energies Article Modeling of Small Productive Processes for the Operation of a Microgrid Danny Espín-Sarzosa 1,2 , Rodrigo Palma-Behnke 1,2, * and Felipe Valencia 2   Citation: Espín-Sarzosa, D.; Palma-Behnke, R.; Valencia, F. Modeling of Small Productive Processes for the Operation of a Microgrid. Energies 2021, 14, 4162. https://doi.org/10.3390/ en14144162 Academic Editor: Adel Merabet Received: 15 June 2021 Accepted: 5 July 2021 Published: 9 July 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Department of Electrical Engineering, Faculty of Physical and Mathematical Sciences, University of Chile, Tupper Av. 2007, Santiago8370451, Chile; despin@ing.uchile.cl 2 Energy Center, Faculty of Physical and Mathematical Sciences, University of Chile, Ercilla 847, Santiago 8370450, Chile; felipe.valencia@sercchile.cl * Correspondence: rodpalma@cec.uchile.cl; Tel.: +56-9-5769-6810 Abstract: Small productive processes (SPPs) are promising drivers that promote the economic use of energy in microgrids (MGs). Both the complex nature of the SPPs and voltage variations make the operation of MGs challenging, since the quality of an energy management system’s (EMS) decisions depend on its characterization. The aim of this work is to propose a methodology for SPPs modeling, and to consider the influence of voltage on load consumption, which has general validity, and can be efficiently integrated into different MG EMS approaches. For this purpose, a novel extended multi- zone ZIP approach for the characterization of SPP loads and sensitivity to voltage changes is proposed. The associated framework herein presented was assessed using actual data collected from SPPs installed near the city of Arica, in northern Chile. The results showed that the proposed methodology was capable of representing the complex load behavior of the SPPs, properly considering the voltage influence. These results were compared with those obtained through common approaches found in the literature. The effectiveness of the proposed approach in representing SPP loads and their sensitivity to voltage changes was verified. The proposed scheme can be efficiently integrated into a wide range of EMS for MGs that include SPPs. Keywords: microgrid; small productive processes; load modeling; energy management system; multi-zone ZIP load model; convex optimization 1. Introduction Microgrids (MGs) are well-known for “taking advantage” of local renewable energy sources (RES) in order to provide energy to communities and, thus, ensuring sustainable development [1,2]. Therefore, the microgrid industry is expected to grow in future years [3]. Alternatively, productive use of energy (PUE), primarily in rural settlements, has received much attention in recent years due to its potential to contribute to the economic growth and social progress of communities [4]. Consequently, the benefits of MGs com- bined with the PUE have stimulated the deployment of several small productive processes (SPPs), which can be embedded in MGs (see Figure 1) and offer different economic benefits to communities. According to the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ), the PUE is defined as “agricultural, commercial, and industrial activities involving electricity services as a direct input to the production of goods or provision of services” [5]. In this context, SPPs consist of integrating technological solutions in traditional and small-scale productive activities to add value to their goods and services. These SPPs may include small-scale industrial and household loads, distributed energy resources (DERs), e.g., photovoltaic panels (PV), and in some cases, a storage unit (see Figure 1). Energies 2021, 14, 4162. https://doi.org/10.3390/en14144162 https://www.mdpi.com/journal/energies