Monitoring of Time Varying Harmonics

Power quality has gained increased importance in power industry in the last two decades. The quality of power is getting affected due to use of power electronic converters and all types of dynamic and non-linear loads. Harmonic pollution increases plant downtimes and power losses. Harmonics of an electrical signal is the content of the signal whose frequency is an integer multiple of the fundamental system frequency. In power system, harmonic analysis is used to determine the impact of harmonic producing load on the power system. This is widely used for system planning, equipment design, troubleshooting etc. The effect of harmonics on a power system can be in the form of power efficiency reduction, overheating in conductors, ageing of electrical insulation, etc. There are several algorithms for harmonic analysis. The Fast Fourier Transform (FFT) is the most widely used computation algorithm. FFT is an efficient algorithm used to compute Discrete Fourier Transform (DFT). DFT uses a finite set of discrete-time samples of an analog signal and produces a finite set of discrete-frequency magnitude spectrum values.