A new methodology for the provision of reserve in an isolated power system

New operating and planning policies are emerging in power utilities throughout the world with the onset of competition and deregulation. These new policies fundamentally differ from those previously implemented. In particular, the approach adopted to power system security is significantly different. Previously, power systems were operated to ensure a certain level of security was maintained at all times. In the new competitive markets, the balance between cost and security is a dominant factor. To illustrate this, a new economic dispatch methodology is proposed for a small isolated power system. This methodology enables the cost of providing sufficient reserves to just avoid load shedding following the loss of any given unit to be calculated and assessed against the risk and cost of load shedding. An illustrative test case is examined in this paper which considers the loss of the three largest units. The dispatch costs are calculated and compared to the cost and probability of load shedding to create a schedule consistent with the new utility policies.