Fluorescent fiber optic electrical high-voltage temperature measurement sensor for online temperature monitoring system of high-voltage switchgear

Temperature measurement methods for high-voltage electrical equipment

From the analysis of the physical mechanism of high-voltage electrical equipment faults, it can be concluded that they mainly involve electrical, magnetic, thermal, and mechanical aspects. The vast majority of equipment faults are manifested as temperature anomalies. Through temperature monitoring of high-voltage electrical equipment, the operating status of the equipment can be accurately and directly reflected. At present, the online temperature monitoring methods for high-voltage electrical equipment at home and abroad have undergone a long period of development, gradually moving from traditional thermistor temperature measurement to infrared temperature measurement, fiber optic temperature measurement, and wireless temperature measurement. Thermal resistance and thermocouple temperature measurement method. Thermistors have the advantages of small volume, fast temperature response, and mature products, and the application cost of this method is relatively low. However, during temperature measurement, each thermistor needs to be independently wired, resulting in a complex overall circuit layout. Additionally, due to the inability of sensors to self check, frequent calibration is necessary, resulting in a large workload. The use of this method in high-voltage situations has limitations, as there is a problem of high voltage isolation between the device and the signal transmission line.

Infrared temperature measurement of high-voltage electrical equipment

Infrared temperature measurement method. The infrared temperature sensor adopts a non-contact temperature measurement method and can adapt to working environments with strong magnetic fields and high voltages. In actual temperature monitoring work, handheld infrared thermometers are mainly used for regular inspections, which can directly identify the fault point. However, the shortcomings of this method are also quite obvious: low level of automation, reliance on human limitations, and often inability to set up infrared probes due to safety distance issues; The measurement accuracy is affected by many factors, such as detection distance, external heat sources, optical path obstruction, etc. Although certain correction measures can be taken, due to the multiple and time-varying influencing factors, it cannot be corrected one by one, and its universality is poor, which is not conducive to promotion and application.

High voltage fiber optic temperature measurement

The application advantages of fiber optic temperature measurement method are high accuracy, fast response, good sensitivity and repeatability, and its application in temperature monitoring can achieve remote control. The fiber temperature measurement method has excellent insulation performance and can isolate high voltage inside the switchgear. It can be directly installed on the high voltage contacts inside the switchgear to achieve real-time online monitoring. At the same time, the existence of no electrical signal in fiber optic temperature measurement overcomes the problem of strong electromagnetic field interference, and the fiber optic flexibility performs well, which can be used for temperature monitoring in the tested equipment, achieving temperature rise areas that conventional sensors cannot reach.

In the actual operation of high-voltage power equipment (such as high-voltage switchgear, transformers, transformers, etc.), the hot spot is often at a high potential position, which limits the use of conventional methods. At the same time, insulation and anti electromagnetic interference are also necessary problems that must be faced. Through the analysis of the above temperature monitoring methods, it can be concluded that different online temperature monitoring methods have their own advantages and disadvantages, such as weak anti-interference ability of infrared temperature measurement, susceptibility to various factors, and relatively high cost; Wireless temperature measurement mainly faces network congestion, packet loss, and performance degradation.. The high-voltage switchgear has multiple measurement and control points (such as A/B/C three-phase, circuit breaker contacts, cable joints, knife switch, busbar, etc.), and the system adopts a decentralized centralized control architecture. Each measurement cluster is equipped with 3-24 temperature measurement sub nodes (temperature sensors) and 1 transmitter host, which are transmitted through the main line network.

Fluorescent fiber optic temperature measurement system for switchgear

Temperature data collection and transmission. In the online temperature monitoring system for high-voltage switchgear, the data acquisition and temperature control terminal is the bottom layer of the structure, including temperature measurement sub nodes and collection nodes. The main function is to set the fiber optic temperature sensor at the contact of the high-voltage switchgear and transmit the data to the collection node through the network,

(1) Contact temperature acquisition terminal: The operating environment of high-voltage switchgear is relatively complex, the space is enclosed and narrow, and it faces high voltage and strong electromagnetic environments. After comprehensive comparison, fluorescent fiber optic temperature sensors are selected,

The specific working parameters are as follows: The following is only a general introduction, detailed customization, and contact us

① Working voltage: DC5V;

② Temperature measurement range: -30 ℃ to+125 ℃;

③ Measurement accuracy: ± 1% ℃ or 1% of the full range;

④ Multi channel temperature measurement: 1-16 channels;

⑤ Anti interference situation: High voltage, strong electromagnetic interference ability.

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