• Title/Summary/Keyword: Load composition rate

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A Study on Optimal Configuration Method of Hybrid ESS using Lead-acid and Lithium-ion Batteries for Supply of Variation Loads (변동부하 공급을 위한 하이브리드 ESS의 연축전지와 리튬이온전지의 최적구성방안에 관한 연구)

  • Rho, Dea-seok;Choi, Seong-sik;Lee, Hu-dong;Chang, Byunh-hoon;Kim, Su-yeol
    • KEPCO Journal on Electric Power and Energy
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    • v.2 no.1
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    • pp.49-54
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    • 2016
  • The large scaled lead-acid battery is widely used for efficient operation of the photovoltaic system in many islands. However, lithium-ion battery is now being introduced to mitigate the fluctuation of wind power and to replace lead-acid battery. Therefore, hybrid ESS (Energy Storage system) that combines lithium-ion battery with lead-acid battery is being required because lithium-ion battery is costly in present stage. Under this circumstance, this paper presents the optimal algorithm to create composition rate of hybrid ESS by considering fixed and variable costs in order to maximize advantage of each battery. With minimization of total cost including fixed and variable costs, the optimal composition rate can be calculated based on the various scenarios such as load variation, life cycle and cost trend. From simulation results, it is confirmed that the proposed algorithms are an effective tool to produce a optimal composition rate.

Grouping Method of Loads to Verify the Aggregation of Component Load Models (개별부하 축약을 검증하기 위한 집단부하 구성방법에 관한 연구)

  • Ji, Pyeong-Shik;Lee, Jong-Pil;Lim, Jae-Yoon
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.50 no.4
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    • pp.172-179
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    • 2001
  • A component based method out of load modeling is to aggregate component load model according to the composition rate of each component load at load bus based on the circuit theory. But the most of component loads respond complex nonlinear characteristics respect to voltage and frequency variation due to the control techniques and semiconductor elements applied to component load. It needs to verify this approach through actual experiment of the aggregation of component load even if it can be down. To identify this aggregation method well known, this paper is proposed the classifying method of component load characteristics for component loads to group by quantitative analysis. The component load characteristics were divided into several types by KSOM (kohonen self organizing map), which can classify multi-dimension vector, component load pattern, into two-dimension vector. Some ambiguous cases happened from KSOM were classified by the proposed closing degree.

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Development of Accurate Load Model for Detailed Power System Stability Analysis (전력계통 안정도 정밀해석을 위한 적정 부하모델 개발)

  • Park, S.W.;Kim, K.D.
    • Proceedings of the KIEE Conference
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    • 2001.05a
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    • pp.201-205
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    • 2001
  • This paper presents the load modeling process and bus load models for KEPCO power system. At first, load devices commonly used in KEPCO power systems were selected, and tested for measuring the voltage and frequency sensitivity of active and reactive power. From this test, about 40 voltage and frequency dependent load models have been obtained. The bus load composition rate for KEPCO power system has been determined using the various recent surveys and papers in order to develop the load model for a power system bus. To verify the accuracy of developed bus load models, the field test for measuring active and reactive power according to artificial variation of the bus voltage was performed at 8 substations for spring summer, autumn, winter cases. With data of this seasonal field test, more reliable bus load models for KEPCO power systems were developed.

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Static Load Modeling Based on Artificial Neural Network and Harmonics (고조파를 고려한 신경회로망 기반의 정태부하모델링)

  • Lee, Jong-Pil;Kim, Sung-Soo
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.62 no.2
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    • pp.65-71
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    • 2013
  • Nonlinear loads with harmonics exist in an actual power system where harmonic currents make voltage distortion. The sum of reactive power measured at individual load is different from the measured reactive power at a bus in a power system with linear and non-linear loads. In this study, ANN(artificial neural network) load modeling technique with consideration of harmonics is introduced for more accurate component load modeling and an impact coefficient is proposed for aggregation of component loads. Results of this research show more accurate load modeling method. Since precise data for power system analysis can be acquired, the proposed method will be used for power system planning and maintenance.

A Study on Power System Analysis Considering Special-days Load Mobility of Electric Vehicle (특수일 이동을 고려한 전기자동차 충전부하의 전력계통 영향에 관한 연구)

  • Hwang, Sung-Wook;Kim, Jung-Hoon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.2
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    • pp.253-256
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    • 2016
  • In this paper, the power system with electric vehicles is analyzed considering the mobility and diffusion rate of electric vehicles in the smart grid environment. In the previous studies, load modeling and load composition rates have been researched and the results are applied to develop a new load model to explain the mobility of electric vehicles which could affect on the power system status such as power flow and stability. The results would be utilized to research and develop power system analysis methods considering movable charging characteristics of electric vehicles including movable discharging characteristics which could be affected by the diffusion progress of electric vehicles.

Reasonable Load Characteristic Experiment for Component Load Modeling (개별 부하모델링을 위한 부하의 합리적인 특성실험)

  • Ji, Pyeong-Sik;Lee, Jong-Pil;Im, Jae-Yun;Chu, Jin-Bu;Kim, Jeong-Hun
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.51 no.2
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    • pp.45-52
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    • 2002
  • Load modeling is classified into two methods according to approaching method, so called the measurement and component-based method. The measurement method is to model the load characteristics measured directly at substations and feeders. But it is difficult to measure continuously load characteristics from naturally occurring. system variation. The component-based method consists of the fellowing process; component load modeling, composition rate estimation and aggregation of component loads, etc. In this paper, the characteristic experiment of component loads was performed to obtain data for the component load modeling as the component-based method. At first, representative component loads were selected by the proposed method considering the accuracy of load modeling and the performance possibility of component load experiment in the laboratory. Also an algorithm was Proposed to identify the reliability of data obtained from the component load characteristic experiments. In addition, the results were presented as the case studies.

A Load Modeling to Utilize Power System Analysis Software (전력계통해석용 프로그램에 적용하기 위한 부하모델링)

  • 지평식
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.13 no.4
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    • pp.96-101
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    • 1999
  • Load model is very important to improve accuracy of stability analysis and load flow study in power systems. A power system bus is composed by various loads, and loads have different power consumption due to voltage/frequency changing. Thus the effect of voltage/frequency changing must he considered to load mxleling. In this research, ANN was used to construct component load moddel for more accurate load mxleling. Typical residential load was selected, and characteristics exrerimented on voltage/frequency changing. Acquired data used to construct the component ANN model, and aggregation method of component load model was presented based on component load model and composition rate. Furthennore, it's transfomlation method to the mathematical load model to he used at the traditional power system analysis soft wares was also presented.sented.

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The Study of Gateway Control Module Using SAE J1939 Protocol (SAE J1939 프로토콜기반 Gateway 제어모듈 개발에 관한 연구)

  • Ko, Youngjin;Kim, Doyeong
    • Transactions of the Korean Society of Automotive Engineers
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    • v.21 no.1
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    • pp.128-136
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    • 2013
  • This study presents the development of Gateway Control Module using SAE J1939 protocol for the commercial vehicles. Presently, the load rate of CAN bus is increased by the single network composition and addition of new ECUs for development of intelligent vehicles. Because the embedded system of the integrated network control function has the errors of the CAN bus caused by the increase of ECU, it is needed for development of commercial vehicles. Also, this study presents the development of smart functions that can diagnosis CAN bus errors, fault diagnosis of ECU and basic function that arbitrates CAN bus between ECUs of commercial vehicle. GCM was designed for 4channel separation about Gateway function as solution of load rate decrease and smart functions. HILS(Hardware in the loop simulation)system that can achieve simulation about CAN Messages of all systems on vehicle was applied to evaluate performance and verification of all functions and performance. The load rate on CAN bus was decreased at using functions what was delivery, block and process of GCM. Through this, it was enabled to organize systematic architecture for gateway.

The Mechanical Property by Fiber Orientation Distributions in Fiber-Reinforced Polymeric Composites (섬유강화 고분자 복합재료에서 섬유배향상태에 따른 기계적 성질)

  • Lee, Dong-Gi;Sim, Jae-Ki;Han, Gil-Young;Kim, Hyuk;Kim, Jin-Woo;Lee, Jung-Ju
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2003.04a
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    • pp.202-205
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    • 2003
  • Investigated whether fiber orientation situation of fiber reinforcement macromolecule composition board and the fiber inclusion rate are perpendicular and horizontal direction tensile strength and some correlation. Fiber orientation situation of tensile strength of 0 direction of composition board increased changelessly by aeolotropy in isotropy. Tensile strength of 90 direction that is isotropy and tensile strength of 0 direction that is aeolotropy agreed almost. Get into aeolotropy, the reinforcement rate of fiber decreased. When load interacts for width direction of reinforcement.

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A Study on Scuffing and the Formation of the Protective Layers Based on Dual Film Formation (이중보호막 모델을 이용한 보호막의 형성과 표면파괴에 관한 연구)

  • 이영제
    • Tribology and Lubricants
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    • v.8 no.2
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    • pp.14-19
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    • 1992
  • rate of growth of "protective" films of oxides and compounds derived from the lubricant. The protection afforded by the films is strongly dependent on lubricant and steel composition, initial composite surface roughness and the load/speed sequence or history in the early stages of sliding. The protective films, formed by chemical and mechanical action between lubricant and mating surfaces, delayed the surface roughening and offered higher load capacity. Given the great number of variables involved it is not possible to follow more than a few of the chemical changes on surfaces at the end of experiments. Ellipsometry was therefore used to monitor the formation and loss of dual protective films in real time, and also to find the effect of protective films on scuffing and break-in depending on lubricant conditions.