Eel-Hwan Kim

Maximum Output Power Tracking Control in Variable-Speed Wind Turbine Systems Considering Rotor Inertial Power

This paper proposes a new maximum power point tracking (MPPT) algorithm for variable-speed wind turbine systems, which takes advantage of the rotor inertia power. In this method, a proportional controller is added to the power control to effectively reduce the moment of inertia of the wind turbines, which can improve the fast performance of the MPPT control. The PSIM simulation and experimental results for a doubly-fed induction generator wind turbine system have proved the validity of the proposed algorithm.

Improvement of power quality for PMSG wind turbine systems

This paper proposes an LVRT (low-voltage ride-through) of multi-pole permanent-magnet synchronous generator (PMSG) for wind turbine systems under the grid fault condition and varying wind speed using the energy storage system (ESS) and braking chopper (BC). The proposed topology can reduce the ESS power rating and improve the output performance. A detailed design procedure and control strategy for the ESS and BC are presented. The PSIM simulation results prove that the proposed system can give the ride-through capability and power smoothening for the PMSG wind turbine system. The validity of the proposed system is also verified by experiment results.

Modeling and analysis of power system operation connected with wind turbine generation system and HVDC in Jeju island using PSCAD/EMTDC

This paper presents the modeling and analysis of Jeju power system operation connected with wind farm and HVDC system using PSCAD/EMTDC program. It is for indicating the influence of wind farm operation in Jeju power system. For the computer simulation, there are three main models, which are 100(MW) wind farm, 300(MW) HVDC system and Jeju power load. To verify the effectiveness of the proposed method, two kinds of simulation are carried out . One is the 50(MW) cut off and the other is 100(MW) cut off from the Jeju power grid instantaneously over the rated wind velocity . With the comparison of these results, this method shows the excellent performance. So it is very useful for understanding and applications of linking the wind farm to the power grid.

Modeling of Jeju island power grid system using PSCAD/EMTDC

This paper presents the modeling of Jeju island power grid system connected with wind farm, current source type HVDC system, and thermal power plant using PSCAD/EMTDC. It is for analyzing the characteristics of thermal power plant, HVDC system and wind farm operation in steady and transient state. For the computer simulation, four kinds of main items are modeled, which are 83(MW) wind farm, 300(MW) HVDC system, thermal power plant and Jeju power grid load. To analyze the influence of the wind power generation in Jeju power grid system, two kinds of simulations are carried out. One is the steady state operation under the variable wind speed, and the other is the transient state operation when all of wind farms in Jeju island are disconnected from the Jeju power grid instantaneously due to the over rated wind speed. With the simulation results, it is useful to analyze the operating characteristics of power thermal plant, HVDC system, and wind farms on Jeju island power grid system, and the system stabilities.

Application of MMC-HVDC System for Regulating Grid Voltage Based on Jeju Island Power System

This paper presents a control method of the modular multilevel converter - high-voltage direct current (MMC-HVDC) system to regulate grid voltage on the basis of the Jeju Island power system. In this case, the MMC-HVDC system is controlled as a static synchronous compensator (Statcom) to exchange the reactive power with the power grid. The operation of the MMC-HVDC system is verified by using the PSCAD/EMTDC simulation program. The Jeju Island power system is first established on the basis of the parameters and measured data from the real Jeju Island power system. This power system consists of two line-commutated converter - high-voltage direct current (LCC-HVDC) systems, two Statcom systems, wind farms, thermal power plants, transformers, and transmission and distribution lines. The proposed control method is then applied by replacing one LCC-HVDC system with a MMC-HVDC system. Simulation results with and without using the MMC-HVDC system are compared to evaluate the effectiveness of the control method.

Flicker Mitigation in a Wind Farm by Controlling a Permanent Magnet Synchronous Generator

The power quality of wind energy becomes more and more important in connecting wind-farms to the grid, especially weak grid. This paper presents the simulation of a wind farm of a permanent magnet synchronous generator (PMSG) and a doubly fed induction generator (DFIG). Flicker mitigation is performed by using PMSG as a static synchronous compensator (STATCOM) to regulate the voltage at the point of common coupling (PCC). A benefit of the measure is that integrating two function of to control the active power flow and to reduce the voltage flicker in a wind farm. Simulation results show that controlling PMSG is an effective and economic measure in reducing the flicker during continuous operation of grid connected wind turbines regardless of short circuit capacity ratio, turbulence intensity and grid impedance angle.