Condition diagnostics of energized electrical equipment: case studies

Loose connections and degraded contact surfaces in current carrying path of electrical equipment induce conduction problems resulting in local temperature rise, which contributes to the downgrading of contact quality and deterioration of insulating material. Continuous on-line temperature monitoring provides the means to evaluate current condition of equipment and detect abnormality, which if not fixed may result in possible disruption of electrical service. It allows timely corrective measures to be taken to prevent upcoming failure. Continuous temperature monitoring of energized equipment in wide temperature range is achieved with a wireless system using miniature temperature sensors located in strategically important points. The paper presents the results of wireless temperature monitoring of switchgear at two power plants in the USA and demonstrates the importance of continuous temperature monitoring for properly and timely performed condition-based maintenance