Method and device for estimating harmonic state of electric power system

The invention provides a method and device for estimating the harmonic state of an electric power system. The method includes the steps of collecting network topology information corresponding to the electric power system, collecting measuring point position information in the electric power system, collecting measuring point harmonic information in the electric power system, making network topology observability analysis and determining the observability range in the current electric power system according to the network topology information, the measuring point position information and the measuring point harmonic information, and determining a harmonic state parameter corresponding to the current electric power system according to the observability range in the current electric power system. Suspicious harmonic injection nodes are led to an observability analytic logical judgment method, the whole network analysis is achieved by the adoption of a recursive algorithm, measuring point optimal allocation is achieved according to different user needs, and the problems that the algorithm is complex, the calculated quantity is large, and the fact that a measurement device has voltage and current measuring capacity at the same time is not considered in the prior art are solved.