On-Line Fault Diagnosis for Structural Health of Wind Power Dedicated Busbar Trunking

Abstract

The key objective in structural health monitoring of wind power dedicated busbar trunking (WPDBT) is to detect abnormal events in structural behavior by monitoring of severity of fixing bolt looseness in the linear connection unit of WPDBT. However, it is difficult to directly monitor the looseness of the fixing bolts online. The tightening torque of the fixing bolt directly reflects the looseness of the bolt. A novel quantitative indirect measurement method of tightening torque employing temperature rise, operation current, structure and material parameters as direct measurement is proposed in this paper. Based on the proposed physical model of the connection between the tightening torque, the temperature rise and the operation current of the linear connection unit, a magnetic-electric-thermal multi-physics coupling model of WPDBT is established. The bolt tightening torque can be directly calculated from the temperature rise and the operation current by the physical model presented in the paper. To further demonstrate the accuracy of the method and achieve online monitoring of structural health, an online monitoring system for fault diagnosis of the linear connection unit of WPDBT is designed based on this physical model. The online monitoring system was applied to an experimental platform for WPDBT. The effectiveness of the method proposed in this paper is further verified. It is proved that the temperature rise and operation current of the linear connection unit can indirectly measure the looseness of the fixing bolts. Finally, a method of structural health assessment for WPDBT is given. The new approach opens the way for real-time monitoring the structural health for WPDBT.