Candidate
Haytham Mohamed AbdElrahman Mohamed Ahmed
Title
Optimal Planning and Operation of AC-DC Hybrid Distribution Systems
Supervisor
Magdy Salama
Abstract
Recent years have been marked by a significant increase in interest in green technologies, which have led to radical changes in the way electric power is generated and utilized. These changes have been accompanied by greater utilization of DC-based distributed generators (DGs), such as photovoltaic (PV) panels and fuel cells, as well as DC-based load demands, such as electric vehicles (EVs) and modern electronic loads. In addition to accommodating these technologies, future distribution systems (DSs) will also need to support the integration of additional battery storage systems with renewable DGs. A further factor is the number of policies that have been implemented in Ontario, Canada, with the goal of encouraging the use of clean energy. The first, the feed-in-tariff (FIT) program, was introduced to promote the application of renewable DGs, including PV panels and wind DGs, and a second, new program that offers incentives for switching to EVs has been announced. The result is that future DSs must include additional DC loads and DC-based DGs along with their present AC loads and energy resources. Future DSs should thus become AC-DC hybrids if they are to provide optimal accommodation of all types of AC and DC loads and DGs. These considerations accentuate the need for reliable techniques appropriate for the planning and operation of future hybrid DSs.
This thesis presents new directions for the planning and operation of AC-DC hybrid DSs. The main target of the research presented in this thesis is to optimally accommodate the expected high penetration of DC loads and DC-based DGs in future DSs. Achieving this target entailed the completion of four consecutive parts: 1) developing a unified load flow (LF) model for AC-DC hybrid DSs, 2) introducing a two-stage energy management scheme (EMS) that can achieve optimal and reliable operation for AC-DC hybrid DSs, 3) introducing a novel stochastic planning model to determine the optimal AC-DC network configuration that minimizes the hybrid DS costs, and 4) developing a reliability-based stochastic planning framework for the simultaneous optimization of the DS costs and reliability. The developed planning framework represents an effective technique that can be used by DS operators to identify the optimal AC-DC network configuration of future hybrid DSs.