Independent Power Supply Research Articles

Optimum Redundancy of an Independent Power Supply System and Comparative Analysis of Its Solutions

This article discusses the issue of structural redundancy with reference to improving the reliability of independent power supply. The problem of optimum redundancy has been formulated, and its mathematical interpretation has been given. The sequence of solution steps is described. Precise and approximate methods of its solution are considered. Drawbacks of the most used methods are highlighted. A mathematical formulation of optimum redundancy is presented using the dynamic programming method as a tool for decreasing the amount of tested versions. The number of computations used in various methods is compared. The regions of application of precise and approximate solutions of optimum redundancy are defined taking into account design development phases.

Research on High Efficiency and Optimization of Compact Wind Power Generation System applying "Mahalanobis-Taguchi-System"

Abstract: While global reinforcement of countermeasures against global warming is required, Japan depends on overseas imports for over 95% of energy consumption. From the resource production site to the domestic final consumption, it is important to continuously build a stable energy supply system. With the accident at TEPCO Fukushima nuclear power plant occurred on March 11, 2011, the expectation for renewable energy is rapidly rising. Among them, the eyes to wind power generation are changing in particular. At the end of 2012, the amount of wind power generation equipment installed worldwide corresponds to 280 nuclear power plants. National Institute of Technology Tsuruoka College introduced a fully independent power supply system by wind power as a part of human resource development project for engineers. In this research, we were able to extract the task by analyzing the power generation characteristics applying Mahalanobis-Taguchi-System (MTS), diagnosing the cause and optimizing power generation efficiency.

Влияние характеристик трансформатора на качество автоматического регулирования в системах электроснабжения

The necessity of applying the basic laws and rules of the automatic control theory with respect to the processes that take place in a classical transformer is substantiated. It is noted that transformers can be referred to the class of self-tuned automatic control systems. A transformer operating on an active load is considered, and the equations describing the processes occurring in this system are presented. In solving the equations, the magnetic material main magnetization curve was used as the magnetic characteristic. The solution of the equations is based on using the magnetization curve linear part, taking into account that the magnetization depends on the core material. The equations were solved in the form of Laplace transforms, and the structural-dynamic schemes were constructed using the automatic control theory. It is shown that improvement of the magnetic circuit is a method for obtaining linearity of the transformer nonlinear characteristics, due to which its performance is improved. In terms of power supply reliability, the Russian Electrical Installations Code (PUE) distinguishes consumers of the first, second and third categories, for which the permissible time of power supply interruption and the power supply network design features are determined: the number of independent power supply sources and feed lines. In case of network operation in the post-emergency mode, the deviations of electric power quality indicators shall not exceed the maximum permissible values, the duration of which cannot be more than 5% of the operation time. The country's power supply system includes many transformers, which are located in different regions and interconnected by a unified electrical network. For general-purpose electrical networks, the permissible and maximum voltage deviations equal to ±5 and ±10%, respectively, have been established. Changes take place in the measurement limits and in the set of additional functions, such as measurement of reactive component impedances and frequency. The current and voltage measurement limits are established individually. Under field conditions, the conclusion about the compliance of electric power quality with the requirements of GOST 13109-97 can only be drawn from the results of electrical network examination during a week. Counterload control of reactive power balance is also widely used to control the network operation mode.

Preparation and optimization of miniaturized radioisotope thermoelectric generator based on concentric filament architecture

Given independent and flexible power supply requirements of space apparatus, miniaturized radioisotope thermoelectric generators are currently playing an increasing role in space power systems. This study creatively proposes a miniaturized integrated-design radioisotope thermoelectric generator based on concentric filament architecture and is the first to formulate a practical battery entity. When heat source temperature is 398.15 K, the maximum open-circuit voltage of 418.82 mV and the maximum output power of 150.95 μW are obtained. The COMSOL is used to simulate precisely the thermoelectric conversion process and optimize the structural size of the radioisotope thermoelectric generator. The optimal results are obtained when the ratio of N- to P-type circle radius and the thermoelectric filament's length are 0.1 and 20 mm, respectively. In this case, the battery obtains the maximum output power of 423.50 μW and open-circuit voltage of 605.84 mV when heat source temperature is 398.15 K. When the thermoelectric filament's curvature is 170°, the electrical density value increases more remarkably than that of 0°. Its effective open-circuit voltage density and output power density are 73.79 mV cm−3 and 53.76 μW cm−3, respectively. The optimized miniaturized radioisotope thermoelectric generator is able to provide power support for space microelectronic devices.

Interface circuit analysis of wind-induced vibration power generation with piezoelectric bimorph

Wind-induced vibration energy recovery has been widely used in wireless sensor nodes as well as portable electronic devices. Because of the high energy density, simple structure and easy system integration, it is particularly suitable for micro systems with independent power supply. A circuit equivalent model of piezoelectric bimorph was developed with the basic structure of piezoelectric energy recovery device. Standard, SECE, and SCEI interface circuit and their control process was simulated via LT-spice software. Both SECE and SCEI performed stable output power over a large load range, while the remaining three interface circuits are somewhat deficient in output power or stability. The control of SECE interface circuit is simpler than SCEI, and the SECE interface circuit is more suitable for wind-induced vibration power generation with piezoelectric bimorph.

Research on Electric Energy Router Based on Limited Capacity Independent Power Supply System

At present in the frontier outpost, Sea Island and other area, which is not covered by the power grid, there are many disadvantages in the mode of power supply. Electronic energy router can provide multiple types of electric interfaces for new energy power generation device, storage device and load, and achieve energy bidirectional flow, at the same time, the AC and DC bus interface can be provided through the power electronic transformation technology. Take advantage of these features, an electric energy router based on a limited capacity independent power supply system is proposed. And the specific system structure and network structure are designed.

Development of technology for a long-term monitoring and automatic data acquisition system

The Central Research Institute of Electric Power Industry conducted research to develop a long-term monitoring technology to clarify pore water pressure and water chemistry in drilled boreholes. An automatic data acquisition system for the long-term monitoring was also developed. The automatic data acquisition system has an independent electric power supply and data communication system. The electric power is supplied from solar and wind power. The data communication is secured through a satellite or 3G/4G line. A very low power consumption system can be readily installed by creating personal area networks between measuring devices using Zigbee digital radio. A demonstration of the system was conducted under harsh natural conditions for 18 months. It was confirmed that the system has sufficient reliability for actual operation.

Demand Analysis of Wireless Sensor Networks for New Energy Micro-grid

Wireless sensor networks are self-organizing networks composed of a large number of energy-limited sensor nodes. Due to the factors such as distributed power, energy storage equipment, power load density, operation mode and geo-environment in the microgrid region of the new energy grid, each device in the new energy microgrid has multiple regions and diversified forms, So it is difficult to carry out a unified real-time monitoring. Therefore, this paper designs to integrate the detailed operation status of the independent new energy power supply network into the existing station monitoring system through the wireless sensor network to implement unified energy management. According to the real-time acquisition, immediately to take appropriate measures to greatly improve work efficiency.

Sources of independent power supply for protection relay

Sources of independent power supply for protection relay

Study into energy efficiency of the drive of electric vehicles with an independent power supply depending on the configuration of the power source

The electric vehicle with an independent power supply is the object of this research. At present, such vehicles are becoming more popular in the automobile market, pushing out their rivals with internal combustion engines, owing to their superior energy efficiency. The advantage over the internal combustion engine vehicles being obvious, the efficiency of electric vehicles is still considerably low in comparison to other electric devices. The problem that causes these limitations lies in the power supply – li-ion accumulator – which has high impedance.In order to solve this disadvantage, the system with an ultracapacitor battery connected in parallel to the accumulator was considered using an example of the electric scooter drive with a squirrel-caged induction motor. Ultracapacitors have significantly lesser impedance than accumulators, thus they carry with themselves most of instant load during acceleration and braking when a power source supplies the highest currents.Our study has shown that this configuration improves energy efficiency of the electric vehicles. Moreover, there is an optimal amount of ultracapacitor capacitance for achieving the best efficiency (the lowest energy consumption). This follows from the fact that an ultracapacitor battery is a rather heavy object; a significant increase in its capacitance leads to the increased vehicle weight and thus enhances energy consumption. An additional modernized system of supply was considered at which ultracapacitor’s charging is accelerated during vehicle stops. Such a system has made it possible to improve the results and decrease energy consumption even larger.Compared to previous studies, this research demonstrates the importance of correct choice of ultracapacitor capacitance and supply distribution system. The existence of the optimum point has been proven; the difference of energy consumption at this point has been demonstrated in numbers.

Ways to ensure uninterrupted power supply to consumers having a bus system 6-10 kV and two independent power supply of 6-10 kV

Ways to ensure uninterrupted power supply to consumers having a bus system 6-10 kV and two independent power supply of 6-10 kV

Control method of Three-phase Four-leg converter based on repetitive control

The research chose the magnetic levitation force of wind power generation system as the object. In order to improve the power quality problem caused by unbalanced load in power supply system, we combined the characteristics and repetitive control principle of magnetic levitation wind power generation system, and then an independent control strategy for three-phase four-leg converter was proposed. In this paper, based on the symmetric component method, the second order generalized integrator was used to generate the positive and negative sequence of signals, and the decoupling control was carried out under the synchronous rotating reference frame, in which the positive and negative sequence voltage is PI double closed loop, and a PI regulator with repetitive control was introduced to eliminate the static error regarding the fundamental frequency fluctuation characteristic of zero sequence component. The simulation results based on Matlab/Simulink show that the proposed control project can effectively suppress the disturbance caused by unbalanced loads and maintain the load voltage balance. The project is easy to be achieved and remarkably improves the quality of the independent power supply system.

RESEARCH OF THE ELECTRIC SCOOTER DRIVE ENERGY TRANSFORMATION EFFICIENCY DEPENDING ON POWER SUPPLY AND LOAD

In modern world society there is a tendency to decrease natural resources consumption. This leads to switch-over from the internal combustion engine vehicles to the electric vehicles. However, the electric drive system of the latter is not perfect as well, particularly due to high impedance of the independent power supply. So the efficiency of this system can be improved with the connection of supercapacitors in-parallel to the accumulator. This research, provided with the help of a computer model of the elec-tric drive, was made to analyze the effectiveness of utilizing supercapacitors in electric vehicles with independent power supply by testing the computer model on steady-state working modes as well as on the urban driving cycle. The obtained numeric result has shown the increasing of the electric drive efficiency caused by the including a supercapacitor to the drive power supply.

STUDY OF THE ENERGY POTENTIAL OF RENEWABLE ENERGY SOURCES IN THE REGION OF GABROVO FOR USE IN HYBRID WIND-PHOTOVOLTAIC STAND-ALONE SYSTEM

This paper presents the measurements conducted for two periods (winter and summer) in the region of Gabrovo, Bulgaria for solar radiation and wind conditions using the digital measuring equipment. The aim is to evaluate and predict the possible production of electricity from already installed low power hybrid system. The conclusion is that a combination of a wind generator and a photovoltaic system in the hybrid system for independent power supply has a good economic effect and allows fuller use of energy from renewable sources.

Research on Application of Automatic Weather Station Based on Internet of Things

In this paper, the Internet of Things is briefly introduced, and then its application in the weather station is studied. A method of data acquisition and transmission based on NB-iot communication mode is proposed, Introduction of Internet of things technology, Sensor digital and independent power supply as the technical basis, In the construction of Automatic To realize the intelligent interconnection of the automatic weather station, and then to form an automatic weather station based on the Internet of things. A network structure of automatic weather station based on Internet of things technology is constructed to realize the independent operation of intelligent sensors and wireless data transmission. Research on networking data collection and dissemination of meteorological data, through the data platform for data analysis, the preliminary work of meteorological information publishing standards, networking of meteorological information receiving terminal provides the data interface, to the wisdom of the city, the wisdom of the purpose of the meteorological service.

Independent power supply operating control to minimize diesel fuel usage

Independent power supply operating control to minimize diesel fuel usage

水素吸蔵合金と空気熱交換式容器を用いた住宅・自立電源用水素貯蔵システムに関する研究 : 第2報-水素吸放出特性に与える高平衡圧合金とフィン付・小径容器の効果

水素吸蔵合金と空気熱交換式容器を用いた住宅・自立電源用水素貯蔵システムに関する研究 : 第2報-水素吸放出特性に与える高平衡圧合金とフィン付・小径容器の効果

(Invited) Template Assisted Electrochemical Deposition and High Power Factor Materials for Integrated Thermoelectric Devices

Next generation integrated micro-scale thermoelectric devices are envisioned for spot cooling of active electronic parts or as independent power supply units to exploit small hot spots within electronic circuits. In the first case, a thermoelectric cooler is added to manage the temperature stability of sensitive electronic or photonic devices, hence to remove high density heat fluxes from these critical parts. In the second case, a thermoelectric generator is intended to recover a proportion of waste heat of a hot spot, i.e. a small, but otherwise unlimited heat source, in the electronic circuits. Both cases are technologically challenging since they request for a fabrication route that is compatible with a CMOS back-end processing. But especially the latter application provides also novel requirements to the thermoelectric material. The typical paradigm of thermoelectric material's development aims towards low thermal conductivity. This is not necessarily helpful for the given example of application where the heat has to be efficiently removed from the active electronic part, utilizing a proportion of this heat for thermoelectric power generation. Hence, this paradigm has to shift towards the development of high power factor materials, rather than low thermal conductivity materials. A processing that, at least in principle, can be fully compatible with CMOS back-end technology is given by the combination of lithographic structuring and the electrochemical deposition of the functional thick films into pre-structured cavities. A material class that provides both, high power factors and sufficiently high thermal conductivity for the removal of waste heat, is given by metallic alloys. This paper will therefore provide experimental details of the processing technology of integrated micro-scale thermoelectric devices and a discussion of high power factor materials for thermoelectric devices.

Note: Self-biased voltage to suppress secondary electrons by a ZnO varistor in a compact pulsed neutron generator.

A large amount of back streaming electrons will bring about a part of current drain on power supply, cause sparking or high-voltage breakdowns, and affect the neutron yield and waveform for a compact sealed-tube pulsed neutron generator. A novel idea which uses a ZnO varistor to provide a constant self-biased voltage to suppress the secondary electrons is introduced. The I-V curve for the ZnO varistor was measured in the experiment. The effects of suppressing the secondary electrons were investigated using a ZnO varistor, linear resistors, and an independent power supply, respectively. The results show that the secondary electrons are suppressed effectively by the compact ZnO varistor, while not increasing the size and the component of the device. It is a promising design for compact sealed-tube neutron generators.

Some problems related to using automatic control of voltage of synchronous generators in case of frequency change

Considered is the possibility of using a proportional type automatic excitation regulation implemented in the form of compounding devices with an electromagnetic voltage corrector changing excitation depending on the frequency and voltage at the generator terminals in particular power supply systems. It is demonstrated that the suggested solution is more efficient compared to automatic excitation regulators having no frequency control. Graphs are provided showing changes in consumption of active and reactive power by an equivalent load characteristic of industrial customers, depending on frequency, and depending on voltage. Analysis of the evaluation results shows that implementation of the proposed solution reduces the active power imbalance from 6.5% to 3.5% (with a 10% frequency decrease). Proportional type automatic excitation controls with frequency control may find application in in-house power supplies of companies with a continuous operation process, where high quality of power supply is achieved by using a second independent power supply generated on a standalone basis, with no connection to the power grid. As the record of operation of such enterprises shows, the effectiveness of such a solution is quite high due to minimization of damage from voltage dips that occur in the external power supply system due to damage and abnormal conditions in 110 and 220 kV networks. As recommendations, features are assessed of the proposed automatic excitation regulator with frequency control in an embodiment providing for generators of the companies’ own power supplies operating in parallel with the external power grid, as well as in cases of some disruptions of static stability.