Temperature measurement of busbar trunking in switchgear

Busbar temperature in switchgear can be effectively monitored using infrared sensors or fiber optic Linear Heat Detection systems, providing early warning of overheating and enabling proactive maintenance.Infrared (IR) Sensor MonitoringIR sensors, such as the PyroMiniBus system, are widely used for busbar temperature measurement in switchgear cubicles. These sensors detect infrared radiation emitted from the busbar surface, allowing non-contact temperature measurement. Key features include:Sensor Placement: Typically, six sensors per cabinet are used—three on input busbars and three on output busbars—to monitor critical connections and joints where overheating is most likely to occur .Measurement Range: PyroMiniBus sensors can measure temperatures from -20°C to 1000°C, and operate in ambient temperatures up to 120°C without additional cooling .Surface Preparation: Busbar surfaces should be painted, coated, or shrink-wrapped to create a non-reflective surface, improving measurement accuracy .Optics Considerations: Wide-angle optics (2:1) are suitable for short distances, while narrow optics (20:1) allow longer measurement distances for high-voltage busbars. Focused optics can measure narrow or edge-on busbars .Integration: Sensors connect to a hub (e.g., PM180) for temperature display, data logging, and alarm outputs. Multiple hubs can be networked, and data can be accessed via Ethernet or SCADA systems for centralized monitoring .Fiber Optic Linear Heat Detection (LHD)Fiber optic LHD systems provide continuous temperature profiling along the entire busbar or switchgear assembly:Sensor Configuration: A single fiber optic cable runs along the busbar, detecting temperature changes along its length .Rapid Detection: The system measures a complete temperature profile within seconds, enabling fast detection of hotspots and abnormal temperature rises .Alarm Management: Configurable alarm zones allow operators to receive precise location alerts for elevated temperatures, with options for static, rate-of-rise, maximum, and adaptive thresholds .Integration: LHD systems can be integrated with SCADA for visualization, logging, and further processing of temperature data .Best PracticesMonitoring Critical Points: Focus on busbar joints and bolted connections, as these are most susceptible to overheating due to increased contact resistance .Early Warning: Continuous monitoring allows detection of thermal anomalies 72–96 hours before potential failure, enabling scheduled maintenance and preventing catastrophic switchgear failures .Data Logging and Analysis: Use systems capable of logging temperature trends to identify gradual degradation and plan maintenance interventions effectively .ConclusionFor busbar trunking in switchgear, infrared sensors are ideal for localized, non-contact temperature measurement, especially in space-constrained environments, while fiber optic LHD systems provide comprehensive, continuous monitoring along the entire busbar. Both methods can be integrated with SCADA systems for centralized monitoring, early warning, and proactive maintenance, significantly reducing the risk of thermal-related failures and associated operational and financial impacts .