Future transmiss

FUTURE TRANSMISSIQN Andrew F. Corry Boston Edison Company Boston, Mass.

UNDERGROUND?
E. Kasum Philadelphia Electric Company Philadelphia, Pa.

Abstract-Future transmission systems will handle larger blocks of power and a greater percentage will be installed underground. Solutions to the present limitations on operating such systems are being developed and it is anticipated that theeconomies of size will reduce the competitive disadvantage. It is important that continued effort be directed in this field so that the necessary systems are developed.

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PROJECTION OF U.S. NON -COINCIDENT PEAK POWER DEMAND TO TIHE YEAR 2000* I

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INTRODUCTION There are two basic premises which dominate the planning of the needs of the electric utility industry. 1. Thetotal U.S.A. electric system load to the end of the Century is presently estimated to continue to double every 10 to 12 years, resulting in approximately a five to sevenfold increase by the year 2000. 2. Public interest in environmental esthetics will continue to grow, with resultant mounting objections to overhead transmission lines. Concurrently, development of more stringent regulations againstair and water pollution makes it appear that many future generating stations may be located 20 to 50 miles from their major load centers. There will be pressure for the undergrounding of the large capacity transmission lines that will be needed to carry the heavy blocks of power to the principal service areas. Therefore, the electric utility industry can anticipate: a. More undergrounding in areaswhere formerly lower cost overhead construction was standard practice. b. Installation of higher capacity underground lines over longer distances. c. Growing pressure to narrow the competitive disadvantage of underground transmission.
Future Requirements
A projection of electric power system peak demand to the year 2000 is shown in Figure 1. It is based on forecast data to the year 1900 issued inlate 1969 by the Federal Power Commission1. Extrapolation of the FPC data up to the year 2000 was made on the basis of an analysis of the trend of the incremental growth rates shown in the study. The curve indicates a non-coincident peak demand for the contiguous United States in the year 2000 of about 1,950 gigawatts - about a seven-fold increase in the next 30 years. The following additionalpoints which appear in the individual Advisory Committee Reports1 are of particular interest: 1. Generating plant size is expected to increase to 6000-8000 MW in many cases, with individual plants as large as 11,000 MW. 2. Maximum generator ratings up to 2500 MW, and in one case possibly as high as 2800 MW, are expected to be in use. This indicates that plant and generator sizes will increase at apace somewhat comparable to the expected increase in total power demand. It seems logical, therefore, to expect that the capacity levels for underground transmnission circuits also will need to keep pace with system load growth. Figure 2 shows a comparison of the capacity levels of presently available and of advanced technology systems in relation to time of expected commercial availability and therange of capacity
Paper 72 CHO 608-0-PWR, recommended and approved by the Transmission and Distribution Committee of the IEEE Power Engineering Society for presentation at the IEEE PES Conference on Underground.Transmission, Pittsburgh, Pa., May 21-24, 1972. Manuscript submitted January 24, 1972; made available for printing May 25, 1972.

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OF 1970-1990 FORECASTS PREPARED BY SIX REGIONAL ADVISORY COMMITTEES FOR THE FEDERAL POWER COMMISSION. SUMMARIZED IN F P C NEWS RELEASE NO. 16323, ISSUED SEPTEMBER 24, 1969.

EXTRAPOLATION

Fig. 1.

levels that are expected to be needed at that...