Research On Power Flow Optimal Control Strategy Of Continuous Cophase Power Supply System

In recent years,rail transit has been developed rapidly in China and world-renowned achievements has been achieved,but the power quality problems such as negative sequence and electrical phase separation have restricted its further development.The electromechanical process of an electric train passing through the electrical phase separation is complicated,which is tend to cause malfunctions,and passing the electrical phase separation will cause the loss of speed and traction of the train,so the electrical phase separation is the weakest link in the traction power supply system.In addition,power quality is related to the safe and economical operation of the power system.With the high-speed and heavy-loading of electrified railways,power quality problems such as negative sequence,reactive power,and harmonics in the traction power supply system also need to be resolved urgently.At present,the continuous co-phase power supply based on the co-phase power supply device is considered to be an important means to solve these problems.It can provide the same phase voltage for the electric locomotives in each power supply section,thereby eliminating the electrical phase separation and improving the power quality,which will achieve a win-win situation for railways and power systems.In this paper,the continuous co-phase power supply model and the intelligent optimization algorithm are combined,and the optimal control strategy for coordinated control of the output power of the in-phase compensation device to comprehensively adjust the negative sequence power of the entire line and the traction network voltage is studied.Specifically,the principle and power flow control of the continuous co-phase power supply technology are introduced first,and its negative sequence compensation capability,network voltage control capability and capacity configuration method are analyzed.Next,the mathematical model of the continuous co-phase power supply system is introduced,including the traction network model,the co-phase power supply traction substation model.On this basis,the principle and method steps of the continuous co-phase power flow calculation are introduced,and the simulation verified its correctness.Then,the multi-objective particle swarm algorithm is introduced and improved to optimize its performance.Furthermore,considering the specific working conditions,an optimization model under the working conditions is given,and a comprehensive and efficient algorithm process is developed to apply the optimization algorithm to the continuous co-phase power supply system to achieve the control goal under the premise of covering all working conditions.Finally,combined with typical calculation examples,taking the negative sequence of the whole line and the traction network voltage as indicators,comparing different optimization models and the results of optimized control and traditional control,the effectiveness and superiority of the optimal control plan are illustrated.