Abstract:The low inertia characteristic of new power system brings serious challenge for its frequency security. In order to quickly and accurately assess the frequency response of large power grids after disturbance, a joint data physical driven intelligent assessment method for frequency security of large power grids is proposed. To realize the effective combination of data model and physical model, a credible ensemble learning method for frequency security assessment is designed to realize the accurate credibility evaluation of data driven frequency security results, and the credibility threshold is set as the basis for switching between data model and physical model. If the credibility index of data model is higher than the threshold, it is adopted as a reliable data driven frequency safety evaluation result, otherwise it is switched to the physical model based time domain simulation method for evaluation. The simulation model of Sichuan power grid is utilized to generate datasets and carry out model performance analysis, and the results show that the proposed method combines the rapidity and accuracy of frequency safety assessment.