6 Individual Utility Transmission Planning Each utility plans and establishes operating limits for its transmission facilities. Technical studies are performed using specific criteria for equipment loadings, voltages, and system stability under normal conditions and for equipment out of service. Each utility improves its local distribution system based on anticipated local growth. This provides appropriate reliability at the individual customer level. 8 Generation Maintenance Utilities perform generating unit maintenance based on a manufacturers' specifications and maintenance activity is coordinated for reliability purposes.
Major maintenance is coordinated with generation to minimize total system costs.
Maintenance frequency is determined by manufacturers' recommendations, and utility experience determined by historical tracking of equipment trouble and outages. 10 Coordination of Maintenance Activities Arizona utilities coordinate generation and transmission equipment maintenance activities with each other and other utilities in New Mexico, California, and Southern Nevada. Generation and transmission owners will be driven by different economic incentives making coordination more challenging 11 Short Term Load Forecasting Load projections are continuously updated so that short term resource plans can be developed with the most accurate load data possible. All operating reserves must be fully available within 10 minutes. Retail competition may bring about changes in the assignment of responsibilities and mechanisms for compensation for this activity.