scholarly journals DFIG wind turbine under unbalanced power system conditions using adaptive fuzzy virtual inertia controller

Energetika ◽  
2019 ◽  
Vol 65 (1) ◽  
Author(s):  
Mohamed Zellagui ◽  
Heba Ahmed Hassan ◽  
Mohamed Nassim Kraimia
Keyword(s):  
Power System ◽  
Wind Turbines ◽  
Wind Farm ◽  
Frequency Stability ◽  
Area Network ◽  
Negative Effects ◽  
Adaptive Fuzzy ◽  
Point Tracking ◽  
Virtual Inertia ◽  
Inertia Response

The Doubly-Fed Induction Generator (DFIG) based Wind Turbines Generator (WTG) with traditional Maximum Power Point Tracking (MPPT) control provides no inertia response under system frequency events. Recently, the DFIG wind turbines have been equipped with the Virtual Inertia Controller (VIC) to enhance the frequency stability of the power system. However, the conventional VICs with fixed gain have negative effects on the inter-area oscillations of regional networks. To cope with this drawback, this paper proposes a novel adaptive VIC to improve both the inter-area oscillations and frequency stability. In the proposed scheme, the gain of the VIC is dynamically adjusted using fuzzy logic. The effectiveness and control performance of the adaptive fuzzy VIC is evaluated under different frequency events such as loss of generation and three-phase fault with load shedding. The simulation studies are performed on a generic two-area network integrated with a DFIG wind farm, and the comparative results are presented for these three cases: DFIG without VIC, DFIG with fixed gain VIC, and DFIG with adaptive fuzzy VIC. The results confirm the ability of the proposed adaptive fuzzy VIC in improving both the interarea oscillations and frequency stability of the system.

scholarly journals Wind Inertial Response Based on the Center of Inertia Frequency of a Control Area

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6177
Author(s):  
Alija Mujcinagic ◽  
Mirza Kusljugic ◽  
Emir Nukic
Keyword(s):  
Power System ◽  
Wind Power ◽  
Power Plants ◽  
Frequency Stability ◽  
Control Area ◽  
Rotational Inertia ◽  
Wind Power Plants ◽  
Inertial Response ◽  
Virtual Inertia ◽  
Inertia Response

As a result of the increased integration of power converter-connected variable speed wind generators (VSWG), which do not provide rotational inertia, concerns about the frequency stability of interconnected power systems permanently arise. If the inertia of a power system is insufficient, wind power plants’ participation in the inertial response should be required. A trendy solution for the frequency stability improvement in low inertia systems is based on utilizing so-called “synthetic” or “virtual” inertia from modern VSWG. This paper presents a control scheme for the virtual inertia response of wind power plants based on the center of inertia (COI) frequency of a control area. The PSS/E user written wind inertial controller based on COI frequency is developed using FORTRAN. The efficiency of the controller is tested and applied to the real interconnected power system of Southeast Europe. The performed simulations show certain conceptual advantages of the proposed controller in comparison to traditional schemes that use the local frequency to trigger the wind inertial response. The frequency response metrics, COI frequency calculation and graphical plots are obtained using Python.

scholarly journals Virtual Inertia Coordinated Allocation Method Considering Inertia Demand and Wind Turbine Inertia Response Capability

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5002
Author(s):  
Bo Xu ◽  
Linwei Zhang ◽  
Yin Yao ◽  
Xiangdong Yu ◽  
Yixin Yang ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
System Level ◽  
Evaluation Index ◽  
Synchronous Generators ◽  
Allocation Method ◽  
Virtual Inertia ◽  
Inertia Response ◽  
Response Capability

Wind turbines can have inertia characteristics similar to synchronous generators through virtual inertia control, which helps to provide the inertia support for the system. However, there is the problem of how to coordinate the allocation of virtual inertia among wind turbines. In response to this problem, this paper first analyzes the inertia response capabilities of wind turbines and puts forward an evaluation index that quantifies the inertia response capability of wind turbines. The inertia response capability of a wind farm is evaluated at the entire system level. Based on the evaluation index, the virtual inertia coordinated allocation method considers the system inertia demand and the inertia response capabilities of the wind turbines. It is proposed to release the inertia response capability of each wind turbine while avoiding an excessive release of kinetic energy and bring a second impact by wind turbines’ exiting operation. Finally, the effectiveness of the proposed method is verified by a simulation case study.

scholarly journals Improved Control Strategy of MMC–HVDC to Improve Frequency Support of AC System

2020 ◽  
Vol 10 (20) ◽  
pp. 7282
Author(s):  
Zicong Zhang ◽  
Junghun Lee ◽  
Gilsoo Jang
Keyword(s):  
Wind Turbines ◽  
Wind Farm ◽  
Control Method ◽  
Short Circuit ◽  
Synchronous Generator ◽  
Frequency Stability ◽  
Offshore Wind ◽  
Inertial Response ◽  
Control Evaluation ◽  
The Impact

With the continuous development of power electronics technology, variable-speed offshore wind turbines that penetrated the grid system caused the problem of inertia reduction. This study investigates the frequency stability of synchronous, offshore wind-farm integration through a modular-multilevel-converter high-voltage direct-current (MMC–HVDC) transmission system. When full-scale converter wind turbines (type 4) penetrate the AC grid, the AC system debilitates, and it becomes difficult to maintain the AC system frequency stability. In this paper, we present an improved inertial-response-control method to solve this problem. The mathematical model of the synchronous generator is based on the swing equation and is theoretically derived by establishing a MMC–HVDC. Based on the above model, the inertia constant is analyzed using a model that integrates the MMC–HVDC and offshore synchronous generator. With the new improved control method, a more sensitive and accurate inertia index can be obtained using the formula related to the effective short-circuit ratio of the AC system. Moreover, it is advantageous to provide a more accurate inertial control evaluation for AC systems under various conditions. Furthermore, the impact of the MMC–HVDC on system safety is assessed based on the capacitor time constant. This simulation was implemented using the PSCAD/EMTDC platform.

scholarly journals Analysis of the Implementation of the Primary and/or Inertial Frequency Control in Variable Speed Wind Turbines in an Isolated Power System with High Renewable Penetration. Case Study: El Hierro Power System

Electronics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 901 ◽  
Author(s):  
Guillermo Martínez-Lucas ◽  
José Ignacio Sarasúa ◽  
Juan Ignacio Pérez-Díaz ◽  
Sergio Martínez ◽  
Danny Ochoa
Keyword(s):  
Wind Speed ◽  
Power Systems ◽  
Power System ◽  
Wind Turbines ◽  
Wind Farm ◽  
Frequency Control ◽  
Frequency Regulation ◽  
Variable Speed ◽  
El Hierro

With high levels of wind energy penetration, the frequency response of isolated power systems is more likely to be affected in the event of a sudden frequency disturbance or fluctuating wind conditions. In order to minimize excessive frequency deviations, several techniques and control strategies involving Variable Speed Wind Turbines (VSWTs) have been investigated in isolated power systems. In this paper, the main benefits and disadvantages of introducing VSWTs—both their inertial contribution and primary frequency regulation—in an exclusively renewable isolated power system have been analyzed. Special attention has been paid to the influence of the delays of control signals in the wind farm when VSWTs provide primary regulation as well as to the wind power reserve value which is needed. To achieve this objective, a methodology has been proposed and applied to a case study: El Hierro power system. A mathematical dynamic model of the isolated power system, including exclusively renewable technologies, has been described. Representative generation schedules and wind speed signals have been fixed according to the observed system. Finally, in order to obtain conclusions, realistic system events such as fluctuations in wind speed and the outage of the generation unit with the higher assigned power in the power system have been simulated.

scholarly journals Analytical Approach to Understanding the Effects of Implementing Fast-Frequency Response by Wind Turbines on the Short-Term Operation of Power Systems

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3660
Author(s):  
Danny Ochoa ◽  
Sergio Martinez
Keyword(s):  
Power Systems ◽  
Power System ◽  
Wind Turbines ◽  
Analytical Approach ◽  
Frequency Control ◽  
Test System ◽  
Term Operation ◽  
Inertial Response ◽  
Virtual Inertia ◽  
Grid Operators

The significant presence of variable-speed wind turbines in worldwide power systems has led to planners and grid operators requiring them to participate in frequency control tasks. To address this demand, a large number of wind frequency control proposals have been reported in the literature in recent years. Many of these solutions have been tested by specific experiments carried out in computer simulation environments. This paper proposes a methodology to evaluate the effects of enabling frequency support by wind turbines on the magnitudes that characterize the inertial response of a power system by using an analytical approach. The derived formulation and the illustrations are designed to provide a better understanding of both the mechanisms that determine the frequency stability indices and the improvement achieved by enabling the inertial response of wind turbines by implementing a virtual inertia-based method on the active power controllers of these machines. To facilitate the comprehension of the results obtained, the analytical approach is complemented with time-domain simulations in a predefined test system implemented in MATLAB/Simulink®. The proposed methodology achieves a generalization of the results and can be used for the assessment of any power system configuration.

scholarly journals An Analysis of Wind Power Generation on the Electric Transmission System of Southern Vietnam

2021 ◽  
Vol 16 ◽  
pp. 204-212
Author(s):  
Minh-Hoa Nguyen ◽  
Van-Tan Tran ◽  
Tan-Hung Pham ◽  
Thanh-Luu Cao
Keyword(s):  
Power Generation ◽  
Power Systems ◽  
Power System ◽  
Wind Energy ◽  
Wind Turbines ◽  
Wind Farm ◽  
Wind Farms ◽  
Wind Speeds ◽  
Southern Vietnam ◽  
Three Phase

Renewable energy is an emerging candidate in power generation for the compensation of the exhausted fossil fuel, in which wind energy plays an important role. However, how wind farms impact existing power systems has still been a subject on which many researchers are studying. This study has analyzed and evaluated the four wind farms consisting of Ca-Mau (300 MW), Bac-Lieu (99 MW), Soc-Trang (100 MW) and Tra-Vinh (33 MW) located in Southern Vietnam via using the commercial package, WAsP software. Ca-Mau wind farm has the highest planned rated capacity with 51.7% among the wind farms. Each wind farm is built from three different types of wind turbines (1 MW, 2 MW and 3 MW). The estimation has shown that all of the wind farms could produce 2,265 GWh annually, and the 3-MW wind turbines are the most efficient and give the smallest losses for producing wind energy. The wind farms, with respect to environmentally friendly aspects, could avoid 978,544 tCO2 emitted to the environment annually. Additionally, the ETAP program has also been applied to simulate the effects of the proposed wind farms on the national power system including the disturbances from wind speeds, three-phase bus faults, tripping off wind farms and three-phase line faults on the power system. The results show that the wind farms are only slightly impacted.

The Influence of Wind Power Grid to Power System Small Disturbance Stability Study

2014 ◽  
Vol 986-987 ◽  
pp. 606-610
Author(s):  
Zhi Jie Wang ◽  
San Ming Liu ◽  
Pan Xi ◽  
Ze Yang Pei ◽  
Xin Xia Su ◽  
...  
Keyword(s):  
Power System ◽  
Wind Power ◽  
Wind Turbines ◽  
Wind Farm ◽  
Sparse Matrix ◽  
Power Grid ◽  
Oscillation Mode ◽  
Rayleigh Quotient ◽  
Small Disturbance ◽  
State Matrix

Setting up a practical power system containing wind farm small disturbance stability mathematical model, and the linearized equation of wind turbines and original equations of linear system, power system containing wind turbines augmented state formation matrix, turn the inverse iteration with PSASP software Rayleigh (Rayleigh quotient iterative algorithm and sparse matrix technique for large state matrix eigenvalues. In this paper, the Inner Mongolia power grid, wind power access to power system oscillation mode and the influence of the oscillation characteristics and meet the requirements of small disturbance stability of wind scale and operation control scheme. The influence of the wind farm is proposed for power system damping characteristics will not greater than the same capacity of synchronous generator's point of view.

scholarly journals Control Strategy of BESS for Providing Both Virtual Inertia and Primary Frequency Response in the Korean Power System

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4060 ◽  
Author(s):  
Choi ◽  
Kook ◽  
Yu
Keyword(s):  
Power System ◽  
Frequency Response ◽  
Control Strategy ◽  
Frequency Control ◽  
Storage System ◽  
Renewable Energy Resources ◽  
Virtual Inertia ◽  
Primary Frequency ◽  
Primary Frequency Response ◽  
Inertia Response

As the battery energy storage system (BESS) has been considered to be a solution to the diminished performance of frequency response in the Korean power system, in which renewable energy resources (RESs) are expected to increase rapidly, this paper proposes a control strategy for providing both the virtual inertia and primary frequency response considering the MW-scale BESS installed by the Korea Electricity Power Corporation (KEPCO). The benefit of such a fast and flexible BESS can be maximized by the proposed control strategy for making it provide both the inertia and primary frequency response, which would be deficit with the increased RES. In the proposed control strategy, the state of charge (SOC) is maintained in the specific range in which the life cycle is maximized, the interference of SOC recovery by frequency control is minimized, the responding capacity for providing the virtual inertia response is maximized during the transient period, and the performance requirements for frequency response are satisfied. The effectiveness of the proposed strategy is verified by both Korean power system model-based simulation and on-site operations.

scholarly journals Analysis of Control Strategies Based on Virtual Inertia for the Improvement of Frequency Stability in an Islanded Grid with Wind Generators and Battery Energy Storage Systems

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 698
Author(s):  
Iván Pazmiño ◽  
Sergio Martinez ◽  
Danny Ochoa
Keyword(s):  
Power System ◽  
Control Strategies ◽  
Frequency Control ◽  
Frequency Stability ◽  
Battery Energy Storage ◽  
Battery Energy Storage Systems ◽  
Virtual Inertia ◽  
Battery Energy ◽  
Primary Frequency ◽  
Primary Frequency Control

Rising levels of non-synchronous generation in power systems are leading to increasing difficulties in primary frequency control. In response, there has been much research effort aimed at providing individual electronic interfaced generators with different frequency response capabilities. There is now a growing research interest in analyzing the interactions among different power system elements that include these features. This paper explores how the implementation of control strategies based on the concept of virtual inertia can help to improve frequency stability. More specifically, the work is focused on islanded systems with high share of wind generation interacting with battery energy storage systems. The paper presents a methodology for modeling a power system with virtual primary frequency control, as an aid to power system planning and operation. The methodology and its implementation are illustrated with a real case study.

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