In this paper

a set of standard method for measuring the acid value of transformer insulation paper is de-termined under laboratory conditions. Through a variety of experimental means of comparison

the core step of mea-suring acid value is to extract the acid value of the insulating paper with pure water. The KOH solution titration meth-od is used to calculate the acid value of extract.The acid both in the solvent and residual oil in the paper is consideredto correct the results. At the same time

with the proposed method

the acid value of the paper in the aging test oftransformer oil-paper is measured. It is concluded that the correlation between the acid value and the degree of polymerization is strong

verifying the accuracy of the proposed method.