High Quality Power Supply Research Articles

ON THE CHOICE OF OPTIMAL METHODS FOR FEATURE EXTRACTION AND CLASSIFICATION OF VOLTAGE DISTURBANCES

Power quality (PQ) disturbances classification plays an essential role in ensuring high quality power supply of the power grid. Therefore, most of the researchers have aimed to achieve accurate and fast classification. But yet one of the main issues is how to extract the “right” features from massive amount of voltage and current data. The feature extraction should be performed for the aim of not only increasing the classification accuracy, but in the same time reducing the computational complexity of the classification algorithm. Once the optimal feature combination is found, the next challenge is to determine the most appropriate number of input signals for training the classifier, so as the classifier achieves maximum accuracy for the given features. In this paper we investigate the effectiveness of the wavelet based features in order to find less numerous features combination that attains high classification accuracy. Furthermore, using that combination, we investigate the influence of the different number of input voltage signals for training the corresponding classifier, in order to obtain optimal classification method.

Development of a Real-Time Web-Based Power Monitoring System for the Substation of Petrochemical Facilities

Petrochemical industry not only consumes a large amount of electricity every year but also requires high-quality power supplies. Any unexpected power failure could shut down the entire production line and cause significant financial loss. Meanwhile, due to the large electricity consumption and intensive power demand, in-house cogeneration plants have been equipped for most petrochemical facilities. Thus, any power interruption or disturbance between a petrochemical facility and interconnected power grids could affect both sides of the power systems. Therefore, having high power quality becomes one of the most critical parts for petrochemical facilities. To avoid unexpected power failure and to provide a better understanding of the power system at petrochemical facilities, a fast, precise, and reliable power monitoring system is required. A novel real-time web-based power monitoring system on field-programmable gate array platform is developed in this paper for a power substation at the petrochemical facility. Besides the data collecting with event-triggering mechanism and measurement data recording functions, subsynchronous oscillation detection application is also developed in this system. This monitoring system could provide precise data to help engineers with insightful analysis of the electric system to prevent a power failure, and it also could help system operators to have a better understanding of the system operation characteristics.

N. Ryazanova. The system of energy and logistics clusters as an element of the development of alternative energy.

The purpose of the article is to substantiate the system of energy and logistics clusters as an element of the development of alternative energy. The article discusses the integrated energy system of Ukraine from the point of view of the logistics approach, as the main object of macro-energy systems, which includes producers and suppliers of electricity, as well as electrical networks. Macroenergy systems are regional energy systems. Microenergy systems - enterprises that are objects of microenergy. It is analyzed that the process of energy supply is closely dependent on the process of energy consumption, that is, there is a direct functional relationship. The relationship of the participants in the energy supply process is inextricable. In this connection, a complete logistics chain is formed and a logistics network is being formed. The fundamental principles of energy logistics are considered. Definitely one of the most important tasks of energy logistics is the implementation of real-time energy flow management in order to ensure reliable and high-quality power supply to the end user. Reflected trends in the development of the global market of logistics services and the market of logistics services in Ukraine. The expediency of creating energy and logistics clusters has been substantiated. It was noted that by minimizing costs in the areas of logistics and alternative energy, the formation of energy and logistics clusters can be an effective tool for the sustainable development of the national economy. A comparative analysis of various models of clusters in the developed countries of the world has been carried out, and it has been determined which of them is most appropriate for the formation of energy-logistics clusters. The most appropriate for the logistics of energy systems is the Italian model of cluster policy. In this model, there is a state program to support small and medium-sized enterprises, aimed at the cooperation of production with the scientific sphere. The European four-step gradation of clusters is considered and analyzed on the example of the EU countries and Ukraine. Six stages in the life cycle of the energy and logistics cluster have been identified. The structure of the energy-logistics cluster is presented. The development of the energy-logistics cluster should be considered as a specific program, which consists of a set of interrelated projects. The introduction and operation of clusters and cluster technologies in the context of modern challenges, globalization, increased competition is considered one of the promising means of ensuring the competitiveness of the national and regional economies.

Research and Simulation of grid connected strategy for microgrid

With the growing demand for electricity, fossil energy gradually dried up, energy crisis and environmental pollution problems become increasingly serious, the global power industry is facing great challenges, so the micro grid from distributed generation arises at the historic moment. Flexible operation mode and high quality power supply service are the advantages of microgrid, but it needs perfect control system support. Therefore, the research of microgrid control strategy is of great significance. In view of this, a brief analysis of several important factors need to be considered when the micro grid connected to the grid, and then combined with the topological structure of a power academy microgrid experimental platform of control, research on micro grid control strategy, and through the MATLAB simulation with actual data.

Active Power Line Conditioner with Impulse Asymmetric Current Battery Charging System

A scheme of an active power line conditioner with a battery charge system with impulse asymmetric current battery charging system is presented. Numerous publications point to the expediency of constructing a system that would realize both functions of compensation of reactive power and the provision of guaranteed power supply. The existing nonlinearity of loads affects the reduction of the power factor and the increase of the content of higher harmonics of consumpted current, which leads to distortion of form of network voltage. Many loads require high quality power supply, and their high-quality work can only be achieved with low content of higher harmonics and a shape factor that corresponds to the ideal sinusoidal voltage. In addition, the deviation of the power factor from one and the corresponding current distortion result in energy losses in the networks and equipment, which in turn is one of the reasons for additional heating and a decrease in the life of the devices. From the analysis of battery charge methods, it follows that the method of impulse asymmetric current battery charging exceeds the quality of the other and provides a reduction in the charge: the memory effect, peak values of temperature and internal pressure of the battery, which can increase the life of the battery in 1.5-3 times. The main disadvantage of this method of battery charge is a relatively low efficiency, but with the use of circuit solutions that allow using the energy of a bit pulse repeatedly to charge the battery, the efficiency is increased to 80-90% and above. Total increase in the efficiency compared with existing devices reaches 12-34%. The purpose of the work is to calculate the reactive elements and the main parameters of the filter-compensating converter when used together with the system for the sake of the battery with impulse asymmetric current. Time diagrams describing the main operating modes of the device, as well as equivalent circuits of the converter, that describes its operation at the appropriate time intervals are given. Using the balance of energy and the method of calculation on average currents and voltages, expressions for calculating the basic parameters of the compensator, provided the consumed additional energy for charging the battery are derived. It is determined that the capacity of the storage capacitor increases in proportion to the additional energy required to charge the battery, with the constant value of the inductance of the smoothing inductor.Ref. 10, fig. 3, tabl. 1.

INCREASE OF ENERGY EFFICIENCY IN SYSTEMS WITHOUT RIGID ELECTRIC SUPPLY

The article solves the problem of increasing energy efficiency in a non-traction power supply system by integrating a diesel-inertia plant of guaranteed power and a wind power plant into the power supply system of traction substations. The rationale for the efficiency of the application of diesel-inertia units on the newest block-module traction substations has been fulfilled.A scheme of diesel-inertia UGW is developed on the basis of a combined asynchronized electric machine with a different number of turns of stator windings. The proposed system of power supply for VL STP using a combined installation allows, in contrast to existing ones, to ensure the quality of voltage is required on the power supply buses of the HV SC with fluctuations and voltage cutoffs on the RU 10 kV buses of the substation, as well as for various abnormal phenomena in the RU 10 kV circles.The proposed methods for providing high-quality power supply to electric receivers, based on adaptive system control when the voltage of the network input changes before it disappears. The introduction of this power supply system of the HV STP makes it possible to compensate the reactive power of the load, is powered from the buses of the 10 kV substation, without the use of high cost static reactive power compensation equipment. The research of transient processes of UWW is carried out in the application package of modeling MATLAB & Simulink.

Biotechnology and Performance of SMEs in Nigeria

Nigerian SMEs suffers greatly in terms of struggling for survival. Access to finance is seen as the root of the major constrains including; limited access to water and power supply, good and quality raw-materials as well as modern infrastructures and processing methods. This paper adopts the desk research approach to review the cause and possible solutions and alternatives that can by-pass such constraints. Biotechnology, due to its natural and broad spectrum of application is seen as the potential solution to many of the problems that paralyses performance of Nigerian SMEs. When applied responsibly, the technology has potential of providing alternative source of; sufficient and high quality raw-materials, water and power supply as well as processing methods for industries at a considerably low price, thus, enhancing environmental friendliness, besides improving opportunities for new initiatives, and also enhancing performance efficiency of existing firms.

Digital Generator Control Unit Design for a Variable Frequency Synchronous Generator in MEA

Variable frequency power generation systems have been adopted for modern aircraft power systems, thus, a new generator control unit (GCU) must be designed to regulate the output voltage and obtain high quality power supply under a wide frequency range from 360 Hz to 800 Hz. In this paper, a dual digital signal processor (DSP) structure-based GCU was proposed. Multi-loop control structure was adopted with the controller parameters varying adaptively at different working conditions to obtain better performance. Different root-mean-square (RMS) calculation algorithms have been compared and the final RMS calculation scheme was determined to realize the trade-off between accuracy and computing efficiency. Experimental results show considerable performance improvements of the generator output voltage under various operating conditions with the proposed GCU.

Sustainability of Community-Owned Mini-Grids: Evidence From India

Background: To ensure universal access to electricity, community-owned mini-grid systems are gaining popularity, particularly for remote locations in developing countries where central grid extension is technically and economically challenging. However, our understanding of the conditions ensuring the long-term sustainability of these solutions and their ability to produce socio-economic benefits is still limited. To reveal these issues, we study 24 community-owned Solar Mini-Grids (SMGs) using a multi-dimensional and multi-tier framework. These implementations are developed by a single social enterprise and span a few months to over five years of operation. Results: We find that the underlying model analysed is capable of providing a consistently high quality, durable, reliable and affordable power supply. Strong community engagement from early stages helps to create effective and inclusive governance, motivating users to make regular payments, thus ensuring economic model sustenance and overall satisfaction of the users. These factors contribute to social and environmental benefits, particularly in terms of increased safety, a strong sense of community connectedness, child education, and improved air quality. However, energy consumption and engagement in productive activities remains marginal. Conclusions: The multi-dimensional analysis revealed that community-owned energy interventions can be developed sustainably, provided quality of power supply is good and there is a deep engagement with local communities. However, dedicated interventions are needed for communities to benefit from energy access beyond the purpose of illumination. Particularly, those at the nexus of energy and rural development, for example agriculture, water and sanitation, can help in creating environments suitable for sustainable rural living.

Design and implementation of feeder automation

With the development of national economy, the demand for electricity from all walks of life has been gradually increased. People also put forward higher requests to the reliability of power supply. Feeder automation can quickly cut off the faulty line to ensure the safe and stable operation of the line. Under the sustainable development of modern society, people attach a great importance to all aspects of smart power grid construction, which is also significant for the smart grid distribution work. To ensure the reliable and high-quality power supply environment, the scientific and reasonable design and planning of power distribution automation system shall pay attention to arranging power distribution, and the appropriate feeder automation operation mode shall be selected. Only in this way can we ensure that the power outage is short once a fault happening in power grid system. At the same time, the line loss rate can be reduced, the efficiency of power supply can be raised, and issues in power equipment investment can be effectively treated. This paper mainly discusses the design and implementation of feeder automation, puts forward some practical application measures, and provides reference for the stable operation of feeder automation.

Verification of HTS SMES Lumped Parameter Network Model

HTS Superconducting superconducting magnetic energy storage (SMES) can be utilized to ensure stable operation and high high-quality power supply in power systems. The lumped parameter network model of the magnet, which is taken example by transformer transient model, composed of self-inductances, mutual couplings, and series and shunt capacitances,is typically used to analyze the voltage distribution on the HTS magnet. The model is helpful in regards to the insulation design of SMES magnets, so its accuracy is a crucial consideration. This paper introduces an HTS SMES lumped parameter network model and corresponding parameter calculation technique. Tests were run on under various conditions and the results were compared against the simulation results to verify the model's accuracy. Suggestions for insulation design and transient suppression are presented based on our observations.

Research and Application of Voltage Quality Evaluation and Control Strategy for Distribution Network

Power system aims reliable and high quality power supply, which makes voltage quality essential. This paper at first introduces the existing voltage quality assessment methods and points out its shortcomings. After that, a new voltage quality evaluation method based on probability and statistics is proposed, which is applied to the analysis of voltage monitoring points of Type D (380/220V customer side phase/line voltage points) to overcome these shortcomings. This method adopts continuous evaluation rather than discrete evaluation, which helps to show voltage quality in a more intuitive and reasonable way, providing scientific basis for voltage quality control strategy of distribution network.

Implementation of inverse calculation method in diagnostics of digital electric substations

Diagnostics of the equipment of a substation is an important element of effective work of the machine-building industry in view of the fact that engineering plants need continuous and high-quality power supply. The article presents the solution for the accelerated analysis of the complex technical system equipment condition by the example of a digital substation. It is based on Boolean algebra and logic-numerical polynomic models. This approach can be applied to state estimation of the power equipment and digital devices of the substation.

고품질 전력공급을 위한 독립형 마이크로그리드의 전압제어 해석

고품질 전력공급을 위한 독립형 마이크로그리드의 전압제어 해석

Voltage Distribution Characteristic of HTS SMES Magnet

HTS superconducting magnetic energy storage (SMES) system can be utilized to ensure stable operation and high-quality power supply in power systems. In SMES system, the power conditioning system (PCS) interfaces the superconducting magnet and the ac system, controlling the active and reactive power flow. Due to high-frequency switching of the PCS, the voltage distribution on the HTS magnet will affect the magnet insulation and quench detection. Considering the interaction between the PCS and the magnet, the output characteristics of the voltage-source-type and current-source-type PCSs are analyzed. Subsequently, the transient model of magnet is deduced to analyze the voltage distribution on the HTS magnet. The voltage distribution on an HTS magnet model is analyzed with the proposed method, which is later utilized to evaluate its insulation design.

Strategic directions of personnel potential forming of a building complex

The analysis of directions of strategic approach forming of labor potential management of a building complex is carried out in this paper. On the basis of this analysis the system of actions for strategy forming divided into consecutive stages is offered. The development of the personnel forecast is a strategic planning basis. One of personnel forecast variants is the correlation of needs estimates in personnel of a building complex with available allowances. On the basis of the personnel forecast strategic analysis it is possible to compose working programs for the stated goals of implementation. Operational assessment of personnel requirements of a building complex is proved to be combined with strategic objectives. Some assessment approaches to qualitative and quantitative need for specialists of a building complex are offered. The fact that high-quality labor power supply system of a building complex with should be based on industry development forecast and increase in construction products competitiveness is revealed in the article. Strategic management priority will allow to react immediately to the current situation changes, to introduce amendments both into tactical, and operational management.

Research on Microgrid System in the DC-Building

In order to achieve the objectives of energy-saving and emission reduction for modern buildings and provide high quality power supply, a DC microgrid system of thermoelectric energy comprehensive control is proposed. The system includes two subsystems of electric energy and heat energy system, and realizes electric and heat energy transformation and combination through cogeneration unit and electronic heating device. To achieve efficient use of energy, integrated management strategies is also proposed. Distributed generations are controlled by the maximum power tracking strategy, and the hybrid energy storage system uses droop control strategy to stabilize DC bus voltage. In the connection point between the grid and microgrid, the bidirectional converter uses vector decoupling control strategy with double closed loop for pulse width modulation (PWM) to solve the problem of bidirectional power flow with the grid. The simulation results indicate that the system can provide high quality, energy saving, stable power for the modern building.

Development of a Sensor Network-Based SMPS System: A Smart LED Monitoring Application Based on Wireless Sensor Network

As the specifications of personal, industrial, and medical devices become increasingly sophisticated, the demand for high power devices is also growing rapidly. Because high power supply devices are needed in order to operate high power devices with high specifications, stability and reliability are important factors to consider when it comes to high power supply devices. Therefore, there have been calls for further research on high quality power supply and monitoring system for high power supply. This paper proposes a sensor network-based smart SMPS (switch mode power supply) system. The proposed system makes power supply stable and efficient by providing output current control and sensor network-based monitoring. The functions of the proposed system were verified through both LED control simulation and monitoring simulation. The feasibility of the proposed system was also examined through various experiments and the results were discussed.

A positive Buck-Boost voltage balancer for DC distribution system

This paper analyzes the load unbalance problem and voltage fluctuation problem in a 3-wire DC distribution system. It also analyzes a solution to these problems; a positive Buck-Boost voltage balancer is proposed and explored in order to fulfill the requirements of high quality power supply for the loads on its load side. Compared with the conventional balancer, a positive Buck-Boost converter is added to solve the voltage fluctuation problem, and the theories and methods of the voltage balancer are extended to analyze the working principle, derive the design equations, explore the stability, and calculate the efficiency. Both simulations and small power experiments are carried out to verify the validity of the working principle, the topology, and the control strategy.

Electromechanics complex of the wind power generating fluidizer the use in underground making of iron-ore mines

Today, the problem of high-quality power supply to consumers occupies one of the most prominent places in power engineering and electrical engineering. Considering the wind electromechanical complex operation, it is necessary to pay attention to the fact that the wind wheel operation is variable in nature, caused by the stochastic feature of the air flow. Operation of generator, which is a part of the wind electromechanical complex, depends directly on the wind wheel operation nature, therefore, the generator output parameters such as voltage and frequency will vary depending on the air flow speed and, consequently, generator shaft rotation speed. In view of the above features, the issue of output parameters control of wind electromechanical complex is relevant and so there is a need to solve this problem. It is proposed to solve the problem of variable output generator parameters by creating a control system based on microcontroller. Control is proposed to carry out using fuzzy sets, which will allow to take into account changes in the system, caused by the stochastic nature of air flows. Using this control system for wind electromechanical complexes will provide stable and high-quality power supply to consumers.