Phasor measurement unit (PMU) data is increasingly used in supervisory control and data acquisition. The low frequency disturbance mixed in PMU data will affect the steady-state analysis results when forced low frequency oscillation is triggered in the power grid. In order to obtain the normal 50 Hz parameter from PMU data

a method is proposed based on the theoretical analysis of low frequency disturbance to the PMU data. The validity of the method proposed was verified by analysis of real PMU data under the influence of forced low frequency oscillation in the power grid. The results of theoretical analysis and real PMU data analysis show that the normal 50 Hz parameter can be obtained quickly. The accuracy of steady-state analysis and wide application of PMU data could be improved by this method.