Reliability-based impact analysis of independent power producers for power system operations under deregulation

In this paper, the authors present an evaluation procedure of independent power producers´ impact on reliability and associated costs of existing power systems under deregulation. Independent power producers (IPPs) with competitive electricity prices can contribute to the cost reduction of electricity supply under the open access power systems. However, there is a concern that the high standard of power system reliability may not be maintained because of possible failures of such new generators. IPPs´ effects on supply reliability are closely related to generation and transmission operation of existing power systems. In the proposed approach, the reliability is measured by expected unserved power (EUP) and the additional cost of reliability maintenance is calculated by the cost of generation adjustment. The optimal redispatch problem is solved with the reliability index as a constraint. Also, a transmission system congestion is considered in the redispatch. Numerical simulations have been conducted on a model system with six nodes and seven branches.