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

Abstract

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.

A Mixed-Integer Second-Order Cone Programming Algorithm for the Optimal Power Distribution of AC-DC Parallel Transmission Channels

“…It is always formulated as an optimal power flow (OPF) model for AC-DC systems. At present, the conventional OPF model for AC-DC systems is generally used in the optimal operation of AC-DC systems [5][6][7][8][9][10][11][12][13][14]. The optimal reactive power flow (ORPF) problem for AC-DC systems was studied in [5][6][7][8][9].…”

“…In [9], a stability-constrained ORPF model for reactive power compensation and HVDC regulation was established, and several derivative-free algorithms were proposed. Moreover, the general OPF problem for AC-DC systems was studied in [10][11][12]. In [10], the adaptive simplified human learning optimization algorithm was used to solve the OPF problem of AC-DC systems.…”

“…In [10], the adaptive simplified human learning optimization algorithm was used to solve the OPF problem of AC-DC systems. Aragüés-Peñalba et al [11] proposed a method for solving the OPF problem of offshore wind farms with an HVDC connection, and they used an information gap decision theory to deal with the uncertainty of the wind power fluctuations. Kılıç et al [12] used a genetic algorithm to solve the OPF problem of an AC-DC power grid.…”

Optimal Operation of DC Networks to Support Power System Outage Management

“…Nowadays, direct current networks are present in microgrids and smart grids, in electronic power distribution systems and in supergrids dedicated to integrating continental renewable resources [2][3][4]. Therefore, several studies have proposed tools to achieve optimal power flow (OPF) in combined ac-dc networks [5][6][7][8].…”

Optimal power flow tool for hybrid AC/DC systems

“…The tool in the present study has similar features to [18], but is implemented through MATLAB R Optimization toolbox (function fmincon). On the other hand, this tool was already applied to a probable future scenario: a system with large integration of offshore wind, in [19], where it was proven that the results obtained when minimizing losses in a 4 DC 5 AC node system with two different softwares (GAMS R and MATLAB R ) coincided. This paper is organised as follows.…”