Highvoltage.dk is a Danish consulting engineering firm with expertise in lightning protection and high-voltage engineering. The company, founded in 2005, tackles complex problems such as general high-voltage design engineering for the power industry, lightning protection concepts and findings for wind turbines, and high-voltage material tests. The engineers at Highvoltage.dk are experienced users of numerical analysis tools to simulate magnetic and electric fields, current distribution, and lightning attachment points.

Figure 1. To compute physical conditions within Wind Turbine Nacelles, SpaceClaim was used to precondition the comprehensive CAD drawings.
When complex structures such as wind turbines are struck by lightning, the discharge may interfere with the electronic equipment within the turbine. Engineers must ensure that the most vulnerable areas of the turbine are not exposed to potential strikes that could cause the turbine to fail or sustain damage. As the cost of commercial- scale wind turbines runs in the millions, being able to optimize the design is critical.

When approaching the simulation and analysis of turbine designs, Highvoltage.dk has to model the physical behavior to gain knowledge of the system without empirical validation. To perform these simulations, Casper Falkenstrøm Mieritz, Consulting Engineer, uses COMSOL Multiphysics® simulation software. Before SpaceClaim®, Casper had to discuss the CAD preconditioning with the customers, which added time and cost to the process, and took some of the control out of the hands of Highvoltage.dk.

Figure 2. The Magnetic Field within the nacelle structure is used for specifying the necessary level of protection of panels and installations. The calculated magnetic fields of more than 30 kA/m corresponds to a situation where the turbine is struck by a 200 kA lightning strike.
To analyze the real physical structures, customer geometry must be simplified to the appropriate level of detail for the numerical methods involved. Customers typically send Highvoltage.dk fully featured CAD geometry that is unsuitable for meshing. SpaceClaim’s automated model simplification tools allow Casper to remove irrelevant details such as bolts, nuts, and small edges. Once the model is de-featured, Casper leverages SpaceClaim to further refine the geometry and move it directly to COMSOL through the LiveLink interface to SpaceClaim, which fuses direct modeling and multiphysics in a tightly integrated environment.

“We used to spend a lot of time and resources in making our customers deliver the CAD drawings with the required level of detail, which was a time drain and ineffective. Now with SpaceClaim, I can continue to make edits and perform simulation as a continuous loop until we’re satisfied with the results. This has saved us at least 50 percent in time to model,” according to Falkenstrøm Mieritz.

High-voltage or high-current testing involves the development of a test plan, the numerical modeling and actual testing, and the evaluation of the results. The technical documentation of the test results includes design guidelines for the customer’s product, final test reports, and the translation of requirements into application specific descriptions. Including very realistic visual representations of the product and recommendations created in SpaceClaim has made a big difference to Highvoltage. dk’s communications with its customers.

Figure 3. To investigate the magnetic field and determine the requirements for protection at a certain location in the nacelle, a Volume of Interest is added to the model. The volume could represent a control panel, in which protection might be crucial. The magnetic field is illustrated by an isosurface plot, where each color represents different values of the magnetic field.
“With SpaceClaim, we are able to create 3D drawings that clearly represent our recommendations and make it much more understandable to our customers. SpaceClaim has definitely improved the visual content of our work,” said Falkenstrøm Mieritz. Additionally, SpaceClaim has enabled engineers to take on small design projects to help customers optimize the design of a small part, as an example. Prior to using SpaceClaim, these new opportunities were cumbersome, as Falkenstrøm Mieritz did not have the right tool — he would have to ask the customer to draw the part. Through Finite Element Analysis (FEA), Highvoltage.dk is able to handle a broad range of complex tasks including modeling of lighting attachment points on large wind turbines, current distribution and electric potentials surrounding sacrificial anodes on offshore installations, and the design of high-voltage switchgear.

“Lightning protection of wind turbines has become mandatory and increasingly our customers look to Highvoltage.dk to determine the necessary shielding of panels and cables and foresee current amplitudes in shielded cables and other components. SpaceClaim has changed our business for the better and enabled us to move more quickly and be more creative in our approach to optimizing electrical applications,” said Falkenstrøm Mieritz.

This work was done by Casper Falkenstrøm Mieritz, Consulting Engineer at Highvoltage.dk, using SpaceClaim and COMSOL software. For more information, Click Here 


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This article first appeared in the September, 2012 issue of Software Tech Briefs Magazine.

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