Adjoint variable method for transient nonlinear electroquasistatic problems

Abstract

Many optimization problems in electrical engineering consider a large number of design parameters. A sensitivity analysis identifies the design parameters with the strongest influence on the problem of interest. This paper introduces the adjoint variable method as an efficient approach to study sensitivities of nonlinear electroquasistatic problems in time domain. In contrast to the more common direct sensitivity method, the adjoint variable method has a computational cost nearly independent of the number of parameters. The method is applied to study the sensitivity of the field grading material parameters on the performance of a 320 kV cable joint specimen, which is modeled as a finite element nonlinear transient electroquasistatic problem. Special attention is paid to the treatment of quantities of interest, which are evaluated at specific points in time or space. It is shown that the method is a valuable tool to study this strongly nonlinear and highly transient technical example.

Transient forward harmonic adjoint sensitivity analysis

“…Transient adjoint sensitivity analysis [10,11] as well as sensitivity analysis based on HB solvers [12,13] have been published and used before. In more recent publications, transient adjoint sensitivity analyses have been applied for a larger variety of nonlinear problems such as electromagnetics, electroquasistatics or nonlinear damped mechanical systems [14][15][16]. Transient adjoint sensitivity analysis is an efficient approach for the analysis of strongly nonlinear systems.…”