Considerations for Generation in an Islanded Operation

This paper discusses the conceptual design and operation of an isolated power system, recognizing the reality that generator or turbine trips will occur. The level of reserve generating capacity must be set with proper balancing of capital expenditures and operating costs against revenue lost in a production shutdown. The way that reserve capacity is provided is as important as the amount of reserve; seemingly adequate reserve can turn out to be badly insufficient if it is not well distributed across the available reserve sources. The dynamic behavior of reserve capacity, as much as the amount of capacity that is ultimately available, is critical in determining how an isolated facility will behave in the wake of a unit trip or the loss of a grid connection. In this paper, experiences with detailed dynamic simulations of a range of isolated systems are described. These are related to test work and operational incidents that have provided practical calibrations. Based on simulation and experience, some guidelines are offered for configuring generation and selecting strategies for maintaining stability in large, isolated continuous-process facilities.