• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.3
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• pp.263-269
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• 2009

This paper describes comparative analysis results about the dynamic interaction of interconnected wind power system using the actual-size hardware simulator and the simulation model with PSCAD/EMTDC. The hardware simulator, which is composed of 2.0MVA induction motor with drive system and 1.5MW doubly-fed induction generator, was built and tested in Go-Chang Test Site of KEPCO for analyzing the dynamic interaction with the interconnected distribution system. The operation of hardware simulator was verified through comparative analysis between experimental results and simulation results obtained by simulation model with PSCAD/EMTDC. The developed hardware simulator and simulation model could be effectively used for analyzing the dynamic interaction, which has various phenomena depending on the wind variation and the network state of interconnected power system.

• Journal of the Korean Solar Energy Society
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• v.32 no.3
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• pp.19-25
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• 2012

About supply and demand to see that you need to match, the limitations of wind power capacity is low demand and the commitment of the general generator will exist between the minimum generation. if the turbine's output can be controlled, The limitation of wind power capacity will be adopted based on instant power generation. Namely, The minimum limits of wind power generation based load operation by calculating the amount that is higher than if the output should be restricted to highest operation. in this paper, we committed to the demand for low enough that the combination of the general generator of wind power capacity to accommodate the operation of determining whether the limit is intended to. For this, power system analysis program PSS/E was used, Jeju system by implementing the model simulations were performed.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.542-545
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• 2009

고창의 전력품질 실증시험장에서 계통에 연계된 풍력발전 시뮬레이터를 이용하여 풍력발전기의 특성을 파악하기 위해, 가변 풍속에서 이중여자 풍력발전기의 회전속도와 유효전력의 변화가 계통에 미치는 영향을 분석하였다. 고창의 전력품질 실증시험장은 22.9kV 계통에 전력품질 향상기기(DVR, STATCOM, SSTS)와 전력품질 외란 발생장치 등이 구축되어 있다. 모터와 VVVF를 이용하여 풍력발전기의 블레이드를 구현하고, 유도형과 이중여자 유도형 풍력발전기를 모의할 수 있는 시뮬레이터를 개발하였다. 선로의 길이를 20 kM로 가정하고, 덕적도의 풍속데이터를 이용한 가변풍속 패턴을 설정하여 풍력발전기의 회전속도에 대한 출력특성을 확인하였다.

• Journal of Power Electronics
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• v.10 no.1
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• pp.72-78
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• 2010

In this paper the operation of a double-fed wound-rotor induction machine, coupled to a wind turbine, as a generator at sub-synchronous speeds is investigated. A novel approach is used in the analysis, namely, the rotor power flow approach. The conditions necessary for operating the machine as a double-fed induction generator (DFIG) are deduced. Formulae describing the factors affecting the range of sub-synchronous speeds within which generation occurs are deduced. The variations in the magnitude and phase angle of the voltage injected to the rotor circuit as the speed of the machine changes to achieve generation at the widest possible sub-synchronous speed range is presented. Also, the effect of the rotor parameters on the generation range is presented. The analysis proved that the generation range could increase from sub-synchronous to super-synchronous speeds, which increases the amount of energy captured by the wind energy conversion system (WECS) as result of utilizing the power available in the wind at low wind speeds.

• Journal of Power Electronics
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• v.9 no.4
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• pp.612-622
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• 2009

The short circuit ratio (SCR) of a given grid is able to show the stability of the system in the case of unwanted elements, such as wind turbulence. This paper presents the simulation of a model of the doubly fed induction generator in the simulation software PSCAD/EMTDC. This model has been used to study flicker during continuous operation and the effect of SCR and grid impedance angle on flicker emission. Simulation results show that compensation of the stator reactive power is an effective method to considerably reduce the flicker levels, irrespective of the grid conditions.

• New & Renewable Energy
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• v.20 no.2
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• pp.55-64
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• 2024

To ensure the frequency stability of wind power generation, we analyzedd the existing technology and proposedd a method for changing the gain value with respect to to the rotor speed by adding the MPPT reference value and output reference value that reflect the system frequency. The MPPT control and output were compared and calculated for performance verification. Subsequently, the application of the proposed algorithm led to an increased output when compared with that of the existing control method.

• Journal of Electrical Engineering and Technology
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• v.10 no.2
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• pp.496-503
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• 2015

In order to let a wind generator (WG) support the frequency control of a power system, a conventional inertial control algorithm using the rate of change of frequency (ROCOF) and frequency deviation loops was suggested. The ROCOF loop is prevailing at the initial stage of the disturbance, but the contribution becomes smaller as time goes on. Moreover, its contribution becomes negative after the frequency rebound. This paper proposes an inertial control algorithm of a wind power plant (WPP) using the maximum ROCOF and frequency deviation loops. The proposed algorithm replaces the ROCOF loop in the conventional inertial control algorithm with the maximum ROCOF loop to retain the maximum value of the ROCOF and eliminate the negative effect after the frequency rebound. The algorithm releases more kinetic energy both before and after the frequency rebound and increases the frequency nadir more than the conventional ROCOF and frequency loops. The performance of the algorithm was investigated under various wind conditions in a model system, which includes a doubly-fed induction generator-based WPP using an EMTP-RV simulator. The results indicate that the algorithm can improve the frequency drop for a disturbance by releasing more kinetic energy.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.8
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• pp.150-157
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• 2005

This paper presents the simulation modeling and analysis of variable wind speed turbine system(VWTS) using the doubly fed induction generator(DFIG) connected the back to back converter system in the rotor side. In the simulation, using the model system which has the 660[kW] rated power, blade control and the dual converter system are modeled for verifying the control characteristics. The VWTS is controlled by the optimal pitch angle for maximum output power under the rated wind speed, and for the rated output power over the rated wind speed. And also power factor is controlled by the reactive power. To verify the effectiveness of the proposed method, simulation results are compared with the actual data from the V47 VWTS located in Hangwon wind farm in Jeju-Do. According to the comparison of these results, this method shows excellent performance.

• Journal of Electrical Engineering and Technology
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• v.10 no.6
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• pp.2240-2248
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• 2015

The integration of the large-scale wind power brings great challenge to the stability of the power grid. This paper investigates and studies the fault on May 14, 2012 of the large-scale cascading trip-off of wind turbines in North China. According to the characteristics of the voltage variation, the fault process is divided into three stages: the pre-event stage, the critical stage before cascading, and the cascading stage. The scenes in the fault are reproduced, using the full-size actual power system model. Simulation models of double-fed induction generators (DFIGs) and SVCs including protection settings and controller strategies are carefully chosen to find out the reason of voltage instability in each stage. Some voltage dynamic that have never been observed before in the faults of the same kind are analyzed in detail, and an equivalent voltage sensitive dynamic model of DFIG is proposed for the fast computation. The conclusions about the voltage dynamics are validated by the actual PMU observation evidence.

• Journal of Power Electronics
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• v.9 no.1
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• pp.109-116
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• 2009

This paper addresses the output control of a utility-connected double-fed induction machine (DFIM) for wind power generation systems (WPGS). DFIM has a back-to-back converter to control outputs of DFIM driven by the wind turbine for WPGS. To supply commercially the power of WPGS to the grid without any problems related to power quality, the real and reactive powers (PQ) at the stator side of DFIM are strictly controlled at the required level, which in this paper is realized with the Fuzzy PI controller based on the field orientation control. For the Sinusoidal Pulse Width Modulation (SPWM) converter connected to the rotor side of DFIG to maintain the controllability of PQ at the state side of DFIM, the DC voltage of the DC link capacitor is also controlled at a certain level with the conventional Proportion-Integral (PI) controller of the real power. In addition, the power quality at the grid connected to the rotor side of DFIM through the back-to-back converter is maintained in a certain level with a PI controller of the reactive power. The controllers for the PQ at the stator side of DFIM, the DC link voltage of the back-to-back inverter and the reactive power at the grid connected to the rotor side of DFIM are designed and simulated in the PSIM program, of which the result verifies the performance of the proposed controllers.