• New & Renewable Energy
• /
• v.7 no.3
• /
• pp.74-82
• /
• 2011

Because concern on the problem of the limited energy is growing and the wind energy is considered as one of the biggest solutions, the researches on the wind energy and turbine are accomplished vigorously. The simulation tools on the non-linear characteristics of wind turbine system are various and it could describe the non-linear characteristics well but, the tool and methodology to apply non-linear control theory rarely exist. In this paper, the application procedure of sliding mode control theory to 2-DOF non-linear wind turbine system is suggested and the application results of it are also shown as compared with a torque loop control theory.

• New & Renewable Energy
• /
• v.6 no.2
• /
• pp.19-26
• /
• 2010

Experiences in wind farm operation are very limited in Korea, and the foundation for setting standards in power system connection is weak. Therefore, connection and operation standards for wind farms in other countries must be reviewed and power system operation criteria need to be established in order to set up connection standards and optimal operation plans according to the Jeju power system. In this study, reactive power control characteristics of a wind farm were analyzed using a wind farm model of the Jeju power system to propose power system connection operation standards for wind generation within the Jeju power system. Also, change in characteristics of the power system for the application of each reactive power control standard was confirmed, and the results were verified through trial tests arm was analyzed.

• Journal of Electrical Engineering and Technology
• /
• v.9 no.3
• /
• pp.1080-1088
• /
• 2014

By combining a wind turbine with an energy storage system (ESS), we are able to attenuate the intermittent wind power characteristic making the power derived from a wind farm dispatchable. This paper evaluates the influence of the phase delay of the low-pass filter in the conventional smoothing power control on the ESS capacity; longer phase delays require a larger ESS capacity. In order to eliminate the effect of the phase delay, we optimize the power dispatch using a zero-phase low-pass filter that results in a non-delayed response in the power dispatch. The proposed power dispatching method significantly minimizes the ESS capacity. In addition, the zero-phase low-pass filter, which is a symmetrical forward-reverse finite impulse response type, is designed simply with a small number of coefficients. Therefore, the proposed dispatching method is not only optimal, but can also be feasibly applied to real wind farms. The efficacy of the proposed dispatching method is verified by integrating a 3 MW wind turbine into the grid using wind data measured on Jeju Island.

• Journal of Electrical Engineering and Technology
• /
• v.12 no.5
• /
• pp.2043-2050
• /
• 2017

This paper presents two MPC (Model Predictive Control) based charging and discharging algorithms of BESS (Battery Energy Storage System) for capacity firming of wind generation. To deal with the intermittency of the output of wind generation, a single BESS is employed. The proposed algorithms not only make the output of combined systems of wind generation and BESS track the predefined reference, but also keep the SoC (State of Charge) of BESS within its physical limitation. Since the proposed algorithms are both presented in simple if-then statements which are the optimal solutions of related optimization problems, they are both easy to implement in a real-time system. Finally, simulations of the two strategies are done using a realistic wind farm library and a BESS model. The results on both simulations show that the proposed algorithms effectively achieve capacity firming while fulfilling all physical constraints.

• Journal of the Korean Solar Energy Society
• /
• v.29 no.2
• /
• pp.22-30
• /
• 2009

In order to clarify predictive accuracy for the wind resource predicted by running WindPRO(Ver. 2.5) which is software for wind farm design developed by EMD from Denmark, an investigation was carried out at the northeast region of Jeju island. The Hangwon, Susan and Hoichun sites of Jeju island were selected for this study. The measurement period of wind at the sites was for one year. As a result, when the sites had different energy roses, though the two Wind Statistics made by STATGEN module were used for the prediction, it was difficult to exactly predict the energy rose at a given site. On the other hand, when the two Wind Statistics were used to predict the average wind speed, the wind power density and the annual energy production, the relative error was under ${\pm}20%$ which improved more than that when using only one Wind Statistics.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.271-272
• /
• 2008

Renewable energy resources such as wind, wave, solar, micro hydro, tidal and biomass etc are becoming important stage by stage, considering the effect of environment. Wind energy is one of the most successful sources of renewable energy for the production of electrical energy. What's more, due to wind speed random variation the wind turbine generators can not make two-state model as conventional generators. The method of obtaining reliability evaluation indices of wind turbine generators is different from the conventional generators. This paper presents a study on the reliability evaluation of power system considering wind turbine generators with a simplified multi-state model.

• Proceedings of the KIEE Conference
• /
• 2008.11a
• /
• pp.16-18
• /
• 2008

Because of being environmentally friendly, renewable energy resources has been growing at a high rate. Wind energy is one of the most successfully utilized of such sources for producing electrical energy. Due to the randomness of wind speed, wind farms can not supply power with a balanceable level as well as conventional power plants. The reliability evaluation of wind power is more and more important. Capacity credit is used to estimate the capacity credit of power systems including wind farms. This paper presents a method of capacity credit calculation for a power system considered wind farms and shows how it gets study on an actual power system (the Jeju Island power system). The paper describes the step of capacity credit calculation and presents test results, which indicate its effectiveness.

• 한국신재생에너지학회:학술대회논문집
• /
• 2005.11a
• /
• pp.702-705
• /
• 2005

The wind power is known as the most promising future energy source to obtain the electricity. Induction generator is a simple energy conversion wit in the wind power generation system but it consumes the reactive power from the interconnected power system. Switched capacitor banks are normally used to compensate the reactive power, which bring about the transient overvoltage. This paper proposes a method for compensating the reactive power with STATCOM. A detail simulation model for analyzing the interaction between the wind power system and the commercial power system was developed using EMTDC software. The developed simulation model can be effectively utilized to plan the reactive power compensation for newly designed wind power system.

• Journal of IKEEE
• /
• v.22 no.2
• /
• pp.460-475
• /
• 2018

In the variable-speed wind energy system, to achieve maximum power point tracking (MPPT), the wind turbine should run close to its optimal angular speed according to the wind speed. Non-linear control methods that consider the dynamic behavior of wind speed are generally used to provide maximum power and improved efficiency. In this perspective, the mechanical power is estimated using Kalman filter. And then, from the estimated mechanical power, the wind speed is estimated with Newton-Raphson method to achieve maximum power without anemometer. However, the blade shape and air density get changed with time and the generator efficiency is also degraded. This results in incorrect estimation of wind speed and MPPT. It causes not only the power loss but also incorrect wind resource assessment of site. In this paper, the adaptive maximum power point tracking control algorithm for wind turbine system based on the estimation of wind speed is proposed. The proposed method applies correction factor to wind turbine system to have accurate wind speed estimation for exact MPPT. The proposed method is validated with numerical simulations and the results show an improved performance.

• Journal of Environmental Science International
• /
• v.18 no.8
• /
• pp.927-932
• /
• 2009

Wind turbine noise become main environmental problem as wind energy have been installed all around. Noise from large wind turbine give annoyance to listener, moreover it increase loading to whole system by restricting blade tip speed. However accurate noise mechanism of wind turbine is not yet examined. This paper reviewed noise source and analysis theory. Broadband noise if main component of wind turbine noise and airfoil self noise is main noise source. These make acoustic analogy hard to apply for analysis. For this reason, experimental equation is method for wind turbine noise prediction up to now. Spectrum analysis shows that vortex shedding noise exists around $1k{\sim}2k$ Hz. This region is most sensitive frequency range to human. Thus it is necessary to reduce this noise source.