An investigation of the temperature distribution in cast-resintransformer windings

摘要

A comprehensive thermal test program was conducted on a 2000 kVAcast-resin dry type transformer with 300 embedded thermocouples todetermine the hottest spot temperature allowance and to obtain data todevelop mathematical models. Nineteen thermal test runs were performedat different loads, tap positions, and core excitations under naturaland forced air operating conditions. The test data indicated that thehottest spot temperature allowance used in the IEC standard was too low.In the IEEE standard the hottest spot temperature allowance appearsconservative up to about 115° C average winding temperature rise. Thelocations of the hottest spot for the primary and secondary winding weredetermined. Conclusions about thermal testing and loading are presented