Pine Point Mines dragline— application of a peak shaver on a small power system

CIM Bulletin, Vol. 73, No. 823, 1980

T.E. SMITH, Chief Electrical Engineer, Engineering Cominco Ltd., Trail, British Columbia, D. PHILLIPS Assistant Manager, Systems Engineering Division, Montrea Engineering Company, Limited, Calgary, Alberta

This paper describes the application of a motor-driven flywheel unit, known as a peak shaver, to compensate for the cyclic load fluctuations of a large electric dragline installed at Pine Point Mines, near Great Slave Lake in the Northwest Territories. Of particular interest in this application is the fact that the power system supplying the dragline is a relatively small isolated system, with the major generating source approximately 170 miles from the mine.The cyclic load fluctuations of the dragline are theoretically capable of producing a maximum swing of up to 11 megawatts, which approaches nearly 50% of the installed generating capacity. To reduce these load fluctuations to acceptable limits various alternatives were considered, leading to a decision to install apeak shaver to optimize the operations of both the mine and the power system. Without the peak shaver, the dragline operations would be severely curtailed and additional diesel generation would have to be run at considerable expense, otherwise the power system frequency fluctuations would be totally unacceptable. With the peak shaver, power and frequency fluctuations are kept within tolerable limits, and optimum economic operation of the diesel generation is obtained.The paper outlines the steps leading to the selection of the peak shaver as the compensating device, describes the equipment installed and gives details of operating experience with the dragline/peak shaver combination since installation early in 1979. This peak shaver is the first of its kind in North America, the only other peak shaver installation being in Australia.
Keywords: Equipment, Draglines, Pine Point Mines Ltd., Peak shavers, Power systems, Electricity.