Evaluation of a Functional Life Test Model for Power Transformers

A power transformer life model and its related, test procedure have been evaluated and found to provide more meaningful information on retained operational capability of the winding insulation than can be derived from simple material tests. Both paper and enamel conductor insulation demonstrated retained functional ity after aging for time periods in excess of 5 times the life defined in industry loading guides. In addition, valuable knowledge was revealed about the behavior of conductor turn insulation with free gas entrapment, where the gas source was either oil supersaturation with dissolved gas or thermal evolution from overheated cellulose.

[1]  A. T. Chadwick,et al.  Oil Preservation Systems; Factors Affecting Ionization in Large Transrormers , 1960, Transactions of the American Institute of Electrical Engineers. Part III: Power Apparatus and Systems.

[2]  F. Heinrichs,et al.  Bubble Formation in Power Transformer Windings at Overload Temperatures , 1979, IEEE Transactions on Power Apparatus and Systems.

[3]  J. MacDonald,et al.  Short-Time Failure Mode Considerations Associated With Power Transformer Overloading , 1980, IEEE Transactions on Power Apparatus and Systems.

[4]  W.J. McNutt.  A proposed functional life test model for power transformers , 1977, IEEE Transactions on Power Apparatus and Systems.

[5]  W. G. Lawson,et al.  Thermal Ageing of Cellulose Paper Insulation , 1976, IEEE Transactions on Electrical Insulation.

[6]  J. R. Meador,et al.  Transformer Oil Preservation , 1957, Transactions of the American Institute of Electrical Engineers. Part III: Power Apparatus and Systems.

[7]  R. B. Kaufman,et al.  The Effect of Transformer-Oil-Preservation Methods on the Dielectric Strength of Oil , 1957, Transactions of the American Institute of Electrical Engineers Part III Power Apparatus and Systems.