• Title/Summary/Keyword: Ramp-up/down Rate

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A Study on Discharge Characteristics of the PDP Packaged with In-situ Vacuum Sealing with the MgO Protective Layer Deposited by Optimal Evaporation Rate (최적 증착 속도로 형성된 MgO를 갖는 인-라인 진공 실장된 플라즈마 디스플레이 패널의 방전 특성에 관한 연구)

  • Li, Zhao-Hui;Cho, Eou-Sik;Kwon, Sang-Jik
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.21 no.10
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    • pp.916-922
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    • 2008
  • AC PDP with MgO protective layer coated with the optimum evaporation rate of $5{\AA}/s$ can generate more enhanced efficiency through the vacuum in-line sealing process. However, the optimized process conditions still require the optimum driving scheme on the ramp-up and ramp-down slope of the reset waveform for enhancing the efficiency. In this paper, for the in-situ vacuum sealed PDP with the optimum evaporation rate of MgO protective layer, the address delay time was investigated with various slopes of ramp waveform during a reset ramp-up and ramp-down period. In this study, the minimum statistical delay time was obtained at the ramp-up rate of $6.0 V/{\mu}s$ and the ramp-down rate of $0.7 V/{\mu}s$ of the reset waveform.

Supervised Shutdown of an Off-shore Wind Farm to meet the Grid Code in a Storm-driven Situation (강풍 시 전력망 연계기준을 만족하는 해상풍력발전단지 강제종료 방법)

  • You, Yue;Kim, Yeon-Hee;Zheng, Tai-Ying;Kang, Yong-Cheol
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.7
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    • pp.1299-1304
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    • 2011
  • A wind turbine (WT) should be shut down as fast as possible to minimize its own damage in a storm-driven situation. Shutdown of a large wind farm requires a power grid to have a ramp-up capability large enough to balance between generation and consumption of electrical energy. This paper proposes a supervised shutdown algorithm of a wind farm to meet a required ramp-down rate in a grid code in the case of a storm-driven situation. The information on the speed and the direction of wind is measured at a wind mast (WM) installed around a wind farm. If the wind speed exceeds a cut-out speed, the number of WTs to be shut down simultaneously is decided to meet a required ramp-down rate of a grid-code. Arrival times to each WT from the WM are calculated and sorted in the order of time. Then a sequence of groups is generated. The shutdown start/end times of each group are decided to avoid superposition between adjacent two groups. The performance of the proposed shutdown algorithm is verified under various storm scenarios. Results indicate that the proposed algorithm can not only protect the wind farm in the case of a storm-driven situation but also meet the required ramp-down rate. In addition, the algorithm can produce more energy than that of a conventional shutdown algorithm.

A Study of Optimal Fuel-Mix Considering Power Generation Operation (발전기 출력특성을 고려한 최적전원구성 연구)

  • Jung, Young-Beom;Kim, Kil-Sin;Park, Chang-Ho;Yoon, Yong-Beom
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.25 no.10
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    • pp.28-37
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    • 2011
  • Though Korea has introduced CBP(Cost Based pool) power trading system since 2001, long-term Generation system planning has been executed by government for Cost minimization every 2 years. Until currently the model which is used for Generation system planning and best-mix only considers cost minimization and total yearly or quarterly electricity demand every year. In a view point of one day power supply operation, technical characteristics, like the ramp up/down rate of total generation system, minimum up/down time and GFRQ(Governor Free Response Quantity), are very important. this paper analyzes Optimal Fuel-Mix for 2022 Korea generation system satisfying these constraints of each fuel type and considering pump storage plants, construction cost and $CO_2$ emission charge Using MILP(Mixed Integer Linear Programming) method. Also the sensitivity analysis which follows in future power industry environmental change accomplished.

Hybrid Artificial Immune System Approach for Profit Based Unit Commitment Problem

  • Lakshmi, K.;Vasantharathna, S.
    • Journal of Electrical Engineering and Technology
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    • v.8 no.5
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    • pp.959-968
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    • 2013
  • This paper presents a new approach with artificial immune system algorithm to solve the profit based unit commitment problem. The objective of this work is to find the optimal generation scheduling and to maximize the profit of generation companies (Gencos) when subjected to various constraints such as power balance, spinning reserve, minimum up/down time and ramp rate limits. The proposed hybrid method is developed through adaptive search which is inspired from artificial immune system and genetic algorithm to carry out profit maximization of generation companies. The effectiveness of the proposed approach has been tested for different Gencos consists of 3, 10 and 36 generating units and the results are compared with the existing methods.

Performance Comparison of Multicast ABR Flow Control Algorithms with Fast Overload Indication in ATM Networks (ATM망에서 신속한 폭주통지 기능을 지닌 멀티캐스트 ABR 흐름제어 알고리즘의 성능비교)

  • Kim, Dong-Ho;Kim, Byung-Chul;Cho, You-Ze;Kwon, Yul
    • Journal of KIISE:Information Networking
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    • v.27 no.1
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    • pp.98-107
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    • 2000
  • This paper compares the performance of feedback consolidation algorithms with or without a fast overload indication function which has been recently proposed in the ATM Forum for multicast ABR (Available Bit Rate) services in ATM networks. We use the performance criteria such as the ACR (Allowed Cell Rate) of a source, queue length at a switch, link utilization, fairness, and BRM (Backward Resource Management) cell overhead. Simulation results show that performance of the feedback consolidation algorithms with a fast overload indication function can be improved sign.ificantly than that of algorithms without this function in terms of ramp-down delay, particularly in initial start-up period or under a severe overload situation. The fast overload indication function can be combined with any feedback consolidation algorithm, whereas its performance is highly dependent on an underlying basic feedback consolidation algorithm.

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