Study On The Influence Of UPFC And New Energy Equipment On Power System Stability

With the increase of electricity load in recent years,the old power grid infrastructure has been unable to meet the requirements,but it is really difficult to construct new power transmission corridors due to grid structure,land resources and environmental protection.Therefore,for the power industry,in the existing power grid on the basis of fully tap the transmission potential,through the use of advanced technology to solve the power flow control of power grid and improve operational stability and other issues,has become increasingly urgent.Unified power flow controller(UPFC)is the most powerful flexible AC transmission system(FACTS)device,which has been cause for concern.The first UPFC was installed in China and put into operation successfully,filled the gaps in engineering application of UPFC,which makes the research work of UPFC in this paper is more practical significance.At the same time,due to rapid economic development in recent years brought about by environmental pollution is becoming increasingly serious in China in recent years,the traditional energy resources are constantly consumed and the regeneration cycle is very long,vigorously developing clean energy has become a new direction of energy development in China.Wind energy and solar energy are two important parts of the new clean energy,wind power and photovoltaic power generation in the proportion of the field is increasing year by year,so study on the new energy power plant access to the power system is particularly important.This paper studies the influence of UPFC and new energy devices access to power system,the main contributions are as follows:Firstly,the basic structure and operation principle of UPFC are introduced,the static model,dynamic model and linear model of UPFC is given,and the influence of UPFC on the actual power system oscillation mode is studied.Then,according to the damping torque analysis method,the segmented design method of additional stabilizer on UPFC is proposed.By using the direct optimization method,coordinate designed the parameters of multiple additional stabilizers attached to UPFC.Designed supplementary stabilizers of the phase angle controlled and the vector controlled UPFC respectively,impact of stabilizers to power system stability were compared under two kinds of control methods.Lastly,the dynamic model of wind power plant and photovoltaic power plant is built,and the output of new energy generating unit is simulated in MATLB to replace the output of thermal power generating unit,and the influence of partial replacement and total replacement on the stability of the system is studied.Design of wind turbines and photovoltaic generator stabilizer to improve the stability of the power system.The parameters of the unit stabilizer are designed by using the fish algorithm,and the effect of the stabilizer on the wind turbine and the photovoltaic generator is verified according to the change of the oscillation mode and the simulation results of the system.