ADEQUENCY ASSESSMENT AT HLI INCLUDING ENERGY LIMITED UNITS

Adequacy assessment at hierarchical level I (HLI) can be carried out with the data on unit capacity outages, if there is no limitation on the energy supply to any of the generating units in a system. The impact of energy shortfalls in a system may affect the reliability more seriously than the impact of capacity outages. An energy limited unit spends more lime in reserve shut-down state due to energy shortfalls compared to normal units. Outages due to energy shortfalls must be distinguished with forced or planned outages. This fact leads to the modeling of energy limited units using modified four-state models. A new method is proposed in the paper to perform adequacy assessment in systems with energy limited units. The method has been developed based upon a peak shaving approach with modified four state model. In the peak shaving approach, energy limited hydro units are scheduled to serve the peak load levels under some specified hydraulic constraints. A representative test systems, IEEE-Reliability Test System (IEEE-RTS), is utilized in the paper to illustrated some numerical examples. Some units of this test system are assumed as energy limited units.

ADEQUENCY ASSESSMENT AT HLI INCLUDING ENERGY LIMITED UNITS Keywords:

Energy Limited Units , Four-State Models , Peak Shaving Approach