VFT - a smart transmission technology that is compatible with the existing and future grid

Marken, Paul E.; Marczewski, J.J.; D’Aquila, R.; Hassink, Paul; Roedel, Jim; Bodo, Richard L.

doi:10.1109/psce.2009.4840083

Cited by 25 publications

(9 citation statements)

References 4 publications

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“…If a disturbance of the state variable is applied at the limit cycle , then (3) takes the form (4) The linearization of (4) taking first-order terms in the Taylor series expansion results in (5) where the matrix of partial derivatives represents the Jacobian matrix of (3). Simplifying (5) it follows: (6) and the perturbation evolves according to [13] (7)…”

Section: Limit Cycle Methodsmentioning

confidence: 99%

“…The DA method requires a sequential perturbation of the state variables and the evaluation of the Jacobian involved in the variational problem (6). The initial vectors required to solve (6) are defined with the following expression: (9) where and are the column vectors of the identity matrix .…”

Section: A Direct Approach Proceduresmentioning

confidence: 99%

“…Two power-flow concepts based on a back-to-back HVDC and 0885-8977/$26.00 © 2011 IEEE a VFT are evaluated for power-flow control in a weak power grid using PSS/E simulations [5]. Furthermore, a review of actual and potential VFT installations is presented in [6], which emphasizes increasing interest to operate a set of VFTs in a coordinated fashion with a back-to-back HVDC. In timely contributions [7], [8], the steady-state and dynamic solutions are reported for a new VFT Park model consisting of a group of VFTs connected in parallel to increase the power transfer between two asynchronous networks.…”

Section: Introductionmentioning

confidence: 99%

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Stability Analyses of a VFT Park Using a Sequential Continuation Scheme and the Limit Cycle Method

Contreras-Aguilar

García

2011

IEEE Trans. Power Delivery

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A new procedure to determine the stability of a steady-state solution based on a sequential continuation scheme, Floquet theory and the limit cycle method is presented in this paper. The continuation scheme relies on an efficient predictor-corrector scheme, where the correction is accomplished through the limit cycle method. Furthermore, a comprehensive variable frequency transformer (VFT) Park model is proposed to study the stability of asynchronous links. The VFT Park allows the simulation of multiunit VFTs operated in parallel in order to increase the power transfer between two electric power networks. Each VFT unit consists of a wound-rotor asynchronous machine, a dc motor, and a control system, which provides power transfer regulation using power and speed controllers. The steady-state operating point of a VFT Park consisting of three 100-MW VFT units is computed with the limit cycle method for a set of heterogeneous operating scenarios. Stability diagrams are reported for changes of the VFT parameters, power transfer, and frequency on both sides of the asynchronous link. Even though the VFT is operated within its rated power transfer limits, simulation results reveal that a VFT may become unstable not only for changes of power transfer but also for variations of frequency.Index Terms-Floquet theory, limit cycle method, sequential continuation scheme, stability analyses, variable-frequency transformer (VFT), wound-rotor induction machine. NOMENCLATUREFlux linkage. Stator leakage reactance. Rotor leakage reactance. Magnetizing reactance. Stator angular velocity. Rotor angular velocity. Base angular velocity. Synchronous reference frame. Stator reference frame. Rotor reference frame. Quadrature-axis quantity. Transition matrix. Manuscript received

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Section: Limit Cycle Methodsmentioning

confidence: 99%

Section: A Direct Approach Proceduresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Stability Analyses of a VFT Park Using a Sequential Continuation Scheme and the Limit Cycle Method

Contreras-Aguilar

García

2011

IEEE Trans. Power Delivery

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“…The VFT is similar to a generator, being a rotating machine with a large inertia. This allows the VFT to ride through grid disturbances smoothly [2]. Also, in contrast to power-electronic based devices that could be used to transfer controlled power, the VFT avoids the risk of subsynchronous torsional interaction with generators that are nearby [3].…”

Section: A Grid Compatibilitymentioning

confidence: 99%

“…The VFT was an attractive alternative since it has continuous control of power flow and does not adversely interact with existing PSTs. In fact, studies showed that the addition of the Linden VFT improved the ability of one nearby PST to control power flow, since it moved away from its lower limit on taps [2].…”

Section: A Grid Compatibilitymentioning

confidence: 99%

First multi-channel VFT application - the Linden project

Pratico¹,

Wegner²,

Marken³

et al. 2010

IEEE PES T&D 2010

Self Cite

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A multi-channel Variable Frequency Transformer (VFT) has been commissioned in Linden, New Jersey to provide control of 300 MW into New York City. The first two VFT installations, at Hydro-Québec's Langlois substation and at AEP's Laredo substation, are single-channel applications, and the Linden VFT is the first multi-channel VFT, with three channels in parallel. The core technology of the VFT is a rotary transformer with three-phase windings on both rotor and stator. The power flow through the VFT is controlled with a motor and drive system which adjusts the rotational position of the rotor relative to the stator. Although the VFT can interconnect two asynchronous power grids, the Linden VFT is connected between synchronous systems that have existing ties. The VFT was the preferred technology chosen for the Linden application because of its ability to continuously control power flow, its low risk of grid interactions, and its relatively small physical footprint. This paper describes the VFT application at Linden and demonstrates its performance and seamless integration.

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Offshore Transmission Technology

Anaya‐Lara¹,

Tande²

2018

Offshore Wind Energy Technology

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VFT - a smart transmission technology that is compatible with the existing and future grid

Cited by 25 publications

References 4 publications

Stability Analyses of a VFT Park Using a Sequential Continuation Scheme and the Limit Cycle Method

Stability Analyses of a VFT Park Using a Sequential Continuation Scheme and the Limit Cycle Method

First multi-channel VFT application - the Linden project

Offshore Transmission Technology

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