Integration of Small Productive Processes Into an Energy Management System for Microgrids

Abstract

Small productive processes (SPPs) have recently emerged as attractive alternatives to contribute to the socio-economic development of communities, primarily in rural contexts. However, SPPs have a complicated electrical behavior involving the interaction between various types of loads, such as, conventional, and complex ones. Further, the SPPs generally include voltage-dependent loads, which may increase/decrease the load consumption. Thus, these characteristics make the integration of the SPPs into energy management systems (EMSs) for microgrids a challenging task. This work proposes a novel integration of the SPPs into an EMS considering the SPPs’ voltage sensitivity and complexity. For this purpose, we enhanced a previously proposed extended multi-zone ZIP load model (EMZ-ZIP) to be integrated into a convex AC multi-nodal EMS approach. The latter was formulated based on invertible nonlinear convex transformations and a binomial approximation method. The associated framework was assessed using a modified 9-bus test system with the characteristics of a low-voltage isolated microgrid with the integration of an SPP. The results demonstrate that the microgrid operation exhibits better technical and economic performance when the EMZ-ZIP model is an integral part of the EMS. In addition to an operating cost reduction of approximately 5% when considering voltage dependency, relevant practical advantage in scenarios of work shift and solar radiation variability are also presented. These results were compared with those obtained using other approaches like the time-variant ZIP and the constant power model.

Keywords

• Convex optimization
• energy management system
• microgrid
• multi-zone ZIP load model
• small productive processes