Optimized Distribution and Subtransmission Planning by Digital Computer IV-Subtransmission System Design

A computer program for studying the economics of subtransmission system design is described, and the results of its use on a load area of the Arizona Public Service Company are summarized. The program, which can be used independently or in conjunction with programs for studying secondary and primary system economics, examines each of many possible subtransmission designs, determines investment and operating costs, and compares the total cost with that of other possible designs. The use of the program with data for a specific load area for four different load levels produced cost savings on the order of 9 percent of total secondary plus primary plus subtransmission costs and established the low cost combinations of subtransmission voltage, conductor size, distribution substation rating, and bulk power station locations and capacities.