Parameter Identification Of Load Model With Photovoltaic Power Generation System And Study On Power Grid Stability

With the continuous development of renewable energy generation,China’s attention to renewable energy has been increasing,and renewable energy,typically solar and wind energy,as the main form of grid connection,has gradually become an unstoppable development trend of new power systems.The capacity of distributed photovoltaic leads to the traditional load model cannot well describe the dynamic characteristics of the system.And the load characteristics play an important role in the system simulation calculation results,and different load models have different degrees of influence on the system stability problems.Therefore,it is important to study the load models of PV-containing systems and analyze their effects on grid stability.Based on the above background,this paper focuses on the following aspects.(1)Introducing the structure of load model and PV generation system model,building a distribution network system containing distributed PV generation based on PSD-BPA platform,studying the dynamic description capability of the integrated load model for the system under different PV penetration rates,and establishing an integrated load model for the system containing PV generation.(2)The Chaotic Seagull Optimization algorithm,which combines the Chaotic Optimization algorithm and the Seagull Optimization algorithm,is proposed for the identification of the load model parameters of the PV-containing system,and the important parameters to be identified are analyzed and compared with the Seagull Optimization algorithm and the classical particle swarm algorithm to prove the superiority and feasibility of the algorithm.(3)To study the influence of load model parameters on the voltage stability.The influence of load model parameters on voltage stability is studied based on the single machine-load system,and the mechanism of voltage instability is analyzed,showing that the increase of induction motor slip leads to absorbing more reactive power and the slip cannot be recovered thus causing voltage instability.Parameter sensitivity analysis is carried out with the 2024 grid under the southern border power grid receiving limit as the index,and the results show that the static load composition and motor ratio have a large impact on voltage stability,and the motor load factor,inertia time constant,rotor reactance and distribution impedance have relatively small impact on voltage stability.(4)To study the effect of large-scale PV power access on power system power angle stability.Based on the equal area rule,we analyze the effect of PV access on the acceleration energy and deceleration energy of the unit,build a multi-machine-infinity system containing water,fire and light through the PSD-BPA platform,and analyze the effects of PV penetration rate,system inertia and low-voltage ride-through control strategy on the power angle stability.The results show that the system inertia and conventional unit output is unchanged,PV output increases,and the transient angle of attack stability decreases;the system inertia and total power supply output is unchanged,PV output increases and conventional power supply output decreases,and the transient stability of the system improves;the total power supply output is unchanged,and PV generation replaces conventional unit,resulting in the reduction of system inertia and the transient stability of the system decreases;the active output decreases or reactive output increases during LVRT,and the transient stability of the system improves.The system transient stability is improved by increasing the reactive power output during LVRT.