1,682,332 research outputs found
Challenges of Primary Frequency Control and Benefits of Primary Frequency Response Support from Electric Vehicles
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
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
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
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
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
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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