Abstract：With the accelerated construction of new power system，the harmonic characteristics of power grid

are becoming more and more complex. It is of great significance to study the effective statistical management of

harmonic data for evaluating the power quality of power grid. A statistical method of harmonic evaluation index

based on maximum entropy principle was proposed. By recording and saving the average value and center distance

of harmonic data，the maximum entropy principle was used to fit the probability distribution of harmonics，so as to

save and identify the harmonic characteristics and facilitate data storage. Two harmonic evaluation criteria of

harmonic 95% probability value and 99% probability value were obtained by using the fitted probability

distribution，which ensures the accuracy and consistency of the index. Finally，the effectiveness of the proposed

method was verified by the example analysis of harmonic measured data.

      Key words：maximum entropy principle；harmonic evaluation；95% probability value；99% probability value