Search

Distribution networks are suffering a transformation process with the insertion of distributed energy resources, changing from a passive part of the power grid into an active system. Aiming to reduce the challenges for the distribution system operators to keep the power grid operating inside of the quality levels it is possible to propose some ancillary services. Optimum Power flow is an optimization method used to plan the distribution grid operation. Additionally, the distributed energy resources can be modeled on it and ancillary services provisioning can be considered, as proposed in this work. In this way, the objective of the present work is to formulate a Multiperiod Optimum Power Flow (MPOPF) with the insertion of distributed generation, energy storage systems, microgrids, and electric vehicles at the distribution grid. This MPOPF considers the provisioning of ancillary services by the inverters associated with the equipment connected to the main grid. In the formulation, the entire grid is modeled, considering the placement of classic equipment as a voltage regulator and capacitor banks, in addition to modern technologies as DFACTS (Distribution - Flexible AC Transmission System) and four-quadrant inverters. The MPOPF was simulated for several scenarios considering a 90-bus test feeder and a real distribution grid from Curitiba – Brazil. From the results, the MPOPF proved to be highly robust, being able to simulate the grid with all the equipment connected simultaneously, performing the optimal dispatch of active and reactive power, as well as allowing the operation of ancillary services such as voltage support, peak-shaving, and demand-side management.

The growth of photovoltaic systems (PV) and battery energy storage systems (BESS) will become a challenge for distribution players. In this way it is important to understand how these systems can impact on the distribution grid operation. For this, a study was developed considering the insertion of PV on IEEE 13 buses test feeder, based on different penetration levels. These levels were calculated contemplating two different parameters: the one most used in Brazil, and the parameter that consists in an extended criterion used worldwide. Considering these possibilities, different penetration levels of photovoltaic were defined. In conjunction with photovoltaic generation, a BESS was inserted in the same feeder, in order to evaluate the impacts of this system. From the simulations was possible to evaluate the tap changes, the voltage profile, power losses and the total energy, including if there was reverse power flow at any moment during one day.

Energy storage systems have been increasingly used in applications at the power grid. In this way, to develop electrical analyses of these systems connected to the grid, is necessary to know how the electrical simulations tools model these elements. Therefore, the present paper present a comparison analysis of the software DIgSILENT PowerFactory, EMTP/ATP, GridLAB-D, Matlab/Simulink, OpenDSS, PowerWorld and PSCAD in order to evaluate the energy storage system modeling and the power system simulation, focusing in the efficiency and flexibility of the simulation tools. The software comparison were developed using an Impact Effort Matrix, in which each software was graded according with criteria of efforts and impact.

The increase in distributed generation, mainly using photovoltaic solar energy, is a growing reality for the Brazilian electric system. In addition, the installation of systems capable of storing energy and allowing greater management of the demand for the load are a trend for the electric sector. In this way, understanding the impacts caused by these systems in the distribution grid is very important. In order to allow the elaboration of the modeling of this system in the computational tool DIgSILENT PowerFactory, this work focuses on the search for knowledge about the operation of these systems and their main characteristics was carried out. The modeling system consists of the Photovoltaic Plant of the Lactec Institutes, located in Curitiba, Brazil, and where it was possible to carry out measurements in order to validate the model developed in the tool. With the developed model, it was possible to elaborate different scenarios of simulation, being only one with the photovoltaic system and another two with the photovoltaic system plus batteries, these with different dimensions. For each of the scenarios, the analysis of active and reactive power balance, voltage profile, transformer load and power factor analysis were performed, as well as load factor analysis for the three cases. With this work it was possible to verify how the system behaves and what are the points at which it causes greater impact in the distribution network.