Optimal power flow tool for hybrid AC/DC systems

Aragüés‐Peñalba, Mònica; Beerten, Jef; Rimez, Johan; Hertem, Dirk Van; Gomis‐Bellmunt, Oriol

doi:10.1049/cp.2015.0077

Cited by 13 publications

(10 citation statements)

References 19 publications

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“…It was first implemented through MATLAB R Optimization toolbox and it was benchmarked with the OPF tool from [21], implemented in MATPOWER R . Both tools led to the same results for the system analysed (5 AC 3 DC) when minimising losses and when minimising the deviation from a preset voltage profile [20]. On the other hand, the OPF AC/DC tool was also implemented in GAMS R [14], leading to the same results that MATLAB R Optimization toolbox for small and large power systems.…”

Section: Optimization Problemmentioning

confidence: 99%

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Optimal operation of hybrid high voltage direct current and alternating current networks based on OPF combined with droop voltage control

Aragüés‐Peñalba

Bassols

Arellano

et al. 2018

International Journal of Electrical Power & Energy Systems

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This study focuses on the operation and control of HVDC multi-terminal systems that transmit the power being generated in offshore wind farms to the terrestrial AC grids. The aim of the paper is to propose and validate an algorithm to ensure optimal operation of HVDC-HVAC systems. This algorithm is implemented in a central controller that, knowing the electrical characteristics of the DC and AC systems, the power generation from the wind farms and the power demand, executes periodically an AC/DC Optimal Power Flow (OPF) and sends the appropriate voltage references to the grid side converter's control. The voltage control of the DC grid is distributed and based on droop law, implemented in grid side converters. The droop offset is modified periodically so as to adapt to the actual operating conditions and ensure optimal operation according to a specified objective function. Dynamic simulations show the system optimal operation in terms of loss minimization under wind speed changes, loss of communications and demand variation. These results are validated experimentally after implementing the control scheme in an HVDC scaled experimental platform. Dynamic simulations are also performed to show that the system can still be operated based on the proposed strategy even during contingencies implying the disconnection of a power system element (converter and DC cable).

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Section: Optimization Problemmentioning

confidence: 99%

“…It is worth mentioning that the OPF AC/DC leading to the following formulation was previously validated [14,20]. It was first implemented through MATLAB R Optimization toolbox and it was benchmarked with the OPF tool from [21], implemented in MATPOWER R .…”

Section: Optimization Problemmentioning

confidence: 99%

Optimal operation of hybrid high voltage direct current and alternating current networks based on OPF combined with droop voltage control

Aragüés‐Peñalba

Bassols

Arellano

et al. 2018

International Journal of Electrical Power & Energy Systems

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“…This constraint can be implemented easily. Operating limits of VSCs and voltage and thermal limits in DC grids are given by (see [9], for example):…”

Section: A Modelling Approachmentioning

confidence: 99%

“…The work in [3]- [5], [7], [9], [11] presented the guidelines for modelling VSC-HVDC multi-terminal systems (VSC-MTDC, for short) in OPF problems. Those algorithms have been used succesfully for a wide range of applications in VSC-based AC/DC systems, such as minimisation of generation costs [3], [4], [14], minimisation of system losses [5], [11], [15], analysis of different objective functions [9], cost-benefit analysis of VSC-MTDC installations with different topologies [7], optimal operation in multi-area systems with different TSOs [8], [10], [16], analysis of the impact of VSC losses on OPF solutions [13] and optimisation in active distribution grids [17], among others. Meanwhile, several security-constrained OPF models for hybrid AC/DC systems were proposed in [6], [12], [18]- [21].…”

Section: Introductionmentioning

confidence: 99%

A simplified algorithm to solve optimal power flows in hybrid VSC-based AC/DC systems

Renedo

Ibrahim

Kazemtabrizi

et al. 2019

International Journal of Electrical Power & Energy Systems

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2019) 'A simplied algorithm to solve optimal power ows in hybrid VSC-based AC/DC systems.', International journal of electrical power and energy systems, 110 . pp. 781-794.The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractHigh Voltage Direct Current systems based on Voltage Source Converters (VSC-HVDC) are increasingly being considered as a viable technology with advantages, above all when using underground or submarine cables for bulk power transmission. In order to fully understand how VSC-HVDC systems can be best used within existing power systems, it is necessary to adapt conventional tools to carry out system-wide studies including this technology. Along this line, this paper proposes a simplified algorithm to solve optimal power flows (OPFs) in hybrid VSCbased Alternating Current / Direct Current (AC/DC) grids with multi-terminal VSC-HVDC systems. The proposed algorithm makes it possible to seamlessly extend a previous large-scale AC case to which several multi-terminal VSC-HVDC systems must be added. The proposed approach combines two ideas used previously in two different modelling approaches: each VSC is modelled as two generators with a coupling constraint; and DC grids are modelled as notional AC grids, since, in per unit, the equations for the former are a particular case of the latter with resistive lines and no reactive-power injections. In the proposed approach, the hybrid VSC-based AC/DC system is transformed into an equivalent only-AC system. Therefore, the OPF solution of the AC/DC system can be found with the same tool used for the previous AC problem and a simple extension of the original case.Index Terms VSC HVDC, HVDC transmission, multi-terminal, optimal power flow, power systems. NOMENCLATUREA G , A bus , A branch , A slacks : Sets of the generators, buses, branches and slack buses of the AC grids, respectively. A vsc , A dcbus , A dcbranch : Sets of the VSC stations, buses and branches of the multi-terminal VSC-HVDC systems. V i = V i ∠θ i : Voltage at AC bus ī S G,i = P G,i + jQ G,i : Active-(P) and reactive-power (Q) generation (bus i) S D,i = P D,i + jQ D,i : P/Q consumed by the loads (bus i) S i = P i + jQ i : P/Q injections into the AC grid at bus ī Y bus,ik = G ik + jB ik : Admittance matrix of AC line (i, k) I ik : Current through AC branch (i, k) (leaving bus i) (magnitude) S ik = P ac,ik + jQ ac,ik : P and Q flows through AC branch (i, k) (leaving AC bus i) Z ac,ik = R ac,ik + jX ac,ik : Series impedance of AC branch (i, k) B ac,sh,ik : Shunt susceptance of AC branch (i, k) V s,i = V s,i ∠δ s,i ...

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“…Selected Papers from the European Wind Energy Association 2014 functions, in [17], so it was validated. Secondly, it was implemented in GAMS ® , reducing the computation time significantly compared with the MATLAB implementation.…”

Section: Iet Renewable Power Generationmentioning

confidence: 99%

Optimal power flow tool for mixed high‐voltage alternating current and high‐voltage direct current systems for grid integration of large wind power plants

Aragüés‐Peñalba

Egea‐Àlvarez

Arellano

et al. 2015

IET Renewable Power Generation

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This study presents a tool for solving optimal power flows (OPFs) in hybrid high-voltage direct current (HVDC) and high-voltage alternating current (HVAC) systems for grid integration of large wind power plants, located either offshore or onshore. The OPF departs from the assumption that the power being produced from the wind power plants is known, as well as the demand from the AC grid. To model the interaction between the DC and AC grids, the active power conservation is expressed between the AC side and DC side of each converter, taking into consideration converter losses (modelled as a second-order polynomial). The tool developed determines the voltages and the active and reactive power in each bus and branch that ensure the selected objective function. All the electrical variables are limited. Moreover, the currents flowing in each DC and AC branch are also limited. The maximum AC voltage that can be applied by the converters is also limited. To develop the tool, both HVDC and HVAC grids need to be represented appropriately through its impedances and admittances. The tool has been implemented through MATLAB ® optimisation toolbox and through a more specific optimisation software GAMS ® , leading to the same results for the study case presented.

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Optimal power flow tool for hybrid AC/DC systems

Cited by 13 publications

References 19 publications

Optimal operation of hybrid high voltage direct current and alternating current networks based on OPF combined with droop voltage control

Optimal operation of hybrid high voltage direct current and alternating current networks based on OPF combined with droop voltage control

A simplified algorithm to solve optimal power flows in hybrid VSC-based AC/DC systems

Optimal power flow tool for mixed high‐voltage alternating current and high‐voltage direct current systems for grid integration of large wind power plants

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