How to measure temperature in switchgear using fluorescent fiber optic sensors

Sensor de temperatura de fibra óptica, Sistema de monitoramento inteligente, Fabricante de fibra óptica distribuída na China

1、 Temperature monitoring method for switchgear

There are various methods for monitoring the temperature of switchgear, and the following are common ones:

Sensor de temperatura de fibra óptica fluorescente method:

A temperature measurement method based on fluorescence afterglow fiber sensing technology, utilizing the principle of fiber afterglow lifetime to achieve temperature measurement and monitoring. By installing fluorescent fiber optic sensors inside the high-voltage switchgear, real-time temperature information can be obtained at different locations. This method has the advantages of high accuracy and strong resistance to electromagnetic interference, and is suitable for continuous monitoring of multi-point temperatures. Due to its excellent insulation properties, optical fibers have higher safety in high-voltage environments such as switchgear, and can be flexibly arranged in locations that require monitoring, covering a larger area.

Contato wireless temperature sensor method:

This is a reliable temperature measurement method for high-voltage switchgear. By installing contact sensors (such as thermocouples, Termistores, etc.) inside or at critical locations of the switchgear, directly contacting the surface of the object to be measured, real-time temperature data of the object surface can be obtained. This method has high accuracy and fast response speed, and is suitable for precise monitoring of specific locations or components. Por exemplo, installing thermocouple sensors at key connection points of some switchgear can accurately measure temperature changes at that point, in order to detect abnormal heating conditions in a timely manner. But this method may have problems such as complex wiring, and if the sensor malfunctions, it may affect the measurement results and be difficult to detect.

 

Infrared temperature measurement method:

This is a handheld temperature measurement tool suitable for fast, non-contact temperature detection of high-voltage switchgear. When in use, simply aim at the target surface to quickly obtain the surface temperature value at that location. The principle is to use the infrared radiation emitted from the surface of an object, which is proportional to its surface temperature. By detecting and processing the infrared radiation, the surface temperature data of the target object can be obtained. Contudo, this method is greatly affected by environmental factors, such as surrounding heat sources, dust, etc., which may interfere with the measurement results. Moreover, it can only measure surface temperature and may not accurately reflect deep-seated temperature changes inside the switchgear.

CCD camera monitoring method:

Capture images of the interior of the switchgear using a CCD camera, and then analyze the temperature information in the images using relevant algorithms. Contudo, this method has limitations as it may not be able to accurately distinguish the temperature of different components, and may not be able to effectively monitor the temperature of some obscured areas. Além disso, the accuracy and environmental adaptability of CCD cameras themselves can also affect the accuracy of temperature monitoring.

Temperature wax monitoring method:

This is a more traditional temperature monitoring method. The temperature indicating wax sheet will change color or shape according to temperature changes, and the temperature inside the switchgear can be determined by observing the changes in the wax sheet. Contudo, this method can only provide a rough temperature range, cannot accurately measure temperature values, and cannot be monitored in real time. It requires regular manual monitoring. Once the temperature exceeds the response temperature of the wax sheet, it can only be known afterwards and cannot be alerted in a timely manner.

2、 Aplicação de Fluorescent Fiber Optic Temperature Measurement in Temperature Monitoring of Switchgear

The basic principle of using fluorescent fiber temperature measurement technology for switchgear temperature monitoring is to utilize the temperature response characteristics of fluorescent materials. When the fluorescent fiber is irradiated with excitation light, it will emit fluorescence, and the lifetime of fluorescence has a specific relationship with temperature. The temperature value can be determined by measuring the fluorescence lifetime. In the switchgear, fluorescent fiber optic sensors can be installed near key components such as busbars, moving contacts, and stationary contacts to monitor temperature changes in these areas. Por exemplo, for the moving contacts in the switchgear, due to the accumulation of heat during the opening and closing process, the use of fluorescent fiber optic sensors can monitor their temperature in real time. Once the temperature rises abnormally, an alarm can be issued in a timely manner to prevent accidents. The fluorescence fiber optic temperature measurement system also has strong anti-interference ability, small coverage blind spots, real-time monitoring and remote monitoring, making it very suitable for temperature monitoring needs in complex environments such as switchgear.

 

3、 The advantages of fiber optic temperature measurement

high-precision:
Fiber optic temperature sensors can achieve high-precision temperature measurement. Taking fluorescent fiber optic sensors as an example, they are very sensitive to temperature changes and can detect small temperature changes. This high-precision measurement capability enables timely detection of subtle abnormal temperature increases in switchgear temperature monitoring, and early warning of potential fault risks. Por exemplo, in the monitoring of key components in some switch cabinets with extremely high temperature requirements, fiber optic temperature measurement can accurately measure temperature changes up to a few tenths of a degree, while traditional temperature measurement methods may not be able to achieve such accuracy.

Strong anti-interference ability:

Fiber optic temperature measurement has unique advantages in environments full of electromagnetic interference, such as switchgear. Fiber optic itself is non-conductive and will not be affected by electromagnetic interference. Whether it is the strong electromagnetic field generated during the operation of the high-voltage switchgear or the electromagnetic interference generated by other surrounding electrical equipment, it will not interfere with the fiber optic temperature measurement system. This enables the fiber optic temperature measurement system to work stably and accurately, ensuring the reliability of temperature monitoring data. In contrast, some electronic temperature sensors may experience measurement errors or even malfunction due to electromagnetic interference.

Safe and reliable:

Fiber optic cables have good insulation properties, which makes fiber optic temperature measurement very safe in high-voltage environments such as switchgear. In the switchgear, optical fibers can directly contact high-voltage components for temperature measurement without the risk of electric shock like some metal sensors. Moreover, optical fibers do not generate safety hazards such as electric sparks and are suitable for various hazardous environments. Por exemplo, in flammable and explosive environments, fiber optic temperature measurement systems can operate safely and reliably, ensuring smooth temperature monitoring of switchgear.

Suitable for multi-point monitoring:

Fiber optic cables can be conveniently arranged in a distributed manner, enabling simultaneous temperature monitoring of multiple points inside the switchgear. By installing fiber optic sensors at different locations of the switchgear, such as busbars, contacts, and connection points, a comprehensive temperature monitoring network can be constructed. In this way, temperature information from multiple locations can be obtained at once, making it easier to analyze the overall temperature distribution and trend of the switchgear. Por exemplo, in a large switchgear system, various sensors can be connected through optical fibers to monitor the temperature situation at different locations throughout the system in real time and detect local overheating issues in a timely manner.

Small coverage blind spot:

The fiber optic temperature measurement system can flexibly arrange fiber optic sensors according to the internal structure of the switchgear, which can effectively reduce monitoring blind spots. Whether it is the narrow space inside the switchgear or around complex shaped components, temperature monitoring can be achieved by arranging optical fibers reasonably. In contrast, some other temperature measurement methods, such as CCD camera monitoring, may have blind spots that cannot be detected, while fiber optic temperature measurement can more comprehensively cover various parts inside the switchgear.

Can achieve remote monitoring:

The fiber optic temperature measurement system can transmit the collected temperature data to a remote monitoring center through optical fibers. This allows operation and maintenance personnel to view temperature data in real-time from a remote location away from the cabinet for remote monitoring and management. Por exemplo, in a large substation, operation and maintenance personnel can monitor the temperature of each switchgear in real-time using temperature data transmitted through optical fibers from the main control room. Once abnormal temperature is detected, timely measures can be taken to improve the efficiency and convenience of operation and maintenance.

4、 Comparison between fiber optic temperature measurement and other methods in switchgear temperature monitoring

Comparison with contact wireless temperature sensor method:

In terms of accuracy, fiber optic temperature measurement has the characteristic of high precision and can detect small temperature changes. Although the contact wireless temperature sensor method also has high accuracy, in some situations where high precision is required, fiber optic temperature measurement may have more advantages. Por exemplo, when monitoring the temperature of small connection points inside a switchgear, fiber optic temperature measurement can be accurate to a few tenths of a degree, while contact sensors may have a certain range of errors.

Anti interference ability: Fiber optic temperature measurement has strong anti electromagnetic interference ability and can work stably in strong electromagnetic environments such as switchgear; Contact sensors may be affected by electromagnetic interference, which may affect their measurement accuracy, especially in complex electromagnetic environments inside switchgear, and additional anti-interference measures may be required.

Safety: Fiber optic cables have good insulation properties, making them safer to use in high-voltage environments of switchgear; If insulation damage occurs during the installation or use of contact sensors, it may pose a risk of electric shock.

Multi point monitoring capability: Fiber optic temperature measurement is suitable for multi-point monitoring and can easily deploy sensors at multiple locations inside the switchgear to build a monitoring network; If contact sensors need to perform multi-point monitoring, they may require more wiring and equipment, and installation and management are relatively complex.

Compared with infrared temperature measurement method:

Measurement method: Infrared temperature measurement is a non-contact and rapid measurement method that can only measure the surface temperature of an object; Fiber optic temperature measurement can be achieved by contacting or approaching the measured object through fiber optic sensors, which can measure the temperature inside or on the surface of the object and achieve continuous monitoring. Por exemplo, for temperature monitoring of components deep inside the switchgear, infrared temperature measurement method cannot accurately obtain it, while fiber optic temperature measurement can arrange sensors at corresponding positions for measurement.

Environmental adaptability: Infrared temperature measurement is greatly affected by environmental factors, such as surrounding heat sources, dust, smoke, etc., which may interfere with the measurement results; Fiber optic temperature measurement is less affected by environmental factors, has strong anti-interference ability, and can accurately measure temperature in complex environments.

Accuracy and stability: Fiber optic temperature measurement has high accuracy and good stability, and can monitor temperature changes stably for a long time; The accuracy of infrared temperature measurement is relatively low, and the measurement results may be unstable due to fluctuations in environmental factors.

Comparison with CCD camera monitoring method:

Precisão da medição de temperatura: CCD camera monitoring method obtains temperature information through image analysis, which has relatively low accuracy and is difficult to accurately distinguish the temperature of different components; Fiber optic temperature measurement can directly measure temperature with higher accuracy, and can accurately obtain the temperature value at each sensor position.
Monitoring blind spots: CCD camera monitoring method may have monitoring blind spots, which cannot effectively monitor the obstructed parts; Fiber optic temperature measurement can reduce monitoring blind spots and achieve more comprehensive temperature monitoring by arranging fiber optic sensors reasonably.

Real time performance: Fiber optic temperature measurement can monitor temperature changes in real time and provide timely feedback of data; The CCD camera monitoring method may have some delay as it requires image acquisition, processamento, and analysis to obtain temperature information.

Comparison with temperature wax monitoring method:
Precisão de medição: The temperature wax monitoring method can only provide a rough temperature range and cannot accurately measure temperature values; Fiber optic temperature measurement can accurately measure temperature and provide accurate temperature data.

Real time performance and warning capability: The temperature wax monitoring method cannot monitor temperature in real time and requires regular manual inspection, which cannot provide timely warnings; Fiber optic temperature measurement can monitor temperature changes in real time, and when the temperature exceeds the set threshold, it can issue an alarm in a timely manner, facilitating timely measures to be taken.

5、 Example analysis of fiber optic temperature measurement in switchgear temperature monitoring

Application of Fiber Bragg Grating Temperature Measurement Using a Substation Switchgear as an Example:
In the temperature monitoring system of the switchgear in a certain substation, fluorescent fiber optic temperature measurement technology is used. Fluorescent fiber optic sensors have been installed at key locations such as busbars, contacts, and connection points in the switchgear. These sensors are connected to the monitoring host through fluorescent optical fibers. Due to the operation of the switchgear, parts such as busbars and contacts are prone to generate heat due to excessive current and poor contact. By using fluorescent fiber optic sensors, temperature changes in these areas can be monitored in real time. Por exemplo, when there is poor contact between the contacts, local overheating occurs. Fluorescent fiber optic sensors can quickly detect the temperature increase and transmit the temperature signal in the form of fiber optic to the monitoring host. Monitor the host for analysis and obtain specific temperature values. Once the temperature exceeds the set safety threshold, the system will immediately issue an alarm to notify the operation and maintenance personnel. This real-time monitoring and warning function effectively avoids switchgear failures caused by overheating and improves the operational safety of the substation. Moreover, as fluorescent fiber optic sensors can achieve high-precision temperature measurement, they can accurately reflect subtle changes in temperature, which helps maintenance personnel to detect potential problems in a timely manner. Por exemplo, during normal operation, the temperature of the busbar may fluctuate slightly due to changes in load. Fluorescent fiber optic sensors can accurately measure these fluctuations and provide detailed temperature trend information for maintenance personnel to make reasonable maintenance decisions.

Application examples of fluorescent fiber optic temperature measurement in switchgear:

The switchgear of a certain enterprise adopts a fluorescent fiber optic temperature measurement system. Fluorescent fiber optic sensors are installed in the busbar, moving contacts, stationary contacts, and other parts inside the switchgear. Fluorescent fiber optic sensors utilize the temperature response characteristics of fluorescent materials to determine temperature by measuring fluorescence lifetime. In actual operation, when the load of the switchgear changes or components fail, the temperature of the corresponding parts will change. Por exemplo, when the moving contact experiences wear and tear after prolonged operation, the contact resistance increases, leading to an increase in temperature. Fluorescent fiber optic sensors can detect temperature changes in a timely manner and transmit data to the monitoring system. The monitoring system determines whether the temperature is abnormal based on the received data, and sends an alarm signal if it is abnormal. Meanwhile, due to the strong anti-interference ability and small coverage blind zone of the fluorescent fiber optic temperature measurement system, it can stably and comprehensively monitor temperature in the complex electromagnetic environment and compact structural space of switchgear. Compared with traditional temperature measurement methods, the adoption of a fluorescent fiber optic temperature measurement system by the enterprise greatly improves the accuracy and reliability of temperature monitoring for switchgear, reduces equipment failures and downtime caused by temperature anomalies, and improves production efficiency.