scholarly journals Frequency Support from a Variable-Speed Wind Turbine Generator Using Different Variable Droop Characteristics

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4477
Author(s):  
Dejian Yang ◽  
Jingjiao Li ◽  
Xinsong Zhang ◽  
Liang Hua
Keyword(s):  
Frequency Response ◽  
Control Method ◽  
Frequency Control ◽  
Test System ◽  
Ancillary Service ◽  
Load Variations ◽  
Induction Generators ◽  
Doubly Fed ◽  
System Frequency ◽  
Response Capability

Doubly-fed induction generators (DFIGs) are capable of boosting frequency response capability while preventing the rotor speed from stalling during under-frequency disturbances, by employing variable droop characteristics. However, the frequency response capability during over-frequency disturbances is shortened because the potential for storing the kinetic energy is inversely proportional to the variable droop characteristics used for under-frequency disturbances. This paper designs a frequency control method of a DFIG to boost the frequency response capability during over-frequency disturbances while preserving the frequency response capability during under-frequency disturbances, by employing different variable droop characteristics. The effectiveness of the proposed frequency control method is investigated in a test system. The investigation results under five scenarios with different load variations, wind power penetrations and wind conditions clearly demonstrate that the proposed frequency control method suppresses the maximum system frequency deviations. As such, the proposed frequency control method can provide an effective solution for the frequency control ancillary service of a power system with large integrations of wind energy.

The Control Strategy Study of Doubly-Fed Wind Turbine Participated in Frequency Regulation

2012 ◽  
Vol 512-515 ◽  
pp. 788-793
Author(s):  
Xiao Hua Zhou ◽  
Ming Qiang Wang ◽  
Wei Wei Zou
Keyword(s):  
Wind Turbine ◽  
Control Strategy ◽  
Large Scale ◽  
Control Strategies ◽  
Frequency Control ◽  
Frequency Regulation ◽  
Strategy Study ◽  
Fuzzy Control Strategy ◽  
Doubly Fed ◽  
System Frequency

Traditional decoupling control strategy of doubly-fed induction generator (DFIG) wind turbine makes little contribution to system inertia and do not participate in the system frequency control, the synchronization of large-scale wind power requires wind turbine have the ability to participate in the regulation of power system frequency. This paper adds a frequency control segment to traditional DFIG wind turbine and considers the doubly-fed wind turbine operating on the state of the super-synchronous speed, by analysis the effect of inertia and proportional control strategies, a fuzzy control strategy which combines the advantages of the former two control strategies is proposed, simulation results show that this control strategy can more effectively improve the system frequency response.

scholarly journals Evaluation of DFIGs’ Primary Frequency Regulation Capability for Power Systems with High Penetration of Wind Power

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6178
Author(s):  
Changgang Li ◽  
Zhi Hang ◽  
Hengxu Zhang ◽  
Qi Guo ◽  
Yihua Zhu ◽  
...  
Keyword(s):  
Power Systems ◽  
Wind Power ◽  
Frequency Control ◽  
Frequency Regulation ◽  
Continuous Increase ◽  
Factors Affecting ◽  
Doubly Fed ◽  
Primary Frequency ◽  
Regulation Model ◽  
System Frequency

Accompanying the continuous increase in wind power penetration, the power system inertia is reduced, and the system frequency regulation performance deteriorates. Wind turbine generators are required to participate in primary frequency regulation (PFR) to support system frequency. Here, the PFR capability of the widely-used doubly-fed induction generator (DFIG) is evaluated to estimate the participation of the DFIG in system frequency control. The frequency regulation model of the DFIG is established and briefly discussed. The equivalent PFR droop coefficient is then deduced from the model using a small signal increment method to evaluate the DFIG’s PFR capability. Key factors affecting the equivalent droop coefficient are studied, and the droop control is optimized to keep the equivalent droop coefficient in the desired range. The proposed method is verified utilizing a provincial power grid model of China.

scholarly journals Approach Control of DFIG Rotor Side Converter Based on Grid Frequency Coordinated Control

2021 ◽  
Author(s):  
Zakieldeen M. E. Elhassan ◽  
Abusabah I. A. Ahmed ◽  
Othman Hassan Abdalla
Keyword(s):  
Case Studies ◽  
Reactive Power ◽  
Control Method ◽  
Coordinated Control ◽  
Wind Speeds ◽  
Speed Regulation ◽  
Doubly Fed ◽  
Grid Side ◽  
Rotor Side Converter ◽  
System Frequency

Abstract. This paper presents an approach frequency coordinated control of Doubly Fed Induction Generator (DFIG) applying in the Rotor Side Converter (RSC) using an order reference active power (Pref ). Pref is obtained from the frequency deviation, speed regulation and kinetic energy stored in the DIFG. The Pref is employed as a main controller parameter of the dq-axis currents in the RSC under two case studies. In case1 study, the Pref is used to regulate the q-axis reference current and the grid reactive power controlled d- axis reference current. Whilst in case2 study, the d- axis reference current is produced by Pref , and the rotormechanical speed responsible to generate the q-axis reference current. The modified vector control method is used to control the Grid Side Converter (GSC) in two case studies. The transient performance of two case studies is simulated by PSCAD/EMDTC program under constant, step and variable wind speeds. A comparative result between two case studies shown that the frequency coordinated control has an ability to control both rotor dq-axis currents, and it enhancing the system frequency as well as improved DFIG voltage stability.However, case2 study has a better response than case1 study during system operated under random wind speed.

scholarly journals Frequency Performance Distribution Index for Short-Term System Frequency Reliability Forecast Considering Renewable Energy Integration

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2945
Author(s):  
Kofi Afrifa Agyeman ◽  
Ryota Umezawa ◽  
Sekyung Han
Keyword(s):  
Renewable Energy ◽  
Frequency Control ◽  
Storage System ◽  
Energy Storage System ◽  
Operational Reliability ◽  
Test System ◽  
Frequency Regulation ◽  
Energy Integration ◽  
Short Term ◽  
System Frequency

Risk in a power system’s ability to survive imminent disturbances without recourse to low operational cost and non-interruptive energy delivery remains the responsibility of every grid operator. Intermittencies in renewable energy and dynamic load variations influence the quality of power supply. The sudden changes affect the system frequency, compromising the reliability of the system grid; generation response to frequency regulation is momentous in such an incident. Slower response or smaller reserve capacity may cause a power shortage. This paper proposes a novel predictive scheme for a short-term operational reliability evaluation for system operations planning. The proposed method evaluates the operational reliability of system frequency whiles considering high renewable power penetration and energy storage system incorporation. Required energy generations, and other grid parameters, are modelled as stochastic inputs to the framework. We formulate a reliability index as a frequency distribution considering system frequency control dynamics and processes. The IEEE Reliability Test System (RTS) is used to prove the efficacy of the proposed model.

scholarly journals Enhanced Inertial Response Capability of a Variable Wind Energy Conversion System

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8132
Author(s):  
Jun Wang ◽  
Yien Xu ◽  
Xiaoxin Wu ◽  
Jiejie Huang ◽  
Xinsong Zhang ◽  
...  
Keyword(s):  
Control Strategy ◽  
Maximum Rate ◽  
Rate Of Change ◽  
Frequency Deviation ◽  
Control Coefficient ◽  
Maximum Frequency ◽  
Induction Generators ◽  
Inertial Response ◽  
System Frequency ◽  
Response Capability

An inertial response emulated control strategy of doubly-fed induction generators (DFIGs) is able to arrest their frequency decline following a severe frequency event. Nevertheless, the control coefficient is unchanged, so as to limit the benefit potentiality of improving the inertial response capability for various disturbances and provide less of a benefit for boosting the frequency nadir. This paper addresses an enhanced inertial response emulated control scheme for a DFIG to improve the maximum frequency deviation and maximum rate of change of frequency for various disturbances. To this end, the control coefficient is coupled with the system frequency deviation so as to regulate the control coefficient according to the system frequency deviation (i.e., sizes of the disturbance). Results clearly indicate that the proposed inertial response emulated control strategy provides better performance in terms of improving the maximum rate of change of frequency and maximum frequency deviation under various sizes of disturbance and random wind speed conditions.

Study on the Influence of DFIG Units with Additional Frequency Control on Power System Emergency Control

2012 ◽  
Vol 608-609 ◽  
pp. 579-583
Author(s):  
Yao Fei Hou ◽  
Guang Kai Li ◽  
Jian Ding ◽  
Jie Shen ◽  
Song Teng
Keyword(s):  
Power System ◽  
Wind Turbines ◽  
Frequency Control ◽  
Control Measures ◽  
Frequency Regulation ◽  
Variable Speed ◽  
Large Power ◽  
Emergency Control ◽  
Doubly Fed ◽  
System Frequency

The variable-speed doubly-fed wind turbines (DFIG) were able to participate in frequency regulation by adding an additional frequency control. The influences exerted by the additional frequency control of DFIG units and conventional units governors on system frequency emergency control measures were analyzed. When the power shortage is small, it is recommended to consider the DFIG units to participate in frequency regulation, While a large power shortage it is not recommended.

System Frequency Stabilization Using Doubly Fed Induction Generators Based Wind Energy Conversion Systems

2011 ◽  
Vol 347-353 ◽  
pp. 1442-1453
Author(s):  
Ying Cheng Xue ◽  
Neng Ling Tai
Keyword(s):  
Wind Turbines ◽  
Frequency Control ◽  
Wind Farms ◽  
Response Speed ◽  
Fast Response ◽  
Frequency Regulation ◽  
Frequency Error ◽  
Inertial Response ◽  
Doubly Fed ◽  
System Frequency

The conventional decoupling controls of variable-speed doubly fed wind turbines provide minimal support to the regulation of system frequency. The characteristics of doubly fed induction generator (DFIG) wind turbines and conventional power plans are compared, and the contributions of DFIG to system inertial response and frequency regulation are investigated. The influence of auxiliary loop parameters on the inertial response is illustrated. We also introduce a novel algorithm to enhance the participation of DFIG in existing frequency regulation mechanisms. The proposed approach takes advantage of the fast responses associated with DFIGs. The control system consists of four functional modules, namely, frequency control, rotational speed delay recovery, speed protection, and coordination control with conventional generators. The simulation results show that the control strategy has a fast response speed to the transient frequency error, thereby proving that wind farms can participate in system frequency regulation to a certain extent.

Study of Multi-factor Coordinated Frequency Control Strategy by DFIG Wind Turbine

2019 ◽  
Vol 12 (1) ◽  
pp. 86-93
Author(s):  
Wang Yin-Sha ◽  
Li Wen-Yi ◽  
Li Zhi-Wen
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Frequency Response ◽  
Control Strategy ◽  
Large Scale ◽  
Frequency Control ◽  
Operating Conditions ◽  
Frequency Change ◽  
System Frequency ◽  
Inertia Response

Background: With the large-scale Doubly Fed Induction Generator (DFIG) wind turbine integrated into the power system, the DFIG inertia response of the wind turbine should be provided. Also, the frequency response should be similar to the conventional generation technologies. This paper investigated the influence of frequency response term and wind speed conditions on system frequency control. Methods: The specific operating conditions of four control strategies, including inertia control, droop control, over speed control and pitch angle control were researched in this paper. Multi-factor coordinated frequency control strategy of DFIG wind turbine was established based on the above researches. The strategy was composed of wind speed ranging from low to high. Results: According to the simulation results, the DFIG wind turbine, which was based on multifactor coordinated frequency control strategy, could respond to the system’s frequency change of power grid, effectively. Conclusion: It helps system frequency return to stable states better and faster than DFIG wind turbine and also could reduce the fluctuation of system frequency.

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