The electric utility industry talks about wind farms like they are power plants. Actually, they resemble distributed generation and low-voltage distribution more than they do power plants. Of course, there is a heck of a lot of distributed generation in one of these facilities. It is more akin to distributed generation on steroids.

Take 2,000 acres (809 hectares) of real estate and sprinkle a few hundred wind turbines all over it. Those hundreds of turbines are individual generators. They are connected together into circuits of 20 MW to 25 MW. Put enough of these circuits in the collector system and that produces hundreds of megawatts. A facility of 600 MW has a lot of 25-MW circuits, which the industry usually tends to overlook.

There is a tremendous infrastructure required to turn these individual generators into a wind farm. It is a significant part of the project costs. It also can be the critical path in many projects. Typically, it consists of civil and electrical works.

The civil works include a road system, site drainage, foundations for turbines, transformers and buildings. The electrical works include overhead and underground cable networks forming the medium-voltage (typically 34.5-kV) collector system to the rows of wind turbines. Underground power cables require thermal backfill systems to dissipate heat and protect the cable.

There also are padmounted transformers and switchgear at the wind turbine associated with the collector system, which can be found either inside or outside the turbine. Turbines and collector systems require grounding systems, control cable and conduit systems along with communications between the control center and turbine.

The collector systems meet at the collector substation, which connects the wind farm's output to the utility. It contains the collector switchgear, large power transformers, power circuit breakers, instrument transformers, disconnect switches and all the other typical equipment found in a substation.

Back in the early days, the components came from the “small” guys, sources that would not have been considered mainstream suppliers. Some of them would have given “shade-tree” mechanics a bad name, but as with all processes, the test of time weeds out those with dubious pedigrees.

The table below is not meant to be a comprehensive listing of manufacturers making the components necessary to tie the turbines to the system. It is provided to give a sense of where the industry is today, with major manufacturers providing quality components and materials.