Switch cabinet passive wireless temperature measurement system based on RFID

Abstract

The invention provides a switch cabinet passive wireless temperature measurement system based on RFID, and relates to the technical field of power equipment temperature measurement. Comprising an RFID temperature measurement sensor for acquiring the temperature of a monitoring node in the switch cabinet, a reader-writer for reading temperature data in the RFID temperature measurement sensor through an RFID wireless radio frequency identification technology, a data transmission device for uploading the data of the reader-writer to a cloud server, and the like. According to the invention, the RFID temperature measurement sensors with built-in RFID electronic tags are arranged at each monitoring node in the switch cabinet, the internal temperature can be accurately detected, the temperature data are wirelessly transmitted to the reader-writer through the RFID technology, no extra power supply is needed, no wiring is needed, and no secondary potential safety hazard is caused.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature measurement of electric power equipment, and in particular to a passive wireless temperature measurement system of a switch cabinet based on RFID. Background Art

[0002] Switchgear is an important power equipment in the power system, and its safety and stability are directly related to the safety and stability of the power grid. Switchgear belongs to combined equipment, which is generally composed of circuit breakers, busbars, inductors, capacitors, mutual inductors, busbars, lightning arresters, measuring equipment, relay protection devices and other equipment. They are assembled in a closed metal cabinet to receive and distribute electrical energy in the distribution system. Switchgear is currently widely used in power grids of various voltage levels, and plays a very important role in ensuring the safe and stable operation of the power system. At the same time, as switchgear is widely used in power grids, it has also experienced many failures in the actual operation process, causing considerable economic losses and bringing great safety hazards to people's lives and industrial production. During operation, various contact parts in the switch cabinet are prone to loose contact due to aging, poor contact, and vibration during operation, which leads to increased resistance in various contact parts (such as cable heads and busbar nodes). When installing cable terminal connectors, the bolts at the wiring terminals are loose or in poor contact due to improper installation. When a large current flows through the contact parts, a large amount of heat will be generated, causing severe local heating. If not handled in time, it is easy to cause various power system failures or even accidents.

[0003] In order to ensure the safe and stable operation of the switch cabinet, various contact parts and other necessary temperature measurement points in the switch cabinet must be monitored in real time, so as to detect problems in time and prevent serious power accidents caused by heat.

[0004] At present, the temperature measurement of power equipment mainly adopts infrared temperature measurement, optical fiber temperature measurement and other technologies to detect the temperature rise status of equipment. The commonly used temperature measurement methods of switch cabinets are mainly infrared thermal imaging, CT temperature measurement and surface acoustic wave. The commonly used technology for cable joint temperature detection is through active wired and active wireless temperature measurement devices. Active wireless temperature measurement mainly refers to the combination of temperature sensors and wireless communication technology. The temperature sensor measures the heating element and transmits the measured temperature signal to the terminal monitoring device through the wireless chip. The terminal monitoring device receives the temperature signal and converts it into temperature information for display. The active wireless temperature measurement method can directly monitor the temperature change of the cable joint. It has the advantages of low cost, no wiring, good stability and wireless transmission of temperature signals.

[0005] However, the above-mentioned various power equipment temperature measurement technologies have the following disadvantages: 1. Infrared temperature measurement technology has great limitations because infrared rays have weak penetration ability and different materials, temperature and other environmental factors have a great impact on the emissivity. It cannot accurately display the internal temperature of high-voltage electrical equipment (such as the internal structure of the 10kV central cabinet) in the form of thermal images. For cable joints, only the outer surface temperature of the cable joint can be measured, and the actual connection point temperature cannot be measured inside the joint.

[0006] 2. The optical fiber temperature measurement system has a complex structure, high technical requirements, and many equipment connection lines. It is difficult to wire in the cabinet and the cost is high. At the same time, the optical fiber is easy to bend, easy to break, not resistant to high temperature, and the insulation is easily reduced after dust accumulation. It is not easy to be widely used in voltage levels of 110kV and below.

[0007] 3. PT temperature measurement cannot accurately reflect the temperature, and the deployment cost is high.

[0008] 4. Active wired active devices have a lot of cables, which are troublesome to wire in the limited space of the switch cabinet and will bring secondary safety hazards.

[0009] 5. The temperature sensor in the active wireless temperature measurement device needs a battery or a small CT (current transformer) to work. The power supply of a small CT usually depends on the current passing through the CT. If the current is too small, it may not provide enough power for the sensor, causing the sensor to fail to work properly. The long-term stability of the small CT power supply may be affected by factors such as current fluctuations and temperature changes, causing the sensor performance to deteriorate or fail.

[0010] Based on this, the present invention is proposed. Summary of the invention

[0011] The purpose of the present invention is to provide a passive wireless temperature measurement system for switch cabinets based on RFID, which can accurately detect the internal temperature without the need for wiring and will not bring secondary safety hazards. It is a simple, efficient, safe and accurate temperature measurement system.

[0012] To achieve the above object, the present invention provides the following technical solutions: A passive wireless temperature measurement system for a switch cabinet based on RFID, comprising: an RFID temperature measurement sensor, a built-in RFID electronic tag, a plurality of which are arranged on monitoring nodes inside the switch cabinet, for obtaining the temperature of the monitoring node and storing the temperature data in the RFID electronic tag; a reader / writer, which transmits data with the RFID electronic tag in the RFID temperature measurement sensor through a wireless radio frequency signal, and is at least used to read the temperature data in the RFID electronic tag; a data transmission device, which is used for data transmission between the reader / writer and a cloud server; a cloud server, which is used to process and analyze the temperature data obtained from the reader / writer; at least comprising: the cloud server processes and analyzes the temperature data as follows: compares the temperature data with a pre-set warning threshold and an abnormal threshold, marks the monitoring node whose temperature exceeds the warning threshold but does not exceed the abnormal threshold as a warning node, marks the monitoring node whose temperature exceeds the abnormal threshold as an abnormal node, distinguishes, displays and reminds the warning node and the abnormal node.

[0013] Furthermore, the cloud server processes and analyzes the temperature data obtained from the reader and writer and also includes: Conduct statistical analysis on the recorded real-time temperature data; Give the highest and lowest temperatures of each device; Give the temperature trend over a period of time.

[0014] Furthermore, the reader / writer includes an RFID wireless radio frequency module for generating RFID wireless radio frequency signals; a radio frequency signal transmission device for transmitting the RFID wireless radio frequency signals into the air by radiating electromagnetic waves; the RFID electronic tag of the RFID temperature sensor obtains energy from the electromagnetic waves emitted by the reader / writer, converts it into electrical energy, provides power supply voltage for the circuit inside the RFID temperature sensor, and starts the internal circuit to work.

[0015] Furthermore, the RFID temperature sensor includes: a sensor, a core control module, a memory, a modulation and demodulation module, an automatic tuning module and a clock module; the sensor is used to detect the temperature of the monitoring node; the modulation and demodulation module is used to modulate the acquired temperature analog signal or demodulate the modulated signal; the automatic tuning module is used to automatically calibrate the temperature reading; the memory is used to store temperature data; the clock module is used to generate time information and send it to the modulation and demodulation module and / or the sensor; the core control module is used to control the sensor to collect temperature, control the modulation and demodulation module to modulate or demodulate the signal, control the memory to store the signal, and control the automatic tuning module to calibrate the temperature reading.

[0016] In order to ensure the stable operation of the RFID temperature sensor, the present invention provides a preferred solution, wherein the RFID temperature sensor also includes: a power management module, which is used to convert the power supply voltage provided by the RFID electronic tag into a stable output voltage required by the internal circuit of the RFID temperature sensor, and monitor the power supply voltage status.

[0017] In order to improve the anti-interference performance of the entire system, the present invention provides a preferred solution, wherein the radio frequency signal transmission device adopts a circularly polarized antenna.

[0018] Compared with the prior art, the above technical solution has the following advantages: The RFID-based passive wireless temperature measurement system for switch cabinets in this embodiment arranges RFID temperature measurement sensors with built-in RFID electronic tags at various monitoring nodes inside the switch cabinet at the power equipment end, such as the bolts and nuts of the cable terminal connectors, to accurately detect the internal temperature, and wirelessly transmit temperature data to the reader / writer through RFID wireless radio frequency identification technology. No additional power supply or wiring is required, achieving "passive wireless" and no secondary safety hazards are caused. It is a simple, efficient, safe and accurate temperature measurement system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0020] Figure 1 This is a schematic diagram of a passive wireless temperature measurement system for a switch cabinet based on RFID according to Embodiment 1 of the present invention; Figure 2 This is a diagram of the internal circuit module of the RFID temperature measurement sensor in the RFID-based switch cabinet passive wireless temperature measurement system in Example 2 of the present invention; Figure 3 This is a schematic diagram of a switch cabinet terminal in a switch cabinet passive wireless temperature measurement system based on RFID according to Embodiment 3 of the present invention; Figure 4 This is a flow chart of the cloud server processing and analyzing temperature data in the RFID-based passive wireless temperature measurement system for a switch cabinet in Example 4 of the present invention.

[0021] The figure numbers are as follows: switch cabinet 100, monitoring node 110, RFID temperature sensor 210, sensor 211, core control module 212, memory 213, modulation and demodulation module 214, automatic tuning module 215, clock module 216, power management module 217, reader 220, radio frequency signal transmission device 221, antenna 221', local display terminal 230, data transmission device 240, cloud server 300. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Example 1 Please refer to Figure 1, this embodiment provides a passive wireless temperature measurement system for switch cabinets based on RFID, which is mainly composed of an RFID temperature measurement sensor, a reader / writer, a data transmission device and a cloud server. The passive wireless temperature measurement system of this embodiment can be applied to the temperature measurement and temperature monitoring of power equipment. Taking the application in the switch cabinet as an example, a monitoring node is set in each switch cabinet to detect and monitor the temperature of each monitoring node. An RFID temperature measurement sensor is installed at each monitoring node to obtain the temperature of the monitoring node. The RFID temperature measurement sensor has an RFID electronic tag built in, and the acquired temperature data is stored in the RFID electronic tag. Then a reader / writer is set outside the switch cabinet. The reader / writer and the RFID electronic tag in the RFID temperature measurement sensor transmit data through wireless radio frequency signals. An RFID wireless radio frequency module and a radio frequency signal transmission device are set inside the reader / writer. The RFID wireless radio frequency module can generate an RFID wireless radio frequency signal, and then the RFID wireless radio frequency signal is transmitted into the air in the form of radiated electromagnetic waves through the radio frequency signal transmission device. The RFID electronic tag in the RFID temperature measurement sensor obtains energy from the electromagnetic waves emitted by the reader / writer, converts it into electrical energy, provides power supply voltage for the circuit inside the RFID temperature measurement sensor, and starts the internal circuit to work. Under the power supply, the RFID temperature sensor collects the temperature of the monitoring node, and then transmits the collected temperature data to the radio frequency signal transmission device through the RFID electronic tag, and then transmits it to the reader / writer by the radio frequency signal transmission device, so that the reader / writer completes the reading of the temperature data in the RFID electronic tag. Of course, if the RFID temperature sensor is required to collect temperature data according to certain requirements (such as according to specific time or frequency), the reader / writer can put the instruction into the RFID wireless radio frequency signal and then write it into the RFID electronic tag. After the reader / writer obtains the temperature data, it uploads the temperature data to the cloud server through the data transmission device. The cloud server processes and analyzes the temperature data obtained from the reader / writer, and can realize the real-time upload of the monitored temperature data for the power supply network operation and maintenance personnel to check.

[0024] The RFID-based passive wireless temperature measurement system for switch cabinets in this embodiment arranges RFID temperature measurement sensors with built-in RFID electronic tags at various monitoring nodes inside the switch cabinet at the power equipment end, such as the bolts and nuts of the cable terminal connectors. It can accurately detect the internal temperature of power equipment and cable connectors, and wirelessly transmit temperature data to the reader / writer through RFID wireless radio frequency identification technology. It does not require additional power supply or wiring in the power equipment, realizing "passive wireless" and will not cause secondary safety hazards. It is a simple, efficient, safe and accurate temperature measurement system.

[0025] The passive wireless temperature measurement system for switch cabinets based on RFID in this embodiment uses the fastening nut of the cable joint as a carrier, can perform wireless passive online real-time temperature measurement on the cable joint, and uses RFID wireless radio frequency identification wireless communication technology for data transmission, to achieve contact temperature measurement between the wireless passive RFID temperature measurement sensor and the conductor at the connection point, thereby ensuring the accuracy of the measurement, and effectively solving the problem of the sensor affecting the electrical performance of the cable joint inside the cable joint, thus reducing the actual loss caused by loose bolts or poor contact of the cable joint. At the same time, it avoids the secondary safety hazards brought by active and wired temperature monitoring solutions, and uploads the temperature data collected by the terminal equipment to the cloud server / data concentrator. The power grid operation and maintenance personnel can view the real-time temperature status of the switch cabinet in real time through the corresponding display terminal, which improves the work efficiency of the inspection and realizes the intelligent management of the switch cabinet.

[0026] Example 2 This embodiment further provides a more preferred implementation method based on the embodiment 1. In it, a detailed implementation method is provided for the internal circuit module composition and principle of the RFID temperature sensor.

[0027] Please refer to Figure 2 , RFID temperature sensor is mainly composed of sensor, core control module, memory, modulation and demodulation module, automatic tuning module, clock module and power management module. The sensor is mainly used to detect the temperature of the monitoring node. The modulation and demodulation module is mainly used to modulate the acquired temperature analog signal or demodulate the modulated signal. The automatic tuning module is mainly used to automatically calibrate the temperature reading. The memory is mainly used to store temperature data. The clock module is mainly used to generate time information and send it to the modulation and demodulation module and the sensor. The core control module is mainly used to control the sensor to collect temperature, control the modulation and demodulation module to modulate or demodulate the signal, control the memory to store the signal, and control the automatic tuning module to calibrate the temperature reading. The power management module is mainly used to convert the power supply voltage provided by the RFID electronic tag into the stable output voltage required by the internal circuit of the RFID temperature sensor, and monitor the power supply voltage status.

[0028] The RFID temperature sensor of this embodiment, combined with the passive UHF RFID electronic tag, can achieve the characteristics of wireless temperature measurement without batteries. The power management module design uses UHF radio wave energy collection technology to collect 840MHz to 960MHz RF electromagnetic wave energy as the chip power supply, without external power supply, thus truly realizing "passive wireless". It has good measurement accuracy and can withstand high temperatures, which can meet the user's monitoring product requirements of low cost, miniaturization, embeddability, passive wireless, and maintenance-free.

[0029] According to the actual needs of switch cabinet temperature measurement, the reader can select an RFID reader with an operating frequency of 902-928MHz. The working voltage of the reader is DC 12-36V and can work at -20℃-75℃. With a 5dBi circular polarization antenna and an RFID temperature sensor, the temperature measurement distance can reach 10 meters. At the same time, the reader has RS485 and RJ45 data interfaces. The reader can transmit data in a strong electromagnetic interference environment.

[0030] Example 3 This embodiment further provides a more preferred implementation method based on Embodiment 2, wherein the specific selection of the radio frequency signal transmission device is given, the specific form of the temperature sensitive element of the RFID temperature sensor is provided, and the specific arrangement scheme and form of the reader / writer and the radio frequency signal transmission device are also given.

[0031] This embodiment provides RFID temperature sensors in the form of multiple temperature sensitive elements, which can be any one of tuning fork type, busbar clamp type, plum blossom contact type or plug type. During the actual installation process, the temperature measurement system can be optimized according to the actual layout and related requirements. The first is to determine the form of the RFID temperature sensor, and determine its form according to the actual temperature measurement point (monitoring node). Generally, a tuning fork type can be selected at the busbar connection point, and a busbar clamp type can be selected on the busbar. The tuning fork type is suitable for temperature measurement at the busbar connection point, the plum blossom contact type is suitable for temperature measurement at the contacts of circuit breakers, etc., and the plug type is suitable for temperature measurement at the plug of the ring network cabinet.

[0032] The radio frequency signal transmission device adopts a circularly polarized antenna, which has an antenna box. A magnet is set in the antenna box and installed on the inner wall of the switch cabinet by magnetic attraction. The gain value of the antenna is selected according to actual needs. In ordinary places, a 5dBi circularly polarized antenna is sufficient. The 12dBi circularly polarized antenna can be used as a general far-field antenna for UHF band RFID applications, with the characteristics of high gain and low standing wave. It can be easily used in UHF band RFID occasions such as intelligent transportation, intelligent parking management, access control, warehousing, logistics, etc. In short, compared with ordinary antennas, the use of circularly polarized antennas has the advantages of strong anti-interference ability, wide radiation range and miniaturization.

[0033] Please refer to Figure 3, a practical arrangement of the temperature measurement system is given. For the situation where the switch cabinets are close to each other, in order to improve the cost performance of the system, a four-port reader can be used, that is, it has four antenna interfaces, and one reader monitors the temperature data of four switch cabinets. For the situation where the switch cabinet is relatively isolated, a single-port reader can be used, that is, it has one antenna port, and one reader monitors the temperature data of one switch cabinet. The reader can be hung on the wall outside the switch cabinet or placed directly inside the switch cabinet. After determining the number and installation location of the reader, it is necessary to determine the installation location and number of antennas according to the actual situation. The antenna is generally placed on the cabinet wall inside the switch cabinet.

[0034] The local display terminal of the temperature measurement system of this embodiment is set in the switch cabinet, and is connected to the reader for displaying the temperature data obtained by the reader. The data transmission device adopts RS485 communication device or DTU wireless communication device. The temperature data in the reader and the data transmission between the terminal and the cloud can be displayed directly on the local terminal by using RS485 communication device if the temperature data needs to be displayed on the local terminal; if it needs to be transmitted to the cloud, it can be transmitted by using RS485 communication device or DTU wireless communication device. In general, it is recommended to use RS485. For switch cabinets far away from the central area and relatively isolated, DTU transmission can be used.

[0035] Example 4 This embodiment further provides a more preferred implementation mode based on Embodiment 2. Please refer to Figure 4 In this embodiment, the cloud server mainly processes and analyzes the temperature data as follows: S1 records the real-time temperature data of each monitoring node in each power equipment; S2 determines whether each temperature data exceeds a preset warning threshold; S3 determines whether each temperature data exceeds a preset abnormal threshold; S4 marks the monitoring nodes whose temperature exceeds the warning threshold but does not exceed the abnormal threshold as warning nodes; S5 marks the monitoring nodes whose temperature exceeds the abnormal threshold as abnormal nodes; S6 distinguishes and displays warning nodes and abnormal nodes for reminder; S7 performs statistical analysis on the recorded real-time temperature data; S8 gives the maximum and minimum temperatures of each device; S9 shows the temperature trend over a period of time.

[0036] In the monitoring platform of the cloud server of this embodiment, warning nodes and abnormal nodes are distinguished, and the monitoring nodes with rising temperature can be identified as being transformed into abnormal states, and early warnings can be issued to allow relevant maintenance personnel to intervene in advance, thereby reducing safety hazards and preventing them from happening.

[0037] The temperature measurement implementation method at the elbow cable head of the ring network cabinet in this embodiment is as follows: an RFID temperature sensor is installed at the elbow cable head in the ring network cabinet to collect the temperature data of the elbow cable head in real time. According to the three-phase form of the cable ABC, an RFID temperature sensor is configured for each phase of the cable to collect the temperature of the cable joint of this phase. The cable temperature data collected by the RFID temperature sensor is transmitted to the reader / writer for processing through RFID technology, and the cable joint temperature data obtained by the reader / writer is then transmitted to the local monitoring terminal. At the same time, the local distribution network automation terminal DTU is connected to the distribution automation master station system through optical fiber Ethernet or wirelessly. The communication protocol adopts IEC104 or IEC101 protocol according to the requirements of the master station, thereby realizing remote monitoring and early warning of the master station. The temperature measurement system was piloted and the indoor temperature remained stable. The temperature of the cable joint was related to the line load and the indoor temperature. According to the three-phase temperature curve of the line cable joints continuously measured from November 1 to November 21, 2024, the temperature basically remained between 20 and 30°C, and the three-phase temperature remained basically balanced, and there was no alarm of over-high cable joint temperature.

[0038] Through field measurements and comparison with the surface acoustic wave (SAW) and CT-type power supply wireless temperature measurement solutions that have been used in other substations, the RFID-based switch cabinet passive wireless temperature measurement system of the present invention has strong advantages in temperature measurement accuracy, stability, data communication, maintenance-free, etc., specifically as follows: (1) The temperature measurement system of the present invention can be charged by the electromagnetic wave energy emitted by the reader. During each temperature measurement, the temperature measurement system obtains energy through the coupling between the RFID and the electromagnetic field and activates the temperature measurement system circuit to obtain the temperature of the measurement site. Therefore, the temperature measurement system of the present invention can be maintenance-free, greatly reducing the cost of manual disassembly and assembly.

[0039] (2) The RFID temperature measurement sensor of the temperature measurement system of the present invention has various shapes. According to different temperature measurement locations in the switch cabinet, it can be divided into tuning fork type, busbar clip type, plum blossom contact type, etc., so it can be widely used in various locations and temperature measurement scenarios of the switch cabinet.

[0040] (3) The temperature measurement system of the present invention can aggregate the temperature measurement data to the monitoring platform of the cloud server through the reader / writer, which is convenient for unified management by operation and maintenance personnel. It is easy to deploy and efficient in data acquisition. The deployment strategy can be flexibly changed according to the placement of the on-site switch cabinets, achieving a good balance in applicability, cost control, and deployment difficulty.

[0041] A person skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium, and when the program is executed, it can include the processes of the above-mentioned embodiments of the methods. The storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0042] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0043] The above-described embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A passive wireless temperature measurement system for switch cabinet based on RFID, characterized in that: include: RFID temperature sensor, with built-in RFID electronic tag, is provided in several pieces and arranged on the monitoring node inside the switch cabinet to obtain the temperature of the monitoring node and store the temperature data in the RFID electronic tag; A reader / writer, which transmits data with the RFID electronic tag in the RFID temperature sensor through a wireless radio frequency signal, and is at least used to read the temperature data in the RFID electronic tag; Data transmission device, used for data transmission between the reader and the cloud server; The cloud server is used to process and analyze the temperature data obtained from the reader; at least including: the cloud server processes and analyzes the temperature data as follows: compares the temperature data with the pre-set warning threshold and abnormal threshold, marks the monitoring nodes whose temperature exceeds the warning threshold but does not exceed the abnormal threshold as warning nodes, marks the monitoring nodes whose temperature exceeds the abnormal threshold as abnormal nodes, distinguishes and displays and reminds the warning nodes and abnormal nodes.

2. The RFID-based passive wireless temperature measurement system for switch cabinets according to claim 1 is characterized in that: The cloud server processes and analyzes the temperature data obtained from the reader and writer and also includes: Conduct statistical analysis on the recorded real-time temperature data; Give the highest and lowest temperatures of each device; Give the temperature trend over a period of time.

3. The RFID-based passive wireless temperature measurement system for switch cabinets according to claim 1 is characterized in that: The reader / writer includes an RFID wireless radio frequency module for generating RFID wireless radio frequency signals; a radio frequency signal transmission device for transmitting the RFID wireless radio frequency signals into the air by radiating electromagnetic waves; the RFID electronic tag of the RFID temperature sensor obtains energy from the electromagnetic waves emitted by the reader / writer, converts it into electrical energy, provides power supply voltage for the circuit inside the RFID temperature sensor, and starts the internal circuit to work.

4. The RFID-based passive wireless temperature measurement system for switch cabinets according to claim 3 is characterized in that: The RFID temperature sensor includes: a sensor, a core control module, a memory, a modulation and demodulation module, an automatic tuning module and a clock module; the sensor is used to detect the temperature of the monitoring node; the modulation and demodulation module is used to modulate the acquired temperature analog signal or demodulate the modulated signal; the automatic tuning module is used to automatically calibrate the temperature reading; the memory is used to store temperature data; the clock module is used to generate time information and send it to the modulation and demodulation module and / or the sensor; the core control module is used to control the sensor to collect temperature, control the modulation and demodulation module to modulate or demodulate the signal, control the memory to store the signal, and control the automatic tuning module to calibrate the temperature reading.

5. The RFID-based passive wireless temperature measurement system for switch cabinets according to claim 4 is characterized in that: The RFID temperature sensor also includes: a power management module, which is used to convert the power supply voltage provided by the RFID electronic tag into a stable output voltage required by the internal circuit of the RFID temperature sensor, and monitor the power supply voltage state.

6. The RFID-based passive wireless temperature measurement system for switch cabinets according to claim 3 is characterized in that: The radio frequency signal transmission device adopts a circular polarization antenna.

7. According to the RFID-based passive wireless temperature measurement system for switch cabinets according to claim 3 or 6, the radio frequency signal transmission device is installed on the inner wall of the switch cabinet.

8. The RFID-based passive wireless temperature measurement system for switch cabinets according to claim 1 is characterized in that: The shape of the temperature sensitive element of the RFID temperature sensor is any one of a tuning fork type, a busbar clip type, a plum blossom contact type or a plug type.

9. The RFID-based switch cabinet passive wireless temperature measurement system according to claim 1, characterized in that: It also includes a local display terminal, which is arranged at the end of the power equipment and is connected to the reader for communication and is used to display the temperature data obtained by the reader.

10. The RFID-based passive wireless temperature measurement system for switch cabinets according to claim 1, characterized in that: The data transmission device adopts RS485 communication device or DTU wireless communication equipment.

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