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

This paper presents a basic method of probabilistic transmission planning used in BC Hydro. The method is based on transmission system reliability evaluation and an overall economic analysis including damage cost due to system unreliability. Four alternatives for the Vancouver South 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 configuration changes (''cuts and ties'') in the 69 kV subsystem, the third one operational manipulation and the fourth one curtailable industrial load management. The third and the fourth alternatives can be considered as non-investment reinforcements. The results indicate that the cut-and-tie alternative in the 69 kv subsystem can provide the same reliability level as the 230 kV line addition but with much lower investment and therefore the initial 230 kV line addition could be deferred by 10 years. This deferral allows a major capital expenditure of $ 26.4 million (1997 $) to be avoided. The studies show that the application of quantitative transmission reliability assessment in power system planning can provide utilities with significant economic benefits.