| dc.description.abstract | A legacy electric power distribution system is characterized by a unidirectional power flow from centralized power plants to customers. The role of these customers has been known for many years as power consumers and not power producers. In smart distribution systems, because of the widespread use of distributed energy resources such as roof-top solar photovoltaics and home battery energy storage in residential subdivisions, the role of many of the residential customers has changed to be power producers and consumers; therefore, they are combined in the term prosumers. Moreover, the integration of prosumers owning plug-in electric vehicles into the residential sector may bring several operational challenges to the electric power distribution systems such as distribution transformer overload, which may accelerate the distribution transformer’s aging leading to premature replacement, in addition to an increase in the energy loss and service voltage deviations, leading to additional costs to the utility. Furthermore, these challenges threaten the continuity of the power supply to residential customers. Many studied have introduced several strategies to mitigate these negative impacts. Therefore, this thesis presents novel strategies to mitigate the impact of integrating these distributed energy resources and plug-in electric vehicles. Previous work has identified the secondary distribution system, which is the part of the distribution system starting from the distribution transformers and ending at the customers’ smart meters, as the weakest part of the overall distribution system that would be significantly affected by the change of the residential customer’s role in modern grids. The work presented in this thesis addresses this problem by considering the secondary distribution systems at two different stages. In the first stage, namely the design stage, the focus is on the design of the secondary distribution systems when considering a new residential subdivision. The proposed strategy in this work aims to consider the distributed energy resources and plug-in electric vehicle charging demand, installed at the prosumers’ premises, at the design stage by identifying the sizing of the secondary distribution system components (e.g., distribution transformer, and secondary line conductors).
In the second stage, namely the operational stage, the focus is on the secondary distribution systems that are already in service and which have been designed without taking into consideration the presence of the distributed energy resources and plug-in electric vehicle charging demand. Two strategies for this operational stage are proposed in this work. The first strategy (i.e., an operational stage without distributed energy resources) aims to mitigate the impact of these distributed energy resources by finding the optimal size, location and number of roof-top solar photovoltaics to be connected to improve the system performance and facilitates the integration of the and plug-in electric vehicle. The second strategy (i.e., an operational stage with distributed energy resources and plug-in electric vehicles) is based on the following two approaches. The first approach intends to intelligently design a community battery energy storage system (distributed battery energy storage system) to mitigate the impact of these distributed energy resources and plug-in electric vehicle charging demand while the second approach uses a novel concept of transactive energy market that aims to achieve both the customers’ and electric utilities’ objectives. The results presented in this thesis show the applicability of the proposed strategies to integrate the distributed energy resources and plug-in electric vehicle charging demand in secondary distribution systems at the two different stages (design and operational stages).
In the design stage, the results reveal that the proposed optimal design approach is able to integrate the distributed energy resources and plug-in electric vehicle charging demand without any violations of voltage or a distribution transformer’s aging constraints. In the operational stage, applying the first strategy (optimal size, location and number of prosumers) leads to an improvement in the service voltage at the customers by 4% and a reduction in the secondary distribution system’s annual energy loss by 50%. In addition, applying the second strategy with the first approach (optimal design of the community battery energy storage system) results in improving the service voltage at the customers by 4.5% and reducing the energy loss by 50%. Moreover, applying the second strategy with the second approach (transactive energy market), which is implemented on the overall distribution systems, improves the service voltage by 2.9%, and mitigates the voltage unbalance. | en |
