Study Of D-FSC For Improving Voltage Quality In Distribution Networks

In distribution network, as the load characteristics are very complicated and the distribution frame is very weak, relative to transmission network, the distribution network development is seriously lagging behind. So there are some problems existing in distribution network include:voltage-distribution of the distribution line is not qualified, the voltage flicker frequently and others, that seriously affecte the development of people’s life and economic construction.This paper take solving the universal voltage quality problem in domestic distribution network as research purposes, take fixed series compensation technology as research object. This distribution fixed series compensation (D-FSC) technology has two features of self-adaption to variable load and real-time response, and two main effects of improving the voltage distribution along the line and decreasing voltage flicker degree. Besides, the structure and the control of its device is relatively simple, so that it is just suitable for the demand of domestic distribution network.However, at present, the series compensation technology is widely applied at home and abroad transmission network, but have not been used by domestic distribution network. So in this paper, by theoretical analysis and digital simulation, a comprehensive introduction of fixed series compensation technology applied in distribution network is given.First, the abilities in improving voltage quality capability and working performance of series compensation and parallel compensation are compared. Second, the methods to determine the location and capacity of series compensation device are analized in detail. Third, the design of series compensation capacitor protection scheme and measures to prevent the ferromagnetic resonance and self-excitation of the electric motor are proposed. Fourth, the controller functions of D-FSC are designed. Last, to practice in the actual distribution line, effectiveness of the D-FSC’s function is verified, and the design parameters of the actual device are provided, including the capacitor itself, protective equipment, damping device and the operation of the controller.