Renewable energy systems in power grid creates irregular voltage profile. These electrical perturbations affects the machine linked to the power network, particularly high rating machines are more affected. To have a stable network, predicting the operation of pumped storage power plant enabling doubly fed hydroelectric machine is mandatary. Therefore, this paper analyses the electro-thermomechanical stresses under voltage variation on doubly fed synchronous machine (DFSM) and doubly fed asynchronous machine (DFAM). Hardware experimentation with 3 HP doubly fed machines has been carried out to identify the real time impact. The outcome of the analysed results helps to prevent the power network system from voltage variation issue and provides the countermeasure ideas to develop a robust system. © 2019 IEEE.