Aspects of thermal monitoring of substation equipment

The author describes the performance of inspection techniques used to locate defects on equipment with the main emphasis being on thermal imagers operating in the thermal infrared atmospheric windows. A description is given of monitoring techniques for substation equipment which are being improved to allow increased ratings when there is a variable load. It is possible to utilise the large thermal capacity of a cable or transformer to provide enhanced ratings for short periods. These are very valuable to grid control engineers who use them to ensure system security in the period after a fault when normal security standards are being re-established. Finally, the use of fibre optic cables as temperature sensors, which has many potential applications in a substation, is mentioned