Development and Experimental Field Validation of an Arduino- Based Condition Monitoring System for Heliostat Drive Units

In concentrating solar power tower plants, heliostat drive units (HDUs) are critical components that control the precise two-axis alignment of the heliostats focussing solar radiation onto the receiver. Consequently, the reliable operation of HDUs is essential for safe and stable plant operation. However, existing research on heliostat operation and maintenance (O&M) predominantly focuses on aspects such as soiling, calibration, and the influence of wind loads on heliostat behaviour. In contrast, the operational health of HDUs remains largely unexplored. Addressing this research gap, this study develops a cost-efficient Arduino-based condition monitoring system (ACMS) measuring vibration and magnetic flux density signals of the HDUs. The field validation is conducted at the DLR solar tower research facility in Jülich, Germany (STJ). By this, the high measurement stability and reliability of the ACMS (>99.9% data availability during a 24 h stationary outdoor test measurement) is demonstrated. Thus, the ACMS provides a reliable basis for detecting HDU condition-sensitive changes in the recorded operational data. For example, the ACMS captures an unexpectedly pronounced increase in HDU vibration amplitude during comparable HDU operational movements, reaching approximately ten times the previously observed nominal level. While the underlying cause cannot yet be conclusively identified, this demonstrates the potential of the ACMS to detect emerging abnormal HDU behaviour. Overall, the chosen cost-efficient approach provides a scalable basis for HDU condition monitoring, supporting efforts to enhance heliostat reliability within O&M processes.