CN110736563A - Passive wireless temperature sensor suitable for distribution temperature monitoring early warning system - Google Patents

Abstract

The invention provides passive wireless temperature sensors suitable for a distribution temperature monitoring and early warning system, which comprise a piezoelectric crystal chip and a transduction transceiving antenna, wherein the piezoelectric crystal chip comprises an interdigital transducer, a multi-stage reflecting grating and a piezoelectric substrate, the transduction transceiving antenna receives an electromagnetic wave signal transmitted by a transmitting unit and transmits the electromagnetic wave signal to the interdigital transducer, the interdigital transducer converts the electromagnetic wave signal into a mechanical vibration wave which is transmitted along the surface of the piezoelectric substrate, after the mechanical vibration wave meets the multi-stage reflecting grating, part of the mechanical vibration wave is reflected back to the interdigital transducer to be converted into an echo signal, and then the echo signal is transmitted to a reading unit through the transduction transceiving antenna.

Description

Passive wireless temperature sensor suitable for distribution temperature monitoring early warning system

Technical Field

The invention relates to the field of power distribution temperature monitoring and early warning systems, in particular to passive wireless temperature sensors suitable for the power distribution temperature monitoring and early warning system.

Background

Especially, China is in a period of rapid economic growth, the power supply load of national power grids is increasing day by day, and series safety problems are brought to power distribution electrical equipment while power supply is continuously expanded.

important risks in the grid safety of contacts and splices in grid switchgear.

1) The switch cabinet is used as power equipment widely applied by types of , the switch cabinet is important equipment in a power transmission and distribution system and plays an important role in opening and closing a power line, protecting the line fault and monitoring running electric quantity data, and the contact resistance of the switch equipment is increased due to poor contact of the moving contact and the fixed contact of a high-voltage circuit breaker, long-term large current, ageing of a contact and other factors, so that the switch equipment generates heat for a long time, the temperature rise of the contact is overhigh, and even the high-voltage cabinet burns out the fault finally.

2) The cable joint faults are that along with the prolonging of operation time, the loosening of a compression joint, insulation aging, partial discharge, high-voltage leakage and the like, heating and temperature rising are caused, the conditions are further worsened by due to the temperature rising, the temperature is further promoted to , short circuit blasting and even fire are caused as a result of vicious circle, in actual operation, due to the lack of safe and effective key connection point temperature measuring equipment, effective temperature online monitoring is not carried out on a main bus bar, a breaker contact and a cable joint in a plurality of switch cabinets, and effective distribution switch cabinet key connection point real-time online temperature monitoring equipment is required by policy standards and actual application.

The switch cabinet is the most direct equipment for supplying power to users, and the reliability of the operation of the switch cabinet is directly related to the quality and the reliability of the power supply. In recent years, with the increasing of electric loads of an electric power system, the load current is increased continuously, and particularly, the space of a cabinet body is reduced after the switch cabinet is miniaturized, so that the problem of equipment heating in the switch cabinet is more prominent; the cubical switchboard generates heat for a long time and can cause the short circuit accident, seriously influences the power supply reliability of electric wire netting, consequently: an effective online monitoring means is needed to master the operation state of the switch cabinet in real time, so that accidents are prevented.

At present, the on-line temperature measurement technology of the common switch cabinet at home and abroad mainly comprises grating optical fiber temperature measurement, infrared temperature measurement, semiconductor digital temperature measurement, thermistor temperature measurement and sound surface temperature measurement. The problems existing in the current stage of various temperature measurement technologies are summarized as follows:

1. measuring the temperature by using the grating fiber: the optical fiber temperature sensor transmits temperature signals by adopting optical fibers, and the optical fibers have excellent insulating property and can isolate high voltage in the switch cabinet, so that the optical fiber temperature sensor can be directly arranged on a high-voltage contact in the switch cabinet, accurately measure the operating temperature of the high-voltage contact and realize the online monitoring of the operating temperature of the switch cabinet contact, but under the influence of accumulated dust or water vapor condensation, the creepage distance of the optical fibers is greatly reduced; the optical fiber is easy to break and break, belongs to a wired temperature measurement mode, is influenced by the structure of switch cabinet equipment, and has higher installation difficulty;

2. infrared temperature measurement is non-contact temperature measurement and is applied to a temperature monitoring system more, but because the internal structure of a switch cabinet is complex, elements are shielded more, the accuracy of the temperature data obtained indirectly through an infrared spectrum cannot meet the requirement, the computer identification technology level of the infrared spectrum cannot replace manual identification, the automation degree is low, meanwhile, the cost of the thermal infrared imager is high, the thermal infrared imager is not beneficial to pushing , and is easily influenced by environmental factors such as environmental temperature, humidity, dust in air and the like, and a probe must be kept constant distance from a measured object.

3. Semiconductor digital temperature measurement: the environment with temperature resistance lower than 90 ℃ can be damaged, is not suitable for strong magnetic field and strong electric field environments, and is easy to be interfered.

4. Temperature measurement by a thermistor: special AD conversion and sampling circuits are needed, system insulation is easily affected, voltage and electromagnetic radiation interference are easily caused, voltage is easily induced, breakdown and damage are caused, and data processing is complex.

Disclosure of Invention

According to the advantages and disadvantages of the existing temperature measurement technologies compared with the prior art, the passive wireless temperature sensors which are free of potential energy supply hazards, high in high temperature resistance, free of insulation risks, resistant to electromagnetic interference, truly passive and free of weak current loops are provided, have extremely strong technical advantages in safety, reliability and stability compared with the traditional temperature measurement technologies, and are particularly suitable for application of power distribution temperature monitoring and early warning systems.

The invention is realized by the following technical scheme:

the invention provides passive wireless temperature sensors suitable for a power distribution temperature monitoring and early warning system, which comprise a piezoelectric crystal chip and a transduction transceiving antenna, wherein the piezoelectric crystal chip comprises an interdigital transducer, a multi-stage reflecting grating and a piezoelectric substrate, the transduction transceiving antenna is used for receiving an electromagnetic wave signal with A frequency transmitted by a transmitting unit and transmitting the electromagnetic wave signal to the interdigital transducer, the interdigital transducer converts the received electromagnetic wave signal into a mechanical vibration wave which is transmitted along the surface of the piezoelectric substrate through inverse piezoelectric effect, after the mechanical vibration wave meets the multi-stage reflecting grating, part of the mechanical vibration wave is reflected back to the interdigital transducer and converted into an echo signal by the interdigital transducer, and the echo signal is transmitted to a reading unit through the transduction transceiving antenna.

Further , the echo electric signal is an electromagnetic wave signal with temperature information and frequency B.

Further , the frequency of the echo electrical signal is a linear function of the temperature of the passive wireless temperature sensor.

And , further comprising a ceramic insulating shell for packaging the piezoelectric crystal chip and the transduction transceiver antenna.

The invention has the beneficial effects that:

the passive wireless temperature sensor suitable for the power distribution temperature monitoring and early warning system comprises a piezoelectric crystal chip and a transduction transceiving antenna, wherein the piezoelectric crystal chip comprises an interdigital transducer, a multi-stage reflecting grating and a piezoelectric substrate, the transduction transceiving antenna is used for receiving an electromagnetic wave signal with A frequency transmitted by a transmitting unit and transmitting the electromagnetic wave signal to the interdigital transducer, the interdigital transducer converts the received electromagnetic wave signal into a mechanical vibration wave which is transmitted along the surface of the piezoelectric substrate through inverse piezoelectric effect, after the mechanical vibration wave meets the multi-stage reflecting grating, part of the mechanical vibration wave is reflected back to the interdigital transducer and converted into an echo signal by the interdigital transducer, and the echo signal is transmitted to a reading unit through the transduction transceiving antenna.

Drawings

FIG. 1 is a schematic diagram of the operation of a passive wireless temperature sensor suitable for a power distribution temperature monitoring and early warning system according to the present invention;

FIG. 2 is a schematic diagram of the working flow of a passive wireless temperature sensor suitable for a power distribution temperature monitoring and early warning system according to the present invention;

fig. 3 is a temperature-frequency graph of a sensor in accordance with the present invention.

Detailed Description

In order to more clearly and completely describe the technical solution of the present invention, the following describes the present invention with reference to the accompanying drawings in step .

Referring to fig. 1-2, the present invention provides passive wireless temperature sensors suitable for a power distribution temperature monitoring and early warning system, including a piezoelectric crystal chip, and a transduction transceiver antenna, where the piezoelectric crystal chip includes an interdigital transducer, a multi-stage reflective grating, and a piezoelectric substrate, the transduction transceiver antenna is configured to receive an electromagnetic wave signal of a frequency a emitted by an emitting unit and transmit the electromagnetic wave signal to the interdigital transducer, the interdigital transducer converts the received electromagnetic wave signal into a mechanical vibration wave propagating along the surface of the piezoelectric substrate by an inverse piezoelectric effect, and after the mechanical vibration wave encounters the multi-stage reflective grating, part of the mechanical vibration wave is reflected back to the interdigital transducer and converted into an echo signal by the interdigital transducer, and the echo signal is transmitted to a reading unit by the transduction transceiver antenna.

The piezoelectric crystal chip has the characteristics of high precision, high sensitivity, strong anti-interference capability and relatively simple structure.

The transduction receiving-transmitting antenna has the characteristics of small volume and large receiving and transmitting areas.

Further , the echo electric signal is an electromagnetic wave signal with temperature information and frequency B.

Further , the frequency of the echo electrical signal is a linear function of the temperature of the passive wireless temperature sensor.

In the embodiment, the temperature and the frequency of the passive wireless temperature sensor have high linearity, the temperature coefficient is 17ppm, the working frequency band is 433.92MHz +/-10 MHz, a single channel occupies 1.5MHz bandwidth, and the temperature measurement from-20 ℃ to +120 ℃ can be realized. The sensor temperature versus frequency curve is shown in fig. 3.

, it also includes a ceramic insulation shell for packaging the piezoelectric crystal chip and the transduction receiving and transmitting antenna, which has small volume, light weight, beautiful structure, strong penetration of wireless electromagnetic wave and high insulation property.

The wireless reading unit comprises a transmitting unit and a reading unit, wherein the wireless reading unit transmits constant-frequency electromagnetic wave pulse signals through an antenna and transmits the electromagnetic wave pulse signals to an interdigital transducer, the interdigital transducer converts the electric signals into acoustic signals through piezoelectric effect, the antenna of the wireless reading unit transmits high-frequency query pulses according to constant period, the received high-frequency pulses are converted into surface acoustic waves through the interdigital transducer and are transmitted on the surface of a piezoelectric substrate, acoustic signal processing is carried out, temperature, pressure and gas are detected through expansion and contraction effect, pressure and gas adsorption, the surface acoustic waves are partially reflected by a reflection array arranged through coding and return to the interdigital transducer, the inverse piezoelectric effect is the process of converting the acoustic signals into the electric signals, the interdigital transducer reflects the acoustic pulse strings and converts the electric pulse strings into high-frequency electric pulse strings, and the electric signals are returned to the reading unit through the antenna to realize the wireless detection of parameters to be detected.

The invention discloses a passive wireless temperature sensor suitable for a power distribution temperature monitoring and early warning system, belongs to a temperature sensor of novel surface acoustic wave technologies, is manufactured by adopting a ceramic insulating shell and a high-reliability piezoelectric crystal chip, realizes the physical characteristics of low insertion loss and high quality factor, has excellent high-voltage and electromagnetic radiation resistance, can work in an extremely high or extremely low temperature environment, can stably detect the temperature of a detected object in a passive wireless mode for a long time, and is suitable for a high-voltage and low-voltage power distribution temperature detection system.

Of course, the present invention may have other embodiments, and based on the embodiments, those skilled in the art can obtain other embodiments without any creative effort, and all of them are within the protection scope of the present invention.

Claims (4)

1. The utility model provides a passive wireless temperature sensor suitable for distribution temperature monitoring early warning system, a serial communication port, including piezoelectric crystal chip, transduction transceiver antenna, piezoelectric crystal chip includes interdigital transducer, multistage reflecting grating and piezoelectric substrate, transduction transceiver antenna is used for receiving the electromagnetic wave signal of the A frequency of transmitting element transmission and transmits for interdigital transducer, interdigital transducer converts the electromagnetic wave signal of receiving into the edge through reverse piezoelectric effect piezoelectric substrate's surface propagation's mechanical vibration wave, and this mechanical vibration wave meets behind the multistage reflecting grating, part mechanical vibration wave is reflected back interdigital transducer and by interdigital transducer converts echo signal into, and echo signal passes through again transduction transceiver antenna transmits to the reading unit.
2. 2. The passive wireless temperature sensor suitable for the power distribution temperature monitoring and early warning system as claimed in claim 1, wherein the echo electric signal is an electromagnetic wave signal with temperature information, and the frequency of the echo electric signal is B.
3. 3. The passive wireless temperature sensor suitable for the power distribution temperature monitoring and early warning system as claimed in claim 2, wherein the frequency of the echo electric signal and the temperature of the passive wireless temperature sensor are in a linear function relationship.
4. 4. The passive wireless temperature sensor suitable for the power distribution temperature monitoring and early warning system of claim 1, further comprising a ceramic insulating housing encapsulating the piezoelectric crystal chip and the transduction transceiving antenna.

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