• Title/Summary/Keyword: Grid-based control

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The Consumer Rationality Assumption in Incentive Based Demand Response Program via Reduction Bidding

  • Babar, Muhammad;Imthias Ahamed, T.P.;Alammar, Essam A.
    • Journal of Electrical Engineering and Technology
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    • v.10 no.1
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    • pp.64-74
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    • 2015
  • Because of the burgeoning demand of the energy, the countries are finding sustainable solutions for these emerging challenges. Demand Side Management is playing a significant role in managing the demand with an aim to support the electrical grid during the peak hours. However, advancement in controls and communication technologies, the aggregators are appearing as a third party entity in implementing demand response program. In this paper, a detailed mathematical framework is discussed in which the aggregator acts as an energy service provider between the utility and the consumers, and facilitate the consumers to actively participate in demand side management by introducing the new concept of demand reduction bidding (DRB) under constrained direct load control. Paper also presented an algorithm for the proposed framework and demonstrated the efficacy of the algorithm by considering few case studies and concluded with simulation results and discussions.

A New Required Reserve Capacity Determining Scheme with Regard to Real time Load Imbalance

  • Park, Joon Hyung;Kim, Sun Kyo;Yoon, Yong Tae
    • Journal of Electrical Engineering and Technology
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    • v.10 no.2
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    • pp.511-517
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    • 2015
  • Determination of the required reserve capacity has an important function in operation of power system and it is calculated based on the largest loss of supply. However, conventional method cannot be applied in future power system, because potential grid-connected distributed generator and abnormal temperature cause the large load imbalance. Therefore this paper address new framework for determining the optimal required reserve capacity taking into account the real time load imbalance. At first, we introduce the way of operating reserve resources which are the secondary, tertiary, Direct Load Control (DLC) and Load shedding reserves to make up the load imbalance. Then, the formulated problem can be solved by the Probabilistic Dynamic Programming (PDP) method. In case study, we divide two cases for comparing the cost function between the conventional method and the proposed method.

A Study on Constant Power Control of Doubly-fed Induction Generator for Wind Turbines (풍력발전을 위한 권선형 유도발전기의 정출력 제어에 관한 연구)

  • Kim, Rae-Young;Suh, In-Young;Song, Jong-Hwan
    • Proceedings of the KIEE Conference
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    • 2001.07b
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    • pp.1312-1314
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    • 2001
  • This paper presents a constant power controller for doubly-fed. Induction generators used in wind turbines. When the stator side of the generator is connected to the grid, the generated power depends on the rotor current. To control the rotor current based on it's average value, a cost effective SPC (Slip Power Controller) was developed and is ready for testing with an actual 660KW generator system. Experiment results are presented and discussed.

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2D Grid Map Compensation using an ICP Algorithm (ICP 알고리즘을 이용한 2차원 격자지도 보정)

  • Lee, Dong-Ju;Hwang, Yu-Seop;Yun, Yeol-Min;Lee, Jang-Myung
    • Journal of Institute of Control, Robotics and Systems
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    • v.20 no.11
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    • pp.1170-1174
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    • 2014
  • This paper suggests using the ICP (Iterative Closet Point) algorithm to compensate a two-dimensional map. ICP algorithm is a typical algorithm method using matching distance data. When building a two-dimensional map, using data through the value of a laser scanner, it occurred warping and distortion of a two-dimensional map because of the difference of distance from the value of the sensor. It uses the ICP algorithm in order to reduce any error of line. It validated the proposed method through experiment involving matching a two-dimensional map based reference data and measured the two-dimensional map.

An active damping method based on virtual series resistances with inductors of LCL filter for three-phase grid-tied inverter (인덕터 내부저항을 고려한 LCL 필터의 능동댐핑 특성)

  • Kim, Yong-Jung;Kim, Hyosung
    • Proceedings of the KIPE Conference
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    • 2015.07a
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    • pp.363-364
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    • 2015
  • 최근 에너지 저장장치의 사용과 신재생에너지를 이용한 분산발전의 규모가 점차 확대됨에 따라 계통에 원활한 전류주입과 주입 전류의 스위칭 고조파 리플성분 저감을 위해 LCL 필터를 이용한 계통연계형 인버터가 널리 사용되고 있다. 이러한 계통연계형 인버터의 주입전류 특성은 LCL 필터에 종속적이기 때문에 정밀한 주입전류제어를 위해 LCL 필터의 정확한 해석이 요구된다. 본 논문에서는 명확한 LCL 필터 해석을 위해 LCL 필터의 인덕터 직렬 내부저항을 고려한 LCL 필터 특성을 해석하였으며, 이러한 해석을 기반으로 LCL필터 공진현상에 따른 주입전류의 THD를 저감하기 위한 인덕터 가상 직렬저항 능동댐핑 기법을 제안하고 HILS 실험을 통해 제안하는 능동댐핑 기법의 성능을 검증하였다.

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A Numerical Study on Mixing Characteristics of the Chemical Injection Tank

  • Chang, Keun-Sun;Park, Byeong-Ho
    • Nuclear Engineering and Technology
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    • v.29 no.1
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    • pp.58-67
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    • 1997
  • A numerical study has been peformed to investigate the flow and mixing characteristics of a chemical injection tank in the chemical and volume control system (CVCS) of Yonggwang 5&6 (YGN 5&6). This study was undertaken to provide a basis for modification of the previous design (YGN 3&4) which gave a lot of difficulties in installation and operation of the chemical injection system during the start-up test because it needs a special reciprocating pump with a high actual head. For the tank of length-to-diameter ratios (L/D) of 1,2 and 3, each with and without a baffle inside, calculation results were obtained by solving the unsteady laminar two-dimensional elliptic forms of governing equations for the mass, momentum and species concentration. Finite-difference method was used to obtain discretized equations, and the SIMPLER solution algorithm, which was developed based on the staggered grid control volume, was employed for the calculation procedure. Results showed that the baffle is very effective in enhancing the mixing in the tank and that a baffle should be installed near the tank entrance in order to 110 chemicals into the reactor coolant system (RCS) within the operating time required.

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High-Performance Control of Three-Phase Four-Wire DVR Systems using Feedback Linearization

  • Jeong, Seon-Yeong;Nguyen, Thanh Hai;Le, Quoc Anh;Lee, Dong-Choon
    • Journal of Power Electronics
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    • v.16 no.1
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    • pp.351-361
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    • 2016
  • Power quality is a critical issue in distribution systems, where a dynamic voltage restorer (DVR) is commonly used to mitigate the voltage disturbances for loads. This paper deals with a nonlinear control for the three-phase four-wire (3P-4W) DVR under a grid voltage unbalance and nonlinear loads in the distribution system, where a novel control scheme based on the feedback linearization technique is proposed. Through feedback linearization, a nonlinear model of a DVR with a PWM voltage-source inverter (VSI) and LC filters is linearized. Then, the controller design of the linearized model is performed by applying the linear control theory, where the load voltages are kept constant by controlling the d-q-0 axis components of the DVR output voltages. To keep the load voltage unchanged, an in-phase compensation strategy is employed, where the load voltages are recovered to be the same as the previous voltage without a change in the magnitude. With this strategy, the performance of the DVR becomes faster and more stable even under unbalanced source voltages and nonlinear loads. The validity of the proposed control strategy has been verified by simulation and experimental results.

Impact of Cumulus Parameterization Schemes with Different Horizontal Grid Sizes on Prediction of Heavy Rainfall (적운 모수화 방안이 고해상도 집중호우 예측에 미치는 영향)

  • Lee, Jae-Bok;Lee, Dong-Kyou
    • Atmosphere
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    • v.21 no.4
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    • pp.391-404
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    • 2011
  • This study investigates the impact of cumulus parameterization scheme (CPS) with different horizontal grid sizes on the simulation of the local heavy rainfall case over the Korean Peninsula. The Weather Research and Forecasting (WRF)-based real-time forecast system of the Joint Center for High-impact Weather and Climate Research (JHWC) is used. Three CPSs are used for sensitivity experiments: the BMJ (Betts-Miller-Janjic), GD (Grell-Devenyi ensemble), and KF (Kain-Fritsch) CPSs. The heavy rainfall case selected in this study is characterized by low-level jet and low-level transport of warm and moist air. In 27-km simulations (DM1), simulated precipitation is overestimated in the experiment with BMJ scheme, and it is underestimated with GD scheme. The experiment with KF scheme shows well-developed precipitation cells in the southern and the central region of the Korean Peninsula, which are similar to the observations. All schemes show wet bias and cold bias in the lower troposphere. The simulated rainfall in 27-km horizontal resolution has influence on rainfall forecast in 9-km horizontal resolution, so the statements on 27-km horizontal resolution can be applied to 9-km horizontal resolution. In the sensitivity experiments of CPS for DM3 (3-km resolution), the experiment with BMJ scheme shows better heavy rainfall forecast than the other experiments. The experiments with CPS in 3-km horizontal resolution improve rainfall forecasts compared to the experiments without CPS, especially in rainfall distribution. The experiments with CPS show lower LCL(Lifted Condensation Level) than those without CPS at the maximum rainfall point, and weaker vertical velocity is simulated in the experiments with CPS compared to the experiments without CPS. It means that CPS suppresses convective instability and influences mainly convective rainfall. Consequently, heavy rainfall simulation with BMJ CPS is better than the other CPSs, and even in 3-km horizontal resolution, CPS should be applied to control convective instability. This conclusion can be generalized by conducting more experiments for a variety of cases over the Korean Peninsula.

Smoke Control According to the Ventilation Capacity in Subway Tunnel Fire: I. FDS Simulation (지하철 터널 화재시 환기시설의 용량에 따른 제연효과 I. FDS 시뮬레이션)

  • Park, Kyung-Jun;Lee, Ki-Jun;Hadi, Bettar El;Lee, Jai-Hyo;Shin, Dong-Il
    • Journal of the Korean Institute of Gas
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    • v.15 no.3
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    • pp.31-38
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    • 2011
  • In this study, we investigate simulation studies to confirm the removal of smoke through ventilation when the subway car is on fire and stopped in an underground subway tunnel, by using Fire Dynamics Simulator (FDS) which is being upgraded by NIST. The structure of subway tunnel and train for simulation modeling are based actual data from Seoul metropolitan subway. The main purpose of this study is to assure the removal efficiency of the ventilation when changing the ventilation capacity between 2.0 m/s and 3.0 m/s. The results of the study shows that carbon monoxide (CO) and carbon dioxide ($CO_2$) are reduced by about 35% as the ventilation capacity is increased by 0.5 m/s. This study also performs the grid sensitivity verification of FDS for improved accuracy of the results. To find the effective size of the grid, three cases are simulated and the results are compared.

Mobile Edge Computing based Charging Infrastructure considering Electric Vehicle Charging Efficiency (전기자동차 충전 효율성을 고려한 모바일 에지 컴퓨팅 기반 충전 인프라 구조)

  • Lee, Juyong;Lee, Jihoon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.10
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    • pp.669-674
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    • 2017
  • Due to the depletion of fossil fuels and the increase in environmental pollution, electric vehicles are attracting attention as next-generation transportation and are becoming popular all over the world. As the interest in electric vehicles and the penetration rate increase, studies on the charging infrastructure with vehicle-to-grid (V2G) technology and information technology are actively under way. In particular, communication with the grid network is the most important factor for stable charging and load management of electric vehicles. However, with the existing centralized infrastructure, there are problems when control-message requests increase and the charging infrastructure cannot efficiently operate due to slow response speed. In this paper, we propose a new charging infrastructure using mobile edge computing (MEC) that mitigates congestion and provides low latency by applying distributed cloud computing technology to wireless base stations. Through a performance evaluation, we confirm that the proposed charging infrastructure (with low latency) can cope with peak conditions more efficiently than the existing charging infrastructure.