Additional Power Source Research Articles

Limits of reactive power compensation of a doubly fed induction generator based wind turbine system

The doubly fed induction generator (DFIG) systems feature a significant amount of free power capacity that may be used for reactive power adjustment when they are put into practical use. This change, which is occasionally overlooked, is a significant one. Using DFIG systems for wind turbines (WT), this paper explored strategies for reducing and using reactive power. In order to investigate the power characteristic and how it is regulated in DFIG systems, a mathematical model for the steady-state performance of DFIG WT has been developed and presented. Here is a detailed derivation of the limiting range of DFIG's reactive power capacity as well as the physical constraints on reactive power output. The distribution of the DFIG WT at a distribution network's end is demonstrated by a simulation example. Within this simulation, reactive power management strategy, load fluctuation, and the change in wind speed are all taken into consideration. Due to the possibility of a rise in the voltage at the access point, can concluded that both acceptable and efficient to use DFIG WT's reactive power capabilities as an additional continuous reactive power source for effectiveness.

The Iron Yield of Core-collapse Supernovae

We present a systematic analysis of 191 stripped-envelope supernovae (SE SNe), aimed at computing their 56Ni masses from the luminosity in their radioactive tails () and/or in their maximum light, and the mean 56Ni and iron yields of SE SNe and core-collapse SNe. Our sample consists of SNe IIb, Ib, and Ic from the literature and from the Zwicky Transient Facility Bright Transient Survey. To calculate luminosities from optical photometry, we compute bolometric corrections using 49 SE SNe with optical and near-IR photometry, and develop corrections to account for the unobserved UV and IR flux. We find that the equation of Khatami & Kasen for radioactive 56Ni-powered transients with a single free parameter does not fit the observed peak time–luminosity relation of SE SNe. Instead, we find a correlation between , peak time, peak luminosity, and decline rate, which allows for measuring individual 56Ni masses to a precision of 14%. Applying this method to the whole sample, we find, for SNe IIb, Ib, and Ic, mean 56Ni masses of 0.066 ± 0.006, 0.082 ± 0.009, and 0.132 ± 0.011 M ⊙, respectively. After accounting for their relative rates, for SE SNe as a whole, we compute mean 56Ni and iron yields of 0.090 ± 0.005 and 0.097 ± 0.007 M ⊙, respectively. Combining these results with the recent Type II SN mean 56Ni mass derived by Rodríguez et al., core-collapse SNe, as a whole, have mean 56Ni and iron yields of 0.055 ± 0.006 and 0.058 ± 0.007 M ⊙, respectively. We also find that radioactive 56Ni-powered models typically underestimate the peak luminosity of SE SNe by 60%–70%, suggesting the presence of an additional power source contributing to the luminosity at peak.

ANALYSIS OF INFILTRATION WATER INTAKES PRODUCTIVITY

Purpose. Construction of new and reconstruction of existing water supply systems, in order to increase water consumption, provides for the search and analysis of water supply new sources and water intake facilities. This issue acquires particular importance when looking for additional power sources for water supply systems with relatively low water consumption. To reduce the load on wastewater treatment plants that process water from open sources, infiltration intakes are used, which take water from underground aquifers. Infiltration water intakes can be vertical and consist of wells united by prefabricated pipelines or horizontal and have an underground horizontal water intake part − a drainage pipe. Therefore, the problem arises of determining the water intake that has the highest productivity under the same local conditions. Methodology. The productivity of water intakes is characterized by the influence of determining factors on the flow rate of water intakes with one-way feeding in a free-flow aquifer. The conditions of the location of the intake parts of the intakes in the aquifer and their sizes were considered as factors of influence. Results. The analysis of the existing methods for determining the productivity of underground infiltration water intake structures, depending on their location, the influence of water supply sources and design features. It has been determined that the greatest impact on the productivity of water intakes is the amount of water level decrease in the aquifer during water withdrawal, that is, the position of the dynamic water level relative to the static one. Also, the distance from the intake structure to the water's edge has a significant impact. Reducing the distance between the wells and the length of the drainage pipe, within the limits of the study conditions, has no effect on the results. As a result of the research, it has been established that, under the adopted hydrogeological and technical conditions, horizontal underground water intakes are distinguished by a large flow rate. Scientific novelty. The analysis of factors influencing the choice of infiltration water intake structures is carried out. The results of determining the productivity of structures under the same initial conditions are shown. Practical value. Using the results of the analysis allows you to most quickly and effectively solve the issues of choosing the option for powering water supply systems. The analysis has identified the most significant factors influencing the productivity of water intakes and makes it possible to vary them to achieve a result.

Model Design of Helical Type Vertical Shaft Wind Turbine with Capacity of 5 W

A vertical axis wind turbine (VAWT) is a power generator that uses wind power to generate torque. The VAWT can be pointed in any direction, meaning it doesn't need to be pointed into the wind to generate power. Thus, there is potential for large power plants using VAWTs as their size can be significantly increased. However, there are also some drawbacks to the VAWT. VAWT has the characteristics of self-starting. But still, an additional power source is needed to start the turbine rotation until a certain rotation speed is reached or it must operate at high wind speeds. The main objective of our work is to create a 5 W VAWT model (helical type) to optimize self-starting of vertical axis wind turbines. The outline of this report is regarding the design of our VAWT model, which will have self-starting characteristics. To increase the self-starting status, our efforts are to optimize the type, dimensions and material of the turbine blades. We also optimized the rotor dimensions. As a result, a model helical three-blade turbine was built and tested. The blade turbine made of composites has been balanced with the rotor prior to testing. The test uses 2 fans with a speed of 3-5m/s, the test is carried out to obtain wind turbine performance data.

Reactive power potential of converter-connected renewables using convex power flow optimization

Converter-connected renewable energy sources (RES) in the distribution network alter the power flow in the network. Often, grid reinforcements and additional local reactive power sources are needed to maintain steady state network operation. Converter-connected RES is an accessible local reactive power source for distribution system operators to optimize network operations. However, the non-linearity and non-convexity in the converter equations make their modelling challenging, which further results in the under-utilization of the reactive power capability from these sources. Oftentimes, the converter-connected generator is partially modelled using only apparent power constraints. This paper presents an approach based on Schur’s complement and piecewise planar approximation to incorporate the converter equations in a convex power flow optimization routine. The advantages of employing complete converter capabilities for optimal operation of the distribution network are studied via simulations on a real distribution network dataset. A comparison between deploying reactive power according to the minimum grid codes requirement, partial modelling of the converter, and complete converter capabilities is correspondingly presented. Active power losses decrease by 4.1% over 10 month period with high penetration of renewable generation. Furthermore, the voltage profile in the distribution network is improved and the reactive power dependency on the transmission network is reduced.

Self-powered health monitoring with ultrafast response and recovery enabled by nanostructured silicon moisture-electric generator

Humidity sensors have been widely applied in health management, including respiration monitoring and non-contact sensing for human–machine interaction. Nevertheless, most existing monitoring systems hinging on moisture-sensitive materials require an additional external power source. In addition, the inferior sensitivity and long response/recovery time of the sensors still hinder their desirable healthcare applications. Here, we developed a self-powered humidity sensor built on the moisture-directly triggered electricity generation (MEG) effect, where silicon nanowire arrays (SiNWs) function as the sensing element, exhibiting an ultrafast response to humidity changes with high-level sensitivity. Humidity gradients induce charge directional transport in SiNWs nanochannels, directly actuating electricity signals generation without any additional power units for sensing. The enlarged surface area, oriented nanochannel structure, and superior electrical conductivity of SiNWs facilitate a robust dependence of the output voltage on humidity, enabling the sensor with quick response/recovery (∼0.10 s/∼0.17 s), ultra-high sensitivity, and broad detection range (3.94 mV/1% for 50–95% RH/1.13 mV/1% for 0–50% RH). Furthermore, we designed a smart respiratory monitoring system that can extract various respiration patterns and distinguish different language commands. We also constructed a non-contact human–machine interface leveraging the SiNWs sensor that can effectively disrupt virus propagation and bacterial infection. The elaborate self-powered humidity sensor proposed in our work could as well potentially be exploited for establishing wearable and integrated health monitoring platforms in the future.

THE DIFFERENT APPROACHES TO THE TRANSFORMATION OF REACTIVE POWER INTO AN ACTIVE POWER

The relevance of the development of modern problems of the electric power industry in connection with the depletion of the planet’s natural resources is undeniable and initiates the development of new physical and technical solutions with the practical use of known natural phenomena. The method of this work is to propose, justifying the expediency of a possible scheme of a resonant converter of reactive power into activity and conducting an analysis of the electromagnetic processes occurring in them. The proposed schemes combine the presence of resonant parallel and resonant circuit complexes. The difference is in the way they are implemented. For the data of the joint circuit, the feature is the presence of two inductively coupled active-reactive circuits, but different in the ways of creating resonance conditions. For a circuit without an additional power source, it is shown that the successful implementation of resonance conditions is possible by choosing the appropriate element base. For a circuit with an additional source of harmonic voltage, it is shown that for a suitable setting it is possible to completely eliminate the negative influence of the converter circuit on the source of reactive power. Calculations for the experimental model show that with the appropriate selection of the element base, it is possible to obtain a conversion factor of ~ 1.0 with a minimal effect on the current in reactive power sources. Given the calculated ratios, the mathematical apparatus of the theory of electric circuits was used to substantiate the principle possibility of resonant transformation of electrical energy. Thus, methods of calculating the characteristics of transient processes in closed circuits with active-reactive elements. For the first time, with the justification of practical power, we offer the possibilities of the scheme of resonant transformation of reactive power into active power, and an analysis of the electromagnetic processes occurring in them is carried out. The proposed work was initiated by the current needs of the electric power industry, caused by the depletion of natural resources and the rapidly growing needs of the world economy. The results of the work illustrate the practical possibilities of creating real schemes for converting reactive electricity into active electricity.

An economical hybrid DC circuit breaker with pre-current-limiting capability

Multi-terminal flexible high-voltage-direct-current (HVDC) transmission and DC grid technology are developing rapidly, and the hybrid DC circuit breaker (DCCB) is usually used to protect the DC system, which can quickly remove the fault current and make sure the safe and stable work of system. However, the existing hybrid DCCBs have restrictions regarding one or more of the following characteristics: economy, fast adaptive reclosing, low on-state losses, and no additional pre-charge power source. This paper presents an economical hybrid DCCB with pre-current-limiting capability (EP-HCB), in which the main branch only is made up of mechanical switch (MS) and the fault handling branch consists of fault current transfer circuit, current limiting circuit and breaking circuit. And the proposed EP-HCB itself has inherent pre-charging and adaptive reclosing capabilities and low on-state losses, which efficiently limit the magnitude and rise rate of fault current and thus weaken the opening requirements on the DCCB. Detailed topology structure of the EP-HCB is presented, and the work principle of the fault current commutation and limiting are analyzed. Then, a design method for parameters of the proposed EP-HCB is provided. Finally, based on the 4-terminal simulation system in PSCAD/EMTDC, the feasibility and economy of the EP-HCB are proved by comparison with ABB hybrid DCCB.

Post-emergency reconfiguration of a distribution network as a method for restoring power supply to consumers

The work is aimed at solving the problem of using reconfiguration and additional reactive power sources to restore power to consumers of the medium-voltage distribution network in the case of emergency disconnections of connections by bus section circuit breakers. The reconfiguration problem for a 118-node test distribution network is solved using a high-speed algorithm involving the construction of a maximum spanning tree on a network graph as the basis for determining information about the composition of branches and chords of independent circuits necessary to restore power following disconnection. To ensure acceptable voltage levels following power restoration, additional reactive power sources determined using singular Jacobian matrix analysis methods are installed in the sensor nodes of the network. For the test circuit, the modes for single disconnections of individual sectional switches, including in dead-end sections, are analysed. By optimally reconfiguring the network in the normal mode, it is possible to reduce voltage deviations from 13% to 7%. For the modes caused by disconnections of individual bus section circuit breakers that lead to unacceptable voltage deviations, the set-down locations and reactive power of additional sources are selected. In the most severe of the considered disconnection scenarios, the installation of additional sources provided a reduction in voltage deviations from 18 to 8%. Thus, the methods proposed by the authors make it possible to restore the test network mode following emergency disconnections and ensure that the voltages in the network nodes are maintained within acceptable limits, both in normal and in post-emergency modes.

Review of the potentials for implementation of floating solar panels on lakes and water reservoirs

Many places are dealing with the problem of water scarcity, especially in the summer months. This occurs mostly in the dry areas with hot climates that are exposed to intensive solar insolation which are the main driver for the evaporation of water. Some companies that are in charge of water service, and are operating open water reservoirs, have developed a solution to cover the water with floating balls to limit the solar insolation and to mitigate the evaporation of water. Another good approach is using floating solar panels for the same cause, which will provide an additional power source. It can enhance the productivity of hydropower plants with reservoirs. An additional benefit of the solution is the amount of the available water surfaces for placing the solar panels, instead of potentially useful areas for other purposes (agriculture, buildings …). This paper reviews the current development of the technology, potentials, and best practices. It shows that this technology is feasible and can compete with other power sources, considering the cheapest LCOE being 46 USD/MWh for a 50 MW power plant in Uttar Pradesh, India.

Optimal selection of single tuned passive filters to enhance post‐fault voltage recovery and power quality in a renewable integrated microgrid

AbstractThe harmonic currents produced by nonlinear loads and renewable energy sources (RES) like PV and wind energy have had a growing impact on industrial distribution networks in recent times. Along with harmonic distortions, lack of adequate reactive power support in a heavily loaded renewable‐rich industrial network has made the operation vulnerable to fault‐induced delayed voltage recovery (FIDVR). Due to poor post‐fault voltage recovery, an industrial microgrid is exposed to cascading loss of distributed generators (DGs). Dynamic var sources are being used to prevent cascade tripping. However, they may result in deterioration of the network's THD scenarios. Single tuned passive filters are widely used to suppress harmonic contents. The goal of this work is to design filters so that these become capable to lower overall harmonic distortion while also minimizing the risk of blackouts caused by inadequate post‐fault voltage recovery. To determine the allocation and rating of single tuned passive filters in a renewable‐penetrated industrial microgrid, an optimization model is developed. To show the feasibility and efficacy of the proposed formulation, simulations are performed on a modified IEEE 43 bus system. The findings suggest that the proposed design methodology produces effective solutions to minimize the necessity of additional reactive power sources.

Innovative design and optimized performance of thermoelectric transistor driven by the Seebeck effect

The combination of thermoelectricity and the transistor technology is a promising choice to obtain the high performance of thermoelectric (TE) materials and devices. In this context, the performance optimization always depends on the modulation of the external voltage. TE materials can produce their own voltages by the Seebeck effect, making them possible to form the transistor circuit without additional power sources. Here, the generic operation condition of TE transistor is demonstrated theoretically, considering temperature dependence in Bi2Te3-based materials. Further, the transistor is constructed as a TE generator. And a Direct-Current (DC) equivalent circuit method is introduced to analyze the performance of TE transistor. The method produces an optimized design to attain maximum output power and conversion efficiency. Calculation results show that the maximum output power is 17.8mW and the conversion efficiency is 8.69% at room temperature when the temperature difference is 50 K.

Multifunctional Portable System Based on Digital Images for In-Situ Detecting of Environmental and Food Samples

The development of a portable device created by 3D printing for colorimetric and fluorometric measurements is an efficient tool for analytical applications in situ or in the laboratory presenting a wide field of applications in the environmental and food field. This device uses a light-emitting diode (LED) as radiation source and a webcam as a detector. Digital images obtained by the interaction between the radiation source and the sample were analyzed using a programming language developed in Matlab (Mathworks Inc., Natick, MA, USA), which builds the calibration curves in real-time using the RGB colour model. In addition, the entire system is connected to a notebook which serves as an LED and detector power supply without the need for any additional power source. The proposed device was used for the determination in situ of norfloxacin, allura red, and quinine in water and beverages samples, respectively. For the validation of the developed system, the results obtained were compared with a conventional spectrophotometer and spectrofluorometer respectively with a t-test at a 95% confidence level, which provides satisfactory precision and accuracy values.

Mathematical Modeling and Validation of Saturating and Clampable Cascaded Magnetics for Magnetic Energy Harvesting

Electromagnetic energy harvesting extracts energy from magnetic fields and can provide power to sensors, monitoring nodes, cyber-physical systems and control elements without additional battery and external power source and wiring. This article presents a novel ac-driven electromagnetic energy harvester based on periodically saturating, cascaded magnetics, consisting of a clampable magnetic core and an ungapped high permeability core. The high permeability core guarantees the maximum energy extraction, whereas the clampable core enables the nonintrusive installation of the energy harvester for more pervasive applications. This article first builds a comprehensive mathematical model based on this saturating cascaded magnetic structure, considering the reachability of an individual saturation flux density of the two magnetic cores. This model resolves the new challenges introduced by the cascaded magnetics with respect to a traditional single-core case, providing the accurate calculation of the lengths of the relevant time windows for harvesting and the amount of the harvested power. Our mathematical model is verified against simulation and experiment, showing excellent agreement among them with the maximum discrepancy of less than 6%. This article also reveals that the maximum power extraction occurs when the ungapped core operates in its slightly saturated state and that the harvested power increases with a higher primary current as well as a higher line frequency.

Autonomous Resonant Frequency Tuner for a 6.78MHz Inductive Coupling Wireless Power Transfer System to Stably Maximize Repeater Current

Recently, the resonant inductive coupling wireless power transfer (RIC-WPT) technique is being widely used to charge small IoT devices dispersed in a wide area, e. g., an office desk and warehouse rack. In this application, the repeater is utilized to expand the chargeable area without an additional AC power source. The repeater comprises a LC resonator commonly with a high-quality factor to induce large current in the repeater coil. However, this causes the problem that the repeater performance is highly susceptible to the variation in its resonant frequency due to the manufacturing tolerance of coil inductance and resonant capacitance as well as the variation of the magnetic coupling between the transmitter and repeater coils. To solve this problem, a previous study has proposed a concept of the autonomous resonant frequency tuning circuit to stably maximize repeater coil current, although this study implemented a part of this control system as a practical circuit. This paper aims to develop a complete autonomous resonant frequency tuning circuit that implements the aforementioned concept. The proposed circuit adjusts the resonant frequencies of the transmitter and repeater by utilizing the Automatic Tuning Assist Circuits. These frequencies are optimized using the infrared wireless signal communication from the transmitter to the repeater. Along with the operating principle of the proposed circuit, this study presents detailed circuit design as well as the experimental results, which verified the stable autonomous maximization of the repeater coil current against the variation in the resonant frequency of the repeater resonator.

Cost Effectiveness of the Zero-Net Energy Passive House

Abstract The authors main idea is to build energy plus buildings by means of architectural processes to design passive houses according to the Darmstadt Standard with additional equipment powered by renewable energy. The article presents a comparative financial analysis of passive house buildings with an additional source of power to charge electric cars in Poland and the United States. The analysis is based on market data while also taking into consideration inflation and increases in energy costs. The methodology is based on the calculations required by USA banks for obtaining credit. The emphasis is also on the distinction between commonly used term passive house and the term passive house in accordance with the Darmstadt Standard. The authors are introducing a new terminology to define buildings wrongly named as “passive”. Now Authors will name them Pseudo-Passive Buildings. The research shows that it is profitable to construct nearly zero-energy buildings with photovoltaic installation and the discounted rate on return of investment does not exceed the mortgage length.

Analysis of the Influence of Nodal Reactive Powers on Voltages in a Power System

The paper deals with finding power system nodes where reactive powers have the greatest influence on system voltages. The problem to be solved is important in reactive power planning. Its proper solution indicates in which nodes new sources of reactive power should be installed in order to achieve the assumed goals in the aforementioned planning. So far, the problem formulated earlier has not been satisfactorily resolved. The paper presents an original method, which, based on the entire history of the system operation states, allows a solution to the problem mentioned above to be found. The proposed method assumes the use of measurement data of nodal-voltage magnitudes and nodal reactive power. Correlational relationships between the above-mentioned quantities are investigated. The paper shows that the considered correlational relationships are not linear. In this situation, Kendall’s rank correlation coefficient is used to evaluate the strength of these correlational relationships. Analysis of the strongest relationships allows us to identify those nodal reactive powers that have the greatest influence on the voltages in the power system. The results of the analysis are the basis for determining the location of additional reactive power sources in the power system, which is very essential in reactive power planning. The proposed method is relatively easy to implement and does not require complicated calculations. The paper additionally shows that failure to use the entire spectrum of representative system states when solving the problem under consideration can adversely affect the result.

Offshore wind farms as additional coolant power sources to enhance seismic resilience of nuclear power plants– A case study

Continuous supply of cooling power is a critical aspect in operations of Nuclear Power Plants (NPPs) as evidenced in the major nuclear disasters. Design engineers follow rigorous standard guidelines in planning several levels of safety for power sources in NPPs. However, any unprecedented man-made or natural events may lead to the loss of coolant requirements. This study proposed a seismic resilient strategy using sustainable wind power through which the robustness of cooling power for NPPs during seismic events can be enhanced. Proposed strategy involves various steps starting from estimation of coolant power requirements for nuclear reactors, design of offshore wind turbine (OWT) and supporting system, and seismic safety assessment of proposed OWT for scenario levels at the site of interest. An existing NPP in India (Madras Atomic Power Station-MAPS, Chennai) is chosen as the case study for demonstrating the applicability of proposed strategy. Seismic analysis of proposed OWT is performed incorporating the state-of-the-art understanding on existing seismic scenario, geological and loading conditions, nonlinear seismic soil structure interaction (SSSI), and liquefaction susceptibility. Based on the analysis, it is concluded that the proposed offshore wind farm is seismically resilient for the anticipated scenario at the site and could cater the coolant requirements of MAPS. The current study can advance the research on integration of sustainable and resilient energy sources to increase the reliability of NPPs located in seismic prone regions.

A Method of Vibration Measurement with the Triboelectric Sensor during Geo-Energy Drilling

In the process of geo-energy drilling, the real-time vibration measurement of drill pipes is of significance for an understanding of the downhole conditions and the properties of rock. However, the vibration sensors used in downhole areas at present require additional power sources, such as batteries, and replacing the batteries would significantly reduce production efficiency and increase costs. In our work, a new vibration measurement method using a triboelectric nanogenerator is proposed which will synchronously achieve axial and lateral vibration, and also simultaneously be self-powered. The triboelectric nanogenerator is mainly made of nanomaterials, such as polyimide film and polytetrafluoroethylene (PTFE), and depends on the pulse signal generated by the contact of the two friction layers to measure the vibration frequency. Axial vibration tests show that the output voltage signal amplitude is approximately 3 V, the measurement range is from 0 to 9 Hz, the measurement error is less than 4%, and the maximum output power is 5.63 uW. Additionally, the lateral vibration tests show that the output voltage signal amplitude is approximately 2.5 V, the measurement range is from 0 to 6.8 Hz, the measurement error is less than 6%, and the maximum output power is 4.01 uW. The nanogenerator can typically work in an environment where the temperature is less than 145 °C and the relative humidity is less than 90%.

IASF-2022 results

On 18–19 October 2022, the annual International Automobile Scientific Forum (IASF-2022) “Sustainable Development of Russian Automotive Industry under Present-Day Conditions” took place. The event format assumed both offline and online participation. The issues of providing technological sovereignty of the Russian automotive industry and development of domestic component base, technical and technological developments in the field of innovative land vehicles and systems were discussed during the Forum. Within the Forum, an exhibition of technical achievements of FSUE “NAMI” and manufacturers of automotive vehicles and components was held dedicated to the domestic innovative solutions in terms of vehicle decarbonization, highly automated intelligent vehicles and intelligent control systems. Components of electric, hybrid and intelligent vehicles, electronic control units, assemblies and aggregates of powertrains, electric traction vehicles and hybrid vehicles with additional power sources were also presented. The competition was held in two categories: “Best Student Scientific Paper” and “Best Graduate Student and Young Specialist Scientific Paper”. 18 applications were fi led for the competition from the educational, scientific and production companies and organizations.