Executive Summary : | Modern power electronic equipment provides better control over power system components and parameters. Cycloconverters, variable ac drives, inverters, etc., have brought a paradigm shift in our power system and opened possibilities for new and more sophisticated devices. The rapid growth that the world has seen in the last few years results from modern power electronics. The advanced power electronic systems are deemed to be the most fundamental and an integral part of renewable, green and efficient energy systems. The amount of renewable energy sources being integrated into our power system is not possible without modern power electronics. From modulation of power to the creation of virtual inertia, all this is possible with the help of power electronic devices. While on the one hand, it brings so many benefits; on the other, it distorts the supply system. As a result of these distortions, harmonics and specially interharmonic components are coming into the picture. An increase in the interharmonic content causes flicker, which is very harmful to the human nervous system. Interharmonics also leads to maloperation of the protection relays. Mitigation of these components is very crucial now. To properly remove them, their fast and accurate estimation is needed. The traditional equipment for harmonic analysis uses fast Fourier transform (FFT) based methods. These methods suffer from low spectral resolution, picket fence effect, spectral leakage, etc.; however, the recent literature has countermeasures for these problems like windowing, interpolation, etc., but it further increases the computational burden. If a frequency component is encountered which does not exactly fall in the frequency bin of FFT, then spectral leakage will occur, and the result will be inaccurate. Thus, non-parametric methods like FFT available for this purpose cannot accurately estimate interharmonic components in the supply system. On the other hand, the parametric methods have a very high spectral resolution and can accurately detect interharmonics in the supply system. However, parametric methods suffer from modelling inaccuracies and a high computational burden. The focus of the proposed work will be to develop a less computationally burdened (fast) approach that can accurately estimate the harmonics/interharmonics in the power system by following a different approach along with modification/hybridization of the existing methods. Along with this, the focus will also be on the development of harmonic/interharmonic monitoring methodology that involves low-cost hardware and is also capable of performing onsite/remote monitoring. |