Modeling and analysis of distributed generation systems

Abstract

Of late, the electrical power utilities are undergoing rapid restructuring process worldwide. Indeed, with deregulation, advancement in technologies and concern about the environmental impact, competition is particularly fostered in the generation side thereby allowing increased interconnection of generating units to the utility networks. These generating sources are called distributed generators (DG) and are generally connected to the distribution networks. Various new types of distributed generator systems, such as microturbines and fuel cells, in addition to the more traditional solar and wind power, are creating significant opportunities for the integration of diverse DG systems to the utility. Inter-connection of these generators will offer a number of benefits such as improved reliability, power quality, efficiency, alleviation of system constraints along with the environmental benefits. Technology advancement in power electronics and energy storage devices have further accelerated the penetration of DG into electric power distribution system. With these benefits and due to the growing momentum towards sustainable energy developments, it is expected that a large number of DG systems will be interconnected to the power system in the coming years. Unlike centralized power plants, the DG units are directly connected to the distribution system most often at the customer end. The existing distribution networks are designed and operated in radial configuration with unidirectional power flow from centralized generating station to customers. The increase in interconnection of DG to Utility networks can lead to reverse power flow violating fundamental assumption in their design. This creates complexity in operation and control of existing distribution networks and offers many technical challenges for successful introduction of DG systems. Some of the technical issues are islanding of DG, voltage regulation, protection and stability of the network.