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A COUPLED THERMAL/ELECTRIC CIRCUIT MODEL FOR DESIGN OF MVDC CABLES

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posted on 17.10.2019 by Xiang Zhang
Cables play an important role in the design of a power system. DC cable design presents unique challenges due to the fact that space charge can accumulate within the dielectric over time. Space charge accumulation is a function of temperature, electric field, and dielectric properties. Of particular concern is that the space charge leads to electric fields that are sufficient to break down the cable, particularly during transient conditions such as voltage reversal.

In this research, a focus is on the development of a coupled thermal- and electricalequivalent-circuit model that is general and provides the ability to predict the electric fields and space charge accumulation within single and multi-conductor DC cables. In contrast to traditional analytical models, the approach is more general, allowing for exploration of a wide spectrum of geometries. In contrast to traditional numerical methods, including finite element or finite difference, apriori knowledge of the electric field behavior is used to discretize the dielectric into a small number of electric flux tubes. The electric field dynamics within each tube are then modeled using a first order nonlinear differential equation. The relatively coarse discretization enables the solution to be computed rapidly. This is useful in population-based design where a large number of candidate evaluations is necessary to explore a design space. The modeling approach has been validated using several examples presented in the literature. In addition, its usefulness has been highlighted in the optimization of a 20 kV cable wherein objectives include minimization of mass and loss.

Funding

Office of Naval Research under Grant #N00014-16-1-2956

History

Degree Type

Doctor of Philosophy

Department

Electrical and Computer Engineering

Campus location

West Lafayette

Advisor/Supervisor/Committee Chair

Steven Pekarek

Additional Committee Member 2

Scott Sudhoff

Additional Committee Member 3

Oleg Wasynczuk

Additional Committee Member 4

Jiao Dan

Licence

Exports