Self Unit Commitment:

Because of the changes presented in recent years in the electricity sector industry with the integration of non-conventional renewable energy sources, it is important to correctly model the operating limitations of combined cycle natural gas plants (CCGT), which come to assume an important role, contributing to the reliability in the operation of electricity systems. In practice in Colombia, when the Independent System Operator assigns an initial dispatch, the largest Combined Cycle Natural Gas plant in the system is dispatched according to the results of a heuristic simulation model. Such heuristics omit technical operating constraints such as: hot, warm or cold start-up ramps; minimum required gas turbine hours to start a steam turbine; ratio between the dispatched number of gas and steam turbines, load sharing between gas turbines, additional burners, etc. Most of the unit commitment models in the literature only represent standard technical constraints such as startup, shutdown, ramp up/down and some of them even additional fires. However, they ignore other real-life CCGT operating constraints that are considered in this work. Additionally as shown in this work, these constraints are important because they ensure to avoid equipment damage that can potentially put the combined cycle gas turbine out of service and ultimately reduce operating costs.