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Computerized Economic Analysis of Alternative Line Designs – A "How To" Approach for Quick Solutions. Logan Pleasant, P.E. ESC engineering, Inc. What is Economic Conductor Analysis?. Evaluation of the economic “break-even” point between two or more conductor types and or sizes.
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Computerized Economic Analysis of Alternative Line Designs – A "How To" Approach for Quick Solutions Logan Pleasant, P.E. ESC engineering, Inc.
What is Economic Conductor Analysis? • Evaluation of the economic “break-even” point between two or more conductor types and or sizes. • Multiple Factors influence the time sensitive present worth cost of plant installation. • Equations have been derived • Involved, time consuming and cumbersome to use by hand for sensitivity studies.
Break Even Point - Definition • The point at which the sum of the present worth of all investment, owning and future loss costs are equal for two line construction alternatives: • Present Worth of Capital Investment • Present Worth of Carrying and Owning Charges • Present Worth of Future Loss Costs
Definition of Variables • CC = Carrying Charges • IV2 = Investment cost of larger conductor line • IV1 = Investment cost of smaller conductor line • i = Interest rate in per unit • CL = Initial annual cost of loss in dollars per kWh • ie = Effective discount rate (includes load growth and power cost escalation) • R1 = Resistance of larger conductor size • R2 = Resistance of smaller conductor size • LsF = Loss Factor • kW = Peak kilowatt load • kVLG = Line to ground voltage in kV • P1 = # phases of larger conductor • P2 = # phases of smaller conductor • n = Expected life of line in years.
Sensitivity Analysis • The relative sensitivity of the equations to any given input factor: • Interest Rates • Useful Life • Future Load Growth • Escalation in Wholesale Power Costs • Tree Trimming Costs • Changes in Line Construction Costs • Labor Costs • Power Factor • Operation & Maintenance (O&M) Costs
Sensitivity Analysis • Determination of sensitivity allows the analyst to focus efforts on areas that have the greatest economic impact.
Computerization of Equations • Greater Flexibility • Ease of Interface • Saves Time • Change independent variables quickly (“What if?” scenarios) • Ability to view results graphically • Reduce Chances for Errors • Management Tool