Frequency-response analysis(FRA)is widely used as an effective method for detecting winding deformation faults in transformers. Similarly

the rotor of a turbo-generator can be represented as a two-port network using distributed parameters. For this reason

the characteristics of single-point ground faults in generator rotors were investigated based on FRA method. First

a distributed parameter model of the rotor winding was established. The influence of skin effect and proximity effect on its parameters at different frequencies was analyzed. The capacitance parameters of the model were calculated by the finite element method. Then

a 300 MW turbo-generator was taken as an example. A joint simulation using a two-dimensional finite element model and an external circuit was performed. The amplitude-frequency response characteristics under different fault locations and transition resistances were analyzed. The amplitude-frequency response curves were processed by the correlation coefficient and dynamic time warping(DTW). The curve characteristics and statistical indicators of single-point ground faults in the rotor winding were obtained. Finally

single-point ground faults were simulated on a TZH-225-4-TH type unit. The characteristic analysis of the amplitude-frequency response curves agrees well with the simulation results. This study provides a new approach for the offline detection of single-point ground faults in turbo-generator rotor windings.