Experiment on Grid-Connection Process of Wind Turbines in Fractional Frequency Wind Power System

Wang, Xifan; Wei, Xiaohui; Meng, Yongqing

doi:10.1109/tec.2014.2358498

Cited by 44 publications

(24 citation statements)

References 23 publications

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“…Thus, the fractional calculus can extend the integer-order calculus models to the non-integer order models [24], and is proven to be a very suitable and flexible tool to characterize the genetic memory properties in various chaotic evolutionary processes [23][24][25][26][27][28]. So far, many practical nonlinear systems in electrical energy fields [27][28][29][30][31][32][33][34], such as the energy supply-demand system [27], hydro-turbine governing system [29], and wind turbine [31], have been modelled using fractional differential equations. This paper aims to investigate the modeling and control of the fractionalorder energy-saving and emission-reduction system (FOESERS) to coordinate the dynamic performance of energy conservation, economic growth, carbon emissions, and renewable energy development.…”

Section: Introductionmentioning

confidence: 99%

Fractional-order modeling and sliding mode control of energy-saving and emission-reduction dynamic evolution system

Huang

Zhou

et al. 2018

International Journal of Electrical Power & Energy Systems

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A B S T R A C TThis paper proposes the fractional-order modeling for sliding mode control of a complex four-dimensional energy-saving and emission-reduction system (ESERS). In the proposed methodology, the fractional calculus techniques are employed to accurately model the dynamics of the ESERS, and the fractional-order model of the energy-saving and emission-reduction system (FOESERS) is formulated. With the proposed FOESERS, all of the equilibrium points and the corresponding eigenvalues are obtained, and the instability region and the state trajectories of FOESERS are also given. The FOESERS can represent complex dynamic behaviours with chaotic and unstable states on the energy conservation, carbon emissions, economic growth, and renewable energy development, and have a great impact on the formulation of government energy policies. Furthermore, based on the fractional Lyapunov stability and robust control theory, a sliding-mode controller is designed to control the FOESERS with model uncertainties and external disturbances to the equilibrium point in the finite time. Finally, simulation results confirm the effectiveness and robustness of the proposed scheme.

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Section: Introductionmentioning

confidence: 99%

Fractional-order modeling and sliding mode control of energy-saving and emission-reduction dynamic evolution system

Huang

Zhou

et al. 2018

International Journal of Electrical Power & Energy Systems

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“…Consequently the fractional frequency transmission system (FFTS) [1][2][3][4], sometimes also called the low frequency alternating current (LFAC) [5][6][7][8] transmission system, provides a new scheme to solve these problems. In the proposed FFTS solution, the offshore wind farm and the offshore transmission system work at a relatively low frequency and connect to the industrial frequency grid via a full-size onshore AC/AC converter.…”

Section: Introductionmentioning

confidence: 99%

Control scheme of hexagonal modular multilevel direct converter for offshore wind power integration via fractional frequency transmission system

Meng

Liu²,

Luo³

et al. 2017

J. Mod. Power Syst. Clean Energy

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A fractional frequency transmission system (FFTS) is a promising solution to offshore wind power integration, for which the hexagonal modular multilevel converter (Hexverter) is an attractive choice for power conversion. The Hexverter has recently been proposed to directly connect two three-phase systems of different frequencies and voltage amplitudes, with only six branches in the FFTS in that case. This paper examines for the first time the control scheme of the Hexverter when applied to offshore wind power integration via a FFTS. Firstly, the frequency-decoupled mathematical model of the Hexverter is deduced by introducing the double dq transformation. Then the branch energy of the Hexverter is analyzed in detail and the reactive power constraint equation is obtained. The corresponding control scheme is thoroughly discussed, including the inner loop current control, the outer loop voltage control in both grid-connected mode and passive mode, and a novel optimization method to minimize the circulating current in the Hexverter. Finally, a simulation model of offshore wind power integration via a 4-terminal FFTS based on the Hexverter is built in MATALB/Simulink to verify the feasibility of Hexverter and the effectiveness of the control scheme proposed in this paper.

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“…3. The technical feasibility of LFAC has been comprehensively analyzed [10]- [15] and a laboratory prototype of an LFAC system has also been successfully demonstrated [16] [17] .…”

Section: Introductionmentioning

confidence: 99%

Cost Analysis and Comparison of HVAC, LFAC and HVDC for Offshore Wind Power Connection

Xiang

Merlin

Green

2016

12th IET International Conference on AC and DC Power Transmission (ACDC 2016)

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Low frequency AC (LFAC) has been proposed as a means to avoid some of the large converter station costs of high voltage DC (HVDC) while delivering some of the benefits in terms of better line or cable utilization and its technical feasibility has been established. It is said to offer a lower costs than HVDC or conventional high voltage AC (HVAC) for a range of intermediate distances, with HVDC becoming cheaper over long distances. However, the basis for identifying the distance range and extent of cost saving has not been established. Here, cost estimate methodologies are extended for LFAC. A difficulty is the absence of commercial schemes that can provide practical examples of costs. In this paper, costs are broken down into constituent terms and estimates are made from the most similar equipment from other schemes. The capacity limits and power losses associated with subsea cables are analyzed for low frequency cases. For a given power transfer and for each distance, a choice of operating voltage, cable size and number of parallel circuits is made in order to find the lowest route cost. This yields cost as a function of distance that is a non-linear and discontinuous function. The cost curves for LFAC are compared with HVDC and HVAC options. The results for current cost estimates show that LFAC has a range of route length over which it is the lowest cost option and but this range narrows and eventually ceases to exist for higher power transfer ratings.

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Experiment on Grid-Connection Process of Wind Turbines in Fractional Frequency Wind Power System

Cited by 44 publications

References 23 publications

Fractional-order modeling and sliding mode control of energy-saving and emission-reduction dynamic evolution system

Fractional-order modeling and sliding mode control of energy-saving and emission-reduction dynamic evolution system

Control scheme of hexagonal modular multilevel direct converter for offshore wind power integration via fractional frequency transmission system

Cost Analysis and Comparison of HVAC, LFAC and HVDC for Offshore Wind Power Connection

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