A methodology for evaluation of permissible depth of penetration of distributed generation in urban distribution systems

Distributed generation (DG) promises potential benefits such as clean or renewable generation, grid support, and transmission and distribution deferral for distribution utilities. However, its integration into the passive distribution system has equal potential to cause adverse impacts. This paper presents the results from a joint study between Toronto Hydro Electric System Ltd. and the University of Toronto, to devise a methodology to evaluate the permissible depth of penetration of DG on Toronto Hydropsilas urban distribution system. The impact of conventional generation, and the addition of large amounts of PV-based generation, is studied. Issues relating to ampacity, voltage regulation, short circuit current are simulated in CYMDIST. The limitations to the depth of penetration are identified. Practical optimal locating of DG and impacts towards power quality and protection are also discussed.