Induction Generator Effects on Spot Network Operation

Distributed resources are connected to low voltage distribution systems for various reasons, including energy savings, demand reduction, sale of energy or capacity to a utility company, and providing a backup power source if supply from the utility system is lost. A spot network is one type of distribution system that presents some special problems for connecting a distributed resource. A sample spot network system is analyzed to show the effects of operating an induction generator. Induction generator reactive power requirements, configuration of the turbine generator controls, network relay trip and close characteristics, and external tapped loads all affect operation of the network system. The analysis identifies areas of concern when connecting an induction generator to a spot network and suggests ways to configure the control system and network relays to avoid disrupting normal operation of the network. This paper reviews a two-unit spot network, but the concepts and analysis can be applied to larger spot networks.