How to Meet NIE Power Factor Requirements on Wind Turbines Between 100kW and 5MW

Customer Requirements

The Distribution Network Operator, Northern Ireland Electricity Networks Ltd (NIE), defined a setting schedule in 2017 to ensure a functioning distribution of electricity could be maintained. NIE identified challenges with extant wind turbines in Northern Ireland. All electricity generators between 100kW and 5MW installed after January 2010 must now meet specific requirements for rapid power factor and voltage control.

What is Power Factor?

Electrical power comes in two forms: power that does useful work, and power that does no work. Power factor is the ratio between these. A power factor of 1 represents all the power being useful, and a power factor of 0 represents none of it being useful. Poor power factor is wasteful and challenging for the grid to manage.

In response to a request from Izon, Dumarey Green Power developed power correction hardware specific for the wind turbine application. The hardware is sited alongside the other electrical control equipment for the turbine and corrects the power factor of the energy being sent to the grid. The system is unique in both the speed of response and the degree of correction possible.

As well as power factor correction, Dumarey Green Power turned to a novel application of a centuries old energy storage device to boost energy exports. The PP200 is a flywheel energy system, manufactured in the UK. Using technology originally developed as a KERS for the high-tech world of Formula 1 racing, the flywheel provides temporary energy storage at high power. In the case of wind turbines, the pitch of the blades (the angle of the blades to the wind) is constantly changing to meet the production limit, however changing the pitch of these blades takes time, and a sudden gust cause the export limit to be briefly hit. To avoid this, the flywheel can absorb up to 85kW of power whilst the turbine changes pitch of the blades to reduce production.

When the wind drops, the flywheel discharges to the grid. The result of this is that export exceedances are prevented without any energy being wasted. This allows this grid operator to maintain a stable grid and avoids producers hitting their export power limit.

Results

Over 100 Wind Turbines in Northern Ireland have deployed Dumarey products.

Dumarey’s technology has improved the quality of power being exported to meet NIE requirements.

To date this work has added over 10MVA of reactive power capability to support over 25MW of wind turbines, supporting appropriate functionality and power generation. This in turn is supporting zero-carbon energy generation and the UK’s net zero strategy.