With the development of the power grid

the harmonic problem of substation has developed from a simple load problem to a complex one affected by both system power and load

whichalso brings great challenges to the harmonic source localization of the substation. In this paper

staring from the active and reactive power of harmonics

the positive and negative harmonic power is used to judge the power flow through the physical process analyzing power transfer

and finally achieve accurate location of harmonic source. On this basis

the harmonic power calculation of secondary harmonic of a substation in accordance with the actual test data of harmonics and analysis of the harmonics of 220 kV substation so to achieve locationanalysisofharmonicsourceofthesubstation.