A reliability and economic evaluation of a transmission system-I: Using frequency and duration of failure method

The reliability of a transmission system model consisting of transmission lines, transformers, and circuit breakers is calculated from sample data using the frequency and duration method. The model is modified by adding another transmission line and a transformer to study the effect on reliability. A significant decrease in system down time is found when a transformer is added in parallel with the two existing ones, whereas adding another transmission line produces only a minimal decrease. A study has been conducted to determine whether it is economically feasible to add another transformer to increase the model system´s reliability and decrease its down time. During a twenty-year period, it was found that the savings of energy, and the dollars associated with it, exceeds the costs of the additional transformer