Powersystems Point-on-Wave energisation of 90 MVA transformer

December 22, 2017

Powersystems have successfully energised a 90 MVA transformer using new point-on-wave technology to limit the inrush current and voltage dip at Aikengall II Wind Farm

Community Windpower engaged Powersystems to build the electrical connection for Aikengall II Wind Farm, a new 60.8 MW wind farm located in East Lothian. As part of the connection works Powersystems provided a 90 MVA 132/33 kV transformer. However, initial simulation studies showed that energisation of the transformer would cause significant voltage dips of up to 18% on the 132 kV grid.

To reduce the inrush current and voltage dip, Powersystems’ engineers recommended installing a 132 kV circuit breaker with segregated phase switching in conjunction with a point-on-wave controller which controls the precise time that each phase is closed.

Inrush current can be reduced and virtually eliminated by closing each phase at the precise moment in time when the voltage waveform from the supply side matches the remanent flux that is left in the transformer. Powersystems used a 132 kV circuit breaker supplied by GE Grid Solutions in conjunction with a Visimax SynchroTeq Plus supplied by Enspec Power to measure the transformer remanent flux and control the closing time.

The SynchroTeq Plus performed remarkably. By the completion of commissioning, the voltage dip on the 132 kV system had been reduced from about 7% during an uncontrolled energisation of the transformer, to 0.6% when energisation was controlled by the SynchroTeq Plus.

This is the first 132 kV transformer in the UK to be controlled by the SynchroTeq Plus and these results show that point-on-wave control technology is now a viable option for mitigating transformer inrush currents even for large grid-scale transformers.

Below: Resulting 132 kV Voltage Dip at Completion of SynchroTeq Plus Commissioning

Notes to Editors:

Contact Information:

Powersystems are powering the transition to a carbon free future

As a high voltage specialist electrical engineering company with over 45 years (1977-2022) experience Powersystems have grown by reputation to become a trusted force in the design, installation and commissioning of electrical infrastructure across the UK.

Celebrating 25 years as the first Lloyds National Electricity Registration Scheme ‘s accredited Independent Connection Provider (ICP), Powersystems are capable of delivering contestable grid connections at voltages up to 132 kV.

Since 2000, Powersystems have connected over 6 Gigawatts of renewable energy generation to the UK electricity grid, along with decarbonisation technology which includes; wind energy projects, solar, anaerobic digestion, hydroelectric, electrical vehicle infrastructure, short term operating reserve STOR, combined heat and power (CHP), Grid stability projects like rotating stabilisers,  and battery energy storage systems (BESS) as well as commercial industrial private wire networks.

Working with partners, delivering sustainable power solutions, proudly the Powersystems high voltage specialist team have connected 27% of all U.K. onshore wind farm

At the core of the operation is a commitment to the highest values of health and safety, welfare, quality and the environment. Powersystems Integrated management systems are ISO accredited and their approach under their health and safety ‘Priority No.1’ brand is to aim for the best industry practice in all.

Powersystems UK Ltd. is an Employee-Owned Business and as such has a keen interest in the well-being of all its employees. They encourage and empower you to be imaginative, share great ideas and be involved in the success of the business.

Speak to Powersystems today

You can contact us as follows