arXiv subjects

Thierry Braconnier

Publications and source records attributed to Thierry Braconnier.

3 recordsLinked to original sources

arXiv2018

Cross-infrastructure holistic experiment design for cyber-physical energy system validation

Strong digitalization and shifting from unidirectional to bidirectional topology have transformed the electrical grid into a cyber-physical energy system, i.e. smart grid, with strong interdependency among various domains. It is mandatory to develop a comprehensive and holistic validation approach for such large scale system. However, a single research infrastructure may not have sufficient expertise and equipment for such test, without huge or eventually unfeasible investment. In this paper, we propose another adequate approach: connecting existing and established infrastructures with complementary specialization and facilities into a cross-infrastructure holistic experiment. The proposition enables testing of CPES assessment research in near real-world scenario without significant investment while efficiently exploiting the existing infrastructures. Hybrid cloud based architecture is considered as the support for such setup and the design of cross-infrastructure experiment is also covered.

eess.SY↗

arXiv2017

CIM compliant multiplatform approach for cyber-physical energy system assessment

With high penetration of distributed renewable energy resources along with sophisticated automation and information technology, cyber-physical energy systems (CPES, i.e. Smart Grids here) requires a holistic approach to evaluate the integration at a system level, addressing all relevant domains. Hybrid cloud SCADA (Supervisory, Control And Data Acquisition), allowing laboratories to be linked in a consistent infrastructure can provide the support for such multi-platform experiments. This paper presents the procedure to implement a CIM (Common Information Model) compliant hybrid cloud SCADA, with database and client adaptive to change in system topology, as well as CIM library update. This innovative way ensures interoperability among the partner platforms and provides support to multi-platform holistic approach for CPES assessment.

cs.SE↗

arXiv2006

Convergence and round-off errors in a two-dimensional eigenvalue problem using spectral methods and Arnoldi-Chebyshev algorithm

An efficient way of solving 2D stability problems in fluid mechanics is to use, after discretization of the equations that cast the problem in the form of a generalized eigenvalue problem, the incomplete Arnoldi-Chebyshev method. This method preserves the banded structure sparsity of matrices of the algebraic eigenvalue problem and thus decreases memory use and CPU-time consumption. The errors that affect computed eigenvalues and eigenvectors are due to the truncation in the discretization and to finite precision in the computation of the discretized problem. In this paper we analyze those two errors and the interplay between them. We use as a test case the two-dimensional eigenvalue problem yielded by the computation of inertial modes in a spherical shell. This problem contains many difficulties that make it a very good test case. It turns out that that single modes (especially most-damped modes i.e. with high spatial frequency) can be very sensitive to round-off errors, even when apparently good spectral convergence is achieved. The influence of round-off errors is analyzed using the spectral portrait technique and by comparison of double precision and extended precision computations. Through the analysis we give practical recipes to control the truncation and round-off errors on eigenvalues and eigenvectors.

physics.comp-ph↗