Basic research on transformer life characteristics
Abstract
Basic research of the significant parameters affecting transformer life are covered. Project objectives included test method definition and methods for scaling data obtained on conductor and subsubassembly models to predict the life characteristics of full-size transformers. Major parameters discussed include gas evolution during thermal aging of insulation and thermal, mechanical, and electrical stresses over time, both singly and in combination. The composition and the evolution rate of gases during the thermal aging of cellulose in oil were obtained as a function of time over a range of temperature from 1400 C to 1800 C. Gas initially evolved at 1800 C was basically similar to air with very little CO2. The dielectric strength of the turn insulation decreased in the presence of gas bubbles, but was relatively unaffected by the amount of gas or its composition. Data obtained from the thermal aging, short circuit, and dielectric tests of paper and film insulated conductor samples was used to provide design information for subassembly models. The subassembly models were subjected to life tests at 1800 C and 2000 C. An end of life criterion was arbitrarily set at a fifty percent reduction of the dielectric strength in the conductor insulation.
- Publication:
-
Final Report Westinghouse Electric Corp
- Pub Date:
- September 1982
- Bibcode:
- 1982wec..reptR....A
- Keywords:
-
- Electrical Insulation;
- Performance Tests;
- Research;
- Service Life;
- Transformers;
- Circuit Protection;
- Electrical Grounding;
- Life (Durability);
- Thermal Degradation;
- Thermal Insulation;
- Electronics and Electrical Engineering