulation, as well as to improve the efficiency of online security and stability analysis, an online dynamic equivalent method of interconnected photovoltaic plant was proposed. Take the inverters as the aggregation object, calculate the inverter clustering indexes and cluster the inverters, judge the validity of equivalent scheme through comparing the system dynamic response with the corresponding reference response. In order to improve efficiency, the parameter sensitivities of inverters and reference response curves were calculated and the data base was established offline, while the real data can be matched to the closest value based on real-time condition online. Thus, the precision of equivalent model of the interconnected photovoltaic plant is enough for electromechanical transient stability simulation. The example of real power grid confirmed the validity of the proposed method.