Nyquist Stability Analysis of an AC-Grid Connected VSC-HVDC System Using a Distributed Parameter DC Cable Model
Journal article, 2016

In this paper, a two-terminal VSC-HVDC system embedded in a weak grid ac environment is considered, emphasizing modeling, controller design, and small-signal stability analysis. Traditionally, the dc cable is modeled by \Pi -sections, implying that care has to be taken when using the model for higher frequencies or in cases of higher cable impedance density, such as submarine cables. Here, a distributed parameter cable model is used to overcome this problem. The VSC-HVDC system can be described as two cascaded blocks. The first block is a transfer function that will differ depending on what input and output variables are considered, but which is in all realistic cases stable. The second block is a feedback loop, where the forward path is a rational function and the return path is a dissipative infinite dimensional function, remaining the same in all cases. The stability is then analyzed, using the Nyquist criterion, in a straightforward manner. Numerical examples are given by the use of MATLAB. The result is that if the VSC-HVDC system using a single \Pi -section cable model is stable, so is the VSC-HVDC system using a distributed parameter cable model.

weak ac environment.

Nyquist stability criterion

Distributed parameter cable model

VSC–HVDC system

Author

Yujiao Song

Chalmers, Signals and Systems, Systems and control

Claes Breitholtz

Chalmers, Signals and Systems, Systems and control

IEEE Transactions on Power Delivery

0885-8977 (ISSN) 1937-4208 (eISSN)

Vol. 31 2 898-907 7347446

Areas of Advance

Energy

Subject Categories

Electrical Engineering, Electronic Engineering, Information Engineering

DOI

10.1109/TPWRD.2015.2501459

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4/5/2022 6