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.

Source & Image credit:DNV GL