MARUŠA, R., VORŠIČ, J., PIHLER, J., KOBAL, I., MARUŠA, L.
SELECTION OF A SUITABLE CONDUCTOR FOR GROUNDING THE CABLE SHIELD TO THE TRANSMISSION LINE TOWER
KOMUNALNA ENERGETIKA / POWER ENGINERING, 16
This paper describes which factors to consider when faced with choosing conductor for grounding of surge arresters and high-voltage cables on powerline construction, where transition between powerline construction and powerline cable takes place. For proper grounding of surge arrester and shielded cable, the grounding cables have to be designed to ensure efficient high frequency current flow to the ground that can reach up to 10 kA. During our research and measurements we have chosen such a conductor that at the same time ensures recommended parameters and is not of any particular value to vandalism.
MARUŠA, R., VORŠIČ, J., PIHLER, J., FERLIČ, R., BELAK, L., RIBIČ, J., MARUŠA, L.
TESTING SLIDING GROUNDING CLAMP FOR EARTHING CONDUCTORS TO DOUBLE-CIRCUIT 110 KV TRANSMISSION LINE
KOMUNALNA ENERGETIKA / POWER ENGINERING, 20
This paper presents the testing Sliding clamps for grounding conductor transmission line. For the purpose of an effective transmission line grounding in working with vicinity of high voltage a special form of sliding clamps for grounding has been designed. Grounding device is intended for grounding transmission line conductors, which are dragged along conductor installation on a double-circuit transmission line, the second system operates normally which represents a significant risk for single-phase ground fault . The device must provide such a connection during the sliding along the guide, so that it prevents the arc and effectively discharges ground current into the ground.
Prior to regular usage, it was necessary for grounding the device to perform a series of tests, which are described in this article. A test with the realization of single-phase ground fault was also carried out on the transmission network of 110 kV ELES. All tests have been successful and positive.
ŽELEZNIK, D., SEME, S., TRUČL, P., VORŠIČ, J.
COMPARISON BETWEEN THE MATHEMATICAL CALCULATION OF SHADING AND ELECTRONIC SHADING MEASUREMENT FOR SOLAR POWER PLANT
KOMUNALNA ENERGETIKA / POWER ENGINERING, 7
Harnessing the Sun has lately become increasingly frequent. The Sun, the eternal nuclear reactor, is practically an inexhaustible source of energy. It is clear source, which can assure us an important part of energy for our needs. Therefore the goal has to be to harness this energy to the maximal possible extent; especially we have to use the roofs of already constructed buildings. There are many objects, on which we could build a solar power plant, but not all of them are suitable. There are numerous cases where certain locations do not receive solar radiation due to obstacles, even after more autumn or winter months all the duration of the solar radiation is significantly reduced. The amount of solar energy therefore depends on the season and location.
This paper presents the design of solar power plants and pitfalls which should be considered in planning. Shading is present almost everywhere, whether they are individual objects or just grassland where shading may cause horizon himself or surrounding obstacles, for example, trees. The impact of shading, it is necessary carefully to be considered in locations where there are grouped objects side by side – in the cities.
The article presents a simulation of shading for certain position of roof of a building, which is located in the agglomeration (city). It is made a comparison between the mathematical calculation of shading and electronic shading measurement on the roof of the building.
MARUŠA, R., VORŠIČ, J., PIHLER, J., FERLIČ, R., BEČAN, M., ZAGORIČNIK, A., ULAGA, M.
CORONA AND RADIO-INTERFERENC PHENOMENON REDUCTION ON 220 KV BUSBAR IN PODLOG SUBSTATION
KOMUNALNA ENERGETIKA / POWER ENGINERING, 9
The restoration and the occurrence of corona and radiointerference on the primary high-voltage equipment busbar 220 kV in substation 400/220/110 kV Podlog is presented in this paper. On the busbars 220 kV substation in Podlog was due to wear fully replaced jointing and insulation equipment, including elements of design electric field. After performing assembly work, measurements were taken corona and radiointerference. The results are showed poor results, it was necessary to approach the restoration status. To perform to the repair, were made laboratory measurements of partial discharges and radiointerference. On the basis of tests and comparative measurements have been developed and tested prototypes corona rings. Based on the measurement results, it was concluded that the remediation carried out by corona rings, which have been designed and a prototype was confirmed by measuring the conformity of the appropriate form of the electric field to be replaced suspension and insulation equipment busbar 220 kV substation Podlog.
RIBIČ, J., PIHLER, J., VORŠIČ, J., VORŠIČ, Ž.
MODELING TRANSFORMER IN ELECTRIC NETWORK CALCULATIONS
KOMUNALNA ENERGETIKA / POWER ENGINERING, 15
Computer aided load flow calculations and short-cicuit analyses are well known and technically soficticated software for with solutions for planing and operating are available on market. Deficiency of such software is usually lack of possibility to significantly modify elements. Three windigs transformers are mainly presented as two windings tranmsformers and sometimes lack of data is the obsticle for calculations. Article presents results of the research on how including third windings influence load flow and short-circuit calculations.
MARUŠA, R., VORŠIČ, J., PIHLER, J., ZUPAN, B., GRADNIK, T., BELAK, L., FERLIČ, R.
DETECTION OF COMBUSTIBLE GASES IN THE POWER TRANSFORMER
KOMUNALNA ENERGETIKA / POWER ENGINERING, 22
The paper presents an upgrade of existing gas (Buchholz) relay with a gas detection device, which is used for fault detection and protection of power transformers. The upgrade refers to a sensor for detection of combustible gases in (Buchholz) relay, which are formed during thermal and electrical defects in active parts of power transformer. In the first part paper focuses on describing mechanisms of production of combustible gases in oil, as well as intrusion of air bubbles into transformer tank due to leaking dilatation system. The second part provides description of the simulation setup for testing performance of the gas detection device in real-life conditions. The final section describes the sensor and automation of the transfer and processing of measurement data. It also presents useful practical advantages and opportunities that the upgrade brings for various transformer sizes as well as provides an estimate of installation costs and benefits through analysis of operational reliability increase of the upgraded transformer.
SEME, S., ORGULAN, A., VORŠIČ, J.
AN OVERVIEW OF THE TECHNOLOGIES AND DEVICES FOR ENERGY STORAGE SYSTEMS
KOMUNALNA ENERGETIKA / POWER ENGINERING, 2
The growing need for energy on the one hand and the growing desire for integrating the units for production from renewable sources, on the other hand, inspired the development of energy storage systems. Electric energy production from renewable sources such as solar and wind, primarily depends on the current conditions and there is no possibility of the production in stock. Therefore, the abovementioned sources require the reserve in conventional sources or appropriate energy storage systems. An overview of the technologies and devices for energy storage systems that are most promising nowadays will be presented in this work.
VORŠIČ, Ž., PIHLER, J., VORŠIČ, J.
ELECTRIC FIELD OF OVERHEAD LINE PUAC 2150/495/65 FOR 400KV
KOMUNALNA ENERGETIKA / POWER ENGINERING, 11
Covered conductors are not so vulnerable, because of the outer coat. This fact allows it to reduce the space between the phase conductors of covered conductor to only third of the space, which is the case by uninsulated conductors.
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.
SEME, S., ŠTUMBERGER, G., VORŠIČ, J., TOMAŽIČ, A.
MEASUREMENT OF THE U-I CHARACTERISTICS OF PHOTOVOLTAIC MODULES
KOMUNALNA ENERGETIKA / POWER ENGINERING, 11
This paper deals with measurement of the U-I characteristics of photovoltaic modules. Measurements of the U-I characteristics of photovoltaic modules are defined in standards developed by the Technical Committee IEC TC 82. Unfortunately, we do not have equipment required to perform measurements of U-I characteristics of photovoltaic modules in accordance with the standard. Therefore, a comparative analysis of U-I characteristics measured on different modules under the same technical and weather conditions is performed. The results are given for the photovoltaic modules made of monocrystalline silicon, polycrystalline silicon and amorphous silicon.