A distributed approach to the Optimal Power Flow problem for unbalanced and mesh networks

Ferro, Giulio; Robba, Michela; D’Achiardi, David; Haider, Rabab; Annaswamy, Anuradha M.

doi:10.1016/j.ifacol.2020.12.159

Cited by 13 publications

(4 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To obtain a linear equivalent formulation of the two variables, the McCormick approximation of two variables is implemented [27,28]. This approximation considers that the product of two continuous variables f (x, y) = xy can be approximated as a linear equivalent function with the structure of (19).…”

Section: Model Convexificationmentioning

confidence: 99%

Multi-Objective Dispatch of PV Plants in Monopolar DC Grids Using a Weighted-Based Iterative Convex Solution Methodology

2023

View full text Add to dashboard Cite

The design of an efficient energy management system (EMS) for monopolar DC networks with high penetration of photovoltaic generation plants is addressed in this research through a convex optimization point of view. The EMS is formulated as a multi-objective optimization problem that involves economic, technical, and environmental objective functions subject to typical constraints regarding power balance equilibrium, thermal conductor capabilities, generation source capacities, and voltage regulation constraints, among others, using a nonlinear programming (NLP) model. The main characteristic of this NLP formulation of the EMS for PV plants is that it is a nonconvex optimization problem owing to the product of variables in the power balance constraint. To ensure an effective solution to this NLP problem, a linear approximation of the power balance constraints using the McCormick equivalent for the product of two variables is proposed. In addition, to eliminate the error introduced by the linearization method, an iterative solution methodology (ISM) is proposed. To solve the multi-objective optimization problem, the weighted optimization method is implemented for each pair of objective functions in conflict, with the main advantage that in this extreme the Pareto front has the optimal global solution for the single-objective function optimization approach. Numerical results in the monopolar version of the IEEE 33-bus grid demonstrated that the proposed ISM reaches the optimal global solution for each one of the objective functions under analysis. It demonstrated that the convex optimization theory is more effective in the EMS design when compared with multiple combinatorial optimization methods.

show abstract

Section: Model Convexificationmentioning

confidence: 99%

Multi-Objective Dispatch of PV Plants in Monopolar DC Grids Using a Weighted-Based Iterative Convex Solution Methodology

2023

View full text Add to dashboard Cite

show abstract

“…This is a limiting assumption for many grids, especially with increasing penetration of DERs located on single-phase lines. A recent approach proposed by some of the authors of this paper, denoted as Current Injection (CI) model [27], [28], avoids this assumption and so is an ideal candidate for representing unbalanced grids with various single-phase loads and generation. The CI model uses nodal variables, similar to the Bus Injection model, but the main idea is to represent all loads and generators as nodal current injections, with all power, current, and voltage phasors represented in Cartesian coordinates.…”

Section: Reactive Power Pricingmentioning

confidence: 99%

“…The CI model has been shown to perform well on unbalanced networks with local generation, with maximum 1.2% optimality gap and 0.9% voltage error when compared to the AC-OPF for a number of use cases [27]. The CI model has also been used for solving OPF in a distributed way [28] and for voltage support from inverter-based resources in unbalanced distribution grids [30]. Due to its overall ability to model unbalanced grids and all of the aforementioned advantages including the computational simplicity of the linear model, we adopt the CI approach in this paper.…”

Section: Reactive Power Pricingmentioning

confidence: 99%

See 1 more Smart Citation

A Reactive Power Market for the Future Grid

Potter¹,

Haider²,

Ferro³

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

As pressures to decarbonize the electricity grid increase, the grid edge is witnessing a rapid adoption of distributed and renewable generation. As a result, traditional methods for reactive power management and compensation may become ineffective. Current state of art for reactive power compensation, which rely primarily on capacity payments, exclude distributed generation (DG). We propose an alternative: a reactive power market at the distribution level. The proposed market uses variable payments to compensate DGs equipped with smart inverters, at an increased spatial and temporal granularity, through a distribution-level Locational Marginal Price (d-LMP). We validate our proposed market with a case study of the New England grid on a modified IEEE-123 bus, while varying DG penetration from 5% to 160%. Results show that our market can accommodate such a large penetration, with stable reactive power revenue streams. The market can leverage the considerable flexibility afforded by inverter-based resources to meet over 40% of reactive power load when operating in a power factor range of 0.6 to 0.95. DGs participating in the market can earn up to 11% of their total revenue from reactive power payments. Finally, the corresponding daily d-LMPs determined from the proposed market were observed to exhibit limited volatility.Keywordsreactive power, power distribution economics, power quality, distribution level market, optimal power flow I. INTRODUCTION W ITH a growing demand for zero-carbon generation in the electricity sector comes an increase in grid-edge distributed energy resources (DERs), and in particular, distributed generation (DGs). The increasing penetration of these small-scale resources disrupts the existing industry practice for power dispatch, device control, and market compensation mechanisms. Traditionally, large controllable generators at the transmission level have been responsible for maintaining grid stability and power quality; however new strategies are required for the emerging grid. While recent efforts such as the FERC Order 2222 [1] indicate a move towards accommodation of DERs, new electricity market structures are needed in order to fully embrace their high penetration and lead to a feasible framework for their integration even while preserving grid stability and power quality. This paper proposes one such market structure, with a focus on a reactive power market at the distribution level.Reactive power is intimately connected with power quality, and its regulation is achieved in the transmission grid by altering the power factors (PFs) of large synchronous generators. The outputs of these generators are easily controllable thus

show abstract