A study of voltage rise in distribution grids with high concentration of power generators

Abstract

The growing demand for electric power together with the environmental agencies pressure for decreasing polluting gases emission are the main causes of the big expansion that Distributed Generation systems have been undergoing lately. This kind of electric generation system allows to produce parts of the electricity power nearby the costumers making energy costs cheaper for final consumer and improving the share of clean sources on the energy matrix. Despite Germany’s great experience with photovoltaic plants, Distributed Generation systems are not well widespread around the world. Most governmental regulations about the theme are recent and sometimes do not cover all the specificities, so it has been continuously rewritten. Although Brazilian market has a small concentration of sources connected to the distribution grids, the annual relative growth is significant. High concentration of sources nearby the costumers may cause problems in the operation and in the stability of electric quantities. Some of these problems are voltage rises, harmonics and general damages to electrical equipment. This paper presents the voltage rise effect in distribution grids with high concentration of generators; it also suggests mitigation techniques for this outcome. It becomes clear that is possible to reverse power flow without voltage rise beyond legal limits.