Provision of high quality power supply in distribution networks with renewable energy sources

Abstract

Features of practical application of the developed multifunctional tools which provide reliable power supply and standard voltage quality characteristics in electrical networks of small power systems (microgrid) are considered. It is noted that these distribution systems have a number of known advantages over traditional power supply systems. In particular such system typically includes several sources of distributed generation, distribution substations, power storages and energy converters, which allows such a “Microgrid Plus” system to function offline or synchronously with an external power system. In microgrid, high-quality electrical supply can be achieved by, for example, using unregulated and controlled filtering-balancing devices or hybrid filtercompensating converters as well as the use of renewable energy sources and power accumulation system. The main aspects of the practical implementation of the power unit of a multifunctional bi-directional electric power converter as a part of a unified 300 kW inverter module for use in modern multimodal energy storage systems of significant power with different types of energy sources are considered. It is shown, that use of bi-directional converters in the system of energy accumulation can provide the required level of power quality in «Microgrid Рlus» in normal operating modes, in particular, the values of the THD of the input and output currents of these converters are several percents. In addition, they may, if necessary, compensate reactive power in these microgrid. The practical application of mentioned systems contributes to the implementation of the general concept of Smart Grid & Energy Storage, which aims at expanding the capabilities of renewable energy and integrating into smart electrical networks.