On-line rotor temperature measurements

On-line temperature measurements on hydrogenerators are usually limited to those read by resistive thermal detectors (RTD) on stators and global temperature of the cooling air and water at the input and output of the heat exchangers. Data shows that the proportion of generators where the temperature rise on the rotor is larger than on the stator is non negligible. With such units, temperature monitoring of the rotor should be considered. This paper presents the characterization of an infra-red thermal sensor installed on the stator side to measure the rotor. A single sensor can therefore scan every pole passing in front of it. Preliminary measurements on generators owned by Hydro-Québec (HQ) and Électricité de France (EDF) are presented along with details on the characterization at HQ´s research laboratories (IREQ) in a controlled environment.