Disturbance to the mains voltage

Modern wind farms are connected to the mainland power grid via long submarine cables with a large parasitic capacity. And they are equipped with a large number of power electronics converters that produce harmonics.

Harmonics are deformations of the sinusoidal mains voltage and current. The interactions between these harmonics and the wind farm components create a serious challenge. Higher harmonics are undesirable because they can lead to energy loss, disconnection of protection systems and possible premature failure of components.

The current design approach is on a case-by-case basis with over-dimensioned components. This approach is already leading to delays and price increases and poses risks for future extensions of the offshore grid for additional wind farms.

Offshore wind research project

A new research project has been started at TU Delft to work together with companies and other research institutes on a more standardised, future-proof and cost-effective design approach. This design approach will increase the reliability and efficiency of offshore wind energy and thus make an important contribution to accelerating the energy transition and reducing integration costs.

Cinergia Grid Emulator from TTMS

At TU Delft, the DC Systems, Energy Conversion & Storage (DCE&S) section of the Electrical Sustainable Energy department conducts research using a 20kVA Grid Emulator GE+20 from manufacturer Cinergia. The Grid Emulator, supplied by TTMS, is a programmable voltage source that can provide a stable three-phase AC grid as well as a grid with electrical interference. Based on regenerative and bi-directional four-quadrant amplifiers, it is an important tool for testing renewable energy sources such as solar energy, hydropower, CHP and other grid-connected devices. For each of the three phases, in addition to the basic frequency, all harmonics up to the fifteenth can be programmed separately. In addition, a freely selectable frequency is available between one tenth (0.1) and fifty times the base frequency. A sub-harmonic, inter-harmonic or higher harmonic can be programmed in this way. The Grid Emulator can also be used as a power amplifier for hardware in the Loop tests and is equipped with a powerful and very user-friendly Windows interface.

The project at TU Delft, thanks to measurements with this Grid Emulator from Cinergia, provides an increased knowledge of harmonic phenomena and results in a design methodology to limit the negative effects of harmonics.


The project is coordinated by TNO and is supported by the RvO, under the TKI Wind at Sea programme.

The DCE&S section is led by Professor Pavol Bauer. The research will be carried out by Lucia Beloqui Larumbe under the supervision of Dr. Zian Qin.

Source: TU Delft, Cinergia GE+ datasheet v2.


Arnold Memelink

Arnold Memelink


"The ABB Power Grids Jumet organisation is an innovative development and production facility of ABB that manufactures active filters and battery energy storage systems to support a stable grid. To test these systems we have acquired two Cinergia GE/EL +120kVA eplus units capable of doing grid emulation (AC + DC), operating as an electronic load (AC +DC) and being a battery emulator. We have experienced very good support from TTMS in obtaining these two Cinergia units. This included organising an on-site demonstration and supplying loan systems prior to the delivery of our final systems. This way we could start testing as early as possible. TTMS also organised training for the operators from the original manufacturer. This support allowed us to introduce the first battery energy storage systems even prior to the full delivery of the Cinergia systems."

University of Luxembourg

Sasan Rafii-Tabrizi

University of Luxembourg

“At the Energy and Environment department of the Faculty of Science, Technology and Medicine (FSTM) of the University of Luxembourg we do have different research projects related to green energy contributing to the development of eco-cities. As a long-standing partner of our research unit, TT&MS has proven that they are able to answer even the most complex questions in a professional manner. They have shown that they are always up to date with the latest technology and do not spare any effort to look at the application and even the situation on site. The exchange of ideas was always very pleasant and took place quickly. We look forward to further years of fruitful cooperation.”


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