The advantages and disadvantages of using infrared temperature measurement and wireless temperature measurement in switchgear-INNO

Por que o sistema de energia precisa de medição de temperatura

O equipamento elétrico primário no sistema de energia geralmente consiste em disjuntores, transformadores, cabos, barramentos, comutadores e outros equipamentos elétricos; Eles estão conectados entre si por barramentos, pistas, cabos, etc.. Devido à corrente que flui através do ponto de conexão, o calor é inevitavelmente gerado, e quase todas as falhas elétricas causarão mudanças na temperatura do ponto de falha; Portanto, o monitoramento de temperatura de equipamentos em sistemas de energia, como quadros de distribuição, é uma prática comum para detecção oportuna de falhas. Por muitos anos, devido a limitações tecnológicas, o nível de operação segura do sistema de energia foi restringido até certo ponto. Embora os termômetros infravermelhos, dispositivos de imagem infravermelha, cabos de detecção de temperatura, e ponto tradicional sistemas de medição de temperatura have been used to solve the above problems, real-time monitoring cannot be achieved, and only periodic inspections can be carried out, resulting in safety hazards of missed detection and reporting. For switchgear, in order to improve its operating condition and protect personnel safety, conventional switchgear is now all metal sealed structure. Tradicional métodos de medição de temperatura para comutadores are no longer applicable to new switchgear, especially for central movable switchgear. The conductive parts are all covered by insulation materials during operation, and conventional infrared temperature measurement methods cannot measure the internal equipment. Portanto, it is necessary to use internal measurement methods in the switchgear to monitor the operation of internal components in high current switchgear in real time, detectar a origem das falhas antecipadamente, e evitar que acidentes ocorram.

Medição de temperatura de contato e medição de temperatura sem contato

For switchgear, existem dois métodos de medição de temperatura comumente usados em casa e no exterior: medição de temperatura de contato e medição de temperatura sem contato:

O princípio da medição da temperatura de contato: O método de medição de temperatura de contato consiste em contatar diretamente o sensor com o objeto que está sendo medido, para que o sensor e o objeto que está sendo medido mantenham a mesma temperatura;

O princípio da medição de temperatura sem contato: O sensor não entra em contato direto com o objeto medido, mas mede a temperatura do equipamento medido através do princípio da radiação térmica, que é um método de medição sem contato.

Medição de temperatura infravermelha:

Infrared temperature measurement method is a typical non direct contact measurement method. The basic basis of infrared thermometry is the blackbody radiation law of Stefan Boltzmann, Planck, e outros. Blackbodies are ideal objects that emit the same electromagnetic spectrum at the same temperature, regardless of the specific composition and shape of the blackbody. The size and wavelength distribution of the object’s own infrared radiation energy are closely related to its surface temperature. By measuring the object’s own infrared radiation energy, its surface temperature is determined, which is the basic principle on which infrared radiation thermometry is based. Hoje em dia, infrared thermometers are generally composed of optical systems, infrared detectors, amplificadores de sinal, processamento de sinal, display outputs, e outras peças. The core is the infrared detector, which converts the incident infrared radiation energy into other measurable forms of electrical signals. The signal is calculated and corrected by the amplifier and signal processing circuit according to the internal algorithm of the instrument, and then converted into the temperature value of the measured object, which is displayed on the optical system.

The infrared temperature measurement method began around World War II, and the infrared temperature measurement technology was first applied in the military field. The first generation of infrared imaging devices used in the military field was developed and developed by Texas Land Instruments in the United States, known as the Infrared Sight Finding System (FLIR). In the mid-1960s, the Swedish company AGA developed the first industrial real-time imaging system (THV), but it had the characteristics of high cost, large volume, heavy weight, and inconvenient portability. After several generations of improvements to the instrument, a fully functional thermal imager was launched in 1988, which integrated temperature measurement, modificação, análise, image acquisition, e armazenamento. The instrument’s functionality, precisão, and operability were significantly improved. In the mid-1990s, FSI Corporation in the United States was the first to successfully develop and commercialize an infrared thermal imager (CCD), which was transformed from military technology (FPA) to civilian use. The technical functions were more advanced, and on-site temperature measurement only needed to aim at the target to capture images, e armazene as informações acima no cartão PC dentro da máquina para concluir todas as operações. A configuração de vários parâmetros pode ser retornada ao software interno para modificação e análise de dados, e finalmente, o relatório de detecção pode ser obtido diretamente. Devido a melhorias tecnológicas e mudanças estruturais, digitalização mecânica complexa foi substituída, e o instrumento pesa menos de dois quilogramas. É usado como uma câmera portátil, e pode ser facilmente operado com uma mão. Posteriormente, a tecnologia de medição de temperatura infravermelha foi amplamente aplicada na indústria de energia, e vários sensores infravermelhos de temperatura foram desenvolvidos com sucesso e colocados no mercado em grandes quantidades.

Vantagens da medição de temperatura infravermelha: fácil de operar e de tamanho compacto. Atualmente, infrared thermometers only need to set parameters and align with the measured object to immediately measure the surface temperature of the object. They also have the function of taking photos and automatically finding the highest temperature measurement point. They are very convenient for on-site use and have been widely used, becoming the main technical means for temperature measurement in many power industry equipment.

Disadvantages of infrared temperature measurement: It can only measure equipment exposed to air. Although some universities have also developed infrared temperature measurement systems for high-voltage switchgear, the infrared probe temperature measurement method for high-voltage switchgear is easily affected by the obstruction of the infrared radiation path by internal components of the switchgear, and cannot accurately measure the contact temperature. Although certain corrections can be taken, there are many factors that affect infrared radiation and they are time-varying, making it difficult to calibrate them one by one. Portanto, this method has poor universality and cannot be promoted for use. This method is only applicable to early switchgear structures and cannot be used for measuring high-voltage switchgear with insulation wrapping.

The working principle of wireless temperature measurement

Wireless temperature measurement method is an improvement on contact temperature measurement method, destinado principalmente a resolver o problema de isolamento de alta e baixa tensão entre equipamentos de medição de temperatura e sistema de energia. Geralmente, sistema de medição de temperatura sem fio é composto de três partes: nó de medição de temperatura distribuída, receptor de dados, e sistema de processamento de dados back-end. Os nós de medição de temperatura distribuída são instalados diretamente nas peças que precisam ser medidas, que pertence ao método de medição de temperatura de contato. O receptor de dados é colocado a uma certa distância do corpo do quadro. A comunicação sem fio é usada entre os nós de medição de temperatura distribuída e o receptor de dados para transmissão de dados, conseguindo assim isolamento de alta tensão e coleta de dados de medição de temperatura, solving the problem of the operating temperature of the contacts inside the high-voltage switchgear not being easily monitored by infrared temperature measurement.

Desvantagens de medição de temperatura sem fio
Although wireless temperature measurement effectively solves the safety issues of temperature measurement devices, there are also some problems in practical applications. Entre eles, the stability of the temperature measurement device placed at the switch contact position is the most core problem. Em aplicações práticas, the power supply of this module is often a current induction power supply that obtains energy from the power line (if battery power is used, not only does it need to be replaced regularly, but the battery is also prone to false alarms in high temperature environments and battery feeding states, greatly affecting monitoring accuracy). The magnitude of the energy obtained by this power supply varies greatly with the load of the power line, so the module often experiences insufficient power supply. In response to this problem, some have proposed using batteries, reducing the power consumption of temperature measurement devices, etc.. Método, This method has problems such as the need to regularly replace the battery after it has been consumed, and it can also result in low wireless transmission power and electromagnetic interference from the surrounding environment, leading to errors in temperature measurement data transmission. The battery replacement device requires the high-voltage switchgear to stop power supply, which cannot meet the continuous operation requirements of the high-voltage switchgear.

Passive wireless temperature measurement

Some companies use surface acoustic wave devices to make temperature sensors, which provide feedback on temperature changes through antennas. There is no need to power the sensor components to solve the related problems caused by active wireless temperature measurement batteries. No entanto, this type of device is immature, uses crystal materials with poor thermal stability, is expensive, and does not improve the signal quality of wireless transmission methods.