A short note on optimal repair rates of multiple circuit transmission lines

Multiple transmission lines on a single right of way are commonly used by utilities. The phenomenon of common cause outages was first of all recognized by a Task Force from IEEE subcommittee [1]. The Task Force defined a common mode outage as "an event having a single external cause with multiple failure events, where the events are not consequences of each other". The closed form expressions for steady-state probabilities in 2and 3-line transmission systems have been derived out by Billinton, Medicherla and Sachdev [2], These expressions were used to study the effect of common-cause outages on state probabilities. Thus the study done by Billinton, Medicherla and Sachdev [2] is descriptive one. This paper deals with the prescriptive behaviour of multiple circuit transmission lines. The optimal repair rates of transmission lines have been found out by complementary geometric programming. Sections 2, 3, 4, and 5 deal with the steady-state probabilities of 2-line transmission system, complementary geometric programming, optimization model, and illustration, respectively.