Research On Coordinated Control Strategy Of Distributed Static Series Compensator

Under the guidance of lean operation and maintenance,intelligent management control and precision investment of China’s power grid,flexible AC transmission equipment for the current power grid should be small,distributed,low-cost and easy to install.The distributed static series compensator is such a candidate device that adapts to the flexible regulation requirements of modern power grids.The application of the distributed static series compensator will improve the transmission capacity of the grid,save transmission aisles,delay or reduce the construction of power lines.On the one hand,it improves the access ratio of new energy power sources and the power quality of power grids with a high proportion of power electronics.On the other hand,it meets the flexible regulation needs of the transformation and upgrading of the distribution network.However,the interaction between the distributed static series compensator devices and the research in the field of coordinated control operation are still in the initial stage.Focusing on this issue,our works are summarized as follows:(1)The structural advantages and installation methods of the distributed static series compensator are elaborated in detail,and the compensation characteristics and the principle of power flow control are analyzed at length.At the same time,the mathematical model is established in combination with the actual project.A set of distributed static series compensator is designed to meet the power flow regulation requirements of the transmission network.Last but not least,we verify the effectiveness of the controller by simulation.(2)In order to analyze the interaction effects among multi-converter of distributed static series compensators,we propose a method for an interactive influence analysis of distributed static series compensators with multi-converter based on the relative gain matrix.The power system of distributed static series compensator with two converters is studied,and the state equation model of the system is derived.Then we establish a linearized system state extended Phillips-Heffron model.The transfer function model of the multi-input/multi-output power system is derived,and the corresponding relative gain matrix is established to quantitatively analyze the interaction among multi-converter of the distributed static series compensator.Finally,the interaction results among multi-converter of the distributed static series compensator under different electrical distances calculated by the relative gain matrix are compared with the simulated results to verify the correctness of the analysis.(3)Aiming at the interaction problem among multi-converter of distributed static series compensator,we propose a coordinated control strategy based on multi-objective optimization immune algorithm to design the controllers of the distributed static series compensator.The algorithm transforms the interaction among multi-converter of the distributed static series compensator into the multi-objective optimization problem,and establishes the objective function of controlling the distributed static series compensator.The method of screening antibody adaptability by immune algorithm is used to obtain a set of Pareto optimal solution as controller parameters.Finally,the effectiveness of this coordination strategy is verified by simulation comparison analysis.