Michal Špes

Design and simulation of hybrid system for public lighting power supply

This paper deals with design and simulation of hybrid system which consists of photovoltaic power plant, battery energy storage and load. It is used for power supply of public lighting based on renewable energy. Parameters of public lighting are inspired by real situation in small Slovak village. Hybrid system was designed and sizing optimization of each element was performed based on public lighting data, typical load curves and weather conditions in a locality. For this purpose, Homer software was used. Subsequently, system was modeled in Matlab/Simulink and its behavior under real conditions during random day in a year was observed to verify design correctness. Results from both simulations were compared and evaluated.

Analysis of possibilities for measurement effect of visibility in experimental FSO system

Abstract Nowadays, wireless optical systems are very popular because they offer a a lot of advantages including high speed transmission, high security levels, and low maintenance costs. One of these wireless optical systems is Free Space Optics (FSO). However, their primary drawback relates to the type of transmission medium used. Atmospheric channel is chosen to be the transmission medium for FSO systems. The resulting attenuation relates with all inhomogeneities that occur in the atmosphere. Concentration of water particles represents inhomogeneities which increase the levels of attenuation. Weather conditions are characterized by speciffc concentration of these particles. Visibility is one of the most crucial parameters for FSO communication. It is very important to monitor this parameter in order to switch between primary optical line and backup secondary Radio Frequency (RF) line. The focus of this paper is to analyze and evaluate visibility measurement in FSO system deployed in TUKE (Technical University of Kosice) campus. The measurement of different weather parameters for this system is triggered on TUKE. The Switching method is based on monitoring visibility as the primary parameter. Different measurement approaches provide different processing speeds. Faster and more accurate switching ensures stable system without disruption.

Design of Pyramidal Horn Antenna for 2.45GHz in FEKO for Application in Experimental FSO/RF Hybrid System

Abstract Communication technologies are growing for day to day because demand on data sharing is unstoppable. Users require availability of approach to network at all time. Implementation of smart technologies allows communication of all type of devices. Capacity of data flow have to grow. Video formats HD or 4K require transmit on high data speed. Based on the demands many types of different communication systems which are suitable for these speeds were designed. One of these systems is FSO (Free Space Optics). FSO system is based on transmission of optical beams which carry the information. This system allow high data speed comparable with standard optical fiber in range to 10km. One of drawbacks of this system is LOS (Light of Sight) between communication points. The other drawback is sensitivity to weather changes. Optical beams interfere with water particles and cause attenuation on transmission path. The solution is in implementation using hybrid FSO/RF system which combines optical communication system with RF (Radio Frequency) backup link. We realized FSO communication link on Technical University of Košice. Our research is focused on design of appropriate type of antenna for our RF backup link. Our results in this area were published.

Utilization of energy storages in low voltage grids with renewable energy sources

This paper deals with problems which occurs in low voltage grid in case of high renewable energy penetration, especially with photovoltaic power plants. Also simple way how to utilize energy storage to address these problems is proposed and simple charge/discharge strategy was designed for energy time shifting and capacity firming. Simulation model in Matlab Simulink was developed and two scenarios based on real data were simulated in order to strategy verification. Results are discussed and evaluated, and also some improvements are suggested.