This work presents an alternative approach to power system computations, Graph Trace Analysis (GTA), and applies GTA to the power flow problem. A novel power flow algorithm is presented, where GTA traces are used to implement a modified Gauss-Seidel algorithm coupled with a continuation method. GTA is derived from the Generic Programming Paradigm of computer science. It uses topology iterators to move through components in a model and perform calculations. Two advantages that GTA brings are the separation of system equations from component equations and the ability to distribute calculations across processors. The implementation of KVL and KCL in GTA is described. The GTA based power flow algorithm is shown to solve IEEE standard transmission models, IEEE standard distribution models, and integrated transmission and distribution models (hybrid models) constructed from modifying IEEE standard models. The GTA power flow is shown to solve a set of robustness testing circuits, and solutions are compared with other power flow algorithms. This comparison illustrates convergence characteristics of different power flow algorithms in the presence of voltage stability concerns. It is also demonstrated that the GTA power flow solves integrated transmission and distribution system models. Advantages that GTA power flow bring are the ability to solve realistic, complex circuit models that pose problems to many traditional algorithms; the ability to solve circuits that are operating far from nominal conditions; and the ability to solve transmission and distribution networks together in the same model. / PHD / Power system engineers rely on modeling and analysis of the electric grid to ensure reliable delivery of that electricity to consumers. The algorithms currently being used for this purpose are designed to simulate either the high voltage transmission networks, or the low voltage distribution networks. The rapid growth solar photovoltaics (PV) based distributed generation over the last few years, which is expected to continue in the near future, has demanded a change in this modeling and analysis approach. As the penetration levels of distributed generation increase, accurate analysis of such an electric grid cannot be performed if either the distribution or the transmission network topology is neglected in the models. Integrated transmission and distribution system modeling and simulation, where transmission and distribution networks are modeled as one single unit, has become an important research area in recent years.
This work contributes to this research area by presenting an algorithm that can be used to solve (find operating point) of integrated transmission and distribution system models. An algorithm that can find a solution of challenging network topologies and operating under severe conditions is also presented. Finally, an application of the algorithm is discussed where the impact of solar PV-based distributed generation on voltage stability limits of the electric grid is studied by using an integrated transmission and distribution system model. The dissertation shows that by solving integrated transmission and distribution system models using this algorithm, insights about the impact of solar PV-based distributed generation on the stability limits of the electric grid can be obtained, which the transmission only or distribution only models cannot provide.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/89362 |
| Date | 09 November 2017 |
| Creators | Tbaileh, Ahmad Anan |
| Contributors | Electrical Engineering, Broadwater, Robert P., Rahman, Saifur, Centeno, Virgilio A., Ravindran, Binoy, Beattie, Christopher A. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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