Lightning Protection for Buildings Threatened with Explosion of Solid Explosives

This paper presents the overview of current regulations pertaining to lightning protection of all facilities threatened with explosion of solid explosives, that is buildings where such materials are manufactured or stored. Lightning hazard due to possible thunderbolt striking directly into the building or into its neighbourhood has been analysed. Direct results of lightning current flow have been considered as well as secondary results arising from thermal, electrodynamic and inductive actions of this current. In order to eliminate the existing hazards, application of recognized lightning protection designs has been proposed and justified.

Connection of PV Sources Into Transmission Grid vs. Thermal Overload Risk of Wires and Cables

W artykule opisano wybrane zagadnienia związane z sieciami elektroenergetycznych niskiego napięcia, do których są przyłączane przydomowe elektrownie fotowoltaiczne. Określono ogólne parametry techniczne sieci dystrybucyjnej celem przybliżenia problematyki związanej z ograniczeniami technicznymi sieci. Dokonano symulacji komputerowych celem zweryfikowania skuteczności zabezpieczeń nadprądowych w sieciach dystrybucyjnych, w których występują lokalne źródła energii

Failures of Lightning Air-Termination Rods Fixed by Spacers

Air-termination rods with height above 2,5 m must be fixed to objects by for example spacer bars to ensure proper separation distance. Commercially available spacer bars are suitable in laboratory conditions only. Real-life scenarios show weak points of this solution. Dirty or wet spacers do not fulfil proper isolation strength to ensure proper separation distance. This changes the km factor used to calculate the separation distance. The paper presents laboratory tests for clean spacers, wet spacers and a few real photos of damage caused by spacer bars.

Power Losses and Efficiency in Transformers

Energy efficiency of transformers has been defined in the paper. The continuous progress noted in technology of electrical steel used for transformer laminations results in decreased lossiness and increase of flux density saturation in the core. Therefore, conditions are established for decreasing core weight and, to a lesser degree, decreasing winding weight as well. The examples of idle and load power losses have been provided for distribution transformers manufactured in 1960s and for those manufactured now. The European Commission [8] and European Standards have ruled that further decrease in power losses and increase in efficiency of newly-installed transformers must come into effect by 1st July, 2021.

Adhibition Study of Electric Multiple Units with Energy Storage on Partially Electrified Railway Line Gdansk Orunia - Port Oksywie

Innovation in passenger service structure in Three-City Metropolis is discussed in the paper. In the case of track with alternating electrified and non-electrified sections, the energy demand has been determined. Then, a hypothetical energy storage consisting of batteries and supercapacitors has been selected. The analysis has shown that use of electric multiple units with energy storage might be better than use of Diesel multiple units or construction of traction network.

Control Process Modelling of Thermodynamic Systems Containing a Thermal Energy Storage Tank

The article content constitutes the answer to a growing interest of a heat-flow processes automatisation applied into detached houses heating sector. The paper contains a brief description of a usage of the PID and fuzzy controllers. The methods of the controller’s setting selections (e.g. Ziegler-Nichols method), which are alternative to the classical ones, have been also presented within the paper. The optimization of the controllers’ settings for the executive systems of a thermodynamic cycle is also available in the paper. It was carried out based on the minimum heat flux increase time in the condenser unit of a heat storage tank. For this purpose the Simplex Neldera- Meada algorithm was used. In the article, the results of the changeable work of the thermal energy storage tank have also been presented. The analysis was carried out in the Matlab Simulink environment.

Performance Level (PL) Part I - Basic Parameter of the Machine Safety Function (SF)

The paper discusses the concept of the safety function for the machine control circuit, which is one of the basic concepts that allow to design machines in accordance with the safety requirements. The basics of the architecture of systems implementing safety functions in machines were also discussed. Using the example of the fundamental emergency stop circuit, the basics of the reliability parameters for electromechanical components are explained. The concept of forced contact guidance is also explained. The basic formulas are given and the basis for further clarification of the performance level (PL) is prepared.

Lightning Protection for Metal Air Vents and Similar Objects Installed on the Roof of Building

Lightning hazard occurring when metal air vents connected with installations inside building are installed on the roof without consulting an expert on lightning protection has been analysed in this paper. The application of accepted designs eliminating this hazard has been described (these designs may be found in rules for formal construction of LPS). In the case of technical project which might significantly impact the safety of operation of constructed systems, thorough expert consultation and harmonisation has been suggested.

Nonsynchronous Connection of High-Power Unit to 400 kV Power Grid

One cause of failures in power plants may be traced back to faulty, nonsynchronous synchronisation of a power unit with power grid [1]. This usually results in damage to a generator or a unit transformer. The case of misguided connection of non-excited generator to network has been described in publications [2], [3], [4], this produced very serious damage to the generator

Part 2: Reactive Compensation of the Linear Load in Three-Phase Four-Wire Systems Supplied with Asymmetrical Sinusoidal Voltage Following Currents’ Physical Components Theory

Four-wire systems are the most common ones in everyday life. Electrical installations within the home, office, or industrial plant are mostly four-wire installations. Receivers connected to such a system are mainly single-phase loads, which from the power connection are an unbalanced three-phase load. Apart from, the load imbalance, the supply voltage also has some asymmetry. Voltage asymmetry, load imbalance, the design of reactance compensators are issues that were not simultaneously included in the power equation in fourwire systems. This article presents the mathematical fundamentals of the construction of reactance compensators operating in voltage asymmetry.