Using fiber optic sensors for temperature measurement of isolation switches

Isolation switch fiber optic sensor can be used for high voltage isolation switch temperature measurement, load isolation switch temperature measurement, fuse type isolation switch temperature measurement, low voltage isolation switch temperature measurement, Schneider isolation switch temperature measurement, circuit breaker and isolation switch temperature measurement, outdoor isolation switch temperature measurement, outdoor AC high voltage isolation switch temperature measurement, is isolation switch temperature measurement, fuse isolation on temperature measurement, 10kV isolation switch temperature measurement, power isolation switch temperature measurement, 35kV isolation switch temperature measurement.

High voltage switchgear is an important equipment in the power system and plays a crucial role in power transmission and transformation. Due to the complexity of the working environment, when abnormal situations occur in high-voltage switchgear, according to relevant departments, the first manifestation is thermal failure. The root cause is that the bolts of the busbar or cable connection head are not tightened properly, and the clamping spring of the isolation switch is loose, which leads to an increase in contact resistance and ultimately causes equipment melting or even short circuits. Although the contact resistance value is not easy to obtain, the equipment will generate heat during operation, and the temperature rise of the equipment has a development process. FJINNO has independently developed a fluorescence fiber optic temperature measurement system based on the temperature changes at the contacts of isolation switches, transformers, power cables, busbars, etc. It can accurately monitor the temperature status of isolation switches to determine the working status of the equipment and control the instrument.

There are several main reasons for the heating of 110kV isolation switches.

1、 Outdoor isolation switch equipment that operates exposed to air for a long time is susceptible to erosion by rainwater, dust, and chemicals, which can easily form an oxide film at the handshake and contact points, increasing the resistance of the contact surface and causing heating.

2、 The GW4 type isolation switch with heating is a product produced in an earlier period. Based on years of operating experience, the author has summarized that the heating at the handshake of the isolation switch is a high-frequency defect, which may be related to the metal material and manufacturing process at the handshake of the isolation switch. At the same time, most of the GW4 type isolation switches installed on the 110kV busbar side of Zidong Substation are manually operated mechanisms, and their heating may be due to improper personnel operation, inadequate or over position closing of the isolation switches, resulting in poor contact.
3、 The three sets of isolation switches that generate heat above are all in the open state for a long time under normal annual operation. The contact finger at the handshake is severely oxidized, and the stubbornness coefficient of the spring changes, resulting in uneven looseness and looseness, which is also the cause of heat generation.

Based on the above analysis, it is determined that the heating cause of these three sets of isolation switches is contact resistance heating, and the heating type is current induced heating.