Nordex submits wind turbine components to extended quality testing

Turbine system performance, safety and service life are frequently determined solely by means of calculations, computer simulations or years of field testing. At its Rostock production site, Nordex is now employing additional test rigs to check numerous core components of the Generation Gamma and Generation Delta wind turbines under laboratory conditions as well. The Company scrutinises the entire turbine systems right from the development phase at the Nordex technical centre “Technikum”, whose floor area has now been extended to 3,900 square metres, plus the rotor blade testing facility with a floor area of an additional 2,400 square metres.

Last year, Nordex invested EUR 3.5 million in extensions to the modern “Technikum”, developing new testing facilities and now putting them into operation step by step. With these new test rigs, Nordex is testing the system functions under extreme climatic and mechanical conditions including in the form of long-term endurance tests. In this way, it is able to ensure that its developments satisfy strict quality criteria and that it is able to release a high-quality product for series production. A further goal is to increase the pace of development.

“In addition to larger rotors, a greater installed capacity and growing tower heights, real-life conditions at wind turbine sites, which can be quite harsh in some places, are increasingly playing a role in the development of our systems. Our turbines must operate perfectly in extreme cold or heat, in icy or very humid conditions and under different grid conditions,” explains Dr. Jürgen Zeschky, CEO of Nordex SE.

Nordex uses a project validation plan to make sure that no critical components are neglected during testing and that everything proceeds in sync with current development projects. This plan defines the components which must be tested, the target result, the type of test required and the testing interval.

15 different testing facilities, including an azimuth and motor/vibration test rig, have been installed for complete and thorough testing of the core components fitted to Nordex. In addition, various tests are performed on the blade adjustment system using three different pitch testing systems. The advantage of this is that Nordex is now able to perform advance tests of the turbine software, the pitch converter under load and the entire system comprising switching cabinets, drives and cable loops under normal and also extreme temperatures.

The most important new addition is the climate chamber, which has been expanded and is now more efficient. With a capacity of almost 150 cubic metres and a range from -40°C to +60 °C, it submits the turbine systems to extreme climatic endurance testing. In addition, a relative ambient humidity of 95 percent can be simulated. A further five test benches are devoted solely to tests on slip rings. One of these is also fitted with a climate chamber with a capacity of two cubic metres.

A grid simulator with variable voltages and frequencies at the configuration limits is also available for testing the system capabilities even under difficult grid conditions. In addition, it is possible to generate dynamic grid errors and harmonics. To guarantee the best possible quality of electricity, Nordex also simulates the grid errors of a wind farm in a medium-voltage grid in the field. The fault ride-through capabilities for bridging any drops in voltage are checked on a continuous basis. This also aids the development of grid codes and helps to ensure that the necessary certificates are gained.

The testing system for the Company’s internally produced rotor blades with a length of up to 65 metres has been in operation since 2010 and allows static and dynamic stress testes to be performed. In addition, Nordex started up a cable loop test bench last year.

All tests form part of the standard inspection of the core components of the Generation Gamma and Generation Delta wind turbines. In addition to performing its own tests, Nordex imposes on its suppliers a duty to perform vibration, EMC and lightning protection testing on the components which they deliver. In this connection, Nordex has stipulated in its internal quality requirements that internally developed or externally sourced components must function perfectly in the entire range of different ambient conditions. The findings gained are continuously incorporated in the innovation process, with the results directly ploughed into the turbine development process in order to additionally enhance their quality.