Flickermeter Design: An Improved Method to evaluate Short term Flicker Severity Index (Pst) using Walsh Hadamard Transform (WHT)

This paper proposes a method to estimate the flicker severity index using the Walsh Hadamard transform (WHT). A weighting filter in the sequency domain is utilized for direct computation of the flicker index. The proposed method is compared with a flicker meter in the frequency domain that uses the Fast Fourier Transform (FFT). It is seen by numerical simulations that the proposed method yields flicker severity indices within the stipulated range for six test signals prescribed by the IEC. The computational simplicity of the Hadamard transform is explained with respect to floating point operations(flops). Complexity of FFT increases as order of N Increases and Computational Savings of Hadamard Transform over FFT is shown with respect to number of floating point operations through the simulations carried in MATLAB and C Platforms. Keywordsflicker, Hadamard transforms