Permanent magnet synchronous generators (PMSGs) and doubly-fed induction generators (DFIGs) are key components of wind turbines

and their internal faults significantly affect the long-term stable operation of the turbines. In practical applications

fault data are difficult to obtain

and the power electronic devices in wind turbines exhibit microsecond-level dynamic characteristics

making electromagnetic transient (EMT) simulation essential for fault analysis. However

the gray-box models provided by commercial EMT simulation software fail to support internal fault simulation. Moreover

due to differences in the order of equations between PMSGs and DFIGs

traditional modeling methods lack compatibility. In addition

conventional generator models based on current as the state variable are incapable of capturing internal fault characteristics and fault modeling of the generator itself cannot generate node-equivalent circuits for direct integration with external components. This paper proposes a unified EMT modeling and simulation method for internal faults in both PMSGs and DFIGs. The method employs flux linkage as the state variable to develop a unified node- equivalent circuit

enabling consistent modeling of various fault types and generator configurations. The proposed approach is implemented in PSCAD/EMTDC and compared with results obtained from Matlab. The results demonstrate that the method can accurately reflect the characteristics of internal faults

validating its effectiveness.