The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform

Yao Long - One of the best experts on this subject based on the ideXlab platform.

  • Solution to Short-Term Frequency response of wind farms by using energy storage systems
    IET Renewable Power Generation, 2016
    Co-Authors: Ju Liu, Jinyu Wen, Wei Yao, Yao Long
    Abstract:

    The increasing high penetration of wind power is bringing a serious challenge to the Frequency regulation of power system, for wind turbine generators are unable to naturally contribute to system Frequency response. To address this problem, this study proposes a control strategy to compensate the lack of Short-Term Frequency response ability of wind farms (WFs) by the energy storage system (ESS). First, the rated power and capacity of the ESS, which is installed at the point of common coupling of the WF to make it have similar Short-Term Frequency response ability to that of synchronous generators, are determined. The theoretical minimum rated power of the ESS should be about 5% rated power of the WF, only if the active power output of the ESS is controlled as its rated power during the whole inertial response process. Then, a fuzzy logic controller is designed for the ESS so that the required rated power of the ESS could reach its theoretical minimum value as closer as possible. Simulation results of a simplified practical power system show that WFs with the proposed strategy could response to the Frequency change rapidly and support Short-Term Frequency control effectively under various disturbances.

  • Short-Term Frequency support of power system from wind farms using energy storage system
    2015 IEEE Power & Energy Society General Meeting, 2015
    Co-Authors: Ju Liu, Jinyu Wen, Wei Yao, Yao Long
    Abstract:

    The high penetration of non-dispatch-able, gridconnected wind power is bringing serious challenge to the Frequency regulation of power systems because of the decoupling between the output power of doubly-fed induction generatorbased wind farms and the grid Frequency. Therefore, this paper proposes a compensation strategy to help wind farms to support the system Frequency response by using the energy storage system. Firstly, the conclusion that the wind farm, which is equipped an energy storage system with 5% rated power of wind farm, could have similar Short-Term Frequency response ability as synchronous generators with the same capacity is deduced. Then, a fuzzy logic controller is designed for the energy storage system to achieve this. Simulation results of a simplified practical power system show that wind farms with the proposed compensation strategy could response to the Frequency change of power system rapidly and support the Short-Term Frequency regulation effectively under various disturbances.

A.e. Leon - One of the best experts on this subject based on the ideXlab platform.

  • Short-Term Frequency Regulation and Inertia Emulation Using an MMC-Based MTDC System
    IEEE Transactions on Power Systems, 2018
    Co-Authors: A.e. Leon
    Abstract:

    The continuous displacement of conventional power plants by converter-interfaced generation systems reduces the system inertia and may lead to a degradation of the Frequency stabili-leon-2757258ty. A supplementary control strategy for multi-terminal dc (MTDC) systems to improve the Frequency regulation is presented in this paper. The scenario where the MTDC system cannot resort to the power reserves of either other ac systems or offshore wind farms is particularly studied. The proposed control is able to independently support both the primary Frequency regulation and the system inertia by using the capacitive energy of the MTDC grid converters. On the other hand, the reactive power of the converter stations is coordinately controlled to improve the damping of low-Frequency electromechanical oscillations. The simultaneous Frequency support of the MTDC system and onshore wind farms is also studied and validated in a practical multi-machine power system. Transient and small-signal stability analyses are performed to evaluate and quantify the improvements and the control limitations of the proposed scheme. This enhanced Frequency control can increase the system reliability and reduce the required amount of spinning reserve, diminishing the operation costs and allowing to increase the penetration of renewable energy sources.

  • Hierarchical Wide-Area Control of Power Systems Including Wind Farms and FACTS for Short-Term Frequency Regulation
    IEEE Transactions on Power Systems, 2012
    Co-Authors: A.e. Leon, Juan Manuel Mauricio, Antonio Gomez-exposito, Jorge A. Solsona
    Abstract:

    In this work a hierarchical scheme is proposed for the coordinated control of conventional synchronous generators, wind farm converters and flexible ac transmission systems. It comprises two levels, namely a fully decentralized set of controllers associated with the involved devices and a centralized coordinating controller based on synchronized wide-area signals provided by phasor measurement units. The proposed hierarchy of controllers is mainly focused on two objectives: transient Frequency support and inter-area oscillations damping. Several works have recently proved that the fast-acting power converters of variable-speed generators can greatly improve the Short-Term Frequency regulation capability in scenarios with a large penetration of wind energy. A case study is included showing that the dynamic performance and stability of power systems can indeed be enhanced when windmill converters are properly coordinated via a wide-area centralized controller.

Ju Liu - One of the best experts on this subject based on the ideXlab platform.

  • Solution to Short-Term Frequency response of wind farms by using energy storage systems
    IET Renewable Power Generation, 2016
    Co-Authors: Ju Liu, Jinyu Wen, Wei Yao, Yao Long
    Abstract:

    The increasing high penetration of wind power is bringing a serious challenge to the Frequency regulation of power system, for wind turbine generators are unable to naturally contribute to system Frequency response. To address this problem, this study proposes a control strategy to compensate the lack of Short-Term Frequency response ability of wind farms (WFs) by the energy storage system (ESS). First, the rated power and capacity of the ESS, which is installed at the point of common coupling of the WF to make it have similar Short-Term Frequency response ability to that of synchronous generators, are determined. The theoretical minimum rated power of the ESS should be about 5% rated power of the WF, only if the active power output of the ESS is controlled as its rated power during the whole inertial response process. Then, a fuzzy logic controller is designed for the ESS so that the required rated power of the ESS could reach its theoretical minimum value as closer as possible. Simulation results of a simplified practical power system show that WFs with the proposed strategy could response to the Frequency change rapidly and support Short-Term Frequency control effectively under various disturbances.

  • Short-Term Frequency support of power system from wind farms using energy storage system
    2015 IEEE Power & Energy Society General Meeting, 2015
    Co-Authors: Ju Liu, Jinyu Wen, Wei Yao, Yao Long
    Abstract:

    The high penetration of non-dispatch-able, gridconnected wind power is bringing serious challenge to the Frequency regulation of power systems because of the decoupling between the output power of doubly-fed induction generatorbased wind farms and the grid Frequency. Therefore, this paper proposes a compensation strategy to help wind farms to support the system Frequency response by using the energy storage system. Firstly, the conclusion that the wind farm, which is equipped an energy storage system with 5% rated power of wind farm, could have similar Short-Term Frequency response ability as synchronous generators with the same capacity is deduced. Then, a fuzzy logic controller is designed for the energy storage system to achieve this. Simulation results of a simplified practical power system show that wind farms with the proposed compensation strategy could response to the Frequency change of power system rapidly and support the Short-Term Frequency regulation effectively under various disturbances.

Yong Cheol Kang - One of the best experts on this subject based on the ideXlab platform.

  • Disturbance-Adaptive Short-Term Frequency Support of a DFIG Associated With the Variable Gain Based on the ROCOF and Rotor Speed
    IEEE Transactions on Power Systems, 2017
    Co-Authors: Min Hwang, Eduard Muljadi, Gilsoo Jang, Yong Cheol Kang
    Abstract:

    This paper proposes a disturbance-adaptive Short-Term Frequency support scheme of a doubly fed induction generator (DFIG) that can improve the Frequency-supporting capability while ensuring stable operation. In the proposed scheme, the output of the additional control loop is determined as the product of the Frequency deviation and adaptive gain, which is modified depending on the rate of change of Frequency (ROCOF) and rotor speed. To achieve these objectives, the adaptive gain is set to be high during the early stage of a disturbance, when the ROCOF and rotor speed are high. Until the Frequency nadir (FN), the gain decreases with the ROCOF and rotor speed. After the FN, the gain decreases only with the rotor speed. The simulation results demonstrate that the proposed scheme improves the FN and maximum ROCOF while ensuring the stable operation of a DFIG under various wind conditions irrespective of the disturbance conditions by adaptively changing the control gain with the ROCOF and rotor speed, even if the wind speed decreases and a consecutive disturbance occurs.

  • Stable Short-Term Frequency Support Using Adaptive Gains for a DFIG-Based Wind Power Plant
    IEEE Transactions on Energy Conversion, 2016
    Co-Authors: Jinsik Lee, Eduard Muljadi, Gilsoo Jang, Frede Blaabjerg, Zhe Chen, Yong Cheol Kang
    Abstract:

    For the fixed-gain inertial control of wind power plants (WPPs), a large gain setting provides a large contribution to supporting system Frequency control, but it may cause over-deceleration for a wind turbine generator that has a small amount of kinetic energy (KE). Further, if the wind speed decreases during inertial control, even a small gain may cause over-deceleration. This paper proposes a stable inertial control scheme using adaptive gains for a doubly fed induction generator (DFIG)-based WPP. The scheme aims to improve the Frequency nadir (FN) while ensuring stable operation of all DFIGs, particularly when the wind speed decreases during inertial control. In this scheme, adaptive gains are set to be proportional to the KE stored in DFIGs, which is spatially and temporally dependent. To improve the FN, upon detecting an event, large gains are set to be proportional to the KE of DFIGs; to ensure stable operation, the gains decrease with the declining KE. The simulation results demonstrate that the scheme improves the FN while ensuring stable operation of all DFIGs in various wind and system conditions. Further, it prevents over-deceleration even when the wind speed decreases during inertial control.

Seyed M. Madani - One of the best experts on this subject based on the ideXlab platform.

  • Analytical evaluation of control strategies for participation of doubly fed induction generator-based wind farms in power system Short-Term Frequency regulation
    IET Renewable Power Generation, 2014
    Co-Authors: Mohammad Akbari, Seyed M. Madani
    Abstract:

    Increase in doubly fed induction generator (DFIG)-based wind farms degrades the Short-Term Frequency regulation of power systems. However, such wind farms may have large amount of kinetic energy which can be rapidly injected into the power system to support system Frequency by using an appropriate supplementary control loop. This study first analyses the impacts of DFIGs and their supplementary loop on power system Short-Term Frequency regulation. Then, the average power system Frequency model is modified to include the participation of wind farms in Frequency control. Moreover, a new method is proposed to derive an analytical expression for minimum Frequency of a power system, as an important index of Frequency regulation, after a power imbalance occurrence. This analytical expression provides a tool for better insight into Frequency behaviour of power systems with high levels of wind generation. The results of the analysis are verified by simulation of the nine-bus test system, using MATLAB/SIMULINK.

  • Participation of DFIG based wind turbines in improving short term Frequency regulation
    2010 18th Iranian Conference on Electrical Engineering, 2010
    Co-Authors: M. Akbari, Seyed M. Madani
    Abstract:

    The increasing penetration of variable speed wind turbines in Power grids results in reduction of the number of connected conventional power plants and system inertia consequently. This reduction affects Frequency regulation of the grid. So new grid codes requires wind farms to participate in grid Frequency regulation. This paper provides a new method to improve the contribution of DFIG based wind turbines in system Frequency regulation. The method uses high kinetic energy stored in wind turbine and ability of DFIG to fast control of output power. This is done by introducing a supplementary loop to DFIG active power control loop. The effectiveness of the method is compared with other methods by simulation.