In the project task appropriate new technologies and possibilities for hydro energetic potential of ultra-low heads and moderate flows on water courses of Bela krajina are presented. Simulations of possible electrical energy generation show that units of SHP up to 50 kW of installed electrical power of basic design are reasonable. Managing such plants is less demanding and consequently working reliability is higher. Their overall efficiency is negligibly lower in comparison with the power plants of the most sophisticated design.
F.14 Improvements to existing production methods and tools or processes
COBISS.SI-ID: 9591124Diagnosis of faults in electrical drives is one of relatively new areas of electrical engineering, which has evolved following the advances in measurements techniques, control and power electronics and better understanding of operation of a drive as whole. Aim of diagnostics is an detection of a fault in a drive and adequate reaction, depending on its source and demanded dynamics. Rotor faults (broken rotor bars or end-rings) are usually a consequence of poor machine design or manufacturing, which is additionally enhanced by intermittent operation of servo drives and/or its feeding from a power converter. The lecture has presented problems related to diagnosis of rotor faults, their manifestation and development of suitable diagnostic approaches. Occurrence of faults is visible through a modified frequency signature of stator currents, which usually calls for implementation of sophisticated and costly measurement devices. In a second part, activities of Laboratory of electrical drives and Laboratory of control engineering and power electronics in developing simple, fast and cheap diagnostic methods, has been presented. Thus, standard hardware, already present in a typical electrical drive, could be used.
B.04 Guest lecture
COBISS.SI-ID: 8894804The aim of the lecture is to give a deep insight in the state of the art in the field of power converters for electric motor drives and renewable energy sources. Voltage and current source converters are nowadays most widely used for frequency and voltage conversion in adaptive speed electrical drives. Due to a specific demand, standard bridge converters are modified and some of them were presented. Advanced converter topologies that enable bidirectional power flow, low content of harmonic distortion in the output voltage and current, provide compensation of reactive power, operate at unity power factor and nevertheless can operate with constant output parameters inspire of voltage sags in the input voltage, were presented. Multilevel converters were extensively investigated in last years. Due to a low harmonic distortion of the output voltage, a need for additional filtering is substantially reduced. The development of new control strategies for matrix converters also greatly improved the reliability of their operation in the field medium power electric motor drives.
B.04 Guest lecture
COBISS.SI-ID: 70435329This work deals with inverter-induced bearing currents in low-power brush-less direct-current motors. The types of bearing currents that occur in these motors are identified. Ratio of capacitive coupling of common mode voltage is determined. Correlation between bearing currents and shaft voltage is investigated. Levels and trend line of bearing currents through longer period of time are analysed.
B.04 Guest lecture
COBISS.SI-ID: 9609556Nuclear Power Plant Krško doubted about the credibility of the data and also regarding the possibility to construct the power transformer GT2 based on tenders no. 120230- R1 and 120230-R1A. In addition, the customer wanted the general opinion on these tenders. To clarify the doubts, we verify the following information in both tenders: transformer weight at the given dimensions and other parameters, oil weight, losses, transformer dimensions with consideration of the losses and other given parameters, the implementation of the refrigerators on the high voltage side, the impact of the Zno over-voltage surge arresters on transformer design (comparison of performance with and without the over-voltage surge arresters) and about other mechanical and electrical parameters that are specified in the tender.
F.04 Increase of the technological level
COBISS.SI-ID: 9228116