Research On Intelligent Control Technology Of Load Balance In Medium And Low Voltage Distribution Network

The phenomenon of unbalanced load on the user side occurs from time to time when the power system is in operation.How to solve the problems caused by the imbalance of system parameters,the variation of power supply voltage quality,and the reduction of power factor are the research topics of contemporary scholars,with the development of industry,the problem brought by heavy load input becomes more and more valuable.At present,it is a hot topic to improve the power factor and stabilize the parameters of the three-phase system by using the compensation device to balance the power system intelligently.In this paper,three phase unbalance caused by heavy load is studied,TCR+TSC SVC(static var compensator)compensation device is adopted,relevant compensation algorithm and double closed-loop negative feedback control of voltage and reactive power are applied,through the simulation to verify the theoretical feasibility and superior compensation effect,the research contents of this paper mainly include:(1)To study the loss caused by unbalanced load in the system,explain the necessity of solving the problem of unbalanced load,synthesize several schemes to reduce the influence of load,and put forward the feasibility of using compensation device to balance the load.(2)On the basis of Steinmentz compensation algorithm and three algorithms which can be applied to three phase four wire power system,this paper explains how to apply to compensation device.Finally,based on the control mode of compensation device and compensation algorithm as the core,the algorithm is studied by Matlab Simulation,comparing which algorithm is most suitable for engineering application.(3)The principle and control method of compensation device are introduced in detail,including the principle and advantages of TCR+TSC integrated SVC compensation device,based on the PID double closed loop control method of voltage and reactive power and the nine zone control strategy,a thirteen zone intelligent switch on control method is proposed.(4)Theoretical design of hardware and software for this project,in the hardware design part,TMS320F28335 floating point DSP control chip is used as the hardware main board,which includes the transformer signal conversion circuit,the Level Conversion Circuit,the signal conversion circuit,the protection filter circuit,the zero crossingDetection Circuit,the thyristor trigger circuit,the optocoupler isolation circuit,the communication circuit,the Liquid Crystal Display Circuit,the external expanding memory circuit,the clock circuit,the power up Reset Circuit and so on.In the software design part,the flow chart is designed with the idea of modularization.The flow chart of DSP control,data acquisition,equipment switching,control algorithm application and synchronous triggering is introduced.(5)Using Matlab as the simulation design platform,the simulation curves of various algorithms are obtained,and the optimal algorithm is analyzed and compared,which is more suitable for practical engineering operation.The ideal compensation effect of TCR+TSC SVC in medium and low voltage system is observed and analyzed.