Complex sentence: Wind farm Operation and Maintenance companies (also called Wind O&M contractors, or simply Wind Operators) this rapidly growing industry segment assists with the operation and maintenance of wind farms, under contract with (other) companies which own those wind farms.
Split into simpler sentences: Wind farm Operation and Maintenance companies (also called Wind O&M contractors, or simply Wind Operators). This rapidly growing industry segment assists with the operation and maintenance of wind farms, under contract with (other) companies which own those wind farms.