Determine the reliability must-run units of the Thailand power system

Reliability must-run units (RMR) are generation facilities that are necessary during certain operating conditions in order to maintain the security of power systems in a competitive environment. Absence of RMR units may result in unsecure operation of a system. From a financial point of view, RMR may become a safety net for IPPs who enjoy steady incomes or place to avoid for those who like to participate in the competitive market. This paper presents a practical method to determine RMR units and their must-run output in the Thailand power market. According to the proposed structure of the Thailand deregulated market to be implemented in 2003. The study determines the amount of must-run output in RMR units by finding the necessary amount of generation to avoid the violation of voltage magnitude, thermal limit and voltage stability limit. The proposed procedure to determine RMR units defines the amount of generation capacity to be assigned as RMR and allows must-run units to sell surplus generation capacity to the system.