III--Combined Reliability and Economy in Operation of Large Electric Systems

This paper discusses the practises in use on the Philadelphia Electric Company system in attaining the maximum system economy consistent with high degree of service reliability. The system comprises not only steam electric stations of different efficiencies, but also a large hydroelectric plant and a major high-voltage interconnection with two large neighboring utilities, so that problems of operating economy are both highly important and complex in character. The paper also directs attention to problems of investment economy with a view toward securing the best balance of fixed charges, operating costs, and service reliability.