ROOT CAUSES OF NOISE AND VIBRATION IN WIND TURBINE SYSTEMS

Significantly improved long-term reliability of wind turbines has become critical as they increase their penetration into the national and international electrical power base. The major subsystems in wind turbine systems include blades, gearboxes, generators, power transferring shafts, bearings, and towers. Advanced acoustic and vibration modeling techniques and monitoring systems have been employed to effectively predict and monitor the health of wind turbines. The goal is, in addition to having system capability for determining structural condition, to reduce unscheduled outages, and to predict maintenance cycles in order to avoid failures. By better understanding the root causes of noise and vibration, one could significantly boost performance, maintainability, and reliability while reducing downtime and catastrophic failures of wind turbines that are becoming crucial to meeting our global renewable energy goals. The main root causes of wind turbine wear, damage, failure is excessive vibration. On the other hand, excess noise has become a growing problem for farmers and those living near wind farms. In this paper, the top six of the most important causes of wind turbine machinery failures and excess noise/vibration are discussed. Such root causes are blade mistuning, misalignment, imbalance, resonance, fastener looseness, and bearing damages and defects. It is pointed out that three of these root causes are responsible for over 80% of machinery wear, failure, and downtime.