The three-phase induction machine is widely used in industry. Its equivalent circuit is essential in several applications, like performance evaluation, designing of speed/torque control loops, and failure diagnosis. This work establishes an analytical, non-iterative methodology to estimate the equivalent circuit parameters of this machine with high precision, using only data provided by the manufacturer catalog. The proposed methodology assessment is done by applying it to a total of 789 motors from 3 different manufacturers, with power range from 1 to 700 HP. Having the estimated equivalent circuit, the efficiency and power factor of three operating points (half, three quarters, and full load) are calculated and compared to the data available in the manufacturer catalog. These differences, so called errors, are small in a wide power range, roughly from 5 HP onwards. Also, by means of statistical analysis, the proposed method outperforms two other estimation methodologies, presenting lower errors for almost all considered machines. Finally, an illustrative case is made with a 5 HP machine. The three methods are used to estimate the efficiency and power factor curves of the motor from zero to 120% of the rated power, attesting to the quality of the proposed approach.

One of the challenges faced by Brazilian distribution utilities to enable the connection and operation of microgrids (MGs) is the absence of a solid set of technical standards in the country. An alternative has been to use and adapt existing standards applied to micro- and mini-distributed generation. In this context, this paper presents an analysis of the development status of norms, standards, and general requirements for the connection and operation of microgrids, as well as a proposal for the regulation and structuring of technical and operational requirements related to the implementation of microgrid projects. Some critical points highlighted in the paper include: the modes of operation, the minimum requirements for the different modes of operation, interoperability of systems, a conceptual model with attribution of responsible actors for the decentralized management of microgrids adapted to the institutional standards of the Brazilian sectorial model, a proposal for a standard connection structure considering the point of connection (PoC) implanted using multifunctional relay and recloser, procedures for technical feasibility assessment (operational studies) of MGs connection, and, finally, a discussion of operational issues of storage systems in a microgrid environment.

Distributed generation (DG) and other electric resources such as batteries and electric vehicles are transforming the planning and operation of power distribution system all over the world. Although the operation gets more complex in the presence of DG, it also brings some potential benefits to the grid. In this study, the authors propose an optimisation approach for multiple DG units scheduling, considering a daily load profile. The main objective is to minimise the total energy loss in a period of time, dealing with a specific voltage and unbalance constraints, required by the Brazilian Electricity Regulatory Agency. The problem formulation results in a discontinuous non‐convex objective function. An empirical continuous metaheuristic (ECM) is proposed to solve this challenging optimisation problem. As metaheuristic methods are suitable for this kind of problems, they present some limitations regarding final results variability, relative dependence on initial conditions and usually a large set of parameters to tune. ECM confronts directly these limitations, presenting good quality results in comparison to other well‐known algorithms. By using the Open Distribution System Simulator – OpenDSS, and the well‐known IEEE‐123 distribution system, the proposed approach shows its effectiveness and efficiency to optimise the grid operation, with special attention to the Brazilian requirements for unbalance.

Microgrids have emerged as a popular solution for electric energy distribution due to their reliability, sustainability, and growing accessibility. However, their implementation can be challenging, particularly due to regulatory and market issues. Building smaller-scale microgrids, also known as nanogrids, can present additional challenges, such as high investment costs that need to be justified by local demands. To address these challenges, this work proposes an economic feasibility assessment model that is applied to a real nanogrid under construction in the Brazilian electrical system, with electric vehicle charging stations as its main load. The model, which takes into account uncertainties, evaluates the economic viability of constructing a nanogrid using economic indicators estimated by the Monte Carlo simulation method, with the system operation represented by the OpenDSS software. The model also considers aspects of energy transactions within the net-metering paradigm, with energy compensation between the nanogrid and the main distribution network, and investigates how incentives can impact the viability of these microgrids.