Analysis and evaluation of transactive energy control in active distribution systems

Abstract

The electric power distribution system is experiencing significant operational changes due to the integration of plug-in electric vehicles and intermittent distributed energy resources such as rooftop solar photovoltaics. As plug-in electric vehicle charging represents a significant increase in system loading, both distribution transformers and substation transformers are subject to overload conditions which rapidly degrade transformers lifetime. Furthermore, the increased penetration of rooftop solar photovoltaic in the residential sector may lead to bi-directional power flow and may additionally cause overload to the distribution transformers. In order to accommodate the growing market penetration of plug-in electric vehicles and rooftop solar photovoltaics, the electric utility must employ energy management to prolong the transformers lifetime. Given that transformers represent one of the most expensive assets in the distribution system, failure to resolve transformer lifetime degradation issues require the electric utility to incur the costs of transformer replacement or upgrading. The work in this dissertation proposes a transactive energy control methodology to perform residential energy storage system control as a means of reducing transformer lifetime degradation. The results have shown that the proposed framework may extend median annual distribution transformer lifetime by nearly double the expected lifetime of distribution transformers without transactive energy control. Finally, the proposed transactive control scheme has also been found to reduce active power losses within the system.