Research On The Novel Control Method Of High Voltage Direct Current Transmission System

The network interconnection of the whole country is the inexorable trend with the development of Chinese electric network. Duilding"Transmission electric power from West to East"and"Exchange electric power between South and North"projects is the the desirability for the unbalanced resource distribution and the unbalanced demand. It is also the necessary strategy of our power industry. High voltage direct current (HVDC) transmission system, which is fit for transmission electric power in long distance and large capability, will be one style of the interconnection in power network and be widely applied in our country. This paper researches on the novel HVDC control system's structure, function and mode. A neural network model is proposed to solve the problem existed in the PI controller and a series of relative theroies and application researches are developed.This paper combines the key science & technology project 05GK1001-2 of the Tenth Five Year Plan of Hunan Province– research & manufacture of new-style converter transformer in HVDC power transmitting system, developing a number of studies in the following aspects.The application field and present research status of HVDC transmission projects are overviewed. The control features and applied range of the present HVDC system's PI and PID controllers are analysed, putting forward the limitation of its operation. The advantage in technique for using the neural network in HVDC control is reprensented, pointing out that the single neuron adaptive PID controller can reduce the overshoot significantly and minish the regulating time.Basing on the steady-state model of HVDC transmission system, the operation principle is analysed and the basic system control model is established, pointing out the regulating method to the direct current.The sturcture of the novel HVDC simulator stand is analysed, explaining the composition principle, function and features. The graded sturcture of the control system is given, introducing two basic control methods and control features. The control function blocks of the control system is given, explaining the control function and features of every part of polar control level. The main circuit of converter and design method of control circuit are introduced.The single neuron adaptive PID controller's control mode and implement method are proposed. A single neuron adpative PID controller is designed adopting the second performance index. The controller is simple in structure and fast in control.The simulation and experimental investigation for PI controller are made. The PID and single neuron adaptive PID controllers are simulated. The result show that the control feature can satisfy basically the system requirement by adjusting the parameters of PI and PID controllers, but single neuron adaptive PID controller has better control effect.