Power Flow Control Using Series Voltage Source Converters in Distribution Grids

This study presents an application for a series VSC (voltage source converter) in distribution grids for power flow management. Series devices have been widely studied for FACTS (flexible AC transmission systems), however, more recently these devices have gained increased interest in applications for loading balance in medium voltage distribution grids. As the number of distributed generation (DG) units increases, increasing the capacity and reliability of distribution grids while maximizing the benefits of installed DGs and loading behavior is an ever more important task. In this paper, we describe a test system and control proposals for a practical application of series converters interconnecting two distribution feeders at 13.8 kV under load variation disturbances. This approach provides solutions when installed at the end of distribution lines by interconnecting two feeders, resulting in capacity increases in the feeders without needing grid reconfigurations using a small-rated series VSC

Implementation of harmonic propagation damping feature on a storage and grid support equipment.

Este trabalho trata do amortecimento de propaga??o harm?nica em linhas de distribui??o, visando melhora na qualidade da tens?o. A propaga??o harm?nica ocorre devido ?s resson?ncias entre as imped?ncias indutivas do sistema e bancos de capacitores utilizados em filtros passivos e compensadores de reativos, amplificando a distor??o causada por cargas n?o lineares nas proximidades, e pode ser amortecida atrav?s do uso de filtros ativos emulando resist?ncias harm?nicas. Esta abordagem (ao inv?s do uso convencional dos filtros ativos shunt para diretamente compensar as correntes harm?nicas) ? muito atrativa para sistemas de distribui??o, aonde as cargas n?o lineares est?o distribu?das e inacess?veis. A contribui??o principal deste artigo ? a implementa??o desta resist?ncia harm?nica em um equipamento de armazenamento de energia e suporte de rede como uma funcionalidade extra, sem necessidade de sensores adicionais. Resultados experimentais s?o apresentados em uma bancada de testesThis work discusses harmonic propagation damping on distribution lines, aiming for better voltage quality. The harmonic propagation is due to resonances between the inductive impedances of the system and the capacitor banks installed in passive filters and reactive power compensators, amplifying the distortion caused by non-linear loads nearby, and can be damped with the use of active filters emulating harmonic resistances. This approach (instead of the conventional use of shunt active filters to directly compensate harmonic currents) is very attractive for distribution systems, where the non-linear loads are distributed and inaccessible. The main contribution of this paper is the implementation of this harmonic resistance in an energy storage and grid support equipment as an extra feature, without the need of additional sensors. Experimental results are presented in a test bench

Development and 24 Hour Behavior Analysis of a Peak-Shaving Equipment with Battery Storage

This paper presents the development of a peak-shaving equipment, composed by a multilevel converter in a cascaded H-bridge topology and battery banks on the DC links. Between specific time periods, when the demand is higher, the equipment injects active power from the batteries into the grid to provide support to the system. During the other times of the day, when the demand is lower, the converter charges its battery banks with the exceeding (and low producing cost) energy from the grid. The charge and discharge control algorithms are implemented in a digital signal processor (DSP). The precise time of the day information is obtained from a real-time-clock from a global positioning system module (GPS), which communicates with the DSP through the serial interface. This paper presents the control algorithms and experimental results obtained in a 24 h continuous operation of the equipment