Research On Static On-load Tap Changer For Distribution Load Transformer Using Power Electronic Devices

With the development of the concept of smart grid in China, power quality is paid more and more attention. In recent years, with the access of distributed generation in distribution network, especially the voltage fluctuation of radiation brings a lot of problems in the network. Voltage is an important index of weighing the quality of electric energy. In the case of reactive power is sufficient, on load voltage regulation can be a very good solution to the end of the power grid voltage fluctuation.Traditional on-load voltage regulating transformer tap-changer is mechanical. Although it has been widely used in engineering, but there are still some deficiencies. In order to perfect and improve the structure and performance of on load voltage regulating transformer, to adapt to the new needs of power grid development, there is a very good application prospect of the static on-load tap changer for distribution load transformer using power electronic devices.In this paper, a new hybrid simulation model of transformer is presented. The on load voltage regulating distribution transformer based on power electronic devices are studied. This paper has done the following work:①Based on the principle of transformer, taking into account the ferromagnetic properties of transformer, this article establishes electromagnetic hybrid simulation model of transformer in the MATLAB/Simulink. In this paper, the validity of the model is verified by the mini transformer, and the experiment proves that the model can simulate the electromagnetic process of the transformer running.. Based on the simulation model, the analysis and design of the load distribution transformer can be accomplished. The model can also be applied to other problems in transformer. There is a very good theoretical value of this model.②This paper gives a design scheme of the static on-load tap changer for distribution load transformer. This paper analyzes the parameters which the switch module requirements. This paper gives two switch module structures, through the simulation analysis the advantages and disadvantages of the switch have been compared, and finally established using the bidirectional power switch module with IGBT as the tap-changer. This chapter also designs the absorption buffer circuit, over-current protection circuit, and gives the regulating process.③Based on this simulation model, the model of the static on-load tap changer for distribution load transformer with the bidirectional power switch is established. By using the model, it is verified that the design can complete the constant flux regulating process. The circulation problems are simulated. Finally, the feasibility of the design scheme and the pressure regulation process is verified by experiments...