Temperature rise characteristics of stator winding under air gap eccentricity in synchronous condenser

Air gap eccentricity is a typical mechanical fault in synchronous condensers, which significantly affects their continuous and stable operation. To investigate the temperature rise variation law of stator windings under air gap eccentricity, the loss variation trends under no-load, under-excitation, and over-excitation conditions in both normal and eccentric states are first theoretically derived. Subsequently, a 3D model is constructed to calculate the loss and temperature variations of the stator winding under different operating conditions. Ultimately, the stator winding temperature is actually measured on a built experimental platform. Simulation and experimental results show that with the aggravation of air gap eccentricity, core loss and winding copper loss increase significantly; the maximum winding temperature occurs at the minimum air gap position and rises with increasing eccentricity degree, which is 4~6 ℃ higher than that under normal conditions; Moreover, higher degrees of over-excitation or under-excitation, the more significant the impact of air gap eccentricity on the stator winding temperature rise. This research results provide data support and theoretical guidance for condition monitoring, fault early warning, and thermal design improvement of synchronous condensers.