Dissertation
Temperature dependent transmission line modeling and power flow
Doctor of Philosophy (Ph.D.), Drexel University
Sep 2020
DOI:
https://doi.org/10.17918/00000161
Abstract
Modern electric grids are made up of complex networks of variable system loads, large traditional generation resources, as well as intermittent renewable generation resources, and vastly complex transmission networks. These transmission networks perform an irreplaceable role in the uninterrupted delivery of electricity to consumers, and the safe, reliable, and economic operation of these assets is of paramount importance. The impact made by ambient weather conditions on a transmission line's thermal limit and the impact made by a changing conductor temperature on its electrical impedance are treated as two independent problems. Without monitoring the exact weather conditions surrounding a transmission conductor, utility companies often make conservative assumptions when estimating the line's thermal state. Similarly, a constant operating conductor temperature is assumed when modeling the electrical impedance of a transmission line. It is shown in this work that such assumptions can be costly and will adversely affect the accuracy of real-time monitoring applications that rely on these transmission models. It is the goal of this thesis to formulate static and dynamic electrothermal transmission line models that relate the complex interaction between a conductor's electrical and thermal states. These models consider the intersection of electrical circuitry and fluid dynamics, and are first developed theoretically. Then, empirical validation of the static electrothermal models is discussed using measurement data from three large transmission lines in North America. Measurement error present in typical electric telemetry measurement systems is explored and demonstrated. To remedy this error, algorithmic mitigation techniques and field device modifications are proposed to achieve higher accuracy impedance estimates using end-point electrical measurements. Lastly, static electrothermal transmission models are incorporated into the nonlinear power flow algorithm, where system-wide electrical and thermal states are calculated using an input set of system generation and load power flow data, as well as ambient weather data for each network line segment.
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Details
- Title
- Temperature dependent transmission line modeling and power flow
- Creators
- Shaun R. Murphy
- Contributors
- Dagmar Niebur (Advisor)Karen Nan Miu (Advisor)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- vi, 179 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- College of Engineering (1970-2026); Electrical (and Computer) Engineering (1970-2026); Drexel University
- Other Identifier
- 991014695247304721