Author : Sujin P. R, T. Ruban Deva Prakash, L. Padma Suresh

Human perception of light flicker is almost always the limiting criterion for controlling small voltage fluctuations. Voltage fluctuations in power systems can cause a number of harmful technical effects, resulting in disruption to production processes and substantial costs. But flicker, with its negative physiological results, can affect worker safety as well as productivity. The primary cause of voltage changes is the time variability of the reactive power component of fluctuating loads. The arc furnace is a major source of voltage flicker in industry. Recently, FACTS devices are effectively used for flicker mitigation. In this paper, voltage flicker mitigation with shunt compensator DSTATCOM is analyzed using the MATLAB software. The control strategy adopted to mitigate flicker plays a key role for effective mitigation. SRM algorithm is commonly used for harmonic filtering. This algorithm can be modified for voltage flicker mitigation. The computation is instantaneous but incurs time delays in filtering the DC quantities. In order to overcome this drawback, ANN based control algorithm for voltage flicker mitigation is also proposed in this paper. Since the controls do not include any parameter which is dependent on network condition, the performance of such controller is robust with respect to network structure, fault location and system loading. The control structure is decentralized and does not need any coordination with other compensating devices. The structure of proposed algorithm is easy to understand, easy to implement and attractive from a view-point of engineering .Numerical simulation proved the effectiveness of the controller in compensating voltage flicker. Furthermore, a modified self-charging technique is used for maintaining dc bus voltage, which does not use PI controller.

Keywords: Voltage flicker, Synchronous Reference Frame algorithm, Artificial Neural Network, Distribution Static Synchronous Compensator (DSTATCOM)

Article published in International Journal of Current  Engineering  and Technology, Vol.2,No.2 (June 2012)