Tomasz Siostrzonek

The quality of electrical energy in mining plants is still a topic that is not directly linked to occupational safety and the efficiency of the mining process. Modernisation of hoisting machines should be carried out, taking into account the impact of such a drive on the mine’s power grid. A hoisting machine is one of the largest consumers of electricity in this grid and, as such, can pose a real threat to its proper functioning. The aim of the study was to determine the impact of the hoisting machine drive system on the mine network after a thorough modernisation process. Measurements were taken before and after the process. The assessment was carried out in two aspects, i.e., the measurement results obtained after the modernisation were compared with the applicable regulations. The second approach was to compare the results before and after modernisation. In the authors’ opinion, this second approach is a way of preventing potential phenomena that may occur in the network as a result of the operation of the power electronic system and should complement the analysis described in the regulations. The assessment of the current operation of the system in relation to the previous one makes it possible to evaluate the correctness of the solution applied and may provide guidelines for further steps in the event of a failure or unsafe events.

A hoisting machine is one of the main components of an underground mine process line. The drive systems currently used in these machines are based on direct current, synchronous, or induction (AC) motors. Power electronic converters are used to power and control the speed of the motor, the type and function of which depend on the type of motor. Choosing the right motor is the most important part of the design process. The decision must be based on an evaluation of technical and economic parameters. This article describes the most popular types of hoisting machine drive systems. Four motors that could potentially be used to build a hoisting machine with the assumed parameters were analysed. The selection of the motor was made based on the analyses carried out, and the implementation of the investment and commissioning of the machine with the selected motor confirmed the validity of this choice. The technical–economic analysis of the motor selection for this hoisting machine made it possible to determine how to choose a motor for a specific shaft hoist. The information contained in this article can serve as a guideline during in-depth analyses of motor selection for modernised or constructed hoisting machines due to the possibility of generalising its conclusions.

There are currently more than 30 underground mines operating in Poland. These are mines extracting hard coal, salt, and metal ores. Each of these plants has its own specifics for operation, but all operate under the same regulations. The basic principle is to ensure the safety of the crew and equipment. The progressive mechanization and automation of the mining process results in the installation of power electronic converters in the networks of mining plants, which significantly deteriorate the quality of the power in the plant supply networks. In addition, the constant reconfiguration of these networks related to the progress of the work can affect the safety conditions of the plant. This article describes problems occurring at one underground mining plant that are related to the structure of the power grid. Failures and interruptions in the production process were the result of poor power quality. They directly translated into increased production costs and significantly affected the safety level of the workforce, which could result in further consequences, not only in the financial sphere. The article also addresses the issue of existing legal regulations, the provisions of which may be insufficient in assessing the current state of power quality in mining plants.

The chapter describes the structure of drive systems used in hoisting machinery of underground mines. These devices, due to their special application and power, are characterized by special traits. The most commonly used systems with DC reciprocating motors are described. The so-called complex (multi-pulse) converters are used in those solutions. An extra attention was paid to the impact of these systems on the power supply network, especially the generation of higher harmonics. The results of measurements made under real conditions are presented. Measurements were made before and after the installation of new solution in connection with the modernization of systems due to the need to increase the efficiency of these machines.

For several years, research work has been carried out on energy storage that uses changes in the potential energy of masses being lifted or lowered. The energy of such a solution depends on the mass to be transported and the height to which the weight has to be lifted. Increasing the weight to be lifted is limited by the parameters of the mechanical components, such as ropes. Increasing the height, however, is difficult to implement, if only because of the weather conditions that affect the safe operation of such a system. In fact, the ideal solution is to use mine shafts, which in Poland are up to 1300 m deep. The progressive process of decommissioning the mining industry creates new opportunities to use this part of the infrastructure of mining plants for the construction of energy storage facilities. In the article, possible constructions of gravitational energy storage facilities based on existing hoisting machines are described. There are three main areas in which the operation of an energy store should be analysed if it were to be realised in a mine shaft. The mine shaft, as a working mine and for energy storage, is subject to relevant regulations that need to be met. To confirm the assumptions about the possible use of the existing infrastructure, measurements of one hoisting machine in Poland were carried out and example results of these measurements are included.

W artykule podjęto próbę przedstawienia współczesnych trendów i wyzwań w obszarze jakości dostawy energii elektrycznej w kontekście rozwoju inteligentnych systemów elektroenergetycznych oraz energetyki rozproszonej. Tematyka ta jest bardzo szeroka i wieloaspektowa, szczególnie ze względu na transformację energetyczną, w której uczestniczymy. Autorzy artykułu, członkowie Zespołu Jakości Energii Elektrycznej AGH, brali udział w realizacji wielu prac naukowo-badawczych, eksperymentalno-rozwojowych, dydaktycznych w ramach krajowych i międzynarodowych projektów. Związane one były ze współpracą z energetyką zawodową (OSD, OSP), przemysłem oraz instytucjami działającymi na rzecz rynku energii. Przedstawiono skrótowo przykładowe, wybrane zagadnienia.

Wydawnictwo SIGMA-NOT wydaje czasopisma fachowe informujące swoich czytelników o najnowszych osiągnięciach naukowych i nowoczesnych rozwiązaniach technicznych w Polsce i na świecie, popularyzuje problemy techniczne oraz poszerza wiedzę i kulturę techniczną.

The article presents a method enabling estimation of the selected power quality indicators at a given point of a power network, on the basis of the power quality indicators recorded at the nearest vicinity points. For needs of the estimations, artificial neural network algorithms were applied. The result is a neural model that defines the relationship between the power quality indicators of the same type, at adjacent points. The paper presents results of analyses and tests under real operating conditions of the distribution system.

Modern electronics systems consist of not only with the power electronics converters, but also with the friendly user interface which allow you to read the operating parameters and change them. The simplest solution of the user interface is to use alphanumeric display which displays information about the state of the converter. With a few additional buttons you can change the settings. This solution is simple, inexpensive but allows only local control (within walking distance from the system) and the number of displayed information is low. You can create extensive menu, but it causes problems with access to information. This paper presents the example of a rotating energy storage universal solution which is lack of the above mentioned disadvantages

He paper presents a three-phase rectifier with sinusoidal source current which enables energy to be fed back to the AC supply network. It has been used in a flywheel energy storage system. The principle of operation and control methods of the three-phase rectifier are discussed. The experimental setup employing a DSP controller co-operating with CPLD device is described. Results of experimental investigation for both the steady and transient states are presented in the concluding section.