Search

As the power system evolves and is operated closer to its operational limits, accurate and real-time contignency analysis becomes more critical. The speed of power flow calculation is a limiting factor of contingency analysis real-time applications. In this work, graph theory and NICSLU, a state-of-the-art sparse and parallel circuit solver, are used to analyze how post-contingency power flows can be solved more quickly. Graph theory is used to show that the base case symbolic factorization can be reused to solve contingency cases. Statistical analysis demonstrates that this method is preferable to recomputing or updating the symbolic factorization for contingencies involving few branch elements. Experimental results on Sichuan and MP10790 systems show that symbolic factorization reuse greatly reduces computation time.

Traditional methods of planning investment in Wind Energy Conversion Systems (WECS) focus on selecting sites that individually display the maximum total extractable wind energy. However, cost penalties associated with the uncertainty in Wind Power Production (WPP) may be non-negligible. This paper proposes a more holistic methodology to find the near optimal investment in WECS considering capital costs, uncertainty costs of WPP, and traditional thermal generator costs. The optimal number of turbines to be placed at each potential wind site is found system parameters using Particle Swarm Optimization (PSO), and DC Optimal Power Flow (DCOPF) is used to compute the merit of each candidate solution. The IEEE 14 Bus System is used. Potential wind sites are preselected, and WPP of each site is characterized by a probability distribution function. The impact of the investment costs and transmission capacity on the merit of spatial diversity of wind farms is discussed.

T nHE ancient geographers invested unknown areas on their maps with fabulous and won(lrous inhabitants giants, strange and terrible animals the like of which man has never seen, vast and impenetrable regions, stupendous mountain ranges, and other features in(licating in reality the scope of the imagination of the map makers. Much of the United States was not so long since a terra incognita and even well within the recollection of the present generation, the West held many wild and unexplored regions of large dimensions, peopled with hostile savages and wild beasts reported to be even more dangerous, and whence returned travelers brought wonder tales only a little less unbelievable than the picturings on the maps of the ancients. This condition has passed. There are no large areas that have not been explored and reported on, and none where the present-day explorer may expect to encounter unusual and unknown dangers or hope to discover new empires. All the highest mountains have been climbed and the worst desert areas have been penetrated; moreover, most of them have been accurately mapped. Regional explorations will continue to uncover unknown resources, but the map student can now look forward with some confident expectation of soon being able to study a reasonably accurate, large scale map of the United States. Such a study will, however, be possible only through the completion of the topographic mapping of the country, and it is in connection with this important engineering project that we can now see daylight ahead. The topographic map is the only one on which all the physical features of the country are shown, and the making of this map is one of the major activities of the United States Geological Survey-the great topographic map of the United States. For more than 45 years the work has progressed-much too slowly, it is true, to suit the map users, including the students of economic geography-yet some 40 per cent of our two-billion acre country has been so mapped, anL. the outlook now is increasingly bright for a much more rapid advance in the future and even the possible completion of the other 60 per cent within the next 30 or 40 years. There is small room for argument as to the need for the maps or the desirability of speeding up topographic mapping; indifference or opposition is only the result of ignorance of the dollars and cents value of the map to any and all communities. If the unmapped area is unsettled or unknown there is urgent need for the topographic map to reveal its undeveloped resources; if it is thickly settled-and there are some wellsettled, populous States where the topographic map is almost unknown -there is all the more need for the map as a base and a guide for every ' EDITOR'S NOTE.-SO important to all sound work in geography is a basic contour map that ECONOMIC GEOGRAPHY wishes to call particular attention to this article.