Infrared temperature sensors applied in temperature monitoring of high-voltage switchgear contacts

High-voltage switchgear refers to electrical equipment operating within a voltage range of 3.6 kV to 550 kV, used in power generation, transmission, distribution, energy conversion, and consumption systems for switching, control, or protection purposes. It primarily includes high-voltage circuit breakers, high-voltage disconnectors and earthing switches, high-voltage load switches, high-voltage auto-reclosers and sectionalizers, high-voltage operating mechanisms, high-voltage explosion-proof switchgear, and high-voltage switchgear cabinets. The high-voltage switchgear manufacturing industry is a critical component of the power transmission and transformation equipment sector and holds a vital position in the entire electric power industry.

Switch contacts are the source of the audible "click" sound when a switch is pressed. In simple terms, this sound is generated by the collision or separation of two metal strips or metal balls. The importance of contacts to a switch is no less than the importance of safety to our lives. Here’s why: many manufacturers plate their switch contacts with a thin layer of silver—a common practice that generally satisfies basic conductivity requirements. However, few consider that this silver plating is extremely thin and constantly subjected to mechanical wear during repeated switching operations, placing it in a precarious state where it can easily be worn off over time. Consequently, many companies are now actively exploring ways to enhance switch safety and extend service life.

Temperature monitoring involves using embedded temperature sensors to continuously monitor the operating temperatures of generator stator windings, core laminations, and various cooling media. Temperature sensors installed at critical points collect real-time temperature data, which Smart Electric Power transmits remotely to a receiving unit. This unit then forwards the data—via wired or wireless communication—to a backend computer system, where it is displayed on dedicated software interfaces for operator monitoring.

This temperature monitoring method is widely applied to intelligent thermal protection of components prone to overheating due to poor contact insertion, loose connections, busbar creepage, surface oxidation, electrochemical corrosion, overload, high ambient temperature, or inadequate ventilation. Typical applications include:

• Contacts of withdrawable circuit breaker trucks in medium-voltage switchgear,

• Fixed switchgear disconnector contacts,

• Busbars and cable terminations,

• Reactor windings,

• High-voltage windings of dry-type transformers.

A key advantage of online temperature monitoring is that operation and maintenance personnel can monitor remote equipment temperatures in real time from a central host, enabling early warnings of abnormal conditions or impending failures. This approach eliminates the need for manual inspections, overcomes the temporal and spatial limitations of traditional patrols, and provides uninterrupted, real-time temperature surveillance—making it especially suitable for critical power system equipment monitoring.