Precise Measurement Method Of Signal Containing Harmonics

Electric power quality has been a critical problem in power system because of the increased use of nonlinear loads that introduce distorted signal into the power system networks and hence misrepresenting the supply voltage and current.The purpose of nonlinear devices has increased day by day whichlead more severe problem of harmonics in power system.As the whole World is in developing stage using technologies that are new to the world which can be said as non-linear load in development.Because of more use of these kinds of loads there is a generation of current harmonics in distribution system.Due to these harmonics problems system might not be as efficient as it has to be.Harmonics are the integer multiple of the fundamental frequency that are kind of pollution which can cause losses and reduces the life of the system.The interpolation algorithm is discussed in this thesis to reduce the measurement errors,caused by leakage effects.This interpolation algorithm uses the Fast Fourier Transform(FFT)technique,which is the modified version of Discrete Fourier Transform(DFT),to minimise the leakage effect and give the accurate results.In this research,I have developed a system for precisely measuring the parameters of signal that contains integer multiple of fundamental frequency to improve the accuracy and precision.The interpolation technique used in proposed algorithm that contains the different interpolation formulas that will use the magnitude values of three greatest spectral lines and it use the Chebyshev approximation theory which will further find the interpolation point that will help to find the moth harmonic frequency.In the first part,the work will be done by simulating the signal in MATLAB and getting simulated result and the second part consist of the work done by taking real-time data and using that data to calculate the accurate harmonic parameter values.In the final portion,we have simulated another interpolation algorithm different from proposed algorithm that willuse the magnitude values of two greatest spectral lines with its interpolation formulas and compare the results with results of algorithm presented in this proposed thesis.Depending on the accuracy and measurement of harmonic parameters,the proposed algorithm was tested to verify its better performance and reasonable accuraeyA conclusion has been done on the results of both algorithms to show that the proposed interpolation algorithm is more accurate than the other interpolation algorithm.The proposed interpolation algorithm is accurate,fast and having good anti-jamming capacity over the other interpolation algorithm.