Harmonic Control And Reactive Power Compensation Scheme Design Of A Pipe Fitting Factory

With the increasing dependence of industrial production and people's life on the quality of electric energy,all kinds of current electric equipment,both in terms of quantity and type,have increased significantly compared with the past.On the one hand,it promotes the development of China's power grid,but at the same time,it also causes huge pressure on the stable operation of the power system.Among the various challenges faced by the current power system,power factor reduction and harmonic pollution are the most serious problems.Due to the variety and instability of load in pipe fitting plant,the problems of large harmonic content,three-phase imbalance and low power factor of power grid are brought about.In this paper,two new active power filters and control methods are proposed,which can compensate the harmonic and reactive power of the power grid in time for the three-phase unbalanced load,and bring economic benefits to the construction planning and operation of the pipe fitting plant.The main research contents are as follows:1.In Chapter 3,a method of harmonic suppression and reactive power compensation based on adaptive linear neural network and variable step size leakage least mean square(adaline-vssllms)is proposed.This method can eliminate the harmonics in the load current by automatically adjusting the weight vector of the adaptive linear neural network and the variable step size parameters and leakage coefficient of the variable step size leakage least mean square algorithm.In the iterative process,the variable step size leakage least mean square algorithm can determine the optimal convergence rate in real time.Firstly,the composition of the new hybrid APF and the training process of the algorithm are introduced.Secondly,the influence of the APF on the accuracy of the algorithm when it works under different loads is discussed.Finally,the simulation results show that the method proposed in this chapter has the advantages of high accuracy,fast convergence speed and strong anti-interference ability.2.In Chapter 4,a new method of harmonic suppression and reactive power compensation based on three-phase multi-level inverter is proposed.The significant advantage of this method is that it can reduce a single harmonic current or a specific group of harmonic currents and improve the power quality of the power grid.In this method,multiple synchronous frames are used to detect and control single or a group of harmonics by using d and q variables.Three dimensional space voltage vector modulation(3d-svpwm)converter is used to generate the pulse needed for compensation current.In order to generate compensation current,active power filter adopts multilevel topology structure,It can be used in various secondary transmission and distribution voltage levels to improve the power quality and the practicability of the method.Finally,the simulation results show that the method proposed in this chapter is true and effective.