Simulation of deregulated electrical systems to set balancing reserve margins

In a deregulated electric system, ISO is always responsible for system reliability and security. For this purpose it must provide some system services and, primarily, an adequate amount of power for spinning reserve and of power and energy for balancing operations (nonspinning and replacement reserve). The number of sessions of the day-of spot market, when present, is strongly related to the power and energy for balancing operations and, consequently, to the real time market. In fact, after a load-frequency control process, the spinning reserve power margin must be restored in order to guarantee the assigned availability to the system; this is obtained by using the margins for balancing operations; this type of reserve can be restored only when the nearest session of day-of spot market becomes active. For this reason, the more frequent the day-of spot market is, the less there is the need for balancing reserve. The evaluation of the reserve can be carried out using probabilistic techniques; in this paper a simulation method, based on Monte Carlo technique, is described and a case study regarding a complex generating system is shown.