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The increasing implementation of Distributed Energy Resources (DERs) represents one of the most significant transformations currently affecting modern power systems

Underground mining operations require the preparation of access, development, and production workings to enable the extraction of mineral resources. These excavations serve several functions, among which the transportation of personnel, machinery, materials, and mined rock is essential. Since transportation is frequently carried out along the mine floor, maintaining its proper condition is crucial for ensuring operational safety and efficiency. Existing floor maintenance methods, including manual operations, roadheaders, and crawler tractors equipped with bulldozer blades, are characterized by limited effectiveness, high operating costs, and considerable labor intensity. Moreover, the confined dimensions of underground workings prevent the use of conventional surface earthmoving equipment. The paper presents an innovative solution designed for mine roadway floor maintenance, based on a tracked tractor equipped with a cylindrical milling cutting head with conical picks reinforced with special protective coatings. The proposed cutting head features a modular three-segment design with interchangeable drums of different cutting widths, enabling simultaneous floor profiling and drainage channel construction while remaining compatible with the restricted geometry of underground mine workings. The operating performance of the cutting head was evaluated through numerical simulations for different values of the rock cuttability index (1500 and 3000 N/cm), cutting depth (100 ÷ 300 mm), and machine feed speed (2 ÷ 6 m/min). The operational parameter analysis, based on calculations and simulations, demonstrated that effective floor cutting would be achieved within acceptable values of cutting forces and power consumption. The proposed solution represents a new category of machinery dedicated exclusively to underground mine floor maintenance. The developed concept has the potential to improve transportation safety, reduce roadway maintenance costs, and increase the operational efficiency of underground mining systems.

Currently, the installation of distributed energy sources is growing rapidly, especially renewable sources, for which the goal is to increase energy self-sufficiency across certain parts of the distribution network. The optimization of electricity production and distribution is key to achieving this goal. To optimize the energy distribution system, filters are increasingly being installed to compensate for reactive power, mitigate voltage unbalance, and reduce higher harmonics in small parts of the electrical system and even for single loads. This article verifies the filtration efficiency of a group of single-tuned passive harmonic filters. Two groups are investigated: a group of real filters and a designed optimal filter. This investigation was performed in three important parts: Firstly, measurements of the power quality parameters were taken in a real system (laboratory measurements). Secondly, the configuration of the optimal filter group was calculated, assuming the same reactive power and tuning frequencies as in a real system. In the group structure of such filters, the biggest problem is properly sharing the total reactive power between the filter branches. Thirdly, both filter structures (real and optimal) are compared based on harmonic reduction indexes and the filter efficiency index.

The primary means of rail transport in inclined workings up to 45° are typically single- or double-drum rope winches. These winches are part of a transport system consisting of the winch itself, a rope with a diameter d and length Ll, a track system, and a return drum with a rope tensioning mechanism. A fundamental challenge in employing winches in a given working is accounting for their operational conditions, which include the route length Lu, its inclination αu, and the value of the hauled mass (weight) Gm, given a specified load transport velocity vpł. These factors influence the drive load parameters, such as the winding rope force FC, unwinding rope force FS, and drive motor power Np. Manufacturers of these devices provide their structural (Lumax), kinematic (vpj), and energy-related (Np) parameters. However, it is the responsibility of the prospective user to assess the suitability of a specific winch for the conditions present in their transport excavation. To address this need, an analytical model, algorithm, and computer program have been developed to dynamically determine the required parameters while considering the winch’s operating conditions.

W artykule przedstawiono współczesne trendy i wyzwania w obszarze jakości dostawy energii elektrycznej w kontekście rozwoju „inteligentnych” systemów elektroenergetycznych(smart grids) oraz energetyki rozproszonej. Autorzy artykułu,członkowie Zespołu ds. Jakości i Efektywnego Użytkowania Energii Elektrycznej (JUEE) AGH, dzielą się doświadczeniami z prac naukowo-badawczych, eksperymentalno-rozwojowych oraz dydaktycznych wykonywanych w ramach krajowych i międzynarodowych projektów. Działania były realizowane w ścisłej współpracy z energetyką zawodową (z operatorami sieci przesyłowej– OSP i dystrybucyjnej – OSD), przemysłem oraz instytucjami działającymi na rzecz rynku energii. Rozdział prezentuje skrótowo przykładowe zagadnienia badawcze.

Artykuł prezentuje wybrane działania badawcze trzech wydziałów AGH w obszarze efektywności wytwarzania i użytkowania energii, ze szczególnym uwzględnieniem energetyki rozproszonej.Opisano w nim zagadnienia związane z procesami spalania,chłodzenia, zarządzania energią w budynkach oraz integracją OZE i magazynów energii. Uwzględniono również rozwój metod oceny inteligencji energetycznej budynków (SRI) oraz modelowanie systemów hybrydowych. Prace wspierają transformację energetyczną i rozwój nowoczesnych rozwiązań lokalnych.

Due to their simple design, high reliability, and low energy consumption, belt feeders are a fundamental means of transporting bulk materials, particularly in continuous feeding systems. The most commonly used belt feeders are short ones, with lengths up to 40 meters and belt widths up to 1 meter. In addition to their use in underground and open-pit mining, they are widely applied in energy, metallurgy, and other industrial sectors and in transshipment ports, storage yards, and stockpiles. The proper operation of belt feeders is ensured by maintaining their structure’s required stability and rigidity under specific operational conditions (installation location). It applies to feeders operating on straight stationary supports, particularly on V-type stationary and mobile supports. Various computer programs are used during the design phase of these feeders to assist and facilitate the process because, despite standard components and assemblies, belt feeders are not repeatable solutions and require multi-variant calculations. Based on a typical belt feeder, its analytical model, and dedicated software, the stability and forces acting on the supports are investigated. This software enables and facilitates the analysis of the stability and support loads of a belt feeder during its design phase or when implementing structural modifications. It may be particularly useful for current and future users introducing changes to the feeder’s structure or relocating it to a different operational site. The presented application was employed in the analysis of a belt feeder at an open-pit mine during the process of modifying its drive unit.

A central engineering concern in the use of such winches is their energy intensity, which is significantly influenced by operational factors such as the length and gradient of the transport route, the transported weight, and the target hauling velocity. These variables directly affect the drive system’s load and thus the power demand of the motor, which represents the primary component of the system’s energy consumption. While manufacturers typically provide structural, kinematic, and power-related specifications, the user must evaluate whether a given winch can operate efficiently within the energy constraints imposed by specific site conditions. To aid in this assessment, an analytical model, along with a computational software tool, has been developed. This solution enables the continuous determination of essential parameters, with particular attention paid to the energy requirements of the system, supporting informed selection and implementation of winches with appropriately rated motors to optimize energy consumption. For the analyzed case, it was calculated that doubling the transport distance results in an increase in energy consumption of approximately 50%. Moreover, an increase in the velocity of the transported weight by only 0.5 m/s leads to a rise in energy consumption of approximately 25%.

Belt conveyors, owing to their simple construction, high reliability and relatively low energy consumption, are the basic means of transporting loose and granular materials. Currently, thanks to continuous development, belt conveyors can reach a length of up to several kilometres, and their belt width can be more than two meters. Such possibilities are achieved thanks to increasingly better belts and drives. However, the most common are short belt conveyors with a length of up to 40 m and belt widths of up to 1 m, frequently referred to as belt feeders. Apart from the mining industry, they are widely used in power engineering, metallurgy and other industries (chemical plants, trans-shipment ports, storage yards, etc.). The design of machines, including belt feeders, is based on calculations. Modern design in technology is based on advanced computational methods and the possibilities of computer technology. Multi-variant simulation calculations are necessary, especially in the case of belt feeders, where none of the devices—despite the use of typical elements and subassemblies—are a repeatable solution. Only this procedure guarantees the selection of rational solutions already at the early stages of design. Therefore, in this article, an analytical model of a typical belt feeder was developed and its stability and forces in the supports were determined. This allowed the development of an application for testing the stability of the belt feeder at the design stage or when introducing structural changes.