An Equivalent Method of Distribution Networks Considering the Power Jump Characteristics with Distributed Photovoltaics

With the increase of photovoltaics (PVs) in the distribution network, detailed modeling of each PV is ineffective for simulation. Therefore, the equivalent model is usually used when simulating the distribution network with a high PV rate. However, the power characteristics change of some distributed PVs is nonlinear when PVs enter or exit the low voltage ride through (LVRT) state. When the voltage level of the distribution network changes, PVs may gradually enter or exit the LVRT state. It leads to the power jump characteristics and causes difficulties on the equivalent. Therefore, this paper proposes an equivalent method that considering the power jump characteristics of the distribution network. Firstly, the equivalent method of the equipment in the distribution network is achieved. The difficulty of the distributed PV equivalent is analyzed. Then, an equivalent PV model is established. By increasing parameter groups, the power jump characteristics can be simulated using the equivalent model. The initial value of the equivalent parameter is obtained by weighted calculation. Finally, to improve the accuracy of the equivalent results, the initial value is optimized by the particle swarm optimization (PSO) algorithm to get equivalent parameters. The proposed method is verified based on a test system in the simulation toolkit for electrical power systems (STEPS).