Point-on-Wave technology key in providing grid code compliant solution

Power quality engineering specialists, Enspec Power Limited, today announced another successful power system project at the Fallago Rig Wind Farm, operated by EDF Renewables UK with 80% assets owned by Hermes Infrastructure.

Enspec's uniquely designed switching panel uses Point-on-Wave technology to manage a very complex switching and control requirement that will give Fallago Rig the most cost-effective solution to the site’s voltage control requirements. Fallago Rig was already a fully operational wind farm and included a full STATCOM system, which were historically commonly used for UK grid code compliance in wind farms. The original STATCOM cost several million pounds and has worked very hard to support the transmission network voltage since day one of operation. Whilst Obligatory Reactive Power Service (ORPS) payments were accordingly high, inverter failure rates and associated costs were increasing, and enduring support and risk of non-compliance becoming more of a concern.

To solve this issue, ensuring power quality and compliance, Enspec manufactured and commissioned 50MVAr of PoW switched capacitor banks, as part of a hybrid solution, which cost £1.6mil versus another estimated £5.1mil for a new STATCOM system. Enspec's Point-on-Wave (PoW) system also has nowhere near the maintenance cost, saving EDF £100,000s annually.

“We’ve been incredibly impressed with Enspec’s expertise in not only providing the P-o-W switched capacitor element of the hybrid solution, but also their capacity to identify and mitigate risks associated with adding and switching large capacitor banks onto an existing electrical system in such a manner,”

The solution features Enspec's expertise in Point-on-Wave (PoW) switching to allow for capacitor bank re-energisations within seconds instead of the traditional 8-10 minutes. The PoW banks will then work in conjunction with the upgraded control software of the Vestas turbines and wind farm controller in a hybrid solution to provide dynamic voltage control in line with Grid Code requirements.”

The capacitor banks also offer greatly reduced transients on energisations; where traditional capacitor banks can pull 1000s of Amps of inrush current, PoW banks are energised with inrush current levels only 1.5-2 times higher than the standard capacitor bank rating. This reduces wear on switches and ensures for limited disturbances on the Wind Farm network.

Enspec also applied their established and trusted knowledge in harmonic studies and compliance by carrying out a revised G5/4 harmonic study for the Wind Farm with consideration of the new capacitor banks. This highlighted that normal banks could lead to harmonic resonance and amplification and so guided the design towards a de-tuned type to avoid this phenomenon.

Enspec’s testing and commissioning at Fallago Rig took place last month and the newly installed voltage support system was confirmed to fully satisfy all criteria. Enspec director, Tim Rastall, said;

“Enspec is very grateful for the trust of our long-standing partner EDF Renewables to deliver this significant project for Fallago Rig. We are very proud of our team’s dedication and effort towards the completion of this milestone contract. It is great to see the completed system in operation and delivering the designed grid code compliance support.”

For more information about Enspec Power, go to https://www.enspecpower.com/ or visit their LinkedIn on https://www.linkedin.com/company/enspec-power-ltd/. To find out more about EDF Renewable and Fallago Rig go to: https://www.edf-re.uk/our-sites/fallago-rig or for more information on Hermes Infrastructure, go tohttps://www.hermesgpeinfrastructure.com/.

Image provided by EDF Renewables