PREFACE TO THE THIRD EDITION
Events in the electric utility industry in the fast few decades have made knowledge of transformers and power equipment assume even greater importance. In general, the trend has been toward squeezing out every ounce of capacity to achieve a greater efficiency, all increasing the potential for decreased reliability. Earlier efforts to reduce the demand and consumption of electric energy through load management programs (brought about by the increased cost and difficulty in providing generating facilities), largely through measures affecting consumers:
1. Retrofitting consumers loads with more efficient units; e.g., replacement of incandescent lamps with fluorescent ones.
2. Peak suppression by manipulating consumers’ schedules of operation of specific loads to avoid their coincidence; e.g., clothes washer-dryers not operate at the same time as ranges or air conditioners.
3. Encourage development of cogeneration by large consumers.
Cash bonuses, favorable rates, attractive financing, and other incentives employed to accomplish these objectives. Deregulation of utilities that ostensibly replace monopolies with free market competition between suppliers of electric energy further increased pressures for efficiency improvement. Here the tactics employed, mainly by utility managements:
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1. Intensification of load management programs.
2. Increase the use and capacity of transmission facilities to deliver low cost power from distant, not necessarily contiguous, sources; e.g., increase line capacities by converting to higher voltages.
3. Eliminate, physically or legally, less efficient generating units and other invested capital; e.g., land, buildings, other stranded facilities, no longer necessary or desirable.
In the quest for greater efficiency, efforts are directed principally toward transformers and transmission systems, where the potential for failure is perhaps greatest, where overloads and exposure play a large role. Development of transformers that cannot be overloaded, plastic insulation to replace frangible porcelain, and improved protection from electronic relays, all tend to mitigate the potentially negative effects on service reliability. These are more fully developed in the accompanying text. At a time when advances in the fields of computers, communication, and automation have materially affected the daily activities of almost everyone, and at a time when the demand for greater reliability and quality of electric service is more critical than ever, the potential for degrading service reliability (especially because of deregulating processes) makes imperative that the design, manufacture, construction, installation, operation and maintenance of transformers and power equipment be thoroughly examined, that prudence and caution be exercised in the implementation of load management and deregulation programs.