For the harmonic detection method based on discrete fourier transform（DFT）

the existing window perform low accuracy in measuring the signal with high-order and weak amplitude harmonic component in the situation when the frequency of power grid fluctuate.Therefore

a minimum sidelobe optimization window is proposed and its application in harmonic detection of power grid is analyzed.Firstly

the cosine window function is optimized according to the constraint condition

a minimum sidelobe window is proposed and the spectrum characteristics of the proposed window is analyzed.Then

an improved DFT harmonic detection algorithm based on six-term minimum sidelobe optimization window interpolation is proposed.The calculation formula of harmonic parameters is obtained by applying mathematical fitting method.Furthermore

simulation experiments in complex conditions are carried out to validate the improved performance of the proposed six-term minimum sidelobe optimization window.The research reveal that the six-term minimum sidelobe optimization window have smallest peak sidebobe compared with existing window

which can effectively suppress the interaction of spectrum leakage

improve the measurement accuracy of DFT harmonic detection method

and can meet the acquirement of harmonic measurement in complex situations.