Analysis On Multi-Time Scale Characteristics And Parameter Stability Domain Of Power Generation System With Photovroltaic

With the increasing shortage of fossil fuels,solar power generation has been rapidly developed.While photovoltaic power grids bring in green energy,a large number of power electronic interfaces are also introduced into the system,resulting in the complicated analysis of transient stability of the system.In view of this situation,this paper analyzes the time-scale changes and the corresponding stable domains of the parameters after the inclusion of photovoltaic power supply.(1)The model of each component of photovoltaic power generation system is analyzed,and the state space model of independent photovoltaic power generation system is derived.In PSCAD,a model of photovoltaic power generation system was set up and simulated by simulation.(2)A time scale calculation method suitable for the characteristics of power system is proposed,and the multi-time scale characteristics of photovoltaic access infinity system are analyzed.First of all,the significance and analysis method of time scale are studied.Based on the concepts of control science and second-order system analysis,a time scale calculation method is proposed which is suitable for the characteristics of power system.Furthermore,the eigenvalue is used to analyze the multi-Time scale characteristics.The simulation verifies the effect of sampling step on time scale analysis.That is,high-frequency sampling can reveal slow time scale,and low-frequency adoption can lead to ignoring fast time scale,resulting in information loss.(3)According to the impact of different parameters on different time scales(eigenvalues)for the photovoltaic power system which is connected to the infinite system,the dominant parameters that affect each time scale are determined.The influence of PI control parameters on the time Scale and stability.According to the requirements of stability and control characteristics,the implicit equation is used to characterize the stability field of the dominant parameter and its solution method is given.Finally,the PSCAD simulation is used to verify that the stability of the integrated parameter is well defined Sex and solution effectiveness.(4)Aiming at the situation that a large number of power sources are connected in parallel to an infinite system,the eigenvalue analysis model is given,and the multi-time scale features of the system with photovoltaic and synchronous generators paralleled into an infinite system are analyzed emphatically.The time scale interaction between the PV system and the synchronous motor has the same effect.It is concluded that the introduction of a synchronous motor brings about a change in the time scale of a photovoltaic power plant compared to a single photovoltaic power supply connected to an infinite system.