2012-12-05 - With wind power contributing more to the energy mix, transmission system operators have been forced to tighten their grid connection rules, known as grid codes, to maintain security and power quality in electricity networks.
By ABB Communications
In the early days of wind power there were no requirements for reactive power compensation because turbines were generally small and had little or no effect on the grid. Today with huge gains in both turbine size and the number of turbines resulting from the connection of large wind farms to the grid, more stringent regulations have been introduced to ensure transmission system stability. With wind farms like Whitelee, Europe’s largest onshore wind farm consisting of more than a hundred turbines, reactive power compensation devices must be deployed. For onshore wind farms simple induction wind turbine generators are usually used, which are typically designed to provide only a small amount of reactive power. The addition of more turbines multiplies the effect making it necessary to deploy additional reactive power compensation devices at the grid connection point.
At Whitelee, which is located about 15 kilometers from Glasgow, Scotland’s largest city, the wind farm was extended by an additional 75 turbines. This resulted in a total of 215 turbines with a generating capacity of 539 megawatts (MW), which required a robust and reliable reactive power compensation product.
Installing PCS 6000 STATCOMs at Whitelee wind farm in Scotland
ABB installed and commissioned three liquid cooled PCS 6000 STATCOMs (static synchronous compensators), each of ±15MVAr (megavolts ampere reactive) connected at 33 kilovolts (kV), to ensure the facility would adhere to the strict grid codes imposed by the transmission system operator. The main equipment was installed inside an outdoor container. The scope of delivery also included transformers and external water/air heat exchangers. In addition, ABB was responsible for project management, installation and commissioning.
The PCS 6000 STATCOM enables reactive power generation as well as absorption through the electronic processing of voltage and current waveforms in a voltage source converter (VSC). No additional capacitor banks or shunt reactors are required to provide higher or lower system voltages, respectively. ABB’s STATCOM solution has a compact design, with a small footprint, as well as high power density and low magnetic impact.
Whitelee Wind Farm is now in the final phase of its ambitious plan to have installed capacity of 539MW and provide enough clean energy to power the equivalent of an estimated 304,000 Scottish homes displacing between 570,000 and 1.3 million tons of carbon dioxide emissions per year.
ABB’s PCS 6000 STATCOM technology ranges from 10MVAr to 100MVAr and is a robust, reliable and very efficient solution (98.5 percent efficiency) supporting weak power grids and enabling renewable power generation.
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