Linear optimal power flow (OPF) formulations are powerful tools applied to a large number of problems in power systems, e.g., economic dispatch, expansion planning, state estimation, congestion management, electricity markets, among others. This article proposes a novel mixed-integer linear programming formulation for the ac-OPF of three-phase unbalanced distribution networks. The model aims to minimize the total energy production cost while guaranteeing the network's voltage and current magnitude operational limits. New approximations of the Euclidean norm, which is present in the calculation of nodal voltage and branch current magnitudes, are introduced by applying a linear transformation of weighted norms and a set of intersecting planes. The accuracy, optimality, feasibility, and scalability of the proposed linearizations are compared with common linear approximations in the literature using two unbalanced distribution test systems. The obtained results show that the proposed formulation is computationally more efficient (almost twice) while being as accurate and more conservative than the benchmarked approaches with maximum errors lower than 0.1%. Thus, its potential application in a variety of distribution systems operation and planning optimization problems is endorsed.@en

Demand-side management (DSM) is an effective way to strengthen the present power system's reliability and security with increasing penetration of renewable energy generations. With the fusion of information technology, present-day loads are getting smarter with their ability to modulate the power and control their switching operations in response to signals. The benefits get multiplied when flexibility is planned for a cluster of consumers having a similar load profile. In this paper, a framework based on mixed-integer linear programming (MILP) is developed to quantify flexibility in a large business park with little historical time series data access. The proposed mathematical model considers smart loads such as heat pumps, electric vehicle (EV) charging stations, a centralized energy storage system and renewable energy sources such as photovoltaic power. The quantification of flexibility is cast as a bi-objective optimization problem, which is solved by approximating the set of Pareto-efficient solutions using the epsilon-constraint method. Based on the developed optimization model, numerical simulations across one year with a time step of one hour are performed. The projected yearly monetary saving ranges from 1.5% to 30.8 %, and maximum peak shavings range from 9.6% to 61.4% for different capacities of centralized energy storage.@en

Recent developments, such as smart metering, distributed energy resources, microgrids, and energy storage, have led to an exponential increase in system complexity and have emphasized the need to include customer behavior and social and cultural backgrounds in planning activities. This paper analyzes how emergent behavior in electricity consumption can affect the planning of distribution grids with a smart grid vision. For this, an agent-based model that uses insights from the field of behavioral economics to differentiate four consumer categories (high income, low income, middle class, and early adopters) was used. The model was coupled with a real distribution feeder and customer load curve data, and the results showed that heterogeneity of customer’s preferences, values, and behavior led to very distinct load growth patterns. The results emphasize the relevance of modeling customer’s behavioral aspects in planning increasingly complex power systems.@en

This paper presents a new linear optimal power flow model for three-phase unbalanced electrical distribution systems considering binary variables. The proposed formulation is a mixed-integer linear programming problem, aiming at minimizing the operational costs of the network while guaranteeing operational constraints. Two new linearizations for branch current and nodal voltage magnitudes are introduced. The proposed branch current magnitude linearization provides a discretization of the Euclidean norm through a set of intersecting planes, while the bus voltage magnitude approximation uses a linear combination of the L1 and the L norm. The proposed approach is compared to a nonlinear power flow for an unbalanced distribution system with fixed power injections. The obtained results showed errors of less than 4% for currents and 0.005% for voltages, demonstrating that satisfactory accuracy may be obtained using the proposed linearizations. @en