• Title/Summary/Keyword: Power transfer distribution factor

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Characteristics of Wireless Power Transmission Using Superconductor Coil to Improve the Efficiency According to the Shielding Materials (초전도 공진 코일의 효율성을 높이기 위한 차폐 재질에 따른 무선전력전송 효율비교 분석)

  • Lee, Yu-Kyeong;Jeong, In-Sung;Hwang, Jun-Won;Choi, Hyo-Sang
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.4
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    • pp.684-688
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    • 2016
  • The magnetic resonance method requires high quality factor(Q-factor) of resonators. Superconductor coils were used in this study to increase the Q-factor of wireless power transfer(WPT) systems in the magnetic resonance method. The results showed better transfer efficiency compared to copper coils. However, as superconducting coils should be cooled below critical temperatures, they require cooling containers. In this viewpoint, shielding materials for the cooling containers were applied for the analysis of the WPT characteristics. The shielding materials were applied at both ends of the transmitter and receiver coils. Iron, aluminum, and plastic were used for shielding. The electric field distribution and S-parameters (S11, S21) of superconducting coils were compared and analyzed according to the shield materials. As a result, plastic shielding showed better transfer efficiency, while iron and aluminum had less efficiency. Also, the maximum magnetic field distribution of the coils according to the shielding materials was analyzed. It was found that plastic shielding had 5 times bigger power transfer rate than iron or aluminum. It is suggested that the reliability of superconducting WPT systems can be secured if plastic is used for the cooling containers of superconducting resonance coils.

Optimal Congestion Management Based on Sensitivity in Power System with Wind Farms (민감도를 이용하여 풍력단지가 연계된 송전계통의 최적혼잡처리)

  • Choi, Soo-Hyun;Kim, Kyu-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.12
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    • pp.1965-1970
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    • 2016
  • This paper studies generator rescheduling technique for congestion management in power system with wind farms. The proposed technique is formulated to minimize the rescheduling cost of conventional and wind generators to alleviate congestion subject to operational line overloading. The generator rescheduling method has been used with incorporation of wind farms in the power system. The locations of wind farms are selected based upon power transfer distribution factor (PTDF). Because all generators in the system do not need to participate in congestion management, the rescheduling has been done by generator selection based on the proposed generator sensitivity factor (GSF). The selected generators have been rescheduled using linear programming(LP) optimization techniques to alleviate transmission congestion. The effectiveness of the proposed methodology has been analyzed on IEEE 14-bus systems.

A Study on an Transmission Right Issuance Quantity Assessment Method by using Power Transfer Distribution Factor(PTDF) under FlowGate Right(FGR) (FlowGate Right(FGR) 도입 시 Power Transfer Distribution Factor(PTDF)를 이용한 송전권 계약용량 산정 방법 연구)

  • Baeck, Woong-Ki;Bang, Young-Sun;Chun, Yeong-Han;Kim, Jung-Hoon;Kwak, No-Hong;Lee, Baek-Seok
    • Proceedings of the KIEE Conference
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    • pp.861-863
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    • 2005
  • LMP based congestion management method is suggested as an effective tool, because network congestion can be handled by energy price. It is now being widely used in the North American Electricity Markets. Among them, FGR(Flow-gate rights) is considered to be appropriate for our system, as power flow through the congested line is unidirectional and congestion occurs in the known place. In the CBP market, hedging through transmission right is not necessary even though location pricing system is adopted, because there are no risks in the energy price. Rut, transmission rights should be adopted in the advanced market. Key issue when implementing FGR is how to decide transmission right issuance quantify. This paper deals with a method to decide transmission right issuance quantity by using power. Transfer Distribution Factor(PTDF).

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A Study of TRM and ATC Determination for Electricity Market Restructuring (전력산업 구조개편에 대비한 적정 TRM 및 ATC 결정에 관한 연구)

  • 이효상;최진규;신동준;김진오
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.53 no.3
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    • pp.129-134
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    • 2004
  • The Available Transfer Capability (ATC) is defined as the measure of the transfer capability remaining in the physical transmission network for further commercial activity above already committed uses. The ATC determination s related with Total Transfer Capability (TTC) and two reliability margins-Transmission Reliability Capability (TRM) and Capacity Benefit Margin(CBM) The TRM is the component of ATC that accounts for uncertainties and safety margins. Also the TRM is the amount of transmission capability necessary to ensure that the interconnected network is secure under a reasonable range of uncertainties in system conditions. The CBM is the translation of generator capacity reserve margin determined by the Load Serving Entities. This paper describes a method for determining the TTC and TRM to calculate the ATC in the Bulk power system (HL II). TTC and TRM are calculated using Power Transfer Distribution Factor (PTDF). PTDF is implemented to find generation quantifies without violating system security and to identify the most limiting facilities in determining the network’s TTC. Reactive power is also considered to more accurate TTC calculation. TRM is calculated by alternative cases. CBM is calculated by LOLE. This paper compares ATC and TRM using suggested PTDF with using CPF. The method is illustrated using the IEEE 24 bus RTS (MRTS) in case study.

Transfer Capability Enhancement to Population Center Using VSC HVDC System (부하집중지로의 송전용량 증대를 위한 전압형 HVDC의 활용 방안)

  • Oh, Sea-Seung;Han, Byung-Moon;Cha, Jun-Min;Jang, Gil-Soo
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.55 no.6
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    • pp.236-241
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    • 2006
  • This paper presents a transfer capability enhancement process using VSC HVDC system which can control active power as well as reactive power. The transfer capability is constrained by stability like voltage stability as well as thermal rating of power system components. Transfer capability of the power system limited by these constraints may be enhanced by reactive power control ability and active power flow control ability of the VSC HVDC system. To enhance the transfer capability of the system using VSC HVDC, selection of the HVDC installation site is performed. In this work, power zones which consist of major power plants and their sinks are identified using power tracing and distribution factor. Alternative route of major AC transmission line in the power zone is identified as VSC HVDC system.

A Study on the Minimization of Generation Cost of an Individual Power Generation Considering Available Transfer Capability(ATC) (가용송전용량을 고려한 각 발전회사의 발전비용 최소화 기법 개발에 관한 연구)

  • Jeong, Sung-Won;Gim, Jae-Hveon
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.54 no.12
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    • pp.586-591
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    • 2005
  • This paper presents a method of minimizing of generation cost on individual electrical power utility. The method is based on the Economic Dispatch (ED) and linear Available Transfer Capability (ATC). The economic dispatch redistributes the total load to individual units to minimize the generation cost without transmission network constraints. The proposed method is implemented using ATC calculated from Power Transfer Distribution Factor (PTDF) for the transmission network constraints. The performance of the proposed method has been tested for the IEEE-30 bus system. It has also been observed that the results of the proposed method is compared with that of optimal power flow.

Numerical analysis of heat transfer and friction factors in a duct having circular perforated baffles (원형 다공배플이 있는 덕트에서의 열전달과 마찰계수에 관한 수치해석)

  • Oh, S.K.;Ahn, S.W.;Ary, Bachtiar Krishna Putra;Bae, S.T.
    • Journal of Power System Engineering
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    • v.16 no.4
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    • pp.44-50
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    • 2012
  • The present numerical study was performed to determine how the two perforated baffles( Inclined angle=$5^{\circ}$; perforation diameter=2cm) placed at a rectangular duct affect heat transfer and associated friction factors. The parametric effects of perforated baffles(3, 6 and 12 holes) and flow Reynolds number ranging from 28,900 to 61,000 on the heated target surface are explored. As for the investigation of heat transfer behaviours on the local Nusselt number with two baffles placed at $x/D_h=0.8$ and $x/D_h=0.8$ of the edge baffles, it is evident that the average Nusselt number increases with increasing number of holes, but the friction factor decreases with an increase in the hole number placed at baffles. The numerical results by commercial code CFX 10.0 are confirmed with the experimental data.

An Analysis of Indoor Thermal Environment by Macro Model (매크로 모델에 의한 실내온열환경 검토)

  • Jung, Jae-Hoon
    • Proceedings of the SAREK Conference
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    • pp.584-589
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    • 2008
  • It is known that slab thermal storage which uses concrete slab as thermal material is effective in the load leveling and using the nighttime electric power. The temperature distribution is not constant in plenum in thermal storage time by beams, ducts such as several factor. It is considered that this fact will effect on efficiency of thermal storage and indoor thermal environment. The purpose of this paper is to examine the thermal environment inside plenum. A macro model was made for the analysis of indoor thermal environment as the first step. The flow rate distribution and temperature distribution of object room model was examined by use of basic equations such as airflow by the pressure difference between unit cells, heat flow by air and heat transfer.

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A Numerical Study on the Design of Exchanger for Desiccant Dehumidifier (데시칸트 제습기용 열교환기 설계에 관한 수치해석적 연구)

  • Kim, Chi-Wan;Ahn, Young-Chull;Kim, Gil-Tae
    • Journal of Power System Engineering
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    • v.17 no.6
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    • pp.54-62
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    • 2013
  • A numerical analysis is performed to evaluate mass flow balance in the heat exchanger for the dehumidifier. To improve the mass flow balance for maximum heat transfer performance, inlet, outlet and baffle are changed. Mass flow balance is evaluated by non-uniformity of flow which is the same concept with the standard deviation. Usually, there will occur many paths between the inlet and the outlet, however, it will follow shortest and low resistance ways. The uniform distribution of flow is numerically analyzed for several types of heat exchangers. Making the shortest way between the inlet and the outlet is most important factor. Two types of heat exchangers are installed in the dehumidifier and 4 cases of Type A heat exchangers and 3 cases of Type B heat exchangers are evaluated and optimized. The result of this research is applied to design heat exchanger for commercial dehumidifiers.

Effect of Financial Transmission Rights on the Strategic Bidding Behavior of the Electricity Producers (재무적 송전권이 발전사의 전략적 입찰에 미치는 영향)

  • Lee, Kwang-Ho;Shin, Jae-Hong
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.7
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    • pp.1226-1231
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    • 2010
  • This paper looks at the influence of Financial Transmission Rights (FTRs) on the market value(Social Welfare; SW) in the competitive electricity market. The transmission line constraints make it difficult to compute the Nash Equilibrium (NE) due to causing a mixed strategy NE instead of a pure strategy NE. Computing a mixed strategy is more complicated in a multi-player game. The aim of this paper are to compute a mixed strategy NE and analyze SW in power transaction with FTRs. This paper introduces a formula and a technique for solving NE of multi-player game with FTRs. In addition, it analyzes the influence of holding of FTRs by generation company on SW and it proposes the SW at NE is influenced by Power Transfer Distribution Factor (PTDF) where holder of FTRs are located. The assertion is verified by calculating the mixed strategy utilizing the Cournot model widely used for studies on FTRs.