Admittance Matrices-Based Oscillation Case Studies: A Realistic Distribution System with High Penetration of PVs

In the context of increasing proportion of renewable energy resources, power electronic equipment of the voltage source converters (VSCs) has been significantly integrated into the grid. This paper conducts case studies using actual data from a photovoltaic (PV) grid-connected system in a specific distribution system of Beijing and analyzes oscillation characteristics and stability. The network full-order admittance matrix fitting method was first introduced to fit the admittance matrices of four regions in the area, obtaining the state-space equations and poles of the PV grid-connected system. Real data was used to simulate six PV nodes in the area by establishing nonlinear oscillation analytical model. The impact of renewable energy penetration on nonlinear oscillations was also explored. Finally, by analyzing the pole positions and simulation results, the stability of the PV grid-connected system in all regions of the area was analyzed.