An Energy Management System for PV Sources in Standalone and Connected DC Networks Considering Economic, Technical, and Environmental Indices

Abstract

This research proposes an efficient energy management system for standalone and grid-connected direct current (DC) distribution networks that consider photovoltaic (PV) generation sources. A complete nonlinear programming model is formulated to represent the efficient PV dispatch problem while taking three different objective functions into account. The first objective function corresponds to the minimization of the operational costs with respect to the energy purchasing costs at terminals of the substation, including the maintenance costs of the PV sources. The second objective function is the reduction of the expected daily energy losses regarding all resistive effects of the distribution lines. The third objective function concerns the minimization of the total emissions of CO2 into the atmosphere by the substation bus or its equivalent (diesel generator). These objective functions are minimized using a single-objective optimization approach through the application of the Salp Swarm Algorithm (SSA), which is combined with a matrix hourly power flow formulation that works by using a leader–follower operation scheme. Two test feeders composed of 27 and 33 nodes set for standalone and grid-connected operation are used in the numerical validations. The standalone grid corresponds to an adaptation of the generation and demand curves for the municipality of Capurganá, and the grid-connected system is adapted to the operating conditions in the metropolitan area of Medellín, i.e., a rural area and a major city in Colombia. A numerical comparison with three additional combinatorial optimizers (i.e., particle swarm optimization (PSO), the multiverse optimizer (MVO), and the crow search algorithm (CSA)) demonstrates the effectiveness and robustness of the proposed leader–follower optimization approach to the optimal management of PV generation sources in DC grids while considering different objective function indices.

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

“…Note that to demonstrate the effectiveness of the proposed optimization methodology based on convex approximations, a single-objective function analysis with multiple metaheuristics was performed, evidencing that for all the simulation cases, the iterative solution methodology founds better numerical results than the recently reported values with different combinatorial optimization methods reported by Grisales-Noreña et al in [11]. These comparative algorithms are the crow search algorithm, the particle swarm optimizer, the multi-verse optimizer, and the salp swarm optimization method.…”

“…In the planning case, the main idea is integrating new devices (renewables or batteries) to improve the grid performance regarding operational costs for an expected horizon period of analysis [10]. In the operation case, usually, the idea is to propose efficient energy management systems that allow defining the best daily power injection profiles for renewable generation and energy storage systems [11,12].…”

“…The design of energy management systems (EMSs) is a vast area of research with multiple applications in the contexts of microgrids, and active distribution networks, including applications in seaports [13,14], public buildings [15,16], hospitals [17], farms [18], and electrical distribution networks [11], among others. For this reason, in this research, we are interested in analyzing monopolar DC networks from the optimization point of view by proposing efficient energy management systems (EMS) for monopolar DC grids considering photovoltaic generation [19,20].…”

“…For this reason, in this research, we are interested in analyzing monopolar DC networks from the optimization point of view by proposing efficient energy management systems (EMS) for monopolar DC grids considering photovoltaic generation [19,20]. Using a multi-objective optimization approach, the proposed EMS considers three objective functions (economic, technical, and environmental) [11]. In the current literature, the EMS for monopolar DC networks has been attracting attention in the last few years.…”

“…The authors of [11] have proposed designing an efficient energy management system (EMS) for PV generators integrated into monopolar DC distribution networks considering technical, environmental, and economic objective functions. As constraints, the power balance constraints and the capacities of the devices were considered.…”