This paper proposes a fast and in situ remanent flux detection method for protection current transformer (CT) based on the fluxgate theory. A high frequency voltage source is connected to secondary side of CT, saturates core slightly positive or negative direction. The polarity decided by sign integral voltage. calculated with linear relationship between second harmonic component can be obtaine...

Harmonic extraction methods for the multiparameter eigenvalue problem willbe presented. These techniques are generalizations of their counterparts forthe standard and generalized eigenvalue problem. The methods aim to ap-proximate interior eigenpairs, generally more accurately than the standardextraction does. The process can be combined with any subspace expansionapproa...

This paper considers the finite element approximation of elliptic boundary value problems in divergence form with rough coefficients. The solution of such problems will, in general, be rough, and it is well known that the usual (Ritz or displacement) finite element method will be inaccurate in general. The purpose of the paper is to help clarify the issue of whether the use of mixed variational...

A standard boundary element method (BEM) discretisation for the electromagnetic compatibility (EMC) problem is analysed, revealing the near-singularity of the dense linear system for the lower frequency range. Next, a new basis transformation is presented, that separates the dominating capacitive eeects from the small, but important inductive eeects. On this basis a sparse approximate inverse i...

In this paper a guaranteed upper bound of the global discretization error in linear elastic finite element approximations is presented, based on a generalized Trefftz functional. Therefore, the general concept of complementary energy functionals and the corresponding approximation methods of Ritz, Trefftz, the method of orthogonal projection and the hypercircle method are briefly outlined. Furt...

In this article, a priori error bounds are derived for an hp-local discontinuous Galerkin (LDG) approximation to a parabolic integro-differential equation. It is shown that error estimates in L2-norm of the gradient as well as of the potential are optimal in the discretizing parameter h and suboptimal in the degree of polynomial p. Due to the presence of the integral term, an introduction of an...