Power electronics in Smartgrids - Impact on power system reliability

The leading themes in the distribution network development are the cost effectiveness and system reliability. Also the requirements for reducing pollution and increasing the service quality are issues, which have led to the introduction of SmartGrids network concepts. These network solutions are mostly dependent on power electronics, applied to connection of loads, generation and storages to the independently operable low-voltage (LV) grids. One of such solutions is the low voltage DC (LVDC) distribution system, which is an interesting challenger to the AC low voltage network solutions. An often-asked question is how the shorter lifetimes of power electronics compared to the traditional network components affect on the reliability of the electricity distribution and also to its total costs. In the this paper the question about the reliability development is approached from two mainpoints of view: The component level focusing on the reliability of power electronics based network components, and the system level concentrating on the power quality experienced by the customers and the effects of converters on the entire distribution system reliability. The question of the reliability impact of large-scale utilization of power electronics in electricity distribution is relevant, when considering the direction of the technical development in electricity distribution. This paper is especially aimed at discussing the modelling of the reliability impacts in the case of the LVDC-system.