Records with Subject: Process Operations
Showing records 51 to 75 of 81. [First] Page: 1 2 3 4 Last
Real-Time Optimization of Organic Rankine Cycle Systems by Extremum-Seeking Control
Andres Hernandez, Adriano Desideri, Clara Ionescu, Robin De Keyser, Vincent Lemort, Sylvain Quoilin
November 27, 2018 (v1)
Keywords: extremum-seeking (ES) control, Model Predictive Control, organic Rankine cycle
In this paper, the optimal operation of a stationary sub-critical 11 kW el organic Rankine cycle (ORC) unit for waste heat recovery (WHR) applications is investigated, both in terms of energy production and safety conditions. Simulation results of a validated dynamic model of the ORC power unit are used to derive a correlation for the evaporating temperature, which maximizes the power generation for a range of operating conditions. This idea is further extended using a perturbation-based extremum seeking (ES) algorithm to identify online the optimal evaporating temperature. Regarding safety conditions, we propose the use of the extended prediction self-adaptive control (EPSAC) approach to constrained model predictive control (MPC). Since it uses input/output models for prediction, it avoids the need for state estimators, making it a suitable tool for industrial applications. The performance of the proposed control strategy is compared to PID-like schemes. Results show that E... [more]
Optimal Operation of Combined Photovoltaic Electrolyzer Systems
Arash Khalilnejad, Aditya Sundararajan, Alireza Abbaspour, Arif Sarwat
November 27, 2018 (v1)
Keywords: advanced alkaline electrolyzer, hydrogen storage, imperialistic competitive algorithm (ICA), photovoltaic (PV)
In this study, the design and simulation of a combination of a photovoltaic (PV) array with an alkaline electrolyzer is performed to maximize the production of hydrogen as a reliable power resource. Detailed electrical model of PV system, as long as thermal and electrochemical model of electrolyzer is used. Since an electrolyzer is a non-linear load, its coupling with PV systems to get the best power transfer is very important. Solar irradiation calculations were done for the region of Miami (FL, USA), giving an optimal surface slope of 25.7° for the PV array. The size of the PV array is optimized, considering maximum hydrogen production and minimum excess power production in a diurnal operation of a system using the imperialistic competitive algorithm (ICA). The results show that for a 10 kW alkaline electrolyzer, a PV array with a nominal power of 12.3 kW The results show that 12.3 kW photvoltaic system can be utilized for supplying a 10 kW electrolyzer. Hydrogen production and Farad... [more]
A Novel DC-Bus Sensor-less MPPT Technique for Single-Stage PV Grid-Connected Inverters
Mohamed A. Elsaharty, Hamdy A. Ashour, Elyas Rakhshani, Edris Pouresmaeil, João P. S. Catalão
November 27, 2018 (v1)
Keywords: grid connected, MPPT technique, photovoltaic, sensor-less, single-stage converter
Single-stage grid connected inverters are considered as an economic, compact and simple topology compared with multi-stage inverters. In photovoltaic (PV) grid connected systems, the major requirement is to achieve maximum output power from the source. Maximum Power Point Tracking (MPPT) techniques require measurements on the DC side of the inverter connected to the PV in order to determine the current operating point on the power characteristics. Typically this is achieved by perturbing the reference output power and observe the change in the PV voltage, current or both. Based on the observation, it could be determined whether the current operating point is beyond or below maximum power. This paper presents an MPPT technique for a single-stage PV grid connected inverter where the MPPT algorithm determines the current operating point at different operating conditions based upon observing the inverter controller action. Such approach eliminates the requirement of sensing elements to be... [more]
Optimization of Shift Schedule for Hybrid Electric Vehicle with Automated Manual Transmission
Wenchen Shen, Huilong Yu, Yuhui Hu, Junqiang Xi
November 27, 2018 (v1)
Keywords: automated mechanical transmission (AMT), dynamic programming (DP), gear shift schedule, hybrid electric vehicle (HEV)
Currently, most hybrid electric vehicles (HEVs) equipped with automated mechanical transmission (AMT) are implemented with the conventional two-parameter gear shift schedule based on engineering experience. However, this approach cannot take full advantage of hybrid drives. In other words, the powertrain of an HEV is not able to work at the best fuel-economy points during the whole driving profile. To solve this problem, an optimization method of gear shift schedule for HEVs is proposed based on Dynamic Programming (DP) and a corresponding solving algorithm is also put forward. A gear shift schedule that can be employed in real-vehicle is extracted from the obtained optimal gear shift points by DP approach and is optimized based on analysis of the engineering experience in a typical Chinese urban driving cycle. Compared with the conventional two-parameter gear shift schedule in both simulation and real vehicle experiments, the extracted gear shift schedule is proved to clearly improve... [more]
Tunneling Horizontal IEC 61850 Traffic through Audio Video Bridging Streams for Flexible Microgrid Control and Protection
Michael Short, Fathi Abugchem, Muneeb Dawood
November 27, 2018 (v1)
Keywords: audio video bridging (AVB), IEC 61850, micro grid, smart grid, telecontrol and teleprotection
In this paper, it is argued that some low-level aspects of the usual IEC 61850 mapping to Ethernet are not well suited to microgrids due to their dynamic nature and geographical distribution as compared to substations. It is proposed that the integration of IEEE time-sensitive networking (TSN) concepts (which are currently implemented as audio video bridging (AVB) technologies) within an IEC 61850 / Manufacturing Message Specification framework provides a flexible and reconfigurable platform capable of overcoming such issues. A prototype test platform and bump-in-the-wire device for tunneling horizontal traffic through AVB are described. Experimental results are presented for sending IEC 61850 GOOSE (generic object oriented substation events) and SV (sampled values) messages through AVB tunnels. The obtained results verify that IEC 61850 event and sampled data may be reliably transported within the proposed framework with very low latency, even over a congested network. It is argued th... [more]
An Automatic Switched-Capacitor Cell Balancing Circuit for Series-Connected Battery Strings
Yuanmao Ye, Ka Wai Eric Cheng
November 27, 2018 (v1)
Keywords: battery, battery management system (BMS), energy storage system, switched-capacitor (SC), voltage balancing
In this paper, a novel voltage equalizer is developed for series battery strings based on the two-phase switched capacitor technique. Different from the conventional voltage equalizers which are developed by switched-mode power converters, bulky magnetic components and complex monitoring and control system are avoided in the proposed system. Just a pair of complementary pulse signals with constant switching frequency and fixed duty ratio are required to control all of switches employed in the proposed voltage equalizer, and charge transfers from the higher voltage battery cells to lower voltage ones automatically. The circuit configuration and operation principle are provided in this paper. The model of the proposed voltage equalizer is also derived. Comparison with other works indicates that the proposed method is superior to the conventional switched-capacitor (SC) voltage equalizer for the high stack of series battery strings. Experimental results demonstrate that the proposed volta... [more]
Device Performance Improvement of Double-Pass Wire Mesh Packed Solar Air Heaters under Recycling Operation Conditions
Chii-Dong Ho, Hsuan Chang, Chun-Sheng Lin, Chun-Chieh Chao, Yi-En Tien
November 16, 2018 (v1)
Keywords: double-pass, heat-transfer efficiency, recycling, solar air heater, wire mesh packing
The improvement of device performance of a recycling solar air heater featuring a wire mesh packing was investigated experimentally and theoretically. The application of the wire mesh packing and recycle-effect concept to the present study were proposed aiming to strengthen the convective heat-transfer coefficient due to increased turbulence. Comparisons were made among different designs, including the single-pass, flat-plate double-pass and recycling double-pass wire mesh packed operations. The collector efficiency of the recycling double-pass wire mesh packed solar air heater was much higher than that of the other configurations for various recycle ratios and mass flow rates scenarios. The power consumption increment due to implementing wire mesh in solar air heaters was also discussed considering the economic feasibility. A fairly good agreement between theoretical predictions and experimental measurements was achieved with an analyzed error of 1.07%⁻9.32%.
Capacitor Voltage Ripple Suppression for Z-Source Wind Energy Conversion System
Shoudao Huang, Yang Zhang, Zhikang Shuai
October 23, 2018 (v1)
Keywords: capacitor voltage ripple, pulse width modulation, wind generation system, Z-source inverter
This paper proposes an improved pulse-width modulation (PWM) strategy to reduce the capacitor voltage ripple in Z-source wind energy conversion system. In order to make sure that Z-source capacitor voltage has symmetrical maximum and minimum amplitudes in each active state, the shoot-through time is divided into six unequal parts. According to the active state and zero state, the shoot-through time is rearranged to match the charging time and discharging time of the Z-source capacitors. Theoretically, it is indicated that the voltage ripple of the Z-source capacitors can be reduced effectively by means of the proposed PWM scheme. Finally, simulation and experimental results are given to verify the performance of the presented method.
Optimal Maintenance Management of Offshore Wind Farms
Alberto Pliego Marugán, Fausto Pedro García Márquez, Jesús María Pinar Pérez
October 23, 2018 (v1)
Keywords: binary decision diagrams, fault tree analysis, maintenance management, offshore, wind turbines
Nowadays offshore wind energy is the renewable energy source with the highest growth. Offshore wind farms are composed of large and complex wind turbines, requiring a high level of reliability, availability, maintainability and safety (RAMS). Firms are employing robust remote condition monitoring systems in order to improve RAMS, considering the difficulty to access the wind farm. The main objective of this research work is to optimise the maintenance management of wind farms through the fault probability of each wind turbine. The probability has been calculated by Fault Tree Analysis (FTA) employing the Binary Decision Diagram (BDD) in order to reduce the computational cost. The fault tree presented in this paper has been designed and validated based on qualitative data from the literature and expert from important European collaborative research projects. The basic events of the fault tree have been prioritized employing the criticality method in order to use resources efficiently. E... [more]
Reliability Analysis and Overload Capability Assessment of Oil-Immersed Power Transformers
Chen Wang, Jie Wu, Jianzhou Wang, Weigang Zhao
October 23, 2018 (v1)
Keywords: current measurement, losses, power transformers, reliability estimation, transformer windings
Smart grids have been constructed so as to guarantee the security and stability of the power grid in recent years. Power transformers are a most vital component in the complicated smart grid network. Any transformer failure can cause damage of the whole power system, within which the failures caused by overloading cannot be ignored. This research gives a new insight into overload capability assessment of transformers. The hot-spot temperature of the winding is the most critical factor in measuring the overload capacity of power transformers. Thus, the hot-spot temperature is calculated to obtain the duration running time of the power transformers under overloading conditions. Then the overloading probability is fitted with the mature and widely accepted Weibull probability density function. To guarantee the accuracy of this fitting, a new objective function is proposed to obtain the desired parameters in the Weibull distributions. In addition, ten different mutation scenarios are adopt... [more]
Comparison of the Stator Step Skewed Structures for Cogging Force Reduction of Linear Flux Switching Permanent Magnet Machines
Wenjuan Hao, Yu Wang
September 21, 2018 (v1)
Keywords: cogging force, flux-switching permanent magnet machine, linear machine, step skewed stator
Linear flux switching permanent magnetic (LFSPM) machines, with the armature windings and magnets both on the mover in addition to a robust stator, are a good choice for long stoke applications, however, a large cogging force is also inevitable due to the double salient structure, and will worsen the system performance. Skewing methods are always employed for the rotary machines to reduce the cogging torque, and the rotor step-skewed method is a low-cost approximation of regular skewing. The step skewed method can also be applied to the linear machines, namely, the stator step skewed. In this paper, three stator step skewed structures, which are a three-step skewed stator, a two-step skewed stator and an improved two-step skewed stator, are employed for the cogging force reduction of two types of LFSPM machines. The three structures are analyzed and compared with emphasize on the influence of the skewed displacement on the cogging force and the average thrust force. Based on finite ele... [more]
The Impact of Pulse Charging Parameters on the Life Cycle of Lithium-Ion Polymer Batteries
J. M. Amanor-Boadu, A. Guiseppi-Elie, E. Sánchez-Sinencio
September 21, 2018 (v1)
Keywords: battery impedance, constant current constant voltage, design of experiments, electrochemical impedance spectroscopy, Li-ion polymer battery, life cycle, pulse charging, Taguchi orthogonal arrays
The pulse charging algorithm is seen as a promising battery charging technique to satisfy the needs of electronic device consumers to have fast charging and increased battery charge and energy efficiencies. However, to get the benefits of pulse charging, the pulse charge current parameters have to be chosen carefully to ensure optimal battery performance and also extend the life cycle of the battery. The impact of pulse charge current factors on the life cycle and battery characteristics are seldom investigated. This paper seeks to evaluate the impact of pulse charge current factors, such as frequency and duty cycle, on the life cycle and impedance parameters of lithium-ion polymer batteries (LiPo) while using a design of experiments approach, Taguchi orthogonal arrays. The results are compared with the benchmark constant current-constant voltage (CC-CV) charging algorithm and it is observed that by using a pulse charger at optimal parameters, the cycle life of a LiPo battery can be in... [more]
Power Transfer Efficiency Analysis for Omnidirectional Wireless Power Transfer System Using Three-Phase-Shifted Drive
Zhaohong Ye, Yue Sun, Xiufang Liu, Peiyue Wang, Chunsen Tang, Hailin Tian
September 21, 2018 (v1)
Keywords: mutual inductance coupling, omnidirectional wireless power, power transfer efficiency, three-phase-shifted drive, wireless power transfer (WPT)
In order to implement the omnidirectional wireless power transfer (WPT), a novel three-phase-shifted drive omnidirectional WPT system is proposed. This system is comprised of three independent phase-adjusted excitation sources, three orthogonal transmitting coils, and one planar receiving coil. Based on the mutual coupling theory, the power transfer efficiency is derived and the corresponding control mechanism for maximizing this efficiency is presented. This control mechanism only depends on the currents’ root-mean-square (RMS) values of the three transmitting coils and simple calculations after each location and/or posture change of the receiving coil, which provides the real-time possibility to design an omnidirectional WPT system comparing with the other omnidirectional systems. In aid of computer emulation technique, the efficiency characteristic versus the omnidirectional location and posture of the receiving coil is analyzed, and the analytical results verify the validity of the... [more]
Reconfiguration of a Multilevel Inverter with Trapezoidal Pulse Width Modulation
Nataraj Prabaharan, V. Arun, Padmanaban Sanjeevikumar, Lucian Mihet-Popa, Frede Blaabjerg
September 21, 2018 (v1)
Keywords: FPGA, inverter, multi-carrier pulse width modulation, multilevel inverter, trapezoidal pulse width modulation
This paper presents different multi-carrier unipolar trapezoidal pulse width modulation strategies for a reduced switch asymmetrical multilevel inverter. The different strategies are phase disposition, alternative phase opposition and disposition, and carrier overlapping and variable frequency that involve triangular waves as carriers with a unipolar trapezoidal wave as a reference. The reduced switch, asymmetrical multilevel inverter operation was examined for generating the seven-level output voltage using Matlab/Simulink 2009b and the results were verified with a real-time laboratory-based experimental setup using a field-programmable gate array. Different parameter analyses, such as total harmonic distortion, fundamental root mean square voltage, and distortion factor, were analyzed with different modulation indices to investigate the performance of the selected topology. Unipolar trapezoidal pulse width modulation provides a higher root mean square voltage value.
PLL-Less Three-Phase Four-Wire SAPF with STF-dq0 Technique for Harmonics Mitigation under Distorted Supply Voltage and Unbalanced Load Conditions
Yap Hoon, Mohd Amran Mohd Radzi
September 21, 2018 (v1)
Keywords: dq0 principle, harmonics filtering, neutral current, reference current generation, synchronization phase, unbalanced load, voltage source inverter
This paper presents a non-iterative technique that generates reference current to manage operation of a three-phase four-wire shunt active power filter which employs a three-leg split capacitor voltage source inverter (VSI) topology. The proposed technique integrates together a self-tuning-filter (STF) and direct-quadrature-zero (dq0) principle (referred here as STF-dq0), allowing the controlled shunt active power filter (SAPF) to perform effectively under distorted source voltages and unbalanced load conditions. Unlike the previous technique developed based on the standard dq0 principle, the proposed technique does not require any service from a phase-locked loop (PLL) where two STFs are applied to separate harmonic and fundamental elements for the purpose of generating synchronization phases and reference current, respectively. Simulation work which includes connection of the SAPF circuits, design of control techniques and all the necessary assessments are conducted in MATLAB-Simulin... [more]
The Effect of a Wave Energy Farm Protecting an Aquaculture Installation
Dina Silva, Eugen Rusu, C. Guedes Soares
September 21, 2018 (v1)
Keywords: aquaculture, nearshore protection, sheltering effect, SWAN, wave energy farm
This paper assesses the impact of a farm of wave energy converters on a nearby offshore aquaculture installation and on the nearshore dynamics. The coastal area targeted is Aguçadoura, located in the north of Portugal, where the world’s first wave farm operated in 2008. The study is focused mainly on the evaluation of the sheltering effect provided by the wave farm to the aquaculture cages. Furthermore, the possible impact on the coastal wave climate of such an energy park is also evaluated. These objectives are accomplished by performing simulations, corresponding to the wave conditions, which are more often encountered in that coastal environment. The SWAN model (Simulating WAves Nearshore) was adopted for this. Various transmission scenarios are considered to account for the impact of different types of wave converter farms on the downwave conditions. The results show that such a wave energy park might have a clear positive impact on the wave conditions fish farm installed downwave... [more]
Partial Redesign of an Accelerator Driven System Target for Optimizing the Heat Removal and Minimizing the Pressure Drops
Guglielmo Lomonaco, Giacomo Alessandroni, Walter Borreani
September 21, 2018 (v1)
Keywords: ADS, ANSYS-FLUENT, bayonet tube heat exchanger, Computational Fluid Dynamics, target
Accelerator Driven Systems (ADS) seem to be a good solution for safe nuclear waste transmutation. One of the most important challenges for this kind of machine is the target design, particularly for what concerning the target cooling system. In order to optimize this component a CFD-based approach has been chosen. After the definition of a reference design (Be target cooled by He), some parameters have been varied in order to optimize the thermal-fluid-dynamic features. The final optimized target design has an increased security margin for what regarding Be melting and reduces the maximum coolant velocity (and consequently even more the pressure drops).
Effect of Zonal Hydraulics on Energy Consumption and Boom Structure of a Micro-Excavator
Abinab Niraula, Shuzhong Zhang, Tatiana Minav, Matti Pietola
September 21, 2018 (v1)
Keywords: direct driven hydraulics, efficiency, electric drives, energy consumption, finite element analysis, hydraulic drives, hydraulic excavator, losses, off-road mobile machinery, zonal hydraulics
This paper investigates the effect of extra weight caused by the Direct Driven Hydraulics (DDH) in a micro-excavator. These projects are investigating the implementation of zonal or decentralized hydraulics for non-road mobile machinery (NRMM) and stationary industrial applications. The benefit of DDH is the combination of electric and hydraulic technologies in a compact package compared to conventional hydraulics, which enables a reduction of potential leakage points, flexible tubing, and boosting of the system efficiency due to switching to direct pump control instead of a loss-generating conventional valve-based control. In order to demonstrate these benefits for the excavator case, this paper proposes a system model approach to assess and predict energy consumption of the zonal hydraulics approach implemented with DDH in various working cycles, complemented by a structural analysis. The finite element analysis utilized for this demonstrated that the extra weight and selected locati... [more]
Evaluation of SF₆ Leakage from Gas Insulated Equipment on Electricity Networks in Great Britain
Phillip Widger, Abderrahmane (Manu) Haddad
September 21, 2018 (v1)
Keywords: distribution, emissions, environment, gas insulated line (GIL), gas insulated switchgear (GIS), sulphur hexafluoride (SF6), transmission
This paper examines the data collected from the power industry over the last six years of actual reported emissions of sulphur hexafluoride (SF₆) and the potential impact. The SF₆ emissions have been collated from the 14 different regions in England, Scotland, and Wales (Great Britain) from the six distribution network operators. The emissions of SF₆ due to the transmission network of Great Britain have also been collated from the three different transmission network operators. By collecting this SF₆ emissions data from the power industry, in both the distribution and transmission networks, an overall view of the scale of SF₆ emissions in Great Britain can be evaluated. Data from the power industry also shows the inventory of SF₆ power equipment in use over the last six years in Great Britain and shows the calculated percentage leakage rate of all of this equipment. In this paper, these figures, as reported by the electrical power industry to the UK government, have been used to estima... [more]
Stability Analysis of Deadbeat-Direct Torque and Flux Control for Permanent Magnet Synchronous Motor Drives with Respect to Parameter Variations
Jae Suk Lee
September 21, 2018 (v1)
Keywords: DB-DTFC (deadbeat-direct torque and flux control), PMSM (permanent magnet synchronous motor), stability, torque control
This paper presents a stability analysis and dynamic characteristics investigation of deadbeat-direct torque and flux control (DB-DTFC) of interior permanent magnet synchronous motor (IPMSM) drives with respect to machine parameter variations. Since a DB-DTFC algorithm is developed based on a machine model and parameters, stability with respect to machine parameter variations should be evaluated. Among stability evaluation methods, an eigenvalue (EV) migration is used in this paper because both the stability and dynamic characteristics of a system can be investigated through EV migration. Since an IPMSM drive system is nonlinear, EV migration cannot be directly applied. Therefore, operating point models of DB-DTFC and CVC (current vector control) IPMSM drives are derived to obtain linearized models and to implement EV migration in this paper. Along with DB-DTFC, current vector control (CVC), one of the widely used control algorithms for motor drives, is applied and evaluated at the sam... [more]
Pilot Protection Based on Amplitude of Directional Travelling Wave for Voltage Source Converter-High Voltage Direct Current (VSC-HVDC) Transmission Lines
Lingtong Jiang, Qing Chen, Wudi Huang, Lei Wang, Yu Zeng, Pu Zhao
September 21, 2018 (v1)
Keywords: directional pilot protection, phase-mode transformation, stationary wavelet transform, time difference, VSC-MTDC
This paper presents a novel pilot protection scheme of DC cable line in voltage-source-converter (VSC) based multi-terminal DC (MTDC) grids, which utilizes a novel phase-mode transformation to decouple the bipolar DC cable current into six mode and it uses the stationary wavelet transform to extract the modulus maxima of fault initial traveling waves current (FITWC). With accurate amplitude and polarities of the FITWC being collected from the fault-detection devices located at each terminal, the proposed scheme can correctly determine the faulty segment and the faulty pole. In this paper, the ratio of amplitudes between sixth mode forward and backward travelling wave currents is used to judge the faulty segment and the polarity of fifth mode forward travelling wave current is used to identify the faulty pole. A four-terminal VSC-based MTDC grid was built in PSCAD/EMTDC to evaluate the performance of the fault-protection scheme. Simulation results for different cases demonstrate that th... [more]
Establishment of an Improved Material-Drilling Power Model to Support Energy Management of Drilling Processes
Shun Jia, Qingwen Yuan, Wei Cai, Qinghe Yuan, Conghu Liu, Jingxiang Lv, Zhongwei Zhang
September 21, 2018 (v1)
Keywords: drilling process, energy management, material-drilling power
Drilling processes, as some of the most widely used machining processes in the manufacturing industry, play an important role in manufacturing process energy-saving programs. However, research focus on energy modeling of drilling processes, especially for the modeling of material-drilling power, are really scarce. To bridge this gap, an improved material-drilling power model is proposed in this paper. The obtained material-drilling power model can improve the accuracy of the material-drilling power and lay a good foundation for energy modeling and optimization of drilling processes. Finally, experimental studies were carried out on an XHK-714F CNC machining center (Hangzhou HangJi Machine Tool Co., Ltd., Hangzhou, China) and a JTVM6540 CNC milling machine (Jinan Third Machine Tool Co., Ltd., Jinan, China). The results showed that predictive accuracies with the proposed model are generally higher than 96% for all the test cases.
Joint Operation between a PSO-Based Global MPP Tracker and a PV Module Array Configuration Strategy under Shaded or Malfunctioning Conditions
Pi-Yun Chen, Kuei-Hsiang Chao, Bo-Jyun Liao
September 21, 2018 (v1)
Keywords: configuration strategy, maximum power point tracker, Particle Swarm Optimization, photovoltaic module array, shaded or malfunctioning
This paper aims to present a smart, particle swarm optimization (PSO)-based, real time configuration strategy for a photovoltaic (PV) module array in the event of shadow cast on a PV module(s) and/or module failure as an effective approach to power generation efficiency elevation. At the first step, the respective maximum output power levels provided by a normal operating array at various levels of irradiation and module surface temperatures are measured and entered as references into a database. Subsequently, the maximum output power (MPP) level, tracked by a MPP tracker, is feedbacked for a comparison with an aforementioned reference as a way to tell whether there is either a shadow or a malfunction event on a PV module(s). Once an abnormal operation is detected, the presented smart configuration algorithm is performed to reconfigure the PV module array such that the array is operated at the global MPP as intended. Furthermore, by use of a PIC microcontroller that is a family of micr... [more]
Assessment and Performance Evaluation of a Wind Turbine Power Output
Akintayo Temiloluwa Abolude, Wen Zhou
September 21, 2018 (v1)
Keywords: effective power curve, estimation errors, power output fluctuations, turbine power curve
Estimation errors have constantly been a technology bother for wind power management, often time with deviations of actual power curve (APC) from the turbine power curve (TPC). Power output dispersion for an operational 800 kW turbine was analyzed using three averaging tine steps of 1-min, 5-min, and 15-min. The error between the APC and TPC in kWh was about 25% on average, irrespective of the time of the day, although higher magnitudes of error were observed during low wind speeds and poor wind conditions. The 15-min averaged time series proved more suitable for grid management and energy load scheduling, but the error margin was still a major concern. An effective power curve (EPC) based on the polynomial parametric wind turbine power curve modeling technique was calibrated using turbine and site-specific performance data. The EPC reduced estimation error to about 3% in the aforementioned time series during very good wind conditions. By integrating statistical wind speed forecasting... [more]
A Cost-Effective Redundant Digital Excitation Control System and Test Bed Experiment for Safe Power Supply for Process Industry 4.0
Hoon-Gi Lee, Jun-Ho Huh
July 31, 2018 (v1)
Keywords: Android application, Computer architecture, digital excitation control system, excitation system, job safety, Process industry 4.0, synchronous generator, system architecture
Recently, the energy demand and supply situation in the Republic of Korea (ROK) has been largely affected by the fluctuations in the energy markets around the world. Such a situation has provided a basis for requiring improvements to power plant facilities. The automatic generator voltage control systems in large-scale power plants are adopting a rapid-response static excitation method to improve the transient stability. A domestic commercially developed large-scale triple-redundant excitation system is currently operated by the 1000 MW-class nuclear power plant and its efficiency has been verified at the same site. However, such a system is too costly for smaller power plants so that a reliable and low-cost redundant digital excitation control system was developed and introduced in this study to resolve the cost problem. The system has improved its stability and reliability at the same time through double (redundant) configuration. Additionally, the system’s performance was put to the... [more]
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