Increase in permeability of renewable energy sources (RESs) leads to the prominent problem of voltage stability in power system

so it is urgent to have a system strength evaluation method with both accuracy and practicability to control its access scale within a reasonable range. Therefore

a hybrid intelligence enhancement method is proposed by combining the advantages of mechanism method and data driven method. First

calculation of critical short circuit ratio (CSCR) is set as the direction of intelligent enhancement by taking the multiple renewable energy station short circuit ratio as the quantitative indicator. Then

the construction process of CSCR dataset is proposed

and a batch simulation program of samples is developed accordingly

which provides a data basis for subsequent research. Finally

a multi-task learning model based on progressive layered extraction is used to simultaneously predict CSCR of each RESs connection point

which significantly reduces evaluation error caused by weak links. Predictive performance and anti-noise performance of the proposed method are verified on the CEPRI-FS-102 bus system

which provides strong technical support for real-time monitoring of system strength.