Research On Coordinated Delivery Control Strategy Of High Proportion New Energy Access Hybrid System

With the rapid development of China's society and economy,the demand for electrical energy is increasing.Due to the consumption of large amounts of fossil energy and environmental pollution caused by traditional electrical energy production,the world is actively developing green new energy.In China,the distribution of light and wind energy resources and electricity load are inversely distributed in geographical location.In order to solve the problem of new energy consumption,electric energy must be sent out on a large scale and remotely.In order to achieve delivery,in recent years,China's high-voltage AC and DC lines have been continuously put into operation,and large regional power grids have been interconnected through high-voltage AC and DC transmission lines.A large-scale AC-DC hybrid power grid has been formed,which makes the characteristics of the grid more complicated.Due to the randomness,intermittence and poor controllability of new energy,the connection of new energy to AC and DC hybrid power grids will bring certain security risks and control problems to the power system.How to achieve AC-DC coordinated control to improve the transmission capacity and stability of the new energy transmission system is one of the problems to be solved.This paper studies the problems of large-scale and long-distance transmission of wind and photovoltaic.Specifically completed the following:This dissertation summarizes the significance,problems and research status of new energy power generation in AC-DC hybrid system.The characteristics of wind power and photovoltaic power generation as well as the characteristics of DC power transmission and AC power transmission are studied,and the corresponding control measures and advantages are introduced;the topology diagram of the connection of new energy to AC and DC power transmission systems is given;finally the simulation is completed in the simulation software Build.Using EEAC to theoretically study the connection of a high proportion of new energy generation to AC-DC hybrid transmission systems,and to simulate the connection of new energy to AC-DC hybrid transmission systems influences.The simulation shows that as the proportion and fluctuation range of new energy power generation connection increase,the stability and anti-interference ability of the AC-DC hybrid transmission system decrease.Therefore,the delivery capacity of new energy power generation is limited.Aiming at the stability problems brought by the volatility and intermittency of new energy electric energy to the transmission system,the corresponding AC-DC coordinated control strategy is proposed.Under steady-state conditions,use the large-capacity transmission capacity of the DC system to bear most of the transmission power with small fluctuations,and use the AC system to adapt to the strong change in transmission power to bear the small part of the transmission power with large fluctuations for active power Cooperate to improve system stability and reduce system stability problems caused by power fluctuations;in the event of a fault transient,use the rapid power regulation capability of DC transmission for emergency power support and corresponding reactive power compensation measures to ensure the system's Transient stability.This strategy is applied to the AC-DC hybrid transmission system with a high proportion of new energy for simulation.The simulation results show that the strategy effectively improves the delivery capacity of new energy power generation.