Comprehensive Electric-Thermal Photovoltaic Modeling for Power-Hardware-in-the-Loop Simulation (PHILS) Applications

Xuan Hung Mai,Sang-Kyu Kwak,Jee-Hoon Jung,Kim, Katherine A. Institute of Electrical and Electronics Engineers 2017 IEEE transactions on industrial electronics Vol.64 No.8

<P>This paper presents a dynamic, electricthermal model for a photovoltaic (PV) cell that combines electrical and thermal parameters to accurately emulate PV panels in real time for power-hardware-in-the-loop simulation (PHILS). In this model, the irradiance and ambient temperature are used to calculate the PV cell temperature based on a five-layer thermal model. The cell temperature is then used in the electrical model to accurately adjust the PV electrical characteristics. A custom experimental setup is built to test and verify the electrical and thermal characteristics of the PV cell model. This electric-thermal model is validated using experimental data in realistic scenarios. The model is also tested with PHILS using a real-time simulator and a programmable dc power supply to emulate PV power generation under various load changes. The model is well matched to the experimental measurements with an error within 2.4% for the electrical aspects and within 1.5% for the thermal aspects in the tested scenarios.</P>

Forecasting Day-ahead Electricity Price Using a Hybrid Improved Approach

Hu, Jian-Ming,Wang, Jian-Zhou The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.12 No.6

Electricity price prediction plays a crucial part in making the schedule and managing the risk to the competitive electricity market participants. However, it is a difficult and challenging task owing to the characteristics of the nonlinearity, non-stationarity and uncertainty of the price series. This study proposes a hybrid improved strategy which incorporates data preprocessor components and a forecasting engine component to enhance the forecasting accuracy of the electricity price. In the developed forecasting procedure, the Seasonal Adjustment (SA) method and the Ensemble Empirical Mode Decomposition (EEMD) technique are synthesized as the data preprocessing component; the Coupled Simulated Annealing (CSA) optimization method and the Least Square Support Vector Regression (LSSVR) algorithm construct the prediction engine. The proposed hybrid approach is verified with electricity price data sampled from the power market of New South Wales in Australia. The simulation outcome manifests that the proposed hybrid approach obtains the observable improvement in the forecasting accuracy compared with other approaches, which suggests that the proposed combinational approach occupies preferable predication ability and enough precision.

A Diesel Generator Model with Fluctuating Engine Torque Including Magnetic Saturation for Transient Analysis using XTAP

Sakamoto, Orie The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.3

Diesel engine generators are widely used in the world, especially in remote site power systems as distributed generators. A weak distribution feeder with a small diesel engine may suffer from voltage and power fluctuations due to misfiring of the engine cylinder. In this study, new generator model with example engine torque was developed for the electromagnetic transient analysis program for power systems named XTAP. The configuration and verification results of the developed model are presented in the paper. The model is considered to be useful for analyses of small power systems with those diesel engines.

Multi-Objective Optimization Model of Electricity Behavior Considering the Combination of Household Appliance Correlation and Comfort

Qu, Zhaoyang,Qu, Nan,Liu, Yaowei,Yin, Xiangai,Qu, Chong,Wang, Wanxin,Han, Jing The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.5

With the wide application of intelligent household appliances, the optimization of electricity behavior has become an important component of home-based intelligent electricity. In this study, a multi-objective optimization model in an intelligent electricity environment is proposed based on economy and comfort. Firstly, the domestic consumer's load characteristics are analyzed, and the operating constraints of interruptible and transferable electrical appliances are defined. Then, constraints such as household electrical load, electricity habits, the correlation minimization electricity expenditure model of household appliances, and the comfort model of electricity use are integrated into multi-objective optimization. Finally, a continuous search multi-objective particle swarm algorithm is proposed to solve the optimization problem. The analysis of the corresponding example shows that the multi-objective optimization model can effectively reduce electricity costs and improve electricity use comfort.

Multistress Life Models of Epoxy Encapsulated Magnet wire under High Frequency Pulsating Voltage

Grzybowski, S.,Feilat, E.A.,Knight, P. The Korean Institute of Electrical Engineers 2003 KIEE International Transactions on Electrophysics Vol.3C No.1

This paper presents an attempt to develop probabilistic multistress life models to evaluate the lifetime characteristics of epoxy-encapsulated magnet wire with heavy build polyurethane enamel. A set of accelerated life tests were conducted over a wide range of pulsating voltages, temperatures, and frequencies. Samples of fine gauge twisted pairs of the encapsulated magnet wire were tested us-ing a pulse endurance dielectric test system. An electrical-thermal lifetime function was combined with the Weibull distribution of lifetimes. The parameters of the combined Weibull-electrical-thermal model were estimated using maximum likelihood estimation. Likewise, a generalized electrical-thermal-frequency life model was also developed. The parameters of this new model were estimated using multiple linear regression technique. It was found in this paper that lifetime estimates of the two proposed probabilistic multistress life models are good enough. This suggests the suitability of using the general electrical-thermal-frequency model to estimate the lifetime of the encapsulated magnet wire over a wide range of voltages, temperatures and pulsating frequencies.

An Innovative Solution for the Power Quality Problems in Induction Motor by Using Silica and Alumina Nano Fillers Mixed Enamel for the Coatings of the Windings

Mohanadasse, K.,Sharmeela, C.,Selvaraj, D. Edison The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.4

Power quality has always been a concern of power engineers. Certainly an argument can be successfully made that most parts of power engineering have the ultimate objective to improve power quality. AC motors were widely used in industrial and domestic applications. Generally, AC motors were of two types: Induction and Synchronous motors. In motor many parameters like different load cycling, switching, working in hot weather and unbalances creates harmonics which creates major reasons for temperature rise of the motors. Due to high peak value of voltage, harmonics can weaken insulation in cables, windings and capacitors and different electronic components. Higher value of harmonics increase the motor current and decrease the power factor which will reduce the life time of the motor and increase the overall rating of all electrical equipments. Harmonics reduction of all the motors in India will save more power. Coating of windings of the motor with nano fillers will reduce the amount of harmonics in the motor. Based on the previous project works, actions were taken to use the enamel filled with various nano fillers for the coating of the windings of the different AC motors. Ball mill method was used to convert the micro particles of Al₂O₃, SiO₂, TiO₂, ZrO₂ and ZnO into nano particles. SEM, TEM and XRD were used to augment the particle size of the powder. The synthesized nano powders were mixed with the enamel by using ultrasonic vibrator. Then the enamel mixed with the nano fillers was coated to the windings of the several AC motors. Harmonics were measured in terms of various indices like THD, VHD, CHD and DIN by using Harmonic analyzer. There are many other measures and indices to describe power quality, but none is applicable in all cases and in many instances, these indices may hide more than they show. Sometimes power quality indices were used as a basis of comparison and standardization. The efficiency of the motors was increased by 5 – 10 %. The thermal withstanding capacity of the motor was increased by 5º to 15º C. The harmonics of the motors were reduced by 10 – 50%.

A Study on New Power Business Model Using Power Information Technology

Bae, Sung-Hwan,Kim, Ja-Hee,Lim, Han-Seung The Korean Institute of Electrical Engineers 2010 Journal of Electrical Engineering & Technology Vol.5 No.3

The Korea Electric Power Corporation (KEPCO) recorded 2.9 trillion won deficit in the aftermath of the world financial crisis. KEPCO is trying to escape from the business crisis in every way; however, it is impossible to make huge profit by selling electricity alone. Overseas electrical utilities make profits by selling gas and heat along with electricity. However, it is difficult for KEPCO to enter the gas and the heat selling market because other public companies are already dealing with them. In this situation, improving the business is possible when KEPCO develops a new business model and creates added value using Korean advanced Power IT combined with electricity. This study shows a new business model using Power IT, based on a survey targeting managers in KEPCO branch office and electrical engineers in the field. We hope the new business model suggested in this study is adapted to the real field to create high value in the future.

Impact of Equivalent Oxide Thickness on Threshold Voltage Variation Induced by Work-Function Variation in Multigate Devices

Lee, Youngtaek,Shin, Changhwan Institute of Electrical and Electronics Engineers 2017 IEEE transactions on electron devices Vol. No.

<P>Using 3-D technology computer aided design simulation, we investigated the impact of equivalent oxide thickness (EOT) on threshold voltage (V-TH) variation induced by work-function variation (WFV) in multigate devices. The WFV-induced VTH variation in multigate devices does not significantly vary with the dielectric constant of the gate dielectric material, but increases with decreasingphysicaloxide thickness(T-OX). As T-OX becomes thinner, electric field tends to be locally concentrated, causing a large variation of electrostatic potential in channel. The slope of the ratio of average grain size to gate area (RGG) plot is observed with various oxide thicknesses. It is confirmed that we can alleviate the WFV-induced VTH variation without significant performance degradation if gate dielectric layer becomes thicker with appropriately adopted higher-k engineering. In addition, the impact of EOT (including interface layer) on the WFV-induced VTH variation is studied.</P>

Design Method of an Ultrahigh Speed PM Motor/Generator for Electric-Turbo Compounding System

Jung, Dong-Hoon,Lee, Jae-Kwang,Kim, Jun-Young,Jang, Ik Sang,Lee, Ju,Lee, Ho-Joon Institute of Electrical and Electronics Engineers 2018 IEEE transactions on applied superconductivity Vol.28 No.3

<P>This paper presents the design of an ultrahigh speed permanent magnet (PM) motor/generator driven at a rated output and speed of 10 kW and 70 000 r/min, respectively, for use in an electric-turbo compounding system. When designing the very-high speed motor/generator, the mechanical and structural safety of the rotor and losses that occur when the motor operates at high speed should be considered for safe operation. In this paper, the optimal design of the ultrahigh speed PM motor is performed with finite element analysis and structural analysis. Especially, the electromagnetic and structural characteristics based on the sleeve material are analyzed. The optimal design for PM motor, using carbon fiber is proposed not only to reduce the eddy-current loss, which prominently occurs at very-high speed, but also to ensure its structural safety. Finally, the validity of the design method and the effectiveness of the fabricated prototype of PM motor is verified through experimental tests.</P>

Operational Characteristics of a Small-Scale Novel Hybrid Resistive-Type SFCL With Controlled Power Electronics

Nam, Seokho,Lee, Jiho,Lee, Woo Seung,Park, Young Gun,Song, Seunghyun,Jin, Hongwoo,Ko, Tae Kuk Institute of Electrical and Electronics Engineers 2015 IEEE transactions on applied superconductivity Vol.25 No.3

<P>As electric power systems become more complicated, the fault current experiences more frequent changes. To solve this problem, we suggest a novel hybrid-type superconducting fault current limiter (SFCL). Some issues accompany application of resistive-type SFCLs to electric power systems, including initial installation price, operation and maintenance costs, and high-current problems. To overcome these problems, <I>hybrid SFCLs </I> have been developed in some institutions. This paper presents experimental tests of a novel hybrid-type SFCL composed of a resistive superconducting coil, two thyristors, and a control circuit. The superconducting coil limits the first peak of the fault current, and the thyristors control the magnitude of the fault current other than the first peak by adjusting the firing angles. The interactions between the superconducting coil and the thyristors reduce the use of superconducting wire.</P>