Why do switch cabinets require fiber optic temperature measurement and what are their advantages

Faseroptischer Temperatursensor, Intelligentes Überwachungssystem, Verteilter Glasfaserhersteller in China

Switchgear plays an important role in the power system, with functions such as distribution, transmission, and power conversion. It controls, monitors, measures, and protects the entire power grid line, and its operation is related to the safety and stability of the power grid and the reliability of urban power supply.

Due to the long-term operation of the switchgear under high current and full load conditions, the temperature inside the switchgear will rise when current flows through it. Almost all electrical equipment failures are caused by excessive temperature. Especially the positions of the dynamic and static contacts, Kabelmuffen, and busbar contacts in the switchgear are affected by the environment. After long-term oxidation, wear, and processing technology, the connecting parts become mechanically loose, which reduces the contact area of the contact positions, increases the contact resistance, and makes the heating phenomenon more obvious. If the heat is not dissipated in a timely manner, the equipment inside will be in a high-temperature environment for a long time, which will accelerate the aging rate of the equipment inside the switchgear, increase the degree of oxidation of the conductive material, generate more heat, and cause a vicious cycle. Even more seriously, it can trigger arc short circuits, produce sparks and discharges, and cause major power accidents.

According to reports, there have been many incidents of fires caused by excessive temperature rise inside switchgear worldwide, resulting in certain economic losses and personal injuries. Darunter, accidents caused by high temperatures in the busbar room and contacts are more prominent. According to the relevant regulations of the power grid, it is necessary to regularly inspect the relevant parts of the switchgear, especially the joints that are prone to temperature rise. Temperature monitoring of the switchgear should be carried out during high temperature and overload operation. Deshalb, real-time online monitoring of the contact temperature of the switchgear, identifying abnormal temperature points inside the switchgear, and taking corresponding measures to ensure the safe and reliable operation of the power system are of great importance for people’s lives and property safety.

Due to its special internal structure and operating environment, high-voltage switchgear requires high and specific temperature measurement devices. The specific requirements are as follows:

1. High voltage insulation performance.

The switchgear operates in a completely enclosed and narrow space, with the temperature measuring device monitoring the temperature inside in a high-voltage environment, and the external data receiving device in a low-voltage environment. If the insulation of the data transmission channel does not meet the requirements, high-voltage breakdown may occur, leading to dangerous accidents.

2. It does not affect the normal operation of the switchgear.

A switchgear is a combination equipment consisting of multiple electrical devices, and its internal busbars, circuit breakers, and knife switches all have corresponding operating mechanisms. Deshalb, it is necessary to ensure that the installation of temperature measuring devices will not affect the original operating mechanism inside the switchgear.

3. Anti high electromagnetic interference.

The actual working conditions of high-voltage switchgear are high voltage and strong current, and there is a strong and complex electromagnetic environment, which has a significant impact on the accuracy of temperature monitoring by temperature measuring devices.

Traditional temperature sensing technologies such as thermistors and temperature indicating wax sheets are difficult to apply, and due to factors such as the structure and contact position of the switchgear itself, it is relatively difficult to directly install sensors at the contact position in engineering practice. Deshalb, in engineering applications, the temperature of bypass cables or branch busbars is often used to indirectly reflect the temperature at the contact position, and its reliability and accuracy need to be improved.

A temperature online monitoring device for key positions of power switchgear based on fluorescent fiber optic temperature measurement, using fluorescent fiber optic temperature sensors as temperature sensing probes implanted in the switchgear, has the advantages of anti electromagnetic interference, Eigensicherheit, easy networking, hohe Empfindlichkeit, and high accuracy; Installing a fluorescent fiber optic temperature measurement device in the switchgear can monitor the contact temperature and provide corresponding values, providing practical basis for improving the reliability and accuracy of contact temperature monitoring in the switchgear.