Modelling and control of dynamic voltage restorer to protect sensitive load under non linear loading conditions

摘要

Dynamic voltage restorer (DVR) is used for the protection of sensitive loads from the voltage disturbance like, voltage sag/voltage swell. In this paper, Dqo based PI controller has been used for the detection of voltage sag as well as for yhe generation of compensatingvoltages for controlling DVR. The proposed algorithm works well with any types of loads connected whether linear or non linear. To simulate the actual scenario a double circuit distribution line modelling is being done in matlab and fault is being created in one line to produce voltage sag in the other line.A three phase reference voltage is being generated and the load voltages and the reference voltages are being compared by converting both voltages into Dqo frame using Dqo transformation. The Dqo error is again converted into abc frame to obtain the compensating voltage.The compensating voltage is give to the pi controller which controls the power circuit to inject a voltage in phase with the source voltage to maintain the voltage profileof the load to be purely sinusoidal.Whole of the simulation model is simulated in MATLAB simulation power system. The fourier analysis of the load voltage is performed for harmonic analysis. The result obtained proves the effectiveness of the proposed algorithm..