New Business

Frequency-tight test chamber for wind turbines


Europe is switching to sustainable energy. Wind energy plays a crucial role in this. Wind farms with ever larger turbines will be built, on both land and at sea. A leading supplier in the production of turbines is the German-Spanish concern Siemens Gamesa. In their factory in Cuxhaven, Germany, the company makes increasingly sophisticated turbines.

The influence of radio frequencies in and around the wind turbine is important in the development of parks, which is why the turbine is also being tested for this. This is done in a Faraday cage, which serves as a (high) frequency-tight test chamber. To get a giant turbine in it you need an opening of ten by ten meters. However, as soon as the turbine is in the test chamber, that opening must be closed again and sealed (high) frequency-tight. To achieve this, the Dutch company Comtest, which builds the Faraday cage for Siemens Gamesa, called in the help of KH Engineering.


The sealing is achieved by two heavy hatches that open and close. There are several aspects to the art of hermetically closing the test room. Sealment is achieved with knife-shaped metal plates that slide into precisely tailored slots. The shutters move in two directions, first a little vertically, after which the shutters slide horizontally to either side. KH Engineering has tackled the project with a multidisciplinary approach, with various technical disciplines working together to find the solution. During the concept engineering phase, the end customer was immediately asked to weigh up the various solution directions. Then the next steps were discussed and approved.

KH Engineering uses various in-house expertise. The Mechanical department designed the hatch construction in such a way that required precision in closing can be guaranteed. This department also made an initial design for the steel support structure. The Mechanical department used the 3D engineering tool Inventor and the Finite Element calculation program Ansys. The supporting structure was designed by the “steel” specialists of the CSA (Civil, Structural, Architectural) department. The Electrical and Process Control departments were responsible for the control and the required electrical power, and among other things selected the motors that drive the movements. The drive control of the process has been programmed in a PLC by our Process Control department.


Together with our safety expert from the HSSE department, we performed the DRA (Design Risk Analysis) and DFMEA (Design Failure Mode Effect Analysis). The hatch construction will then be built up at Comtest’s factory. In the presence of the end customer, we can demonstrate through a FAT (Factory Acceptance Test) that the construction does its job flawlessly. All parts are then transported to the factory in Cuxhaven, where the SAT (Site Acceptance Test) and commissioning follow.

Benefit for the customer

By engaging KH Engineering at an early stage, at the conceptual stage, the customer (Comtest and ultimately Siemens Gamesa) was able to take full advantage of a multidisciplinary approach that provides precisely all the expertise required to successfully complete this project. The knowledge ranges from heavy steel structures to precision work in drive system: the aforementioned knife-shaped metal plates of the hatches have to slide into the slots with millimeter precision after moving five meters. As soon as the Faraday Cage is operational (at the end of 2020), Siemens Gamesa can test three wind turbines per day with it.

Activities KH Engineering

  • Conceptual engineering
  • Basic & Detail engineering
  • Strength calculations with, among others, Finite Element software
  • 3D engineering model for the steel construction
  • Mechanical, Electrical & Instrumentation:
  • Mechanical for the basic design of the supporting structure and hatch construction
  • CSA (Civil Structural Architectural) for the steel substructure
  • Electrical engineering for the drive system
  • Process Control and programming via PLC
  • HSSE advice by a Safety Expert
  • Design Risk Analysis & Design Failure Mode Effects Analysis
  • FAT (Factory Acceptance Test)
  • SAT (Site Acceptance Test)

Project leader: Marco Vahrmeijer

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