Loss Evaluation; Part III. Economic Dispatch Studies of Steam-Electric Generating Systems [includes discussion]

A method is presented for predetermining the economic dispatch of a steam-electric generating system including consideration of transmission losses. The equations of economic dispatch are solved for a range of values of delivered power cost to develop the dispatch curves. Novel features include an iterative method of solution which simplifies and shortens the work, and an interpretive study which shows how the single set of dispatch curves may be used to determine the economic dispatch with units out, and to determine the sale power cost at interconnections, and how it may be used for other similar extensions. The complete method for determination of the loss formula to determination and interpretation of the economic-dispatch curves is described using the Ohio Edison system as an example. The feasibility of holding tie power fixed at average values while determining the economic dispatch of generation is demonstrated for this system. The problem of selecting a proper reactive to real power ratio at generating stations is discussed and a solution proposed. This is part of a joint study1,2; which has been participated in by Commonwealth Associates, Inc., Consumers Power Company, Ohio Edison Company, Pennsylvania Power Company, and the Westinghouse Electric Corporation.