Speaker
Aboelsood Ali Abdelrohman Zidan
Title
Self-healing Mechanisms in Distribution Systems with High Distributed Generation (DG) Penetration
Abstract
Recently, interest in Smart Grid (SG) as a tool for modernization and automation of the current distribution system has rapidly increased. This interest can be explained due to the belief that, SG will provide a great enhancement in power system reliability, quality and efficiency. One of the most important objectives of SG is to accommodate a wide variety of generation options. This objective aligns with the new trends and policies which encourage increasing the penetration levels of Distributed Generation (DG) based on environmental, regulatory and economical aspects. Most DG units are low emission energy sources, and thus can meet the Canadian emission portfolios and are attractive for both utilities and customers for different reasons. DG units can postpone large investment in transmission and central generation, reduce energy losses, increase system reliability and quality.
SG is centered around several objectives such as: self-healing, motivating consumers to participate in the grid operation resist attacks, accommodating a wide variety of DG units and storage devices, and optimizing assets. Yet, one of the main goals of SG is to increase the reliability of the power system. Reliability presents a vital factor in power system performance, due to the full dependence on electricity in our daily life and the high cost of system outages especially for critical loads. Therefore, one of the main salient features of SG is its ability of self-healing.
Distribution systems have traditionally been designed based on the assumption that the primary substation is the only source of power. The insertion of DG units into the distribution system, however, renders this assumption invalid. As a result, the interconnection of DG units creates several impacts on different practices such as voltage profile, power flow, power quality, stability, reliability, fault detection, and restoration. The policies currently in use provide for the disconnection of DG units when any failure occurs in the network. However, with a high penetration level of DG units, the utility system cannot operate effectively with respect to overload, generation/load balance, and voltage level without the support of the DG units' capacity. Furthermore, the automatic disconnection of the DG units during faults drastically reduces the expected benefits associated with DG units.
Motivated by these facts, the overall target of this thesis is to introduce operation mechanisms to assist in the effort of realizing the concept of Smart Distribution System (SDS) in restoration mode. In particular, self-healing function (i.e., locate and isolate faults, then decide and implement the restoration plan to restore the out-of-service loads). In order to accomplish this function, two stages are presented: In the first stage, numerous practical aspects related to service restoration problem have been considered, such as variations in the load and the priorities of the customers, the presence of manual and automated switches, and the incorporation of DG units (dispatchable and wind-based DG units).