• Title/Summary/Keyword: Wind power system

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CCT Analysis of Power System Connected to DFIG Wind Turbine (DFIG 풍력터빈이 연계된 전력계통의 CCT 영향분석)

  • Seo, Gyu-Seok;Park, Ji-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.5
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    • pp.2388-2392
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    • 2013
  • Wind generation systems are very different in nature from conventional generation systems. Therefore it is necessary to research dynamic characteristics of wind generation systems connected to a power system. The stability analysis of wind turbine generator is an important issue in the operation of the power system. The result of angular stability of the power system that consists of only synchronous generators is different from that of the power system including wind turbine generators. This is due to the fact that generators connected to wind turbines are generally induction generators. The angular stability assessing synchronization of generators is determined by its corresponding critical clearing time(CCT). Wind turbine models for the analysis of power system are varied and difficult to use, but now these are standardized into four types. In this paper, the analysis of the CCT of the power system connected to wind farm considering the location and capacity is performed by using DFIG(Doubly-Fed induction Generator) wind turbine built-in type3 model in PSS/E-32.

Pitch Angle Control and Wind Speed Prediction Method Using Inverse Input-Output Relation of a Wind Generation System

  • Hyun, Seung Ho;Wang, Jialong
    • Journal of Electrical Engineering and Technology
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    • v.8 no.5
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    • pp.1040-1048
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    • 2013
  • In this paper, a sensorless pitch angle control method for a wind generation system is suggested. One-step-ahead prediction control law is adopted to control the pitch angle of a wind turbine in order for electric output power to track target values. And it is shown that this control scheme using the inverse dynamics of the controlled system enables us to predict current wind speed without an anemometer, to a considerable precision. The inverse input-output of the controlled system is realized by use of an artificial neural network. The proposed control and wind speed prediction method is applied to a Double-Feed Induction Generation system connected to a simple power system through computer simulation to show its effectiveness. The simulation results demonstrate that the suggested method shows better control performances with less control efforts than a conventional Proportional-Integral controller.

Study on Impact of Wind Power in Grid Frequency Quality of Stand-alone Microgrid (독립형 마이크로그리드내 풍력발전출력이 주파수 품질에 미치는 영향 분석)

  • Huh, Jae-Sun;Kim, Jae-Chul
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.30 no.3
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    • pp.79-85
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    • 2016
  • This paper analyzed the influence of wind power fluctuations in grid frequency of a stand-alone microgrid that is hybrid generation system with diesel generator, wind turbine, and Battery Energy Storage System (BESS). The existing island area power system consists of only diesel generators. So the grid frequency can be controllable from load change. But hybrid generation system with Renewable Energy Sources (RES) such as wind energy that has the intermittent output can bring power quality problems. BESS is one of the ways to improve the intermittent output of the RES. In this paper, we analyzed the role of BESS in a stand-alone microgrid. We designed a modelling of wind power system with squirrel-cage induction generator, diesel power system with synchronous generator, and BESS using transient analysis program PSCAD/EMTDC. And we analyzed the variation of the grid frequency according to the output of BESS.

Modified Control Scheme to Regulate the Active Power Output of Doubly Fed Induction Generator (이중여자 권선형 유도발전기의 출력조정을 위한 제어 기법)

  • Park, Young-Ho;Won, Dong-Jun;Park, Jin-Woo;Moon, Seung-Il
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.1232-1233
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    • 2007
  • As the number of wind turbines installed increase, the power from wind energy starts to replace conventional generation units and its influence on power system can not be neglected. Because of the intermittent nature of wind resource, the output power of wind turbine fluctuates according to wind speed variation. In this point of view, it is necessary for wind turbines to be equipped with power regulation ability. The doubly fed induction generator (DFIG) is one of the main techniques used in variable speed wind turbines. This thesis focuses on the development of modified control scheme of DFIG to regulate output power. The proposed control scheme achieves active power output regulation so as to stabilize the power system.

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Voltage Sag Assessment Considering the Characteristics of Wind Power (풍력 발전 특성을 고려한 순간전압강하 평가)

  • Song, Young-Won;Park, Chang-Hyun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.11
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    • pp.1571-1577
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    • 2012
  • This paper presents a method for assessing the voltage sag performance of power system involving wind power generation. Wind power generation is considered as one of the most desirable renewable energy sources. However, wind power generation have uncertain energy output and it is difficult to control the output. The existing methods of voltage sag assessment are not reflected the characteristics of wind power generation. Therefore, in order to more accurately assess the voltage sag performance, the probability of wind power operation is evaluated. In this paper, the probability is determined by combining the wind speed model with the output curve of wind turbine. The probability of wind power operation is reflected as a parameter in voltage sag assessment. The proposed method can provide more accurate results of voltage sag assessment for the case involving the wind power generation.

Analyzing effects of the BESS for wind farm in Jeju Island (제주지역 풍력발전단지의 BESS 적용효과 분석)

  • Lee, Doheon;Kim, Eel-Hwan;Kim, Ho-Min;Kim, Seung Hyun
    • Journal of the Korean Solar Energy Society
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    • v.34 no.4
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    • pp.67-74
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    • 2014
  • The fluctuation of the output power of wind farms will be able to cause the impact on the Jeju power system such as power quality and stability. To settle the matter, many researchers have proposed the use of the BESS(Battery Energy Storage System) in the wind farm. In this paper, The BESS is applied to each wind farms for mitigating the fluctuation of wind power output. The BESS is controlled for smoothing the output of wind farms. Two kinds of simulation will be carried out. First, the simulation results by using PSCAD/EMTDC simulation program are compared to the measured data from the real power grid in Jeju Island. The other is to analyze the output of wind farms when the BESS is applied to the simulation works. The simulation results will demonstrate the effectiveness of using BESS to stabilize for power grid in Jeju Island.

Study of Power System Impact Assessment Standard for Large-scale Wind Farms (풍력발전 계통연계 평가기준 연구)

  • Choy, Young-Do;Jeon, Young-Soo;Park, Young-Shin;Jeon, Dong-Hoon;Yoon, Ki-Kab;Park, Sang-Ho;Shin, Jung-Hoon;Lee, Jae-Gul
    • New & Renewable Energy
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    • v.6 no.1
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    • pp.12-19
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    • 2010
  • In Korea, experiences in wind farm operation are limited and the foundation for setting standards in electrical system connection is still weak in comparison to the operation experience in connection of wind power to the electrical system of other countries around the world. Therefore, standards that are being applied in various countries for connection and optimal operation in wind farms need to be examined, and in addition, procedures for the assessment of the effects on the system are needed for setting connection standards and optimal operation plans in accordance with Korean electrical system characteristics. In this study, procedures for the assessment of effects of wind power connection to the electrical system are presented.

Power Smoothing of a Variable-Speed Wind Turbine Generator Based on the Rotor Speed-Dependent Gain (회전자 속도에 따라 변하는 게인에 기반한 가변속 풍력발전기 출력 평활화)

  • Kim, Yeonhee;Kang, Yong Cheol
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.4
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    • pp.533-538
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    • 2016
  • In a power grid that has a high penetration of wind power, the highly-fluctuating output power of wind turbine generators (WTGs) adversely impacts the power quality in terms of the system frequency. This paper proposes a power smoothing scheme of a variable-speed WTG that can smooth its fluctuating output power caused by varying wind speeds, thereby improving system frequency regulation. To achieve this, an additional loop relying on the frequency deviation that operates in association with the maximum power point tracking control loop, is proposed; its control gain is modified with the rotor speed. For a low rotor speed, to ensure the stable operation of a WTG, the gain is set to be proportional to the square of the rotor speed. For a high rotor speed, to improve the power smoothing capability, the control gain is set to be proportional to the cube of the rotor speed. The performance of the proposed scheme is investigated under varying wind speeds for the IEEE 14-bus system using an EMTP-RV simulator. The simulation results indicate that the proposed scheme can mitigate the output power fluctuation of WTGs caused by varying wind speeds by adjusting the control gain depending on the rotor speed, thereby supporting system frequency regulation.

Flicker Suppression Scheme for Variable-Speed Wind Turbine Systems

  • Van, Tan Luong;Nguyen, Thanh Hai;Lee, Dong-Choon
    • Journal of Power Electronics
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    • v.12 no.2
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    • pp.333-343
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    • 2012
  • This paper proposes a strategy of flicker mitigation for doubly-fed induction generator (DFIG) wind turbine systems. In the weak grid system where the grid impedance ratio is low, the reactive power compensation only cannot suppress the flicker sufficiently due to the limited power capacity of the converters or the DFIG. For the full suppression of flickers, the active power smoothening using the energy storage system (ESS) needs to be utilized together with the reactive power compensation. The effectiveness of the proposed method is verified by PSCAD/EMTDC simulation results for a 2[MW] DFIG wind turbine system and by experimental results for a 3[kW] wind turbine simulator.

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.