Protecting Power Transformers From Common Adverse Conditions

Ali Kazemi, Schweitzer Engineering Laboratories, Inc.
Casper Labuschagne, Schweitzer Engineering Laboratories, Inc.

Power transformers of various size and configuration are applied throughout the power system. These transformers play an important role in power delivery and the integrity of the power system network as a whole. Power transformers have operating limits beyond which transformer loss of life can occur. This paper examines the adverse conditions to which a power transformer might be subjected. Our discussion includes transformer overload, throughfault, and overexcitation protection. We discuss each operating condition and its effect on the power transformer, and provide a solution in the protection scheme for each operating condition.