doc. Ing. Jan Mikeš, Ph.D.

The complementary radio navigation system based on the Very Low Frequency signals produced by lightning is an alternative to today's Global Navigation Satellite Systems. The system operates on different principles and uses different radio frequency bands. The signals have higher availability in problematic places. The analyses based on the historical data of Word Wide Lightning Location Network demonstrated the good availability of the service, sufficient number of lightning strokes and good geometry calculated for a 10-second time window for positioning based on the Time of Arrival principle. The geometry was evaluated with the help of the Geometric Dilution of Precision coefficient. The Geometric Dilution of Precision median for the reception of the lightning signal from a range of 10,000 km moves around one except at the southern polar regions and the probability of the service availability exceeds 80%.

The goal of this paper is to demonstrate the capability of the 1U CubeSat to study the radiation spectra on LEO. The research was realized by the Lucky-7 mission with the primary goal of testing electronics such as a power supply, piNAV L1 GPS receiver, UHF communication system, and other subsystems in the natural space environment, and the secondary goal of testing the possibility of using 1U CubSat class satellites for scientific tasks. The satellite is equipped with a piNAV GPS receiver and piDOSE radiation detector, silicon diode radiation spectrometer, camera, and other sensors. The on-board computer enables storage of 34 h of measurements of the radiation spectrum. These measurements can be downloaded by the UHF communication system during four satellite passes over the monitoring ground station. We successfully verified all necessary instruments and their cooperation and measurement procedure. The UHF communication was identified as the most critical subsystem because of its low capacity, which slowed down the satellite operation. We needed four zenith passes to upload 34 h of measurement.

Safely conducting flowing lightning current into the grounding system via air-terminals and down-conductors constitutes a key method of protecting objects being struck by lightning discharge. At present, there is no other safer method of protection than capturing and conducting lightning current and its dispersion in the ground. By having to conduct powerful lightning current, the protection systems are exposed to excessive thermic and electrical stress. When such protection systems are correctly designed, installed and regularly checked, the threat to objects is considerably reduced as the systems are dimensioned for such purposes. An opposite case occurs when a protection system is damaged, most frequently due to the thermic effects of lightning current. Then, there are only two possibilities of detecting damage: either by providing regular and timely inspections or by means of controls based on the information supplied by a lightning strike counter. The key requirement of the first method is that the relevant object has not been repeatedly struck by lightning current during a period of at least 5 years. The other method provides instant information, in real time, and inspection of the protection system may be carried out immediately. Hence, sooner than another lightning stroke discharge could be repeated. This paper examines the method of detecting lightning current in down-conductor and the possibility of providing real-time information.

Lightning poses a risk to buildings, people, and technical facilities. The lightning air-terminal and down-conductor are the basic protection against direct lightning discharge. In terms of the reliable functioning of the lightning conductor, the key is to monitor the passage of the lightning current through the lightning conductors and to brief the facility manager in real time of the need to carry out appropriate checks. We hereby present a system for contactless monitoring of lightning attacks, and experimental results of testing by means of a lightning impulse current generator (LICG). Finally, we introduce an IoT system for large-scale monitoring.

This paper deals with the measurement of ionising radiation emitted in the vertical field of electric discharge generated between the tip and the grounded plate electrode. The generator set-up was for 400 consecutive negative discharges with voltage amplitude 0.9 MV, waveform shape 1.2/50 mu s, discharge energy 80 kJ and electrodes 1 m apart. Thermoluminescent, passive detectors were used to avoid electromagnetic interference from the discharge. The detectors were placed at the electrodes and three vertical positions 1 m from the discharge axis. This work extends a previous study focused on dosimetry in the plane parallel to the ground. This experiment confirmed the presence of a photon/electron component at the electrode tip and 0.5 m vertical position at a distance of 1 m from the discharge axis. In addition, the presence of neutrons was found for new positions in the vertical axis and the ground electrode.

We investigated the air supply mode effects on ozone production of the surface dielectric barrier discharge in the cylindrical configuration. The air into the discharge volume between two coaxial cylinders was supplied through four nozzles axially or tangentially. Using tangential air supply, the vortex flow in the part of the discharge chamber was created. Because the active electrode was in the form of interconnected rings on the outer surface of the glass tube, we changed the airflow orientation concerning this electrode. The existence of vortex airflow affects the plasmachemical processes taking part in the discharge, and therefore, it affects discharge ozone production. We also paid attention to ozone concentration and temperature of output air measurements as a function of the duration of the experiment for both tangential and axial air supply modes. We found that the time required for the stabilization of generated ozone concentration depends on the discharge power, and for our experimental conditions, it smaller than approximately 70 s. Besides, in the case of tangential air supply into the discharge chamber, the concentration of ozone produced by the discharge is for higher discharge power increased in comparison with the concentration for the axial air supply mode.

Power grids are the arteries of national and transnational integration. They increase the security of supply and ensure economic synergy effects. Whenever the master-minds of European unification presented plans for pan-European power grids in the 1920s, Czechoslovakia was always involved. However, the division of Europe after the Second World War led to Czechoslovakia's integration into grid of the Comecon countries, which was largely decoupled from Western Europe. Since 1995, the Czech network of transmission lines has been an integral part of the European power generation and distribution grid, and the Czech Republic plays an important role in the power supply in Central Europe.

In this study, we focus our attention on the impact of ozone (O3) and ultraviolet radiation (UV) on materials usable for three‐dimensional (3D) printing. Specifically, we have studied the potential degradative effect on the most commonly used filaments, such as polylactic acid (PLA) and acrylonitrile–butadiene–styrene (ABS). The effect has been examined on objects printed on a 3D printer and on the materials of discharge chambers of O3 generators from which they were printed. For the purpose of adequate assessment of the actual impact of O3 and UV, samples were monitored for a period of 18‐hr of exposure. The methods of Raman spectroscopy, optical and scanning electron microscopy and Fourier‐transform infrared spectroscopy (FTIR) have been employed for an objective evaluation of potential modifications. A generator equipped with a chamber printed from a new PLA filament and an active electrode system in the form of a stripes electrode, or more precisely, in the second case, a honeycomb‐active electrode, both cut out of a thin copper foil, was used for the generation of O3 and UV radiation. The tested materials showed substantial resistance to O3 exposure under the test conditions. The result of measurements suggested that these materials could be used for chambers for the O3 as well as for active particle generation. In this study, we focus our attention on the impact of ozone (O3) and ultraviolet radiation on materials usable for three‐dimensional printing.

We studied the effect of the driving voltage of frequencies 4, 7, and 10 kHz and two different active electrode setups on electrical properties, ozone production, and UV radiation of wavelengths 320-420 nm of the dielectric barrier discharge in air. The first active electrode setup comprised the strip electrode made from the copper foil. The second setup comprised the stainless steel wire mesh electrode with square cells. The ozone concentration, as well as the ozone production yield, is higher for the discharge with the strip active electrode setup than for the discharge with the mesh active electrode set up. The increased frequency decreases the voltage required to obtain maximum ozone concentration. The intensity of UV radiation is higher for the discharge with the mesh active electrode setup than for the discharge with the strip active electrode setup for all investigated frequencies. The intensity of UV radiation at a particular voltage depending on the frequency and active electrode setup sharply increases. The high concentrations of ozone produced by the discharge with the strip active electrode setup are accompanied by lower intensities of generated UV radiation. For the discharge with the mesh active electrode setup, the situation is reversed.

We investigated the effect of a non-doped diamond layer deposition on the active electrode of the dielectric barrier discharge in the air on its electrical characteristics and ozone generation. We found that this new non-traditional application of diamond layers affects electrical parameters of the discharge and increases not only the concentration of ozone produced by the discharge but also ozone production yield by similar to 70%. Considering obtained results together with the high corrosion resistivity and chemical inertness of the diamond layers, the application of these layers on the dielectric barrier discharge electrode can be an interesting alternative to the usage of photocatalysts for the enhancement of ozone generation by electrical discharges.

Terrestrial gamma and neutron flashes can result in considerable radiation exposure of aircraft crew and passengers in their close vicinity. Lightning impulse voltage generators imitate selected stages of natural lightning processes and can serve as a test environment for the development and calibration of detector systems for such short term radiation events. This work presents the results of measurements of absorbed dose using thermoluminescent dosimeters for 400 negative discharges at the lightning impulse voltage generator. The thermoluminescent dosimeter CaSO4:Dy and the combination of lithium-fluoride detectors MTS-6, MTS-7, and MTS-N were used to quantify the photon and neutron components of the radiation field. The detectors were placed in four positions near the generator spark gap. The results confirm the presence of thermal neutrons and photon radiation in two positions at the lightning impulse voltage generator.

The authors have rearranged an optimal method for signal processing of interferometric measurements, based on the angle-of-arrival estimation approach, and have analyzed errors of estimating the direction of arrival of intercloud pulse signals. The method was then implemented in the performance of optimized interferometer hardware. This article presents application of an array of plate antennas matched by the 50 omega parallel resistor that are directly connected to 50-omega high-frequency low-noise amplifiers for each channel. The important contribution of the authors is to cover the plate antenna capacitance to the input bandpass filter. The proposed compensation enables to reduce linear distortion of the received signal, which is one of the main sources of errors of the time-of-arrival estimation, and to optimize the antenna impulse response. The novelty of this article can be seen in the application of the artificial intercloud pulse generator for testing, precision calibration of the proposed system, and fixing of potential imperfections and losses in both hardware and processing software. The practical application of the proposed interferometer is demonstrated on the processing of real lightning events. As the interferometer operates in the frequency bands that are dedicated to other radio communication services, this article provides results for measurements of interference that were realized with the aim of finding an optimal installation location.

The article presents the journeys of the professional character of Czech electrical engineers and especially of the structural electrical engineer Vladimír List, in particular from the 1890s to 1939, and their influence on the development of the then technical education, industry, communication possibilities, or scientific international activities and cooperation. His travels related not only to his own studies (the Montefiore Institute in Liège, Belgium, from 1900-1902), to important political-economic-technical matters of the Czech lands and Czechoslovakia (such as his successful participation in the negotiations on the Versailles peace treaty in 1919-1920), but particularly to Listo's work on electrification of Czechoslovakia and the technical-standardization movement (to France, Switzerland, Germany, etc.) or to scientific conferences (essentially to the whole world, including the US, Japan, etc.). List's travels have demonstrated the need for professionals to gain experience through international contacts that capitalize not only on an individual's personal life and expertise, but also contribute significantly to the development of an entire society.

The paper describes selected outputs and focus of applied research concerned on the following areas: the system of active runoff pollutants capture; prevent the negative impact of hydrogeological wells on groundwater; mobile treatment of a decentrally produced hard-to-treat wastewater; advanced oxidation technology for water and environmental applications; treatment and evaluation of sewage sludge together with by-products; hydrogen technology for contaminant removal from the subsurface.

Numerous scientific disciplines such as hydrology, meteorology, oceanography or geology take advantage of remote measuring and monitoring. Data measurement in remote locations and the transmission of measured data is an essential part of these disciplines. The critical element of remote measurement and monitoring systems is a remote station. When designing such a device, it is necessary to solve issues of the construction, power system, data transfer or autonomous operation systems. This paper introduces the Autonomous Groundwater Monitoring Station with Wireless Communication which has been designed and installed in a field application. The individual parts of the station such as construction, software, hardware, wireless communication system or systems for autonomous operation are presented.

VHF interferometer serves for the registration and localization of lightning radio pulses for further analyses of the inter-cloud processes that are connected with charge transfer and emission of radio pulses. As the bandwidth, of the VHF interferometer, is very wide due to the precise measurement of the time difference of arrival, the interferometer generates a large volume of data that must be processed and stored. The triggering system of the VHF lightning interferometer enables to select scientifically valuable data from the data stream. The ideal triggering unit synchronizes data acquisition with the return stroke event. The basic requirements placed on the triggering circuits are a low false alarm rate and a high probability of lightning discharge detection. The unit consists of a whip antenna that is sensitive in the electrical field, an amplifier and a matched filter that is tuned to the return stroke wave. The usage of the correctly designed matched filter increases detection probability of the lightning discharge and reduces false alarm rate. The key problem is laboratory testing of the triggering unit in a near-realistic environment. The paper proposes a method based on the generation of the return stroke wave by a lightning current generator. As the gain of the common electrically short whip antenna cannot be determined with sufficient precision, the electric field of the generator is properly calibrated by an electromagnetic field probe based on a plate radiator. This approach facilitates accurate control of the amplitude of the return stroke radio wave and study of the sensitivity of the triggering circuits on nonstandard waves.

As a technical and scientific branch, electrical engineering (and later also informatics or information science) began to be shaped and developed approximately since the last third of the 19th century, notably since 1881, the year of the convention of the First International Electrotechnical Congress and Exhibition in Paris, a gathering that defined basic electrotechnical units. Greater accent on the development of electrical engineering (and informatics) came at the time of the two World Wars, when—after WWI—all the major countries in the world had started building their national grids which were consequently interconnected primarily for technical and economic reasons. The period after WWII saw the emergence of cybernetics, electronics, electrical engineering and electronic miniaturization and informatics, disciplines fully dependent on a well-functioning and well-proportioned (and in most cases already internationally intertwined) electrification system.

The article deals with the development of electromobility in the Czech lands in historical perspective.

This article discusses an alternative possibility of detecting lightning discharge strike at a lightning protection system, as compared with the classical sensors based on the inductive principle (using a coil) or the principles requiring external feed, such as the application of the Faraday optical transformer. The key advantage offered by our proposed system is its indirect method of evaluating the impacted lightning protection system, which is based on the piezoelectric principle. Other advantages of the proposed system include direct independence on the lightning current passing through the downconductor and thus a lower risk of damage to the sensor by the lightning current, and absolute independence of the inner installation and, therefore, elimination of any risks for its operators and users, as well as a lower risk of an electric discharge flashover and outbreak of fire in a given structure.

The paper presents design and application of a telemetry system for stratospheric balloon based on Internet of Things System of SigFox. The purpose of the telemetry system is balloon tracking during the stratospheric flight. It was tested on experimental flight of FIK III stratospheric balloon equipped with SigFox as main transmitter and UHF transmitter for backup. The payload consisted of ADS-B receiver, and two independent dosimeters for radiation measurement. The paper presents verification of operation of telemetry system on results obtained during experiment. The end of paper covers also some considerations about advantages and drawbacks of such solution.

The authors of the article have devised a lightning monitoring system whose positive features can be divided into two interconnected groups. The first major advantage is greater safety of people and animals living in the buildings hit by lightning discharge. This is the most important goal in terms of safety. With online diagnostication it is possible immediately to set up an evacuation regime for the object, and a rescue operation may be launched in the object well before any undesirable destructive effects of the lightning discharge have time to develop. The second major advantage is unquestionable evidence proving that an object has really been hit by lightning discharge – this particular factor can be used for insurance events, insurance policies and the work of insurance companies themselves.

The Czech (Czechoslovak) technical standardization was institutionalized soon after the disintegration of Austro-Hungary and after the establishment of its successor states, i.e. independent Czechoslovakia on October 28, 1918. The first Czechoslovak standardization institution was founded on December 28, 1922 as the Czechoslovak Standardization Society (Czech acronym ČSN). Enjoying the status of a generally beneficial, non-profit organization, the Society was made up of manufacturing plants, professional unions, commercial organizations, universities etc. Members paid membership fees and participated in the institution’s activities according to their interest and at their own costs. Draft technical standards were drawn up by experts from industrial plants, research institutes, universities etc. The International Association of Standardization Organizations (ISA) was established in Prague six years later, in 1928, initiated by Czech professor Vladimír List (1877-1971) within a group of European technicians. In the years 1932-1934 Vladimír List also served as the ISA President, a post that was accorded to him not only in recognition of his technical achievements and erudition; it also had a great impact on the development of Czechoslovak standardization in general and in the electrical engineering sector in particular.

The paper presents telemetry system for stratospheric balloon mission based on the UHF transceivers designed for Internet of Things. The system operates in 869.5 MHz frequency band. The system uses very short packet without channel coding that can be successfully received and decoded under low signal to noise ratio. The modem sensitivity −124 dBm and the transmission power 25 dBm can ensure reliable communication for distances longer than 100 km with omnidirectional antennas and 200 km with 10 dBi ground station directional antenna. The telemetry system uses GFSK modulation of bit rate 1200 Bd and is designed for a transmission of the balloon position and status.

The article focuses on the development of illumination in the Czech lands. The authors begin with primitive luminous lighting, further they develop the history of gas lighting, especially in larger industrialized cities. The main attention is paid to the comparison of electric lighting in the Czech lands and in Europe, with the emphasis on the contribution of one of the first Czech electrical technicians, František Křižík and the application of his differential arc lamp controller.

160th Anniversary of the Siemens Double-T Anchor in Dynamo-electric Machines. During the 1870s and 1880s electrotechnology grew to be a major component of the industrialization processes in the second stage of the industrial revolution. As an independent scientific discipline it proved to be one of the first branches that established their own industry independent of traditions. The electrotechnological industry began to influence other manufacturing branches and, retroactively, its own research as well. New developments emerged primarily thanks to the simple and reliable electric rotating (dynamo-electric) machines that offered multiple applications and which grew to be competitors to the universal driving steam engines. Initially, the new machines were developed solely as sources of lighting.

In June 2016, the General Assembly of ICOM (International Council of Museums) in its meeting in Milan proposes to reflect on the theme "Museums and cultural landscapes" in the framework of the Sienna Charter. Involving museums in the management and maintenance of the cultural landscape means developing their natural vocation, by extending their responsibilities from collections to heritage and territory.

For surface dielectric barrier discharge in air, we examined the effect of titanium dioxide on various regions of the active electrode on the electrical parameters of discharge, on its emission spectra, and for demonstration of the obtained results also on the concentration of ozone produced by the discharge. We used the active electrode in the form of nine interconnected parallel strips and a square counter electrode. The TiO2 layer covered either only the strips, the region between the strips, or all active electrode. As reference discharge we used the discharge without any layer of TiO2. We found that direct application potential has a version when the strips of the active electrode are covered with a layer of TiO2, because the concentration of ozone produced by the discharge is the highest in all investigated cases. This finding could therefore be used for construction of more efficient ozone generators.

He paints a comprehensive picture, describing how, further to the organizational reform of secondary schools in the Empire, in accordance with a report by two university academics, Franz Exner in Prague and Hermann Bonitz in Berlin, industrial schools for the training of technicians, specialized schools for the preparation of masters’ degrees and ongoing training schools (for the provision of evening classes or Sunday classes) were established from the 1850s onwards, not only in Prague, but in all industrial regions of the Czech states. From the 1880s onwards, electrotechnical courses were introduced, and specialized sections were launched. Technical schools entirely dedicated to electricity were also opened, operating in both the Czech language and the German language. To illustrate this type of training, Jan Mikeš uses the example of a municipal electrotechnical training establishment in Teplice (the Městské Elektrotechnikum, established in 1895), which catered for different levels of study and was considered as a model institution.

The article deals with the legal aspects of the installation and operation of alternative air-conductors ESE in lightning protection.

This study examines the effect of airflow orientation with respect to the strip active electrode on concentration of ozone and nitrogen dioxide produced in a planar generator based on the surface dielectric barrier discharge. The orientation of the airflow was tested in parallel and perpendicular with respect to the strips. It was found that in the investigated range of average discharge power, the ozone concentration increases approximately by 25% when airflow was oriented in parallel with respect to the strips in comparison with perpendicular orientation of the airflow. Similarly the increase of nitrogen dioxide concentration was observed for parallel orientation of the airflow with respect to the strips in comparison with the perpendicular orientation of the airflow. Within the range of wavelengths from 250 to 1100 nm, the changes of intensities of spectral lines associated with airflow orientation have been observed. A 3D numerical model describing ion trajectories and airflow patterns have also been developed.

After the First World War Czechoslovakia was established as a state of Czechs and Slovaks, but – in actual fact – it was a multinational state, from its early days weighed down by nationalist problems, which shaped the formation of the Czechoslovak economy. In economic terms, Czechoslovakia was the strongest successor state of Austro-Hungary with 21% of the territory of the former monarchy (140,000 square kms), with 25% of its inhabitants (13.6 million), and with 70% of the entire industrial production of the erstwhile monarchy. In other respects, the country ranked among smaller Central European states. The capacity of its market accounted for roughly one third of that of the former monarchy. Industrial production, formerly focused on the markets of the entire monarchy, now faced keen competition. Czechoslovakia was poor in raw materials, which had to be imported. That was why the country had to seek new markets for its products. Thanks to the Treaty of Versailles, Czechoslovakia was politically oriented on France, economically on the successor states of Austro-Hungary, and – starting in 1921 – on the countries of the Little Entente (Romania, Bulgaria, Yugoslavia), and in some areas also on Russia and Greece. Proceeding from this basis, the study is aimed at highlighting cooperation between the company Schneider Cie Creusot with the Czech company Škoda Plzeň (and in connection with Živnobanka bank), laying accent on electrical engineering production, both in the interwar period and at the times of communist rule in Czechoslovakia when foreign companies were forced to terminate their business and leave the country without any financial compensation.

We examined the possibility of finding an alternative to the photocatalyst titanium dioxide for enhancement of ozone generation by electrical discharges. As a rough indicator of the photocatalytic activity of the catalysts, we took the concentration of the ozone produced by the surface dielectric barrier electrical discharge in air. This discharge is, apart from the source of the charged and excited species, also the source of ultraviolet radiation, which could be used for the activation of photocatalysts. From various photocatalysts we have chosen zinc oxide. We compared the effect of ZnO and TiO2 on the enhancement of discharge ozone production and we found that for this application ZnO shows almost the same effect as TiO2 photocatalyst.

Developments in the electronics industry and the growing availability of appliances, equipped with electronic components, are two factors contributing annually to the mounting interference risk and surge damages resulting from direct or indirect effect of atmospheric discharges into conductive structures of building. The authors of this study focused on electromagnetic models of buildings that can be verified for specific external (basic) ways to protect buildings through an air termination system (lightning conductor), down conductors (both usually metallic, hence high-voltage cables). The protection system cannot be checked only by a design controlling according to the applicable standards IEC 62305, but on the basis of numerical calculation as well, which definitely provides more accurate and comprehensive results. These make it possible to get an immediate overview of the risks that may occur in buildings. This method is presented in this study. The authors carried out a comparison of the effects of new commercially available construction materials (Polyvinyl chloride – PVC, Polyethylene – PE) materials, which have been found in many architectural and building designs recently. As a reference parameter, the authors monitored separation distance /s/ for each construction material.

The authors of the article accentuate the significance of symmetrical placement of lightning conductors on the position of lightning current in them. The aim of the article is to prove the instructions described in the standard IEC 62305 and confirm the conclusion that buildings should be protected not only by a lightning rod but also by lightning conductors that constitute an irreplaceable component of a comprehensive protection system. If lightning rod influences the safe placement of lightning discharge above a building, then individual lightning conductor determines its safe grounding. Lightning conductors have a major impact on the induction of lightning current in structures. Unfortunately, many buildings whose height is much bigger than their width (towers, lookout towers, high-rise buildings, factory tacks) contain only one lightning conductor, which does not ensure their protection. The authors prove this fact on examples of protection of structures such as lookout towers and wind power plants.

The authors verify the separation distance coefficient /s/ setting of the distance according to the International standards IEC 62305, ed. 2, based on mathematical modeling. The coefficient of the separation distance is established in standards according to the empirical relationships. The authors wants to point out the possibility of more precise verification provided by real model experiments on building materials that are commonly used worldwide. For this purpose, mathematical models were carried out in collaboration with the Czech Technical University in Prague and the company DEHN + SÖHNE and compiled several artificial wall materials (air, concrete, PE and PVC). Behind them, object wiring (installation loop) was adjusted. In front of the wall, down-conductor was established. The assembly was tested by current impulse of 10/350 s; 0.25/100 s; 1/200 s. The result is a set of adjustments that could be accepted by the international standardization committees for the revision of the standards IEC 62305 and the national standards STN 34 1398 and NF C 17-102.

For the surface dielectric barrier discharge in air we investigated the effect of temperature and various arrangements of the input and output of the feeding gas of the discharge chamber together with related changes of electrical parameters on the discharge ozone production for the temperatures in which commercial ozone generators function. The obtained results are useful for the construction of commercial ozone generators because they show the importance of temperature as well as airflow patterns in the discharge chamber on the electrical parameters of the discharge and on its ozone production.

Automated heating, lighting and irrigation systems are nowadays standard features of industrial and commercial buildings, and are also increasingly found in ordinary housing. In addition to the benefits of user comfort, automated technology for buildings saves energy and, above all, it provides enhanced protection against leakage of water and hazardous gases, and against fire hazards. Lightning strikes are a natural phenomenon that poses a significant threat to the safety of buildings. The statistics of the Fire and Rescue Service of the Czech Republic show that buildings are in many cases inadequately protected against lightning strikes, or that systems have been damaged by previous strikes. A subsequent strike can occur within the period between regular inspections, which are normally made at intervals of 2–4 years. Over the whole of Europe, thousands of buildings are subjected to the effects of direct lightning strikes each year. This paper presents ways to carry out wireless monitoring of lightning strikes on buildings and to deal with their impact on lightning conductors. By intervening promptly (disconnecting the power supply, disconnecting the gas supply, sending an engineer to inspect the structure, submitting a report to ARC, etc.) we can prevent many downstream effects of direct lightning strikes on buildings (fires, electric shocks, etc.) This paper introduces a way to enhance contemporary home automation systems for monitoring lightning strikes based on wireless sensor networks technology.

Danger and stress posed to transformer winding through overvoltage still represent a hotly debated and hitherto unresolved technical issue the designers and operators of high-performance equipment have been grappling with. The actual impossibility of accepting all the real parameters of a transformer in its substitute model leaves considerable space for its constant improvement and modifications. Accepting the surrounding phenomena and properties of the transformers gives rise to complex situations and difficulties in the process of solving the model. Models tackling some of the issues pertaining to circuit models or electromagnetic field models have been developed on a long-term basis. Another issue in hand is the very complexity of the process of solving a model. This study introduces a model accepting solely the capacitance influences of transformer components, using the methods derived from the theory of LaxeWendroff’s and LaxeFriedrich’s approximation of differential equations of the hyperbolic type for the solution of the respective equations. It does not represent solutions for all the parameters of a transformer, but provides an overview of the size of the initial impulse stress of transformer winding, doing so with adequate accuracy.

The article offers not only a comparison of the efficiency and size of the protective zone of the first lightning rod by means of a computer model and contemporary mathematical and computing methods (method of the rolling sphere and the apex angle method), but it also highlights the unique social milieu in which Diviš developed his initial idea. It was an interplay of dogmatic religious scholastics and rational enlightenment in physics and natural sciences that was eventually conducive to the construction of one of the first devices for the protection against direct lightning impact. In their article, the authors also examine the transfer of knowledge on the protection against lightning impact from and to the Czech lands. A key approach to the protection against lightning was correct understanding and assessment of lightning charge, an analysis of the contact tip phenomenon and many issues relating to electrostatic phenomena. Seen in a historical perspective, the Czech lands had established an efficient platform of scientific centres, which linked up to and developed the pioneering work of Prokop Diviš several decades later. Also in terms of standardization, the Czech Republic has been active on a long-term basis, while espousing the European standards with its own ČSN EN 62 305 standard. In many other respects, this country has been loyal to traditions; after all, the very first decree on the protection of gunpowder depots against lightning in the Habsburg monarchy came from Empress Maria Theresa and was published shortly after 1778. The lightning protection standard, issued by the Czechoslovak Electrical Engineering Union in the 1950s, had introduced a fundamentally new concept that served for the implementation of most protective systems in this branch until 2006.

The article characterizes the development of electromobility of Czech society from the start of the 19th century until 1945. It attempts to cover the importance of electromobility for Czech industrial and social practice by presenting the three main electric technology entrepreneurs (Křižík, Kolben and Sousedík), all of whom were terribly interested in electromobility, developed the idea and brought it to life.

The article deals with one of series of failures resulting from inadequately instaled modern equipment for the protection of civilian structures against a direct lightning strike based on the principle referred to as ESE (early streamer emission). The difficulties in proving the increased efficiency of active ESE collectors that do not comply with the applicable Czech standards. Due to the failure of the ESE function, the premises remain unprotected.

The article introduces possible methods of resolving lightning protection in a specific environment - specifically a photovoltaic power plant. With the liberaliation of the energy market, with development of diverse electricity generation by wide-ranging unconventional methods, mainly photo voltaic panels, wind farms and biogas stations, the number of failures of these power plants is also increasing in the case of direct lightning strike hitting their electrical and nonelectrical parts. Oftentimes constructions for tens of millions of Czech Crowns are exposed to the hazard of a direct or even indirect lightning strike. The absence of or poorly designed and performed protection forms a risk. The authors present and critically assess potential methods of protection in the specific case of the photovoltaic power plant built in 2008 in the town of Rodvínov in the South Bohemian Region northeast of Jindřichův Hradec at an elevation of 490 m ASL and show how poorly selected type of protection (where the financial aspect was primary) can cause many thousands of Czech Crowns worth of demage.

The article referrs about the newly restored machines of the small hydropower plants on the river of Ostruzna in Čachrov in the birthplace of the prominent Czech electrician Frantisek Krizik.

This paper summarizes the developmental conditions for the emergence of protection against lightning. It reviews the legislation especially in the Czech Republic over the last 15 years, and its application for active lightning conductors. The paper presents examples of the damage caused by lightning strikes on buildings protected by ESE lightning rods constructed using the French national standard NFC 17-102 [1] and STN 34 1391 [2]. Installation of lightning conductors based on these standards is not, however, in accordance with the valid legislation in the Czech Republic and Hungary. In response to a growing number of ESE installations in the Czech Republic, it is vital to inform both the broader professional publc and the lay public of cases involving failures of this type of lightning conductor.

The history of ČKD is rather colourful arising from the development of individual smaller engineering enterprises established gradually on the territory of the Czech lands and developing as part of industrialisation into bigger factories. ČKD was created on the basis of a double merger in 1921 and 1927 when one of the biggest production units of the First Czechoslovak Republic emerged. This stood at the birth of the world famous Made in Czechoslovakia brand.

The paper shows the possible risks coupled with the installation of active conductors. Generally refers about inappropriate choice of protection against direct lightning strike. A strike of lightning, with a lightning current peak value of 111 kA, into a rod or air-termination system ESE, situated on the roof of a hotel, was followed by its flashover from a down-conductor system into the object's inner installation. The hotel's roof construction went up in flames immediately afterwards. The fire was extinguished thanks to early arrival of the units of professional and voluntary firemen. It was extremely fortunate that the hotel was shortly before its opening and, therefore, unoccupied by any guests. The overall damage totalled approximately 300,000 CZK. The hotel's lightning conductor had a valid inspection report...?!

This study introduces a transformer model accepting solely the capacitance influences of transformer components, using the methods derived from the theory of Lax Wendroff´s and Lax-Friedrich´s approximation of differential equations of the hyperbolic type for the solution of the respective equations. It does not represent solutions for all the parameters of a transformer, but provides an overview of the size of the initial impulse stress of transformer winding, doing so with adequate accuracy.

Before World War I, Austro-Hungary was a state that covered a vast territory, comprised many nationalities and inhabitants and was, to a large extent, economically independent. For its part, the newly established Czechoslovak Republic in 1918, a successor state to Austro-Hungary, faced completely different conditions. Yet, almost three quarters of the former monarchy's industries remained in its territory, primarily in the Czech lands. That is why in the years 1918-1938 Czechoslovakia focused on the manufacture and export of goods, but had to import raw materials. The country had to seek new markets and cope with foreign competitors. It was far from easy to win recognition for a new unknown brand Made in Czechoslovakia. And yet, the country succeeded thanks to the quality of its products made by such emerging companies as the complex of Baťa plants in Zlín, the Škoda companies in Pilsen and Českomoravská-Kolben Daněk (Bohemian-Moravian-Kolben-Daněk or ČKD for short) in Prague, companies known all over Europe and throughout the world. As early as in 1898 the architect of the ČKD complex was Emil Kolben (1862-1943), who had just returned from a study visit to Edison in the United States and from Oerlikon in Switzerland. This man figured not only among outstanding theoreticians and experts in heavy-current electrical engineering but was an accomplished manager in his time. The ČKD brand products soon went beyond the local framework of the Czechoslovak Republic, representing the designation Made in Czechoslovakia all over the world throughout the period between the two world wars. During the totalitarian regimes in the country, Kolben´s name, possibly also due to its Jewish origin, was destined to be forgotten forever, but the current Czech Republic has linked up to and been developing his unappreciated entrepreneurial heritage.

The article deals with legal and technical aspects in choosing the appropriate protection of objects against direct and indirect effects of lightning discharges. The technical dates shows how inadequate protection option, affected by the financial savings, may cause damage in thousands of CZK.

This monograph deals with the life of Vladimir Lista from a technical, economic, philosophical perspective. With respect to his education and activities, Vladimír List (1877-1971) was primarily an electrical engineer. Since his studies, however, he was also interested in humanities and economics, he studied foreign languages, and spent one year at the Technical College in Belgium (Liege). In 1923, he made a study trip to the US. The first years of his engineering practice List spent in Prague at František Křižík's plant; Křižík was founder of the electro-technical industry in Bohemia. List spent there eight years and then he entered the Technical University in Brno, where he was appointed a professor. All that contributed to his acquiring an extraordinary knowledge of not only his specific fields, but also of general economic, legal, and sociological issues. Vladimír List followed development of technology in deep social and economic contexts. After establishment of independent Czechoslovakia, List was thinking over the electrification of the new state and enforced standardization both in production and operations. In 1919, he took part at the Peace Conference in Paris as an adviser; he enthusiastically participated in the electrification of the state, in building a system of power plants, especially in Moravia, and brought up new generations of engineers at the Technical University. He was thinking about the role of the technical intelligentsia in the state, he was transferring his rich experience and encouraged engineers to study foreign languages and to go abroad in order to gain experience.

The designer suggested the lightning protection of biogas plant according to French standard NF C 17-102. Yet there was a direct lightning strike to the top of the fermenter, which lay in the protected space ESE air terminal. After a lightning explosion occurred and fire broke out subsequently biogas plant. Control measurement ESE air terminal demonstrated its full functionality at the time of intervention. 10 minutes before the lightning and the subsequent explosion of biogas leaving 4 workers that area due to changes in climatic conditions (rain beginning).

Article deals with historical development of Nuclear Energy in Czechoslovakia. It describes uranium mining, analyzes the development of the Faculty of Nuclear Sciences and Physical Engineering CTU in Prague and the Institute for Nuclear Research in Rež. It also deals with decisions about the construction of nuclear power plants in Jaslovske Bohunice, Mochovce and Temelin. Contribution characterizes the approach of Czechoslovakia forming the world's nuclear power industry since 1945.

This paper deals with the reconstruction of birthplace of inventor František Křižík in Planice near Klatovy. It describes re-adjustement of the exhibition about Křižík´s life and the interactive exposition of power energy in beginning of the 20th century.

This paper focuses on the calculation of the deformation forces when short-circuit occurs in chokes. The aim was to describe the mechanism generating deformation forces and determine the possible resistance of the equipment. The computer program for rapid and accurate calculation of this problem was presented.

This study concerns with unconventional methods of design in lightning protection of buildings. By force assembled physical model of lightning strike into the building, the authors give precision to the recent, intuitive designs of protection, which is based on the empirical predictions (method of rolling sphere, methods of top angles). In the frame of the norm support (ČSN EN 62 305), they analyze the relativity of the calculation accuracy against the practically used designs. The aim of this contribution is to make the overview platform of the methods that are oriented to the decreasing of unprotected parts of the buildings. On the base of electromagnetic model, the lightings strike into the object is compared from the view of accuracy and on the other side from the view of the demands of the calculation in the frame of electrotechnical praxis. The solution is verified with research outputs that were published in the foreign literature.

New technologies of operated risk has been arising which allow the direct management and safe getting down into the areas free of persons, animals, and buildings. However, all these arrangements are based only on the theoretical preconditions. This contribution is aimed to open the discussion about the active lightning protection.

Electrical Engineering, Its Terminology and Its Reflection In Czech Literature. Overview of presented contributions in the Czech literature is presented.

History of electrotechnics in Czech countries. Text presents the key milestones of Czech electrotechnical industry development.

This paper deals with the fast processes and their consequences which occur in the coils of HV transformers (high-voltage transformers). The study is based on the comparison of computer simulation and mathematical model in the case of the one-position coil. The aim of this contribution is to verify the validity of this model and its numerical solution for the practical usage in the construction of transformers. Authors compare the experimentally received data with the discrete mathematical and computer models in order to reach the applicability of their results for real conditions of transformer operation.

This contribution compares the quick phenomenon, which are in progress in one layer and multi layer of high voltage transformer. Study deals with the possibilities of solution in case of alternative scheme of the multi layer coin by way of its discrete model. Aim of this work is to monitor theoretically predicted behaviour of the multi layer winding of transformer (when the pulse wave is going through) on the input threads. Further, the results are compared to the model of the simple coin (tube-shaped). The potential distribution of over voltage wave in the system of coin winding may be the reason for the insulator destruction if the place is weakened. Every decrease of ground capacity (parallel substitution) and simultaneously the increase of pulse voltage, which influences the entrance clips of transformer. The main topic of this study is the impact of setting in case of these parameters by using of multi layer coins, interlaided windings or capacitance shields.