• Journal of the Korean Solar Energy Society
• /
• v.32 no.3
• /
• pp.33-41
• /
• 2012

As the wind farms in large scale demand enormous amount of construction cost, minimizing the economic burden is essential and also it is very important to measure the wind resources and forecast annual energy production correctly to judge the economic feasibility of the proposed site by way of installing a Met mast at or nearby the site. Wind resources were measured by installing a 80[m] high Met mast at WangdeungYeo Island to conduct the research incorporated in this paper and offshore wind farm was designed using WindPRO. Wind farm of 100[MW] was designed making use of 3 and 4.5[MW] wind generator at the place selected to compare their annual energy production and capacity factor applying the loss factor of 10[%] and 20[%] respectively to each farm. As a result, 336,599[MWh] was generated by applying 3[MW] wind generator while 358,565 [MWh] was produced by 4.5[MW] wind generator. Difference in the energy production by 3[MW] generator was 33,660 [MWh] according to the loss factor with the difference in its capacity factor by 3.8[%]. On the other hand, 23 units of 4.5 [MW] wind generators showed the difference of annual energy production by 35,857 [MWh] with 4.0[%] capacity factor difference.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.7
• /
• pp.97-104
• /
• 2011

This paper presents modeling and control for the emerging IGBT converter-based high-voltage direct-current system (IGBT-HVDC). This paper adds to the representation of the IGBT-HVDC system in the dq-synchronous reference frame and its decoupled control scheme. Additionally, since the IGBT-HVDC is able to actively support the grid due to its capacity to control independently active and reactive power production, a reactive power control scheme is presented in order to regulate/contribute to the voltage at a remote location by taking into account its operational state and limits. The ability of the control scheme is assessed and discussed by means of simulations using ahybrid power system, which consists of a permanent magnetic synchronous-generator (PMSG) based wind turbine, an IGBT-HVDC, and a local load.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.59 no.1
• /
• pp.129-133
• /
• 2010

A hybrid system which is combined several complementary new and renewable power sources, such as photovoltaic, fuel-cell, and wind generator, etc., has been presented in various approaches. For instance, a photovoltaic cannot always generate stable output power with ever-changing weather condition, so it might be co-generated with a wind generator, diesel generator, and some other sources. In this paper, a residential PV-FC hybrid system is suggested as a distribution power source, and its operation is optimized by HOMER$^{(R)}$. As a result, it is the most economic that 5[kW] PV, 1[kW] FC, 4 batteries, 2[kW] electrolyzer, 0.5[kg] $H_2$ tank, 3[kW] converter are applied to the hybrid system.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.6
• /
• pp.2221-2227
• /
• 2015

To arrest a frequency nadir, a stepwise inertial control (SIC) scheme generates a constant active power reference signal of a wind turbine generator (WTG) immediately after a disturbance and maintains it for the predetermined time. From that point, however, the reference of a WTG abruptly decreases to restore the rotor speed for the predefined period. The abrupt decrease of WTG output power will inevitably cause a second frequency dip. In this paper, we propose a modified SIC scheme of a doubly-fed induction generator (DFIG) that can prevent a second frequency dip. A reference value of the modified SIC scheme consists of a reference for the maximum power point tracking control and a constant value. The former is set to be proportional to the cube of the rotor speed; the latter is determined so that the rotor speed does not reach the minimum operating limit by considering the mechanical power curve of a DFIG. The performance of the modified SIC was investigated for a 100 MW aggregated DFIG-based wind power plant under various wind conditions using an EMTP-RV simulator. The results show that the proposed SIC scheme significantly increases the frequency nadir without causing a second frequency dip.

• New & Renewable Energy
• /
• v.8 no.4
• /
• pp.13-20
• /
• 2012

This paper describes a transformerless static synchronous campensator (STATCOM) system based on cascade H-bridge multilevel inverter with star configuration. It is designed not only for the dynamic and continuous compensation of the reactive power but also for the improvement of power quality of existing wind power plant. Especially, when the induction generator of wind turbine is directly connected to the grid, reactive power are occurred by exiting current. so a reactive power compensation system based on the cascade H-bridge multilevel STATCOM is proposed because the output power quality and controllability of reactive power are required by grid code in many different countries. Using various The proposed reactive power control strategy using a STATCOM is compared with the conventional scheme using fixed-size of capacitor bank through various simulation results.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.11b
• /
• pp.153-156
• /
• 2001

Maximum Power Point Tracking(MPPT) is used in wind power generation systems to maximize wind power turbin output power, irrespective of wind speed conditions and of the load electrical characteristics. In this paper we do the equivalent modeling the mechanical energy of wind power turbine according to wind speed into the synchronous generator. We analyse the equivalent modeling output part of rectifier into DC/DC converter input part theoretically. We design a control algorithm for variable voltage according to wind speed intensity and density so that load voltage of chopper is controlled steadily using the maximum power point tracking (MPPT) control method. We analyse a battery charging characteristics and a charging circuit for power storage enabling the supply of stable power to the load. We design a system and do the modeling of it analytically so that it supplies a stable power to the load by constructing a DC-AC inverter point. Also we design a charging circuit usable in actual wind power generation system of 30kW and confirm its validity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.11a
• /
• pp.153-156
• /
• 2001

Maximum Power Point Tracking(MPPT) Is used in wind power generation systems to maximize wind power turbin output power, irrespective of wind speed conditions and of the load electrical characteristics. In this paper we do the equivalent modeling the mechanical energy of wind power turbine according to wind speed into the synchronous generator. We analyse the equivalent modeling output part of rectifier into DC/DC converter input part theoretically. We design a control algorithm for variable voltage according to wind speed intensity and density so that load voltage of chopper is controlled steadily using the maximum power point tracking(MPPT) control method. We analyse a battery charging characteristics and a charging circuit for power storage enabling the supply of stable power to the load. We design a system and do the modeling of it analytically so that it supplies a stable power to the load by constructing a DC-AC inverter point. Also we design a charging circuit usable in actual wind power generation system of 30kW and confirm its validity.

• Journal of Electrical Engineering and Technology
• /
• v.9 no.3
• /
• pp.827-834
• /
• 2014

In order to meet the low voltage ride-through requirement in a grid code, a wind power plant (WPP) has to stay connected to a grid, supporting the voltage recovery for a grid fault. To do this, a plant-level controller as well as a wind generator (WG) controller is essential. The dynamic response of a WPP should be analyzed in order to design a plant-level controller. The dynamic response of a WPP for a grid fault is the collective response of all WGs, which depends on the wind speed approaching the WG. Thus, the dynamic response of a WPP should be analyzed by taking the wake effect into consideration, because different wind speeds at WGs will result in different responses of the WPP. This paper analyzes the response of a doubly fed induction generator (DFIG)-based offshore WPP with a grid fault taking into account the wake effect. To obtain the approaching wind speed of a WG in a WPP, we considered the cumulative impact of multiple shadowing and the effect of the wind direction. The voltage, reactive power, and active power at the point of common coupling of a 100 MW DFIG-based offshore WPP were analyzed during and after a grid fault under various wind and fault conditions using an EMTP-RV simulator. The results clearly demonstrate that not considering the wake effect leads to significantly different results, particularly for the reactive power and active power, which could potentially lead to incorrect conclusions and / or control schemes for a WPP.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.52 no.7
• /
• pp.299-306
• /
• 2003

Doubly-Fed Induction Generator(DFIG) is adequate to maximize the energy capture from wind energy, whereby the turbine speed can be adjusted to a speed, at which a rated tip speed ratio be kept. In this paper, a power analysis for DFIG and its characteristics of power flow in grid-connected operation, are dealt with in speed range of super- and sub-synchronous region. In a test of the machine, whereby a doubly excited circuit configuration in stator as well as rotor with back to back PWM inverter have been equipped, a constant input torque is given and in that condition, power new in stator and rotor circuit have been measured and compared with theoretical value. Furthermore, the power factor in stator and rotor circuit have been examined.

• Proceedings of the KIEE Conference
• /
• 2005.07b
• /
• pp.1005-1007
• /
• 2005

Small wind turbines are becoming a viable technology option to supply electricity to landowners. These systems provide energy security, product relatively no environmental harm, and in an appropriate setting can be quite cost-competitive with traditional electricity options. This paper is dealing with the methods how to overcome such inconvenience and with the analysis of characteristic and a field test with a prototype of the stand alone wind turbine was performed. The method applies to small systems, equipped with a coreless axial-flux permanent magnet(AFPM) generator in the turbine, a dc-dc converter and batteries. The analysis concentrates on the effect of the load on the power-wind speed curve of the turbine. The system is designed for direct driven, coupled with turbine and generator with a rated power of, 3kW.