Passive wireless temperature sensor suitable for power distribution temperature monitoring and pre-warning systems

Abstract

The invention discloses a passive wireless temperature sensor suitable for power distribution temperature monitoring and pre-warning systems. The passive wireless temperature sensor comprises a piezo-electric crystal chip and a transducing and transceiving antenna, wherein the piezo-electric crystal chip comprises an interdigital transducer, a multistage reflecting grating and a piezo-electric substrate; the transducing and transceiving antenna receives an electromagnetic wave signal transmitted by a transmission unit and transfers the electromagnetic wave signal to the interdigital transducer; the interdigital transducer converts the electromagnetic wave signal into a mechanical vibration wave which is propagated along the surface of the substrate; and after the mechanical vibration waveencounters the multistage reflecting grating, a part of the mechanical vibration wave is reflected back to the interdigital transducer so as to be converted into an echo electric signal, and then is transferred to a reading unit through the transducing and transceiving antenna. The passive wireless temperature sensor provided by the invention is capable of realizing the physical characteristics oflow insertion loss and high quality factor, has excellent high voltage resistance and electromagnetic radiation resistance, is capable of working under extremely high or low temperature environment and chronically and stably detecting the temperatures of the detected objects through a passive wireless manner, and is suitable for the temperature detection systems in high and low power distribution.

Description

technical field [0001] The invention relates to the field of power distribution temperature monitoring and early warning systems, in particular to a passive wireless temperature sensor suitable for power distribution temperature monitoring and early warning systems. Background technique [0002] The safety and reliability of power distribution equipment is an important part of ultra-large-scale power transmission and distribution and grid security, and it is necessary to monitor the safe operation of power grid power equipment in real time. In particular, our country is in a period of rapid economic growth, and the power supply load of the State Grid is increasing day by day, which brings a series of safety problems to power distribution electrical equipment while continuing to expand power supply. [0003] Contacts and joints in the grid switchgear are an important hidden danger of the grid security. The existing statistical results show that faults mainly occur in the fol...

AI Technical Summary

Problems solved by technology

Due to the poor contact of the dynamic and static contacts of the high-voltage circuit breaker, coupled with long-term high current, contact aging and other factors, the contact resistance of the switchgear is likely to increase, resulting in long-term heating, excessive temperature rise of the contacts, and eventually high voltage. Cabinet burnout failure

[0005] 2) Cable joint failure: With the extension of running time, loosening of crimping joints, aging of insulation, partial discharge, high voltage leakage, etc., it will cause heating and temperature rise, and the rise of temperature will further deteriorate these conditions. The temperature will be further increased, and the result of this vicious circle will cause short-circuit blasting and even fire; There is no effective online temperature monitoring at the cable joint

[0008] 1. Grating optical fiber temperature measurement: The optical fiber temperature sensor uses optical fiber to transmit temperature signals. The optical fiber has excellent insulation performance and can isolate the high voltage in the switch cabinet. Therefore, the optical fiber temperature sensor can be directly installed on the high voltage contact in the switch cabinet. Accurately measure the operating temperature of high-voltage contacts and realize online monitoring of the operating temperature of switchgear contacts. However, under the influence of dust accumulation or water vapor condensation, the creepage distance of optical fibers will be greatly reduced; Temperature mode, affected by the structure of the switchgear equipment, the installation is more difficult;

[0009] 2. Infrared temperature measurement: Infrared temperature measurement is non-contact temperature measurement, which is widely used in temperature monitoring systems. However, due to the complex internal structure of the switch cabinet and the mutual shielding of components, the accuracy of temperature data obtained indirectly through infrared spectrum cannot be guaranteed. To meet the requirements, the level of computer recognition technology for infrared spectra cannot replace manual recognition, and the degree of automation is not high. Dust in the air, etc., the probe must keep a certain distance from the measured object

[0010] 3. Semiconductor digital temperature measurement: The temperature resistance performance is low and the environment above 90°C may be damaged. It is not suitable for strong magnetic field and strong electric field environment, and is susceptible to interference

[0011] 4. Thermistor temperature measurement: special AD conversion and sampling circuits are required, which is easy to affect the system insulation and is susceptible to voltage and electromagnetic radiation interference, and is easy to induce voltage, resulting in breakdown damage and complex data processing

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