1,682,332 research outputs found

    Challenges of Primary Frequency Control and Benefits of Primary Frequency Response Support from Electric Vehicles

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    As the integration of wind generation displaces conventional plants, system inertia provided by rotating mass declines, causing concerns over system frequency stability. This paper implements an advanced stochastic scheduling model with inertia-dependent fast frequency response requirements to investigate the challenges on the primary frequency control in the future Great Britain electricity system. The results suggest that the required volume and the associated cost of primary frequency response increase significantly along with the increased capacity of wind plants. Alternative measures (e.g. electric vehicles) have been proposed to alleviate these concerns. Therefore, this paper also analyses the benefits of primary frequency response support from electric vehicles in reducing system operation cost, wind curtailment and carbon emissions

    Distributed Primary Frequency Control through Multi-Terminal HVDC Transmission Systems

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    This paper presents a decentralized controller for sharing primary AC frequency control reserves through a multi-terminal HVDC grid. By using Lyapunov arguments, the proposed controller is shown to stabilize the equilibrium of the closed-loop system consisting of the interconnected AC and HVDC grids, given any positive controller gains. The static control errors resulting from the proportional controller are quantified and bounded by analyzing the equilibrium of the closed-loop system. The proposed controller is applied to a test grid consisting of three asynchronous AC areas interconnected by an HVDC grid, and its effectiveness is validated through simulation

    Grid frequency control : Secondary frequency control tuning taking into account distributed primary frequency control

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    A new method developed and applied to tune Secondary Control Loop (SCL) for grid frequency control is presented. The presented method is based on an equivalent representation of all active distributed Primary Control Loop (PCL) in the grid for frequency control. The characteristic of each PCL is associated to prime mover and its governors: Hydraulic, gas or steam. The equivalent model of distributed PCL takes into account all active representative composition of PCL in the grid for each typified power flow (seasons, working/not-working day, peak/valley, morning/afternoon/night, etc). By this way, each equivalent model of distributed PCL allows to find the best tuning of SCL for each typified power flow. This method was applied to tune the SCL of Yacyretá, a hydraulic power plant with 20 Kaplan turbines of 155 MW each one. Yacyretá is one of the power plants that have SCL in the “Sistema Argentino de Interconexión” (SADI), the largest power grid of Argentina.Instituto de Investigaciones Tecnológicas para Redes y Equipos Eléctricos (IITREE

    Grid frequency control : Secondary frequency control tuning taking into account distributed primary frequency control

    Get PDF
    A new method developed and applied to tune Secondary Control Loop (SCL) for grid frequency control is presented. The presented method is based on an equivalent representation of all active distributed Primary Control Loop (PCL) in the grid for frequency control. The characteristic of each PCL is associated to prime mover and its governors: Hydraulic, gas or steam. The equivalent model of distributed PCL takes into account all active representative composition of PCL in the grid for each typified power flow (seasons, working/not-working day, peak/valley, morning/afternoon/night, etc). By this way, each equivalent model of distributed PCL allows to find the best tuning of SCL for each typified power flow. This method was applied to tune the SCL of Yacyretá, a hydraulic power plant with 20 Kaplan turbines of 155 MW each one. Yacyretá is one of the power plants that have SCL in the “Sistema Argentino de Interconexión” (SADI), the largest power grid of Argentina.Instituto de Investigaciones Tecnológicas para Redes y Equipos Eléctricos (IITREE

    Design and control of parallel three phase voltage source Inverters in low voltage AC microgrid

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    Design and hierarchical control of three phase parallel Voltage Source Inverters are developed in this paper. The control scheme is based on synchronous reference frame and consists of primary and secondary control levels. The primary control consists of the droop control and the virtual output impedance loops. This control level is designed to share the active and reactive power correctly between the connected VSIs in order to avoid the undesired circulating current and overload of the connected VSIs. The secondary control is designed to clear the magnitude and the frequency deviations caused by the primary control. The control structure is validated through dynamics simulations.The obtained results demonstrate the effectiveness of the control structure

    Fast and Reliable Primary Frequency Reserves From Refrigerators with Decentralized Stochastic Control

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    Due to increasing shares of renewable energy sources, more frequency reserves are required to maintain power system stability. In this paper, we present a decentralized control scheme that allows a large aggregation of refrigerators to provide Primary Frequency Control (PFC) reserves to the grid based on local frequency measurements and without communication. The control is based on stochastic switching of refrigerators depending on the frequency deviation. We develop methods to account for typical lockout constraints of compressors and increased power consumption during the startup phase. In addition, we propose a procedure to dynamically reset the thermostat temperature limits in order to provide reliable PFC reserves, as well as a corrective temperature feedback loop to build robustness to biased frequency deviations. Furthermore, we introduce an additional randomization layer in the controller to account for thermostat resolution limitations, and finally, we modify the control design to account for refrigerator door openings. Extensive simulations with actual frequency signal data and with different aggregation sizes, load characteristics, and control parameters, demonstrate that the proposed controller outperforms a relevant state-of-the-art controller.Comment: 44 pages, 17 figures, 9 Tables, submitted to IEEE Transactions on Power System
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