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.

This paper evaluates the impact of voltage distortion on the electrical quantities measured by revenue meters and the influences on the electrical energy billing. This is done through an experimental setup, which combines the following variables for the first time in an experiment: different total harmonic voltage distortion (THDv) levels; among these levels, different harmonic profiles; and different loads. A programmable alternating current (AC) power source was used in the laboratory to apply voltage signals in three electronic loads: a compact fluorescent lamp (CFL) and two light emitting diode (LED) lighting devices for which voltage signals with THDv 4.9%, 18.8% and 24.5% have been applied. All applied signals contain one or more harmonic order more commonly found in the low voltage grid (3rd, 5th and 7th). For these analyses, a power quality analyzer and a revenue meter were used. The results show that significant and diverse effects on the electrical quantities of individual loads will occur with different THDv levels and harmonic profiles. Comparing with a reference case (sinusoidal condition), when a distorted signal was applied, for the same THDv level, some parameters remained numerically the same, some have improved and some have become worse. This study shows that the effects of combination of the variables such as different THDv level with different harmonic profiles on electrical quantities of loads are not as clear as the effects of considering only one variable. The results of this paper shed light on such effects.

The impact of non-linear loads in electrical systems is a subject that has been of concern of the scientific community for quite some time. More recently, in addition to the aspects associated to power quality, billing concerns also became part of the agenda of the professionals that actuate on in this important area. In this context, this work presents an electronic device, named as Dimmer Flex, which makes it easier to explore the impact of electronic switching on the electrical current that feeds a linear load. By means of the prototype presented at this paper it is possible to analyze the impacts of the switching in the measurement, and consequently, in the energy billing, considering any pre-specified capacitive or inductive power factor value. Once this is a relatively new subject, additional research is still required for deepening the conclusions and results, which could, in turn, lead to the revision of current methods used for the purpose of measurement and billing of electrical power.