Balancing investments and operating costs with customer interruption costs to give increased reliability

This paper considers the task of improving the reliability of electric power to a local area such as a city, major industrial complex or other load center. In simple terms, the reliability of the supply is a function of the following parameters: the load in the area as it fluctuates over time; the maximum amount of power that can be imported from the main grid (this import limit varies by maintenance and forced outage of transmission and generating equipment); and maximum available local generation at any particular time as it is affected by generation maintenance and forced outages. At any particular time, load curtailment will occur if the load exceeds the maximum import into the area plus the maximum generation available in the area. Therefore, reliability of supply to consumers in the area can be measured in terms of statistics of load curtailment. Popular load curtailment measures include frequency of interruptions and energy not served (kWh/year)