Research On AGC Control Strategy Of Two-Region Interconnected Power Grid Including Photovoltaic Grid-connection

Automatic Generation Control(AGC)is an important way to adjust the frequency deviation and power of modern power grids,and it plays an important role in the power quality and stability of the power grid.In an interconnected power grid,it is essential to ensure the safe and stable operation of the power grid to maintain power quality under high standards.Serious frequency deviation of power grid will lead to power accidents,and small-scale frequency fluctuation will also threaten the stable operation of power grid.Continuous abnormal frequency deviation will damage the equipment,affect its operating characteristics,cause transmission line overload and protect equipment malfunction,etc.,thereby affecting the safety,stability and operating efficiency of the system.In this paper,the research on the control strategy of the two-zone automatic power generation control system is carried out.The main research contents are as follows:1.Firstly,the research background and significance of AGC are introduced.The research status of AGC control strategy at home and abroad is expounded.Taking the automatic power generation control system of two regional interconnected power grid as the research object,the main part of it is modeled mathematically.According to its mathematical model,the AGC system model of two regional interconnected power grid is built in MATLAB/Simulink software.2.Aiming at the problem that the performance of traditional load frequency control(LFC)controller in AGC system is insufficient,two controllers are designed to improve the stability of the AGC system.The first controller adopts the idea of double loop control,which divides the original control loop into inner loop and outer loop,an inner loop and an outer loop.The PID is used as the outer loop controller,and the fractional PID is the inner loop controller.The second controller is the fuzzy PID control with dual input and single output.Firstly,the load disturbance simulation experiments were carried out.Both controllers achieve better dynamic performance and steady-state performance than traditional PID controllers.Secondly,the robustness test simulation experiment was carried out to change the AGC system parameters.Finally,the load disturbance simulation experiment was carried out under non-linear link of the AGC system.In the load disturbance simulation experiment under the link,three sets of simulation experiments show that the dual-loop control and fuzzy PID control have better control performance than the traditional PID controller,and the dual-loop control has the best control performance.3.Considering that the AGC system may have noise interference in the process of signal transmission and detection,Kalman filter has excellent filtering performance.The kalman filter is applied to the AGC system,and three sets of simulation control experiments are carried out by combining the kalman filter with the PID controller,the double loop controller and the fuzzy PID controller respectively.The AGC system of each group of experiments is divided into two cases,including kalman filter and without kalman filter.Through comparing three groups of control experiments,it is concluded that in the case of Gauss noise interference AGC system,the Kalman filter combined with the load frequency controller can effectively filter the AGC system and improve the stability of the system when disturbed by noise.4.Taking into account the gradual expansion of the installed capacity of new energy power generation,it is important to study the impact of photovoltaic power generation on the AGC system.Firstly,the principle of photovoltaic power generation is studied,the photovoltaic power generation system model is built,and interference observation method is adopted as the maximum power tracking control strategy.Secondly,adding photovoltaic power generation as a disturbance to the two-region AGC system.Three control strategies,PID,double-loop control and fuzzy PID,were adopted in the AGC system to carry out simulation experiments and finally,taking into account the daily load,the simulation experiment on the tworegion AGC system with photovoltaic grid-connected.The simulation results show that,in the face of random load disturbances caused by photovoltaic grid-connected,the two controllers designed in this paper still maintain good control performance,and can suppress the power disturbances caused by photovoltaic grid-connected.