Transmission System Operations

The objective of this course is to focus attention on the factors that must be considered when dispatching energy and ancillary services under competitive market conditions. Procedures are indicated for a typical ISO, noting that detailed methodology will vary with different locations. After completion of this course, the participant should be able to understand and apply the following concepts in day-to-day work activities.

• The task of the ISO or other system operating authority
• Composition of the total power flow throughout the ISO system at any hour of the day
• Different types of power flow transactions
• Contracted and non-contracted power flows
• Power flows into and out of the system
• Preparing the day ahead generation schedule and demand schedule
• Committed generation to meet contract demand
• Must run units for technical reasons, i.e. some hydro, nuclear, and co-generation units
• Selection of generation to meet non-contracted power demand (spot market, or residual market)
• The generation bid process
• Calculating the least cost dispatch program for different hours of the day
• Estimating the market clearance price (marginal price) for each hour of the following day
• Dispatch of individual generating units by ISO, or by the GENCO local dispatcher
• Load flow study to identify congestion areas and other transmission system problems
• Adjustment of next day schedule to produce the constrained schedule, allowing for transmission limitations
• Scheduling of ancillary services, including regulating capacity, operating reserve capacity, stand-by capacity reserve, supply of reactive power, and black-start capability
• The task of real time dispatch
• Dispatch communications between participants
• Real time adjustment to scheduled energy and ancillary services to meet changing conditions and imbalance between scheduled demand and supply
• Updating the schedule at five minute intervals through activation of the “least cost dispatch program”
• “After-the-fact” reporting to provide each participant with actual operating parameters and provisional energy prices for each settlement period
• ISO activities under emergency operating conditions
• Conditions related to a system alert, system warning, and system emergency
• Suspension of commercial market activity by the ISO during major system collapse.
• Load curtailment and load shedding procedures
• Advantages and obligations related to interconnection with other control areas and ISOs