Computational challenges in electrical power networks

Networks for the high-voltage distribution of electrical energy are currently undergoing farreaching developments. National power grids are evolving fromstatic entities, producingmainly a uni-directional flow from generation to loads, to more dynamic and decentralized structures. These emerging power systems should accommodate the local...

Simulation of arc models with the block modelling method

Simulation of current interruption is currently performed with non-ideal switching devices for large power systems. Nevertheless, for small networks, non-ideal switching devices can be substituted by arc models. However, this substitution has a negative impact on the computation time. At the same time, these simulations are useful to design...

3D Nonlinear transies field-circuit modeling of inductive fault current limiters

Due to increasing levels of fault currents, Fault Current Limiters (FCLs) are expected to play an important role in the protection of future power grids. Inductive saturable FCLs are particularly interesting due to their inherent reaction on the fault. Many different configurations have been proposed in literature. Being difficult or impossible...

Transients in power systems: A literature survey

Numerical Modeling of Rotary Kiln Productivity Increase

Rotary kilns are used in many industrial processes ranging from cement manufacturing to waste incineration. The operating conditions vary widely depending on the process. While there are many models available within the literature and industry, the wide range of operating conditions justifies further modeling work to improve the understanding of...

Isogeometric shape optimization of magnetic density separators

Purpose: The waste recycling industry increasingly relies on magnetic density separators. These devices generate an upward magnetic force in ferro-fluids allowing to separate the immersed particles according to their mass density. Recently a new separator design that significantly reduces the required amount of permanent magnet material has been...

Effective water storage as flood protection; the Rijnstrangen study case

Climate change is expected to cause higher discharge levels in the river Rhine at the Dutch-German border. In this study group project that was commissioned by Rijkswaterstaat , we investigate the possibility of flooding the Rijnstrangen area as a protective measure. We identify three subproblems. We first analyze the data recorded by...

Load flow computations in hybrid transmission - distributed power systems

We interconnect transmission and distribution power systems and perform load flow computations in the hybrid network. In the largest example we managed to build, fifty copies of a distribution network consisting of fifteen nodes is connected to the UCTE study model, resulting in a system consisting of 5003 nodes. For this model, the Newton load...

Influence of stator slotting on the performance of permanent-magnet machines with concentrated windings

The use of slotted stator permanent-magnet machines with concentrated windings is increasing in industry. In this paper, the effect of the slot opening on flux linkage, internal voltage, mean torque, rotor eddy current loss and stator iron losses is evaluated. This gives new insight into the influence of slotting on the performance of machines...

Manifold mapping optimization with of without true gradients

This paper deals with the Space Mapping optimization algorithms in general and with the Manifold Mapping technique in particular. The idea of such algorithms is to optimize a model with a minimum number of each objective function evaluations using a less accurate but faster model. In this optimization procedure, fine and coarse models interact...

On the convergence of inexact Newton methods

The inexact Newton method is widely used to solve systems of non-linear equations. It is well-known that forcing terms should be chosen relatively large at the start of the process, and be made smaller during the iteration process. This paper explores the mechanics behind this behavior theoretically using a simplified problem, and presents...

A scalable Helmholtz solver combining the shifted Laplace preconditioner with multigrid deflation

A Helmholtz solver whose convergence is parameter independent can be obtained by combining the shifted Laplace preconditioner with multigrid deflation. To proof this claim, we develop a Fourier analysis of a two-level variant of the algorithm proposed in [1]. In this algorithm those eigenvalues that prevent the shifted Laplace preconditioner...

Scalable Newton-Krylov solver for very large power flow problems

The power flow problem is generally solved by the Newton-Raphson method with a sparse direct solver for the linear system of equations in each iteration. While this works fine for small power flow problems, we will show that for very large problems the direct solver is very slow and we present alternatives that scale much better in the problem...

Fast iterative solution methods for the Helmholtz equation

Load flow literature survey

Optimal configuration of future electricity grid

This paper considers the scenario of a big new energy source connecting to an existing network of generators and loads. To be able to maintain such a network at the correct settings, the well known load flow equations have to be solved. Since existing software has trouble with solving the load flow equations in the scenario of a very large...

Counteracting ring formation in rotary kilns

Avoiding the formation of rings in rotary kilns is an issue of primary concern to the cement production industry. We developed a numerical combustion model that revealed that in our case study rings are typically formed in zones of maximal radiative heat transfer. This local overheating causes the overproduction of the liquid phase of the...