Notch Filter Based Fundamental Frequency Component Extraction to Control DSTATCOM for Mitigating Current Related Power Quality Problems Bhim Singh, Fellow, IET, Krishan Kant and Sabha Raj Arya Abstract – This paper presents the implementation of a multifunction Distribution Static Compensator (DSTATCOM) using a notch filter based control algorithm for DSTATCOM to mitigate power quality issues. There are many power quality problems such as poor power factor of loads, network pollution due to harmonics injection by the nonlinear loads and excessive neutral current due to nonlinear and unbalanced loads. The function of the notch filter is to extract the fundamental frequency component of the load currents. The notch filter is designed to retain its property of fundamental frequency component extraction without any extra calculation to work even under variation of grid frequency. These components of load currents are used to estimate reference supply currents. This control algorithm is implemented in a Digital Signal Processor (DSP) and tested on a developed prototype of DSTATCOM. Index Terms- Notch Filter, DSTATCOM, Zigzag Transformer, Power Quality, Power Factor Correction (PFC) I. INTRODUCTION With the ever increasing use of power electronics converters in household devices and in industries, the supply network is becoming polluted due to the nonlinear nature of the power electronic devices [1]. Because of the nonlinearity and unbalanced operation, these devices draw large amount of reactive power, inject harmonics currents and result in excessive neutral current in the network, which when flow through the network pollute the voltages at the other buses of the network [2-4]. For mitigation of all these problems, custom power devices can be used in the