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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.
BOGOVIČ, J., MIHALIČ, R.
Flexible Alternating Current Transmission System Devices Compensator for Distribution System
KOMUNALNA ENERGETIKA / POWER ENGINERING, 171
One of the possible solutions for improving voltage conditions in an electric power system (EPS) is applying power electronics based or so called flexible alternating current transmission system (FACTS) devices. However, the appropriate inclusion of a FACTS device into the EPS is not a straightforward procedure. On the contrary, it requires several steps. One of the first steps is the power flow analysis, which requires an appropriate FACTS device modelling.
In the past the models of FACTS devices for Newton-Raphson (NR) power-flow and current-injection calculation methods have been developed. The NR analysis, however, is not always suitable for distribution networks due to convergence problems. This is why new three-phase models of FACTS devices for the forward/backward sweep method are presented in this paper. Their application is demonstrated on an IEEE 34 and 123 bus test systems, in order to clearly present the approach virtues for FACTS modelling in distribution networks with included distributed generation units (DGs).
RUDEŽ, U., MIHALIČ, R.
Impact of Considered SVC Implementation in the Slovenian Power System on Inter-Area ENTSO-E Oscillation Damping
KOMUNALNA ENERGETIKA / POWER ENGINERING, 191
During the planning process of possible future investments into the Slovenian power system, a need arose for the comprehensive analysis related to low-frequency inter-area oscillation damping of a static var compensator (SVC) device. The SVC device was initially considered for solving local steady-state voltage issues on highest 220 kV and 400 kV voltage levels in the region. As the SVC device features fast dynamic response, it seemed reasonable to verify whether its implementation benefits the operation of the entire ENTSO-E interconnection as well. The presented analysis was performed using a complex model for dynamic studies, comprising publicly available ENTSO-E model and internally constructed Slovenian power-system model, which was successfully tested and verified in the past. Modelling of the SVC device was achieved by means of available research publications dealing with the subject, both foreign as well as domestic. By implementing a simple damping strategy, the results showed a positive effect on a small-signal stability and indicated which inter-area oscillations can be successfully damped when considered devices are connected to the Slovenian high-voltage transmission network.
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