High Generation Power Research Articles

Rolling planning model for high proportion renewable energy generation power system considering frequency security constraints

In this paper, a rolling planning model for high proportion renewable energy generation power systems is proposed, considering frequency security constraints, to address the frequency stability challenges posed by increased integration of wind and solar energy into the power grid under the “double carbon” goal. First, this study establishes a frequency response model for a thermal generation unit (TGU) and analyzes the impact of the high proportion of renewable energy on system frequency stability. Subsequently, a dynamic frequency security constraint is formulated, which can be used in generation planning to address the frequency issues. Second, a bi-level rolling planning model for high proportion renewable energy generation power systems considering dynamic frequency security constraints is established. The upper level focuses on investment decisions. The lower level incorporates frequency security constraints into the operational simulation to guarantee the frequency stability of the power system when making decisions on the size of newly built TGUs annually. Finally, case studies are conducted to demonstrate the validity and effectiveness of the proposed rolling planning model.

Operational Data Analysis of a Battery Energy Storage System to Support Wind Energy Generation

The insertion of renewable sources to diversify the energy matrix is one of the alternatives for the energy transition. In this sense, Brazil is one of the largest producers of renewable energy in the world, mainly in wind generation. However, the impact of integrating intermittent sources into the system depends on their penetration level, causing problems in the electrical network. To evaluate this scenario, the present article aims to investigate the power quality problems generated by wind turbines in connection with the electrical system and how battery energy storage systems (BESS) solve or mitigate these disturbances in the network. Knowing the impacts of high generation power variability, the focus of the work is the application of power smoothing. However, results are presented for five applications (factor correction, voltage control, power factor smoothing, frequency control and time shift) that can be carried out at the studied wind farm. This article presents a real BESS, which has a capacity of 1 MW/1.29 MWh, connected in parallel to a group of wind turbines that provides a power of approximately 50.4 MW located in Brazil. In addition to presenting the system simulation in HOMER Pro software, this study validates the effectiveness of this BESS by presenting real operation data for each application.

A Numerical Study on the Performance Evaluation of a Semi-Type Floating Offshore Wind Turbine System According to the Direction of the Incoming Waves

In this study, the performance evaluation of a semi-type floating offshore wind turbine system according to the direction of the incoming waves is investigated. The target model in this this study is a DTU 10 MW reference wind turbine and a LIFES50+ OO-Star Wind Floater Semi 10 MW, which is the semisubmersible platform. Numerical simulation is performed using FAST developed by National Renewable Energy Laboratory (NREL), which is an aero-hydro-servo-elastic fully coupled simulation tool. The analysis condition used in this study is the misalignment condition, which is the wind direction fixed at 0 degree and the wave direction changed at 15 degrees intervals. In this study, two main contents could be confirmed. First, it is confirmed that sway, roll, and yaw motions occur even though the direction of the incoming waves is 0 degree. The cause of the platform’s motion such as sway, roll and yaw is the turbulent wind and gyroscope phenomenon. In addition, the optimal value for the nacelle–yaw angle that maximizes the rotor power and minimizes the tower load is confirmed by solving the multiobjective optimization problem. These results show the conclusion that setting the initial nacelle–yaw angle can reduce the tower load and get a higher generator power. Second, it is confirmed that the platform’s motion and loads may be underestimated depending on the interval angle of incidence of the wind and waves. In particular, through the load diagram results, it is confirmed that most of the results are asymmetric, and the blade and tower loads are especially spiky. Through these results, the importance of examining the interval angle of incidence of the wind and waves is confirmed. Unlike previous studies, this will be a more considerable issue as turbines become larger and platforms become more complex.

Cooling systems of ship equipment of control computer systems high heat generation power

Cooling systems of ship equipment of control computer systems high heat generation power

Development of hybrid cooling method with PCM and Al2O3 nanofluid in aluminium minichannels using heat source model of Li-ion batteries

Lithium ion batteries are considered as the main energy storage option. High temperatures cause capacity fading and can even produce fire. It is, therefore, essential to design an effective thermal management system (TMS) to keep battery temperature in the safe range. In this study, thermal response of lithium ion batteries is investigated in high discharge rates with a new TMS combining active and passive methods. Refined paraffin in blockform (P 42–44 #107150) combined with porous copper metal foam was considered as the passive part and aluminium mini-channel containing coolant flow was regarded as the active part of TMS. The experiments were conducted at three different Reynold numbers in active and hybrid methods and it was shown that at higher flowrates the maximum temperature is lower. The research has also shown that passive cooling was inefficient in keeping the battery temperature below the safety limit of 60 °C in high discharge rates. The hybrid thermal management system (HTMS) reduced the steady-state temperature of batteries by 19.5% compared to active method at a Reynolds number of 340 and heat generation power of 3.7 W. The active method was also ineffective in controlling the battery temperature at high heat generation power levels while HTMS showed an appropriate thermal performance at the same condition. Furthermore, effect of utilizing Al2O3-water nanofluid with two different volume fractions was investigated in both active and hybrid systems. It was shown that, compared to the base case with water flow, nanofluid can reduce the maximum temperature of batteries by 15.5% and 8.5% in active and hybrid methods, respectively.

SHAPING OF AN AUTONOMOUS POWER SYSTEM FOR GUARANTEED POWER SUPPLY WITH THE PREDOMINANCE WIND ENERGY

Optimization of the autonomous wind-diesel plants composition and of their power for guaranteed energy supply, despite the long history of research, the diversity of approaches and methods, is an urgent problem. In this paper, a detailed analysis of the wind energy characteristics is proposed to shape an autonomous power system for a guaranteed power supply with predominance wind energy. The analysis was carried out on the basis of wind speed measurements in the south of the European part of Russia during 8 months at different heights with a discreteness of 10 minutes. As a result, we have obtained a sequence of average daily wind speeds and the sequences constructed by arbitrary variations in the distribution of average daily wind speeds in this interval. These sequences have been used to calculate energy balances in systems (wind turbines + diesel generator + consumer with constant and limited daily energy demand) and (wind turbines + diesel generator + consumer with constant and limited daily energy demand + energy storage). In order to maximize the use of wind energy, the wind turbine integrally for the period in question is assumed to produce the required amount of energy. For the generality of consideration, we have introduced the relative values of the required energy, relative energy produced by the wind turbine and the diesel generator and relative storage capacity by normalizing them to the swept area of the wind wheel. The paper shows the effect of the average wind speed over the period on the energy characteristics of the system (wind turbine + diesel generator + consumer). It was found that the wind turbine energy produced, wind turbine energy used by the consumer, fuel consumption, and fuel economy depend (close to cubic dependence) upon the specified average wind speed. It was found that, for the same system with a limited amount of required energy and high average wind speed over the period, the wind turbines with lower generator power and smaller wind wheel radius use wind energy more efficiently than the wind turbines with higher generator power and larger wind wheel radius at less average wind speed. For the system (wind turbine + diesel generator + energy storage + consumer) with increasing average speed for a given amount of energy required, which in general is covered by the energy production of wind turbines for the period, the maximum size capacity of the storage device decreases. With decreasing the energy storage capacity, the influence of the random nature of the change in wind speed decreases, and at some values of the relative capacity, it can be neglected.

Thermo-Economic Operation Analysis of SOFC–GT Combined Hybrid System for Application in Power Generation Systems

This study investigated the combination of the direct and indirect hybrid systems in order to develop a combined hybrid system. In the proposed system, a direct solid oxide fuel cell (SOFC) and gas turbine (GT) hybrid system and an indirect fuel cell cycle were combined and exchanged the heat through a heat exchanger. Several electrochemical, thermal, and thermodynamic calculations were performed in order to achieve more accurate results; then, beside the parametric investigation of the abovementioned hybrid system, the obtained results were compared to the results of direct and indirect hybrid systems and simple GT cycle. Results indicate that the efficiency of the combined hybrid system was between those of the direct and indirect hybrid systems. The electrical efficiency and the overall efficiency of the combined hybrid system were 43% and 59%, respectively. The generation power in the combined hybrid system was higher than that of both other systems, which was the only advantage of using the combined hybrid system. The generation power in the combined hybrid system was higher than that of the direct hybrid system by 16%; accordingly, it is recommended to be used by the systems that are supposed to have high generation power.

Energy management and design optimization for a series-parallel PHEV city bus

Series-parallel PHEV city buses combine the advantages of series and parallel configurations and have been used in China. However, the design and energy management of series-parallel PHEV city buses based on Chinese driving conditions still need to be investigated. In this paper, an equivalent consumption minimization strategy is provided to optimize energy management for series-parallel PHEV city buses, and the process of the equivalent consumption minimization strategy for series-parallel is presented in this paper. Compared with the validated rule-based energy control strategy, ECMS shows a fuel economy improvement of 8.2 % in the CBCD (Chinese Bus Driving Cycle). Based on the optimal energy management, a design for a generator motor in the series-parallel configuration has been processed. The fuel consumption has been shown to decrease, with an increase in generator power, because the system with the higher generator power can work at a higher efficiency in the series mode and operate the engine in the high efficiency area in the parallel mode. Besides, in terms of costof- ownership for a PHEV bus for lifetime of 8 years, although the high generator power will lead to high purchase cost for series-parallel PHEV bus, a series-parallel PHEV city bus with a generator of 100 kW maximum power will still show small advantage in cost-of-ownership, based on current motor price and natural gas price.

Narrow-band generation and mode correlations in a short Raman fibre laser

We design a Raman fibre laser with a short cavity providing narrow-band generation. The laser is based on a commercial single-mode fibre (980-HP) span of 12 m length. The laser generates up to 11 W of intracavity power. Even at high generation power, the laser spectrum is narrow (less than 200 pm)—several times narrower than for conventional Raman fibre lasers based on longer fibres. The intensity dynamics reveals indications of mode correlations.

119102 垂直軸型風力発電用風車の研究 : フラップと翼の迎え角が風車性能に及ぼす影響(一般05 流体力学・流体工学1)

Experimental study is conducted for the perpendicular axis type windmill. In our study, flap with variable angle is attached to the wings. In our previous study, only flap angles are changed. However, wing attack angles as well as flap angle are changed at this time. And, effect of flap angles and wing attack angles on power generation, efficiency, etc are measured. It is found that using of high wing attack angle is very effective to obtain high generation power. Other findings are that flap angle should be small for low wing attack angle, on the other hand flap angle should be large for high wing attack angle.

Radial properties of high-frequency electrodeless lamps in argon–mercury mixtures

Radial emission properties of high-frequency electrodeless discharge lamps (HFEDLs) in argon–mercury mixtures are investigated both numerically and experimentally. The radial profile of the intensities of the mercury triplet lines 404.7, 435.8 and 546.1 nm are measured for two different values of the high frequency generator power. A model describing physical processes in an HFEDL, including the calculation of radial plasma parameters, is developed. Radial intensity dependences of the lines 404.7, 435.8 and 546.1 nm are calculated and are found to be in good agreement with the experimental measurements.

High-Intensity Focused Ultrasound for ex Vivo Kidney Tissue Ablation: Influence of Generator Power and Pulse Duration

The therapeutic application of noninvasive tissue ablation by high-intensity focused ultrasound (HIFU) requires precise physical definition of the focal size and determination of control parameters. The objective of this study was to measure the extent of ex-vivo porcine kidney tissue ablation at variable generator parameters and to identify parameters to control lesion size. The ultrasound waves generated by a cylindrical piezoceramic element (1.04 MHz) were focused at a depth of 100 mm using a parabolic reflector (diameter 100 mm). A needle hydrophone was used to measure the field distribution of the sound pressure. The morphology and extent of tissue necrosis were examined at generator powers of up to 400 W (P(el)) and single pulse durations of as long as 8 seconds. The two-dimensional field distribution resulted in an approximately ellipsoidal focus of 32 x 4 mm (-6 dB). A sharp demarcation between coagulation necrosis and intact tissue was observed. Lesion size was controlled by both the variation of generator power and the pulse duration. At a constant pulse duration of 2 seconds, a generator power of 100 W remained below the threshold doses for inducing a reproducible lesion. An increase in power to as high as 400 W induced lesions with average dimensions of as much as 11.2 x 3 mm. At constant total energy (generator power x pulse duration), lesion size increased at higher generator power. This ultrasound generator can induce defined and reproducible necrosis in ex-vivo kidney tissue. Lesion size can be controlled by adjusting the generator power and pulse duration. Generator power, in particular, turned out to be a suitable control parameter for obtaining a lesion of a defined size.

Thermal imaging of ultrasonic scaler tips during tooth instrumentation.

During ultrasonic scaling procedures, contact of the scaler tip with the tooth surface will produce frictional heating. The aim of this study was to assess this heat generation using an Agema 900 thermal imaging system. Both the Cavitron sustained performance system (SPS) with TFI-3 tip and the Mini Piezon with P-tip were tested. Handpieces were fixed with their sides facing the thermal camera and thermal image sequences or "movies" created. Measurements were performed with tips under loads of 25, 50 and 100 g, at water flow rates of 10, 20 and 40 ml/min and low, medium and high generator power settings. A measurement point was superimposed on the resulting thermal images at the tip/tooth contact site and the temperature variation with time recorded. All combinations of instrumentation produced an increase in temperature. An increase in temperature was generally observed with increasing load (for given power/water), power setting (for given load/water) and a decrease in water flow rate (for given load/power). Heat generation is minimised by using low/medium power settings and light contact. Care must be taken to ensure adequate water is present at the site of instrumentation to prevent patient discomfort due to excessive heating.

Technique for enhancing generation power density of silicon photovoltaic devices

A new type of photovoltaic system with higher generation power density has been studied in detail. The feature of the proposed system is a V-shaped structure with two polycrystalline solar cells. Compared to solar cells in a conventional approach, the V-shaped structure enhances external quantum efficiency and leads to an increase of 24% in power conversion efficiency.

A07 ハーメティック形スターリングエンジンの性能特性

A hermetic Stirling engine, which has a generator in a pressurized crankcase, is suitable for an application of a generator set. Because the hermetic engine does not have an external seal device between the working space and the atmosphere, and it has small mechanical loss. In this paper, the author reorganizes a 100 W class Stirling engine named "Ecoboy-SCM81" to the hermetic type. The original engine was developed at a RC127 committee of JSME in 1995,and it had a mechanical seal as the external seal device. And, the performance of the hermetic engine is measured for a comparison with that of the original engine. As the result, it is confirmed that the hermetic engine has very smaller mechanical loss and higher generator power than that of the original engine.

Matrix effects during trace elements analysis in plant samples by inductively coupled plasma atomic emission spectrometry with axial view configuration and ultrasonic nebulizer

Plant matrix effects have been characterized during trace element analysis by axial view inductively coupled plasma atomic emission spectrometry with ultrasonic nebulizer. Six elements were studied: As, Cd, Co, Cr, Ni, and Pb. The interferences were simulated by measuring analyte signals on solutions containing various concentrations of elements encountered in mineralized plant samples such as K, Ca, Mg, P, Na, Fe and Mn. Signal suppression is observed for the ionic lines and signal enhancement occurred for atomic lines. The effects were found to be caused by particles and easily ionizable elements (EIEs) into the central channel of the plasma. The particle vaporization led to lower plasma temperatures and decreased emission intensities. EIEs changed the ion/atom ratio toward atom and improved the atomic emission intensities. Use of plant sample on the analytical signal of trace elements led to same conclusions. The matrix effects can be removed by using high generator power especially for the ionic spectra lines.

Matrix effects during trace element analysis in plant samples by inductively coupled plasma atomic emission spectrometry with axial view configuration and pneumatic nebulizer

Plant sample matrix effects have been investigated during trace element analysis by inductively coupled plasma atomic emission spectrometry with axial view and pneumatic nebulizer. Eight elements often analyzed in environmental samples were studied: As, Cd, Co, Cr, Cu, Ni, Pb and Se. To simulate the effects caused by digested plant samples, the spectral line profiles of analytes were measured on solutions containing various concentrations of elements encountered in plant matrix such as K, Ca and Mg. Depressions in the emission intensities occurred and were more dramatic with high concentrations of the concomitant species. The inter-element effects were found to be caused by the matrix amount entering into the central channel of the plasma. In fact, energy consumed for droplets desolvation and particles of salts vaporization leads to lower plasma temperatures and produce changes in excitation mechanisms. Ion emissions were especially affected. The matrix effects can be removed using a high generator power (1.4 kW) and a moderate uptake flow rate of solution into the plasma (pump speed: 15 rev./min). The use of the natural plant sample led to the same conclusions. These operating conditions decreased the sensitivity but routine analyses of the plant material could be carried out.

Low-level determination of non-metals (Cl, Br, I, S, P) in waste oils by inductively coupled plasma optical emission spectrometry using prominent spectral lines in the 130-190 nm range

The non-metals Cl, Br, I, S and P were determined in waste oils by inductively coupled plasma optical emission spectrometry (ICP-OES). Prominent spectral lines in the vacuum ultraviolet spectral region between 130 and 190 nm were applied simultaneously with a nitrogen-filled Spectro polychromator. For example, the intense spectral lines for chlorine (Cl 134.72 nm), bromine (Br 163.34 nm), iodine (I 161.76 nm), sulfur (S 180.70 nm) and phosphorus (P 177.50 nm) were used. The detection limits of Cl, Br, I, P and S in undiluted waste oils are 0.9, 1.6, 0.47, 0.04 and 0.07 mg kg –1 , respectively. To achieve these detection limits the standard oils and samples were diluted 1+4 (m/m) with kerosene. For the analysis of waste oils, small amounts of oxygen (80 ml min –1 ) were added to the outer plasma gas. In order to establish optimized plasma operating conditions for non-metals, a simplex optimization was performed. Compared with metals such as Ba, V, Cd, Al or Ni, a lower nebulizer gas flow and a higher generator power is advantageous to improve the detection limits for the non-metals. Because the detection limit for Cl is more than a factor of 1000 below tolerated limits of waste oil regulations, highly viscous oils could be analyzed after a suitable dilution with kerosene. The determination of the total Cl concentration by ICP-OES can be used as a means of screening for the highest possible concentration of polychlorinated biphenyls (PCBs) in waste oils.

Effect of implant variables on temperatures achieved during ferromagnetic hyperthermia

Effects of ferromagnetic implant variables on steady-state temperature were studied in both in vitro (phantom) and in vivo (rabbit hind limb musculature) models. Thermoseed implant variables included: (1) the presence and number of thermoseed sleeves; (2) variations in thermoseed alignment within the oscillating electromagnetic field; (3) generator power levels of 300 W, 600 W, and 1200 W; and (4) separation of thermoseed tracks by 0.8 cm versus 1 cm. When the thermoseeds were aligned parallel to the electromagnetic field, temperature distributions in the in vivo model using bare thermoseeds and thermoseeds encased in a single sleeve (0.1 mm wall thickness) of polyethylene tubing were statistically higher than in tests performed with thermoseeds encased in a double sleeve (0.25 mm over 0.1 mm wall thickness) of tubing (p = 0.006). Nonetheless, average steady-state temperatures above a therapeutic minimum (greater than or equal to 42 degrees C) were achieved at all generator power levels using thermoseeds encased in a double sleeve of tubing and aligned parallel to the electromagnetic field. Gross misalignment of thermoseeds with the electromagnetic field was partly compensated for by utilizing higher generator power levels. Thermoseed tracks separated by 0.8 cm and aligned parallel to the electromagnetic field yielded average steady-state temperatures that were 0.4-2.2 degrees C higher than those obtained with a thermoseed track separation of 1 cm.

A new high current laboratory and pulsed homopolar generator power supply at the University of Texas

The University of Texas at Austin is constructing a spacious facility for research in pulse power technology at the Balcones Research Center, located in north Austin. The arrangement and capacity of the facility are intended to support high-current experiments. The laboratory power supply being designed consists of six homopolar generators, each capable of delivering ten megajoules of energy. The output bus is configured such that various series, parallel, and series-parallel circuits of homopolar generators are possible. Both resistive and inductive loads can be driven from the power supplies. Research programs will be supported with a wide range of physical facilities, including materials handling, machine shop, data acquisition and analysis, engineering and operating personnel, chemical analysis and metallurgical laboratories, and an information center. These facilities will be available to the U. S. technical community through several types of arrangements with The University through the Center for Electromechanics. Each of the six homopolar generators is designed to deliver 1 MA at 100 V, with a maximum repetition rate of a discharge every five minutes. In addition to EM launch research and applications, other intended uses of the power supply include welding of large cross-sections of metal (up to 650 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> or 100 in. <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> of steel), generation of high magnetic fields in low-impedance magnets, and testing of high-current opening switches. Status of major elements of the project is reported.