Home Renewable Energy DNV GL successfully commissions OVRT test unit for wind turbines
DNV GL successfully commissions OVRT test unit for wind turbines

DNV GL successfully commissions OVRT test unit for wind turbines


DNV GL adds to its service offering offers in the field of electrical measurement for renewable energy producers with a mobile test laboratory for carrying out “Over Voltage Ride Through” (OVRT) tests.

The first measurements have now been successfully started for a major German wind turbine manufacturer at the North German wind turbine test facility Janneby. Further projects have already been commissioned by some well-known turbine manufacturers. The test unit is designed for use in the medium voltage grid, implementing the topology suggested in the relevant standards.

In Germany the latest regulations specify that all local energy suppliers must comply with the Over Voltage Ride Through requirements. As the measurements are very time-consuming, taking between eight and twelve weeks, this only has to be demonstrated on the prototype for efficiency reasons.

OVRT tests are an important component of prototype certification according to national and international standards for the integration of local feed-in suppliers into the network. In the event of a temporary overvoltage on the grid, their generating units must be able to withstand this and stabilise the voltage with reactive power. The mobile test unit simulates this over-voltage in the distribution grid. The entire generation unit is confronted with this overvoltage in order to be certain that no critical components are overlooked and functionality is ensured.

DNV GL developed the mobile test unit for the consistent demonstration of compliance with these requirements. It is installed in three sea containers so that it can be used in almost every project type, both in the field or in the laboratory.

Volker Köhne, Head of Department Measurements at DNV GL – Energy says: As the development of new wind turbines is expected to continue in the coming years, the demand for test units that can be employed flexibly will continue to increase. I am delighted that, following an intensive development period, the ORVT test station has now been successfully put into operation and is well received by turbine manufacturers.”

DNV GL has had nine Under Voltage Ride Through test units in operation since 2003. These formed the technical basis for the new test method. The deployment of the test units is coordinated from the site at Kaiser-Wilhelm-Koog, Germany.

In addition to wind turbine manufacturers and grid operators, the service will in future also be aimed at manufacturers of other decentralised generation units.

With the successful commissioning of the test unit and the associated inclusion of the OVRT tests in its portfolio of services, DNV GL continues to expand its position as one of the leading testing laboratories in the field of renewable energy.


Driven by our purpose of safeguarding life, property and the environment, DNV GL enables organizations to advance the safety and sustainability of their business. We provide classification and technical assurance along with software and independent expert advisory services to the maritime, oil & gas and energy industries. We also provide certification services to customers across a wide range of industries. Operating in more than 100 countries, our professionals are dedicated to helping our customers make the world safer, smarter and greener.

In the Energy industry

In DNV GL we unite the strengths of DNV, KEMA, Garrad Hassan, and GL Renewables Certification. DNV GL’s 2,500 energy experts support customers around the globe in delivering a safe, reliable, efficient, and sustainable energy supply. We deliver world-renowned testing, certification and advisory services to the energy value chain including renewables and energy efficiency. Our expertise spans onshore and offshore wind power, solar, conventional generation, transmission and distribution, smart grids, and sustainable energy use, as well as energy markets and regulations. Our testing, certification and advisory services are delivered independent from each other.



Anand Gupta Editor - EQ Int'l Media Network


Your email address will not be published. Required fields are marked *