Researchers develop mobile test platform for offshore wind turbines

Public energy grids are extremely advanced programs. Wind turbine producers should adjust to technical tips when connecting new generators to keep away from placing grid stability in danger. Within the Mobil-Grid-CoP undertaking, researchers on the Fraunhofer Institute for Wind Vitality Techniques IWES have developed a cell check platform that permits sensible exams to be carried out at full load, even on offshore wind generators out within the open. The know-how is aiding within the technique of validating and certifying generators and is supporting the transformation of the vitality provide with a view to utilizing extra renewable vitality sources.

Connecting wind generators to the general public energy grid is a large problem for producers. It is not sufficient to easily check the performance of latest generators, join them and put them into operation—in addition they should adjust to the restrict values for electrical properties specified within the relevant connection guidelines and compensate for dynamic occasions corresponding to brief circuits and frequency fluctuations. Producers solely obtain their unit certificates as soon as the complete vary of exams and certification procedures have been accomplished.

“It needs to be carried out this manner as a result of energy grids are extremely complex systemsand every wind turbine has to assist preserve them steady,” says Gesa Quistorf, Group Supervisor Energy Electronics and Grid Integration on the Fraunhofer Institute for Wind Vitality Techniques IWES in Bremerhaven.

As generators have gotten bigger in each output and measurement, nonetheless, they’re outgrowing the check programs that decide whether or not a brand new wind turbine or farm meets the related guidelines. That is notably true of huge offshore wind turbines.

As a part of its analysis undertaking entitled Mobil-Grid-CoP (a reputation that refers to a cell check facility for grid compliance exams), Fraunhofer IWES has developed a cell check bench that’s able to testing even very giant wind generators as much as an output of 28 megavolt-amperes (MVA). In consequence, producers can acquire their certification a lot quicker than earlier than.

A check system that emulates the general public grid

Because of the large progress in offshore wind farms, the Fraunhofer researchers centered their efforts on giant offshore generators of their growth work. The check bench is subsequently designed for the everyday offshore voltage degree of 66 kV, which means that even giant generators could be examined underneath sensible situations at full load.

“Our test system is a grid emulator that is switched between the public grid and the test object, simulating the electrical behavior of the power grid to the test object. The public grid is in no way compromised during this process,” explains Quistorf.

Throughout the check, the system examines properties such because the habits throughout frequency modifications, transient modifications in voltage or grid faults corresponding to a brief circuit—all in actual time. For every occasion, the wind turbine has to reply inside milliseconds. Within the occasion of a brief circuit and a subsequent drop in voltage—from 66 kV to 0 kV, for instance—the turbine has to help the grid with what is named reactive present. Not like energetic energy, reactive energy just isn’t usable energy that finally reaches the buyer; as an alternative, it’s wanted to construct up the voltage within the grid.

A check bench in transportable giant containers

The check object solely receives its unit certificates and may solely be put into operation as soon as it has demonstrated all of the required specs, efficiency options and capabilities. The check bench is housed in giant containers which might be transported to the situation of the turbine prototypes.

Within the case of offshore wind generators, these are usually erected on the coast. The containers embody parts corresponding to transformers and converters. The Fraunhofer group makes use of commercially obtainable normal modules for the parts, with researchers taking up the duty of programming the check and evaluation software program.

Mobil-Grid-CoP provides a complete host of clear advantages for the wind vitality sector. It offers producers the choice to hold out strong, sensible and detailed exams on their prototypes to make sure they’re prepared for certification. This permits them to cut back the chance of getting to transform the generators earlier than placing them into operation and helps them get by the certification and commissioning course of quicker. The check bench additionally allows retrospective upgrades or modernization measures to be carried out on a turbine with ease.

At Fraunhofer IWES, the cell check facility will also be mixed with different check benches as a part of infrastructure growth measures—all due to the ability’s versatile setup.

A check platform for the longer term

In contrast with standard test programs, the Fraunhofer researchers are going one step additional with Mobil-Grid-CoP.

“Our aim is to develop a technology platform that facilitates scenario-based, flexible testing of wind turbines. Due to the rapid development in the transition to renewable energy, new connection rules that are unknown as yet could become valid in just a few years. With Mobil-Grid-CoP, we are prepared for this,” explains undertaking supervisor Quistorf.

Via its work, Fraunhofer IWES in Bremerhaven is enjoying a key function in accelerating the transition of vitality grids to renewable sources.