ASU Electronic Theses and Dissertations
This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.
In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.
Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.
Filtering by
- All Subjects: FREEDM
- Creators: Ayyanar, Raja
semiconductor technology, power electronic devices could be utilized to interface re-
newable energy generation and the distribution power grid. However, when directly
connected to the power grid, the semiconductors inside the power electronic devices
could be vulnerable to the power system transient, especially to lightning strikes.
The work of this research focuses on the insulation coordination of power elec-
tronic devices connected directly to the power distribution system. The Solid State
Transformer (SST) in Future Renewable Electric Energy Delivery and Management
(FREEDM) system could be a good example for grid connected power electronic
devices. Simulations were conducted in Power Systems Computer Aided Design
(PSCAD) software. A simulation done to the FREEDM SST showed primary re-
sults which were then compare to simulation done to the grid-connected operating
Voltage Source Converter (VSC) to get more objective results.
Based on the simulation results, voltage surges caused by lightning strikes could
result in damage on the grid-connected electronic devices. Placing Metal Oxide Surge
Arresers (MOSA, also known as Metal Oxide Surge Varistor, MOV) at the front lter
could provide eective protection for those devices from power transient. Part of this
research work was published as a conference paper and was presented at CIGRE US
National Conference: Grid of the Future Symposium [1] and North American Power
Symposium [2].
Some key features of the FREEDM system include improved power flow control, compact design and unity power factor operation. Customers may observe a reduction in the electricity bill by a certain fraction for using renewable sources of generation. There is also a possibility of huge subsidies given to encourage use of renewable energy. This thesis is an attempt to quantify the benefits offered by the FREEDM system in monetary terms and to calculate the time in years required to gain a return on investments made. The elevated cost of FIDs needs to be justified by the advantages they offer. The result of different rates of interest and how they influence the payback period is also studied. The payback periods calculated are observed for viability. A comparison is made between the active power losses on a certain distribution feeder that makes use of distribution level magnetic transformers versus one that makes use of SSTs. The reduction in the annual active power losses in the case of the feeder using SSTs is translated onto annual savings in terms of cost when compared to the conventional case with magnetic transformers. Since the FREEDM system encourages operation at unity power factor, the need for installing capacitor banks for improving the power factor is eliminated and this re-flects in savings in terms of cost. The FREEDM system offers enhanced reliability when compared to a conventional system. The payback periods observed support the concept of introducing the FREEDM system.