APPLICATION OF TRANSMISSION RELIABILITY ASSESSMENT IN PROBABILISTIC PLANNING OF BC-HYDRO VANCOUVER SOUTH METRO SYSTEM

This paper presents a basic method of probabilistic transmission plann ing used in BC Hydro. The method is based on transmission system relia bility evaluation and an overall economic analysis including damage co st due to system unreliability. Four alternatives for the Vancouver So uth Metro system of BC Hydro have been evaluated using the method. The First one is addition of a 230 kV line, the second one local configur ation changes (''cuts and ties'') in the 69 kV subsystem, the third on e operational manipulation and the fourth one curtailable industrial l oad management. The third and the fourth alternatives can be considere d as non-investment reinforcements. The results indicate that the cut- and-tie alternative in the 69 kv subsystem can provide the same reliab ility level as the 230 kV line addition but with much lower investment and therefore the initial 230 kV line addition could be deferred by 1 0 years. This deferral allows a major capital expenditure of $ 26.4 mi llion (1997 $) to be avoided. The studies show that the application of quantitative transmission reliability assessment in power system plan ning can provide utilities with significant economic benefits.