The growing concerns regarding electric power quality and availability have led to the installation of more and more distributed generation. In parallel and in the context of an accelerating trend towards deregulation of the electric industry, the unbundling of services, many grouped under ancillary services, should create a market for some of these services. This paper discusses the potential of distributed generation @G) to provide some of these services. In particular, DG can serve locally as the equivalent of a spinning reserve and voltage support of the ac bus. The main types of distributed generation with emphasis on the power electronic interface and the configurations appropriate to provide ancillary services are reviewed. The flexibility and features provided by the power electronic interface are illustrated. In addition to control of the real power, other functions can be incorporated into the design of the interface to provide services, such as reactive power, and resources associated with power quality. These include voltage sag compensation and harmonic filtering. The implications on the design of the power converter interface are discussed.
This study uses a panel fixed effect model to analyze the impact of intergovernmental grants on municipal spending in Quebec. The data from the 1,084 municipalities covering the period 2001-2007 are used for this purpose. The study shows that grants have flypaper and asymmetric effects and that the extent of these effects is sensitive to the type of grants and municipal expenditures. Furthermore, it suggests that conditional grants seem to be a more effective tool for changing the composition of the supply of municipal services whereas unconditional grants are more suitable to stimulate the level of provision of these services.
This paper introduces the concept of a generalized shell for performing power-system dynamic security analysis. The generalized shell mechanizes routines traditionally carried out by human experts and that are essential to power-system dynamic security analysis, thereby greatly accelerating the realization of complex processes. The shell semantics express high-level goals and tasks using a friendly, highly compact syntax which closely matches the language of operations planners. Typically. the shell will execute appropriate load-flow and transient-stability simulations (i.e. using commercially available simulation software). perform result analysis, make input changes and repeat this process until a user-defined goal has been achieved.A working shell prototype for performing key algorithmic processes is described and results of a typical sensivity study are presented using a 700-bus model of the Hydro-QuCbec network. It is expected that the prototype will reduce study-cycle time, improve the accuracy of dynamic security limits and, indeed. transform the working environment of operations and system planners. Eventually. it can be foreseen that the approach will gravitate towards supporting on-line dynamic security analysis.
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