Fiber Bragg Grating for Temperature Sensing for Power Monitoring

Fiber optic grating temperature sensors can measure the temperature of many objects being measured, with precise measurement and stable performance.

In the development process of China’s power system, the issue of electricity safety has become increasingly prominent. Accidents occur frequently, mostly due to the current passing through certain parts, causing local overheating and not being detected in a timely manner. Based on this, temperature monitoring, display, and alarm for certain key areas. If accidents occur, timely measures should be taken to avoid safety accidents.

The traditional temperature measurement methods in power systems mainly include two types: contact and non-contact measurement. Thermal resistance temperature measurement, thermocouple temperature measurement, and infrared temperature measurement are common temperature measurement methods in practical applications. Traditional methods are susceptible to environmental temperature and electromagnetic interference due to device measurement limitations, making it difficult to measure accurately. En même temps, traditional sensors also bring some problems to the insulation protection of the power system, thus reducing the insulation protection level of the power system. To compensate for the limitations of traditional methods, fiber optic grating temperature measurement technology has emerged. A new type of sensor using fiber optic as the medium overcomes electromagnetic interference in the power system environment, and due to the excellent physical, chemical, mechanical properties and transmission performance of fiber optic, it has advantages that traditional sensors cannot compare with.

fiber bragg grating sensors for temperature measurement

With the development of fiber optic communication and integrated optical technology, fiber optic sensing technology is flourishing in the field of sensors. Compared with traditional methods, the advantages of fiber optic sensors are not functional characteristics, but derived from their own physical characteristics. Fiber optic sensors have the characteristics of light weight, fine diameter, small signal attenuation, strong corrosion resistance, electromagnetic interference resistance, and high temperature resistance. They also have the advantages of integrating information sensing and transmission, which can solve measurement problems that conventional detection techniques cannot solve. Firstly, the optical fiber itself has good insulation performance, which can isolate the high voltage between the power system and measurement equipment, avoiding equipment safety accidents caused by temperature measurement devices, and greatly improving safety. Using optical fibers as carriers for transmitting and sensing signals can overcome the strong electromagnetic interference problem in data transmission in the power system environment, thus obtaining more accurate measurement results. Secondly, due to the good flexibility of the optical fiber, it can detect areas that conventional sensors cannot reach. These advantages make fiber optic sensors stand out in the field of temperature measurement in power systems, gradually replacing other sensor measurement methods and making them more suitable as the main means of temperature measurement for high-voltage switchgear.

fiber bragg grating temperature sensor for practical use

The fiber optic sensor is connected to the fiber optic grating signal processor, and finally communicates with the backend computer through the RS485 communication port; The monitored temperature data is saved in the computer and displayed on the screen, thus achieving the purpose of monitoring the temperature of cable joints. When the temperature of the cable joint is abnormal, the system will give an alarm signal

Fiber optic grating temperature sensors and optical splitter boxes are used to collect data from measurement points and transmit optical paths. Real time temperature detection was conducted on 10 switchgear cabinets, including the 10kV main incoming, connecting bridge, and important branch circuits, in a certain substation. Each switchgear cabinet was tested for the static contacts on the busbar side of the short-circuit breaker, the static contacts on the line side, and the three-phase temperature of the cable connection bar, approximately 9 points. Sensors were installed on the tested nodes, and the optical branch box was installed on the switchgear panel.

FJINNO has solved the commonly used monitoring methods and their advantages and disadvantages for real-time temperature monitoring of high-voltage switchgear. The application of fiber optic gratings in the field of power system temperature control, as a novel sensing and detection technology, has received widespread attention since its inception.