Loading of Ventilated Dry-Type Transformers

This is a continuation of the previously published data on the loading of sealed dry-type transformers.1 With the same representative core and coils as were used in the previous work, and the sealed tank replaced with a louvered casing, the winding temperature rises are measured for a variety of loads following several steady-state conditions. These data are converted to hottest-spot temperatures utilizing previously published hottest-spot increments and the allowable limits specified in the standards. Aging rates are those for the presently used materials in ventilated dry-type transformers. Insulation aging is computed for various overload cycles and the allowable loads determined for normal life expectancy as well as a few specified per cent loss-of-life criteria.

[1]  F. M. Clark.  Factors affecting the mechanical deterioration of cellulose insulation , 1942, Electrical Engineering.

[2]  L. C. Whitman,et al.  Hot-Spot Temperatures in Dry-Type Transformer Windings , 1944, Transactions of the American Institute of Electrical Engineers.

[3]  Thomas W. Dakin,et al.  Electrical Insulation Deterioration Treated as a Chemical Rate Phenomenon , 1948, Transactions of the American Institute of Electrical Engineers.

[4]  L. C. Whitman,et al.  Aging Characteristics of Dry-Type Transformer Insulation at High Temperature , 1948, Transactions of the American Institute of Electrical Engineers.

[5]  L. C. Whitman,et al.  Aging Evaluation of Dry-Type Transformer Insulating Systems [includes discussion] , 1953, Transactions of the American Institute of Electrical Engineers. Part III: Power Apparatus and Systems.

[6]  Paul Narbut,et al.  Temperature Classes for Dry-Type Transformers as Determined by Functional Tests [includes discussion] , 1953, Transactions of the American Institute of Electrical Engineers. Part III: Power Apparatus and Systems.

[7]  A. M. Lockie,et al.  Life Expectancy of Oil-Immersed Insulation Structures [includes discussion] , 1953, Transactions of the American Institute of Electrical Engineers. Part III: Power Apparatus and Systems.

[8]  L. C. Whitman.  Co-ordination of Dry-Type Transformer Models with Transformer Geometry [includes discussion] , 1956, Transactions of the American Institute of Electrical Engineers. Part III: Power Apparatus and Systems.

[9]  L. C. Whitman.  Loading of Sealed Dry-Type Transformers , 1957, Transactions of the American Institute of Electrical Engineers. Part III: Power Apparatus and Systems.