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AŽBE, V., MIHALIČ, R.
A SOFTWARE TOOL FOR PRESENTING FACTS DEVICES IN AN ELECTRIC POWER SYSTEM
KOMUNALNA ENERGETIKA / POWER ENGINERING, 21
The effects of Flexible AC Transmission System (FACTS) devices on an electric-power system (EPS) depend on many parameters. As a result, an easily understood and at the same time comprehensive explanation of these effects can be a difficult task. For this reason we have developed a computer program that can graphically represent the active and the reactive power and the phasors of the voltages and currents in a longitudinal EPS incorporating various FACTS devices. The design of the program makes it easy to change the parameters of the FACTS devices and the parameters of the EPS while the charts are simultaneously refreshed. The program is available, free of charge, on the web (http://lpee.fe.uni-lj.si/index.php?option=com_content&view=category&layout=blog&id=42&Itemid=29). To demonstrate the applicability of the program, a comparison between two similar—but when considering certain parameters, very different—FACTS devices has been performed. Using this program a user can gain a new insight into the effect of FACTS devices on an EPS, i.e., by changing the EPS's parameters and the parameter of a FACTS device, and by observing the changes in the power flow and the movement of the phasors of the voltages and currents. As the numerical results are also available "on-line", the program can be used as a simple control of plausibility of the results for other—more detailed— calculations.
VORŠIČ, J., VOH, J.
POWER SYSTEMS PROBABILITY CALCULATIONS SOFTWARE DEVELOPMENT
KOMUNALNA ENERGETIKA / POWER ENGINERING, 22
Method for planning and operation of power system which considers changes of operational conditions is described in this work. Input parameters - node loads in the load flow probability calculation are passed as probability function resulting from former operation careful analysis.
Based on described method calculation software has been developed. Node voltages, load flows, element currents and losses are calculated from node loads random vector considering connectedness among working and reactive power of same and adjoining nodes. Results (node voltages, load flows, currents and losses) are shown with expected value (arithmetical mean value) and mean square deviation in tabulated form. At the same time elements (lines, transformers) load control according to the natural (lines) and thermic power has been performed. Load flow histograms are real value of this method.
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