An electric power system involves the production and transportation of electrical energy from generating facilities to energy-consuming customers. This is accomplished through a complex network of transmission lines, switching and transformer stations, and other associated facilities. The primary objective in the design of the delivery system is the creation and operation of a safe, reliable, and economic link between the generating supply and the customer load points. Reliability has always been a primary concern in the design and operation of electric power systems. In most of the developed countries throughout the world, a very high level of reliability has been the norm for many years. This is particularly true in North America, where customers have come to expect electricity supply to be available virtually on demand.

The Canadian Electricity Association (CEA) has collected Canadian service continuity statistics for many years...