Transmission Planning Using a Reliability Criterion, Part I: A Reliability Criterion

The utilization of a quantitative reliability criterion in long range transmission planning is proposed. The application of a conditional probability approach the determination of load point reliability indices in practical systems is discussed and illustrated by a simple hypothetical system study. Failure at a bus is defined by three planning criteria and the reliability level obtained in terms of a probability and an expected frequency of bus failure. The method requires ac load flow analysis at several load levels under possible system component outages. The technique is quite general, and any known operating conditions can be included. Planning based on acceptable load bus reliability levels results in optimum utilization of the investment placed in transmission facilities.