| With the increasing complexity of grid structure,the increasing load and the continuous access of large-scale water,wind,photovoltaic outside the area,the uneven distribution of power flow will become more and more serious.However,the transmission corridor of load intensive receiving power grid is scarce,and the cost of new / reconstructed lines in some areas is huge,so it is urgent to introduce new equipment and new technology to solve the transmission problem.The interline power flow controller(IPFC)can control the power flow of multiple transmission channels at the same time,balance the power flow of each transmission channel,so as to greatly increase the power transmission capacity of the grid,which has a broad application prospect.However,the current research on IPFC at home and abroad is still in the initial stage,and there is a lack of research work that can guide the actual IPFC simulation modeling,pre-planning and power flow optimization control technology of the project.Therefore,this paper carries out IPFC steady-state modeling and power flow optimization control research,which aims to provide new ideas for increasing the utilization rate of power grid transmission channels and improving the efficiency of power grid operation,as well as providing technical support for IPFC practical engineering applications.The main research work of this article is as follows:(1)The idea of using injected power variables to construct IPFC capacity and voltage equivalent mathematical constraints is proposed,thereby constructing a new type of IPFC model that is easily convex.First,based on the concept of additional virtual nodes,the power injection of the traditional IPFC model is separated to clearly express the equivalent effect of each converter,avoiding the complicated derivation of the traditional power injection method.Further,based on the power injection variables,the equivalent constraints of the voltage,current,and power balance of the IPFC converters are constructed,thereby constructing a convex IPFC model that involves only the power injection variables.(2)An IPFC step-by-step location and volume determination method considering line safety comprehensive evaluation index is proposed.Firstly,a comprehensive line safety evaluation index considering line load rate and bus voltage offset rate is established.Based on this index,a stepwise location method for IPFC main / auxiliary control lines is given,and the equipment capacity investment and power flow regulation requirements are comprehensively considered.IPFC capacity optimization.Finally,in an actual power grid calculation example,an economic and technical comparison between the IPFC and UPFC schemes is conducted,and the superiority of the IPFC scheme is demonstrated.(3)A multi-objective power flow optimization method for IPFC-containing power systems that takes into account the economic and safety of the power system in consideration of the IPFC power flow regulation domain is proposed.Considering the control capabilities and operating constraints of IPFC equipment,the actual power system is given.The acquisition method of IPFC power flow control domain,and use the control domain to restrict the operating range of IPFC in the optimization process to ensure the feasibility of the optimized solution,and use intelligent algorithms to optimize the solution.Simulation examples verify the effectiveness of the optimization method.(4)A power flow optimization method with IPFC based on mixed integer second-order cone programming is proposed,and the new model of IPFC proposed in this paper is convexized by mathematical transformation to transform the power flow optimization problem with IPFC It is a mixed integer second-order cone programming problem,and the optimization model is solved using MATLAB / GUROBI.The results show that the proposed optimization method has high calculation accuracy and fast solution speed,which can provide theoretical and technical support for the online optimization control of IPFC. |
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