Impact of Smart Grids and Green Power Generation on Distribution Systems

A significant amount of green power is being installed at the distribution level through the installation of green power generation facilities in the U.S. and Canada. This paper discusses green-power-generating sources (of 10 MW or less), which are connected to the utility system at the distribution level, and their impact on the distribution system. This paper also discusses the impact of smart grid and whether this new technology can solve some of the issues raised in this paper. Distribution circuits are designed to supply radial loads. Therefore, the introduction of green generation could mean redistribution of fault and load currents on the feeder circuit, overvoltage, and ferroresonance, plus a possible loss of protection system coordination-all of which can result in customer outages. This paper discusses these issues which are generally not well understood by many distribution protection engineers and can adversely affect distribution system reliability.