Adjoint Variable Method for Transient Nonlinear Electroquasistatic Problems

TL;DR

This paper presents an adjoint variable method for efficiently computing sensitivities in nonlinear electroquasistatic problems over time, significantly reducing computational costs compared to direct methods.

Contribution

It introduces an adjoint sensitivity analysis approach tailored for transient nonlinear electroquasistatic problems, with application to electrical cable joint performance.

Findings

The method reduces computational effort for sensitivity analysis.

Application to a 320 kV cable joint demonstrates effectiveness.

Special treatment of quantities of interest enhances accuracy.

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 shown that the method is a valuable tool to study this strongly nonlinear and highly transient technical example.