In this paper, a novel technique of voltage sag characterization and detection have been presented. In the proposed work, firstly, two types of data inputs, namely, peak, and fundamental component values of voltage signal, have been derived from IEEE test waveform of instantaneous voltage signal. Then, these two derived and one test waveform data, i.e., three data inputs, have been used to obtain WT coefficients and their energies with the help of Maximal Overlap Discrete Wavelet Transform (MODWT). Finally, WT coefficients and their energies, which are obtained with these three data inputs, have been applied to estimate the magnitude, duration, points on wave (POW) of start and recovery of the voltage sag for its characterization and detection. It is found that the magnitude and duration, obtained with the fundamental voltage component data is closer to the real characteristics than the other two data inputs whereas POW of start and recovery provides accurate result with instantaneous data input. Additionally, for computing WT coefficients and their energies, boundary effects in the one cycle sliding window have also been considered here.