High Power VFD Cooling

The world-famous Drax power station produces around 10% of the UKs electricity 24 hours a day, 7 days a week, 365 days a year. It is critical to the country.

Electricity is produced by steam-driven turbines, the steam being generated by either burning either biomass (woodchip) or coal, which is crushed to powder and mixed with air. The mixing of coal/wood dust and air is controlled by 72 huge fans, each one being speed-controlled by a Siemens Variable Frequency Drive.

The operation of these fans is process critical and failure is not an option!

These drives require cooling and the initial cooling modules supplied with the drives failed due to the accumulation of silt from the river water used for cooling. This resulted in overheating of the drives – a highly costly and an unacceptable situation. The temporary solution was to employ a team of maintenance engineers to continuously repair and maintain the cooling units, effectively keeping the system “limping along”.

A much more cost effective and long term remedy was required, and Drax engaged with
GRE , in partnership with Siemens, to find this solution. GRE custom-designed a cooling system to solve these problems. The first two were installed in summer 2014 and have been running without problems ever since.

Key features:

  • Integrated within existing cooler cabinet – within very tight space constraints
  • Run and standby pump set with automatic changeover
  • Custom-designed heat exchanger which does not foul with river water
  • Operated without problems since September 2014 – rolling program underway to replace all 72 coolers.