Identification of the flicker source in the power supply systems

THE PURPOSE. To consider issues related to the study of methods for determining the sources of violations of the quality of electrical energy in power supply systems, in particular consumers which create rapid voltage changes or voltage fluctuations that create rapid changes in the luminous flux in electric lighting installations. Show that electrical receivers with a sharply variable operating mode are sources of fluctuations in the consumed current and voltage in the electrical network of power supply systems, which in turn manifests itself in the form of unacceptable values of one of the indicators of the quality of electricity - flicker, defined as the subjective perception of fluctuations in the luminous flux of lighting devices. To study the possibilities of determining the places of occurrence of significant voltage fluctuations without the use of expensive and complex instruments for measuring flicker values in the electrical network. To develop a simplified method for determining the locations of electricity consumers that negatively affect the operation of electric lighting systems and, ultimately, the vision of personnel. Conduct a check on a computer model of a simplified method for determining the places of occurrence of voltage fluctuations that are inadmissible in their magnitude, which are expressed in the appearance of significant doses of flicker that exceed the standard values.METHODS. Solving the problem, a computer model was used, created in the Simulink extension package of the Matlab scientific and technical calculation system.RESULTS. The article describes the relevance of the problem, discusses the quality of electricity in power supply systems. It has been shown using experimental data that in electrical networks there is an excess of the standard values of flicker doses. The possibility of using interharmonic components of the mains voltage to determine the sources of unacceptable doses of flicker is considered. A simplified method for finding flicker sources based on obtaining the values of the derivatives of currents at various points of the electrical network is presented. Computer simulation of an electrical network diagram with electrical receivers, which have both calm and sharply variable nature of work, has been performed. It is shown that the use of the values of the derivatives of the current at various points of the electrical network makes it possible to identify the sources of the occurrence of unacceptable doses of flicker.CONCLUSION. The occurrence of significant rapid voltage changes in the electrical network negatively affects vision, which is inevitably accompanied by increased personnel fatigue and can lead to industrial injuries. The results obtained by the authors of the article show that it is possible to use it to determine the places of occurrence of large voltage fluctuations, which are manifested in unacceptable doses of flicker of the derivatives of currents. It should be taken into account when conducting surveys of power supply systems in order to use fairly simple hardware to identify sources of disturbance in the quality of electrical energy.

Research of higher harmonic components of voltage and current and their influence on the functioning of shipboard electrical equipment

Одним из направлений научно-технического прогресса на объектах морской индустрии является широкое использование технологий, основанных на нелинейных элементах, что позволяет значительно снизить их массогабаритные показатели и расшить их функциональные возможности. Однако применение таких технологий приводит к ухудшению качества электрической энергии, в первую очередь за счет высших гармонических составляющих напряжения и тока. В статье показана природа высших гармонических, выполнен анализ разделов «Правил классификации и постройки морских судов. 2021», российских и ряда зарубежных стандартов в области качества электроэнергии, регламентирующих уровень высших гармонических составляющих напряжения и тока в электрических сетях и системах. В работе приведены результаты теоретических и экспериментальных исследований влияния высших гармонических составляющих на функционирование судового электрооборудования: асинхронных электродвигателей, силовых кабелей, трансформаторов, конденсаторных батарей и систем освещения. Определены выражения, позволяющие оценить это влияние. Показано, что в основном это влияние проявляется: в дополнительном нагреве электрооборудования за счет поверхностного эффекта; вибрации асинхронных электродвигателей при высоких значениях 5 и 7 гармоник напряжения судовой электрической сети. One of the areas of scientific and technological progress at the facilities of the marine industry is the widespread use of technologies based on nonlinear elements, which can significantly reduce their weight-size parameters and dimensions and expand their functional capabilities. However, the use of such technologies leads to a deterioration in the quality of electrical energy, primarily due to higher harmonic components of voltage and current. The article shows the nature of higher harmonics, analyzes the sections of the «Rules for the Classification and Construction of Sea-Going Vessels. 2021», Russian and a number of foreign standards in the field of electric power quality, regulating the level of higher harmonic components of voltage and current in electrical networks and systems. The paper presents the results of theoretical and experimental studies of the influence of higher harmonic components on the functioning of shipboard electrical equipment: asynchronous electric motors, power cables, transformers, capacitor banks and lighting systems. Formulas have been determined to assess this effect. It is shown that the influence is mainly manifested: in additional heating of electrical equipment due to the skin effect; vibrations of asynchronous electric motors at high values of 5th and 7th voltage harmonics of the ship's electrical network.

Some results of voltage increase in marine electrical propulsion installations

The main voltage parameters of marine electrical propulsion installations, at various load capacities, with further stress assessment are discussed in the article. By considering voltage options, it was revealed that an increase in inductive resistance makes it possible to manufacture a machine with high power, but the quality of electrical energy in transient modes is deteriorated. During starts, reversals, resets and load surges of powerful consumers, large voltage dips will occur on the generator. To solve the problem, including determination of optimal parameters of the generator, based on the multifactorial nature of the task of creating an electric machine for a specific purpose, an analysis of all the necessary parameters was carried out. The main dimensions of the machine depend on its full power, angular speed and electromagnetic loads. The article presents technical solutions considered using the example of a modern multipurpose icebreaker-supply “Vitus Bering”. Also, as an example, an icebreaker of the Taimyr type with a limited draft is considered, for the first time in modern practice, an alternating-changing current EDMS is used. From the experience of operating the icebreakers “Taimyr” and “Vaigach”, the transition to high voltage did not lead to a complication and increase in the complexity of the maintenance of the MPM, although it required strict compliance with safety regulations during the work. During the operation of icebreakers with MPM 6.3 kV, not a single case of single-phase short circuit or electrical injury has been recorded.

Determination of the technical condition of electrical equipment in power supply systems

This article describes the methods and means for determining the technical condition of electrical equipment in power supply systems, particularly in transformer substations. There are many ways to determine the technical condition of electrical equipment. However, their implementation requires complex and additional equipment and devices. In addition, these tests must be carried out when the power supply system is off. This will lead to a decrease in the quality of electrical energy. Determination of the technical condition of electrical equipment using thermal imagers is performed under the voltage and in operating modes, the measurement process does not affect the parameters of the power supply system. The results of research in energy enterprises of the Syrdarya region are presented.

Studi Kualitas Energi Listrik Gedung Fakultas Teknik Universitas Bangka Belitung

One of the performances of the electric power system can be seen from the quality of electrical energy. In this study, the measurement of the quality of electrical energy was carried out using a power quality meter to obtain the values of current, voltage, frequency, total current harmonic distortion and total voltage harmonic distortion in the building of the Faculty of Engineering, Universitas Bangka Belitung. From measurements on the 3 existing buildings, it was found that the measured voltage value range was still at + 5% to - 10% of the 220 Volt secondary distribution voltage value and the frequency value was still in the range of 49.5 Hz to 50.5 Hz. The total value of voltage harmonic distortion is still below the required value, but the total value of current harmonic distortion is above the required value.

Effect on Human Body of the Magnetic Field Induced by the High Voltage Transmission Line

The quality of electrical energy and the fight against energy losses are a crucial issue for electricity companies. The use of high voltage lines can limit energy losses for the transmission of electricity over long distances. But this solution has the disadvantage of the propagation of the electromagnetic wave which has a great influence on human health. The work presented in this study mainly deals with modelling problems that may be encountered by the community working in the field of low frequency electromagnetic fields. In order to model a power line, we are based on geometric data as well as phase and earth conductor data.

ANALYSIS OF VOLTAGE NON-SINUSIDALITY IN POWER SUPPLY SYSTEMS WITH INDUCTION HEATING UNITS

The importance of the problem of improving the quality of electrical energy grew along with the development and widespread introduction of various high-performance technological installations in production, such as arc steel-making furnaces, welding installations, induction furnaces, etc. in accordance with the requirements of the standard GOST 30804.4.7–2013 and in accordance with the measurement program. A method for processing the research results obtained during the experiment is described. All power quality indicators are processed using computer programs created in the Labview graphical programming environment. The analysis of indicators of the quality of electrical energy to the requirements of GOST 32144-2013 was carried out, according to the results of which conductive low-frequency electromagnetic interference was detected in the 0.4 kV electrical network according to the coefficient of the n-th harmonic voltage components. The obtained values ​​of the indicators of the quality of electrical energy, characterizing the coefficient of the n-th harmonic components of the voltage, confirm the need to use technical means to reduce the influence of higher harmonics on electrical networks.

Exploration of influence of led spotlights on quality of electric energy

The results of the study and assessment of the quality of electrical energy measured at a separate phase in the existing electrical installation of the building, with a load in the form of LED floodlights are presented. The problem of the negative impact on the quality of electrical energy of switching power supplies of electronic devices, typical for this type of electrical load, is considered