Is the online temperature monitoring system for high-voltage switchgear using infrared or optical fiber

Fiberoptisk temperatursensor, Intelligent övervakningssystem, Tillverkare av distribuerad fiberoptik i Kina

The importance of temperature measurement system for switchgear

Temperature has always been a very important parameter, and in many fields such as electricity, coal, medical, military, and daily life, temperature measurement devices are needed to detect temperature. Real time temperature monitoring has become one of the important measures taken by various industries to ensure safety production and reduce losses. In industrial systems, temperature is an important parameter that characterizes the normal operation of equipment. With the continuous increase of industrial electricity load, in order to avoid unexpected events caused by equipment heating, automatic temperature monitoring has become an important link in industrial safety production.

Online monitoring of switchgear temperature

With the rapid development of China’s power industry, switchgear is widely used in the power system. In the long-term operation of the switchgear, due to ground settlement and vibration, impact vibration during operation, influence of electric power, oxidation of surrounding air, etc., poor contact between high-voltage conductors of the switchgear may occur, leading to increased resistance and overheating when the load current passes through. Overheating of charged bodies can cause insulation aging or even breakdown, leading to short circuits and major accidents, causing huge economic losses and posing a threat to personal safety. Därför, temperature monitoring of the switchgear to detect and eliminate potential thermal faults in advance is of great significance for the safe and reliable operation of the switchgear. Some defects in the operating electrical equipment can cause abnormal temperature rise of equipment components, resulting in a vicious cycle of temperature and contact resistance values, ultimately leading to equipment malfunction or even burning, causing major quality accidents. Especially for switchgear in high-voltage electrical equipment, existing technology is difficult to monitor temperature in real-time and accurately.

Types of online temperature monitoring systems for high-voltage switchgear

High voltage switchgear is one of the important electrical equipment in substations and power plants. It contains components such as circuit breakers and isolation switches, as well as the busbar where the bus is located. Due to poor installation or structural aging, the contact resistance between the circuit breaker and the bus connection point is too high and generates heat. If the heat is not detected and dealt with in a timely manner, it will burn out the bus and cause a power outage accident. In existing technology, there are generally three temperature measurement methods for high-voltage switchgear, namely wax film temperature measurement method, fiber optic temperature measurement method, and infrared thermal imaging temperature measurement method. The wax strip temperature measurement method is to place special wax strips inside the switchgear, and estimate the contact temperature based on the degree of wax strip discoloration or melting. Due to the exposed high voltage inside the switchgear and the fully enclosed operation of the switchgear, the switchgear can only be closed regularly, and then the cabinet door is opened to observe the wax strips. This temperature measurement method is very untimely and inaccurate. Fiber optic cables are fragile and prone to breakage, and their insulation performance decreases after accumulating dust. It is difficult and costly to wire them inside the switchgear. Infrared thermal imagers are installed outside the switchgear and measured through the cabinet door, resulting in a significant error between the measured temperature and the contact temperature inside the switchgear. The existing temperature measurement methods for high-voltage switchgear cannot measure the contact temperature inside the switchgear in a timely and accurate manner.

Disadvantages of infrared temperature measurement in switchgear

In existing technologies, infrared temperature measurement devices are commonly used in power systems to conduct temperature inspections on power equipment, mainly including handheld infrared thermometers and infrared thermal imagers. Due to the limitations of the principle of infrared temperature measurement, infrared radiation may cause loss when penetrating objects, resulting in measurement results deviation. Därför, it is best to measure directly exposed areas. Emellertid, due to the requirements of protection level and riot prevention, the existing switchgear is mostly a sealed structure, and the switchgear is equipped with a complete “five prevention” device, which prevents the cabinet door from opening during operation. The observation windows installed on the switchgear are mostly made of tempered glass or organic glass materials, which have severe infrared reflection and cannot be accurately measured

The fluorescent fiber optic temperature measurement system for switchgear is a high-tech product of FJINNO. It integrates technologies such as fluorescent fiber optic and temperature signal detection, and is highly welcomed by users in the field of real-time temperature online monitoring of switchgear. It can measure and accurately display the temperature of the contact busbar inside the switchgear at multiple points, and the sensing fiber optic is both a transmission medium and a sensing medium. Fiber optic has the advantages of being uncharged, resistant to radio frequency and electromagnetic interference, flame retardant, explosion-proof, corrosion-resistant, heat-resistant, and has a long service life. It can operate safely in harmful environments.