Authors : T. Ruban Deva Prakash, P.R. Sujin and L. Padma Suresh
Abstract: The quality of electric power is of supreme importance to electrical utilities and their customers. Modern equipments are more sensitive to power system anomalies than in the past. Microprocessor based controls and power electronics devices are sensitive to many types of disturbances. Voltage flicker is caused by loads that exhibit continuous, rapid variations in load current. The phenomenon of flickering has been known since the introduction of power supply networks. However, it grew rapidly along with the increase in the number of loads and the increase in the power consumed. Electric arc furnace is the main generator of voltage flicker which affects the performance of other sensitive loads connected with the system. Hence, mitigation of voltage flicker becomes inevitable. FACTS devices have been gradually introduced for voltage flicker compensation. Dynamic Voltage Restorer (DVR) has been widely used to mitigate voltage flicker. The DVR with series active compensation capability opposed to variations of the arc resistance and suppress voltage flicker at the source. The control strategy adopted to mitigate flicker in an effective and robust manner is the key issue. A scheme based on fuzzy bang-bang control with ANN is proposed for flicker mitigation using DVR in this study. Two dimensional fuzzy control rules are framed based on Lyapunov function analysis and selection of control rule with best response to current state is done using Artificial Neural Network (ANN). Using the proposed control algorithm, the DVR will contribute to the mitigation of flicker without deteriorating the effect of the other compensating devices. The control algorithm is simulated on a power system model with arc furnace load. Numerical simulations show the effectiveness of the controller in compensating voltage flicker.
T. Ruban Deva Prakash, P.R. Sujin and L. Padma Suresh, 2012. Fuzzy Bang-Bang Control with ANN Based Voltage Flicker Mitigation Using DVR. International Journal of Electrical and Power Engineering, 6: 88-93.