Explosion-proof electric appliance overcurrent and temperature rise wireless test system and method based on ultrasonic communication

Abstract

The invention provides an explosion-proof electric appliance overcurrent and temperature rise wireless test system and method based on ultrasonic communication, and relates to the technical field of explosion-proof electric appliance temperature rise tests. The system comprises a temperature acquisition device, an ultrasonic through-wall communication device, an overcurrent protection time acquisition device, a data receiving and storing device and a digital display operation table, wherein the output end of the temperature acquisition device is connected with the input end of the ultrasonic through-wall communication device, the output end of the ultrasonic through-wall communication device is connected with the input end of the data receiving and storing device through wireless communication, and the output end of the overcurrent protection time acquisition device is connected with the input end of the data receiving and storing device; and the data receiving memory is connected with the digital display console through a bidirectional data channel. According to the invention, the anti-interference performance and the test precision of temperature measurement are enhanced, and the multi-node distributed monitoring capability is provided through multi-channel data transmission, so that the overall efficiency of the internal temperature and overcurrent protection monitoring of the explosion-proof electric appliance is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of temperature rise testing technology for explosion-proof electrical appliances, and in particular to a wireless testing system and method for overcurrent and temperature rise of explosion-proof electrical appliances based on ultrasonic communication. Background Technology

[0002] In high-risk industrial sectors such as petrochemicals, underground mining, and dusty environments, the explosive atmospheres underground necessitate that electrical equipment possess certain explosion-proof properties. Explosion-proof electrical equipment is the core device ensuring safe operation in flammable and explosive environments. It achieves dual protection through a high-strength metal casing and multiple sealing technologies: on the one hand, it prevents the leakage of potential electrical sparks, high temperatures, or explosive energy generated inside the equipment, avoiding the ignition of external flammable media; on the other hand, it withstands external explosive impacts, ensuring the structural integrity of the equipment under extreme operating conditions. However, while this sealed physical barrier enhances explosion-proof safety, it also severely hinders the dissipation of internal heat, leading to localized overheating during long-term operation. This can cause aging of insulation materials, degradation of electrical performance, and even become a trigger for secondary explosions. Therefore, both the IEC 60079 series of international standards and the GB 3836 series of national standards mandate that explosion-proof electrical equipment undergo temperature testing to ensure that its surface and internal temperatures remain below the safe threshold, eliminating the risk of thermal runaway at its source.

[0003] Currently, temperature detection for explosion-proof electrical appliances mainly relies on two types of methods: contact and non-contact. Contact temperature measurement methods, such as thermocouple methods or resistance temperature detectors (RTDs), have advantages such as mature technology, low cost, high accuracy (error controllable within ±0.5℃~±1℃), and the ability to directly acquire temperature data from key components. They are particularly suitable for nodes requiring precise monitoring, such as motor windings and wiring terminals. However, this method has significant limitations: sensor installation requires penetrating the explosion-proof enclosure, compromising structural sealing; wiring within complex electrical appliances is difficult, and multi-point deployment is inefficient; furthermore, it is susceptible to interference in strong electromagnetic environments, affecting the accuracy of signal acquisition. Non-contact temperature measurement methods, represented by infrared thermal imaging technology, achieve non-contact temperature measurement by capturing infrared radiation from the equipment surface. They have advantages such as fast response, no contact required, and full-field scanning capability, making them particularly suitable for screening hot spots on the enclosure. However, this method has the following obvious drawbacks: the high reflectivity of the metal casing of explosion-proof electrical appliances will interfere with the radiation signal, causing the measurement results to rely on emissivity correction and the accuracy to be limited (usually ±2℃~±5℃); more importantly, the sealed structure of the equipment completely blocks the direct observation of the internal components, making it impossible to obtain the true temperature of the core heat source such as power devices.

[0004] It is evident that both existing methods face severe challenges due to the unique physical structure of explosion-proof electrical appliances: contact temperature measurement methods require sacrificing equipment integrity, while non-contact methods struggle to penetrate metal barriers and effectively sense internal temperature conditions. This technical contradiction results in inefficient current testing processes, incomplete data coverage, and an inability to meet the standards' requirements for comprehensive verification of thermal stability.

[0005] In electrical design, overload protection mechanisms are the cornerstone of ensuring safety, maintaining equipment lifespan, and ensuring power grid stability. When the current exceeds the limit, the wires and components heat up rapidly due to Joule's law, enough to melt the insulation layer and ignite surrounding flammable materials, leading to an electrical fire. At the same time, conductor exposure due to insulation failure poses a fatal risk of electric shock, causing serious personal injury. For the equipment itself, continuous overcurrent can burn out precision electronic components, damage motor windings, accelerate mechanical wear, leading to complete equipment failure or a sharp drop in performance and lifespan, resulting in economic losses.

[0006] Therefore, developing new overcurrent protection and temperature monitoring technologies that balance measurement accuracy, structural compatibility, and operational efficiency has become an urgent need to improve the intrinsic safety level of explosion-proof electrical appliances. Summary of the Invention

[0007] To address the shortcomings of the existing technologies, this invention proposes a wireless testing system and method for overcurrent and temperature rise of explosion-proof electrical appliances based on ultrasonic communication, aiming to improve the overall efficiency of monitoring internal temperature and overcurrent protection of explosion-proof electrical appliances.

[0008] On one hand, this invention proposes a wireless testing system for overcurrent and temperature rise of explosion-proof electrical appliances based on ultrasonic communication. The system includes:

[0009] A temperature acquisition device is used to acquire the internal temperature of explosion-proof electrical appliances and convert the temperature into a digital temperature signal;

[0010] An ultrasonic through-wall communication device is used to receive the digital temperature signal and modulate it into an ultrasonic signal, which is then wirelessly transmitted through the explosion-proof electrical enclosure. Simultaneously, the device receives and demodulates the ultrasonic signal and temperature data outside the explosion-proof electrical enclosure.

[0011] An overcurrent protection time acquisition device is used to acquire the input current of explosion-proof electrical appliances and record the overcurrent protection time of the explosion-proof electrical appliances;

[0012] A data receiving and storage device is used to receive, decode, and store the temperature data, the input current of the explosion-proof electrical appliance, and the overcurrent protection time of the explosion-proof electrical appliance;

[0013] A digital display control panel is used to provide a human-machine interface and perform at least one of the following functions: setting test parameters, controlling the test process, and real-time data display and processing.

[0014] The output of the temperature acquisition device is connected to the input of the ultrasonic through-wall communication device. The output of the ultrasonic through-wall communication device and the input of the data receiving and storage device are connected wirelessly. The output of the overcurrent protection time acquisition device is connected to the input of the data receiving and storage device. The data receiving and storage device is connected to the digital display console through a bidirectional data channel.

[0015] Furthermore, the temperature acquisition device includes: a T-type thermocouple and a data transmission unit; wherein the test end of the T-type thermocouple is fixed to the test point inside the explosion-proof electrical appliance, and is used to measure the temperature of the test point; the T-type thermocouple transmits the measured temperature to the data transmission unit through a wire connection; the data transmission unit is used to convert the received analog temperature signal into a digital temperature signal, and modulate the digital temperature signal at a preset modulation frequency through magnetic coupling communication, and transmit the obtained analog modulation signal to an ultrasonic through-wall communication device.

[0016] Furthermore, the ultrasonic through-wall communication device includes: a transmitting end disposed inside the explosion-proof electrical appliance and a receiving end disposed on the outer shell of the explosion-proof electrical appliance;

[0017] The transmitting end includes: an electromagnetic signal acquisition module, a voltage follower, a signal amplifier, and an ultrasonic transducer;

[0018] The electromagnetic signal acquisition module receives the analog modulated signal, converts it into a digital signal using a digital signal converter, and modulates the digital signal at a specific frequency using a digital frequency synthesizer controlled by a microcontroller to generate a high-frequency analog signal, which is then transmitted to a voltage follower. The voltage follower buffers and performs impedance transformation on the high-frequency analog signal and transmits the output analog signal to a signal amplifier. The signal amplifier amplifies the received analog signal and transmits it to an ultrasonic transducer. The ultrasonic transducer converts the amplified analog signal into an ultrasonic signal and transmits it to the receiving end.

[0019] The receiving end includes: an ultrasonic receiving transducer, a preamplifier adaptive amplifier, a voltage follower, a voltage comparator, and a digital-to-analog converter;

[0020] The ultrasonic receiving transducer receives ultrasonic signals transmitted from the ultrasonic transmitting transducer and transmits them to a pre-adaptive amplifier; the pre-adaptive amplifier amplifies the received ultrasonic signals and transmits them to a voltage follower; the voltage follower buffers and performs impedance transformation on the amplified ultrasonic signals and transmits the output voltage signal to a voltage comparator; the voltage comparator compares the voltage signal with a reference voltage, shapes the voltage signal to generate a digital square wave signal, and transmits it to a digital-to-analog converter; the digital-to-analog converter converts the digital square wave signal into an analog signal as temperature data and transmits the temperature data to a data receiving and storage device.

[0021] Furthermore, both the ultrasonic transmitting transducer and the ultrasonic receiving transducer are oblique-type transducers; the ultrasonic transmitting surface or ultrasonic receiving surface of the oblique-type transducer is positioned at a predetermined angle to the normal of the metal wall of the explosion-proof electrical appliance, so that the ultrasonic wave propagates within the metal wall via a reflection path, thereby generating a horizontal offset between the exit point outside the metal wall and the incident point inside the metal wall; the reflection path is configured to overcome echo interference caused by direct penetration of the ultrasonic wave.

[0022] Furthermore, the overcurrent protection time acquisition device includes: a current transformer, an overcurrent protection recorder, and a signal transmitter; wherein the current transformer is used to acquire the input current of the explosion-proof electrical appliance and transmit it to the overcurrent protection recorder; the overcurrent protection recorder is used to start timing when the input current exceeds a threshold and stop timing when the explosion-proof electrical appliance triggers overcurrent protection action, thereby obtaining the overcurrent protection time and transmitting it to the signal transmitter; the signal transmitter is used to transmit the input current and overcurrent protection time to a data receiving and storage device.

[0023] Furthermore, the test circuit includes a voltage regulator and a high-current generator; wherein the input terminal of the voltage regulator is connected to the power grid, and the output terminal of the voltage regulator is connected to the input terminal of the high-current generator; the output terminal of the high-current generator is connected to the power input terminal of the explosion-proof electrical appliance under test, for providing an adjustable test current to the explosion-proof electrical appliance.

[0024] Furthermore, the data receiving and storage device includes a data receiver, an ambient temperature and humidity sensor, and a data storage device; wherein the data receiver is used to receive temperature data from the ultrasonic through-wall communication device and input current and overcurrent protection time from the overcurrent protection time acquisition device, and decode them to obtain the temperature, current, and overcurrent protection time of the explosion-proof electrical appliance, and transmit them to the data storage device; the ambient temperature and humidity sensor is used to collect and monitor the ambient temperature and humidity of the laboratory in real time and transmit them to the data storage device; the data storage device is used to store the temperature, current, and overcurrent protection time of the explosion-proof electrical appliance, as well as the ambient temperature and humidity of the laboratory, and transmit data to the digital display operating console through a data transmission channel; when the ambient temperature or humidity deviates from the set range, the data storage device controls the laboratory's constant temperature and humidity device to start or stop through commands.

[0025] Furthermore, the digital display control panel includes: an internal host, a touch screen display, a current generator, a temperature abnormality alarm unit, an electrical parameter testing unit, and a regulated power supply;

[0026] The internal host interacts with the touch screen via an internal bus, receiving commands and displaying data; the internal host controls the output of the current generator according to the received commands; the internal host receives feedback signals from the electrical parameter testing unit for closed-loop control; the internal host monitors the status of the temperature anomaly alarm unit and triggers protection actions; the internal host is connected to a data receiving and storage device via a bidirectional data channel.

[0027] The touch screen is used to provide a human-machine interface, allowing operators to set parameters, switch functions and start / stop tests via touch, and display system status, temperature rise detection test parameters and overcurrent protection test parameters in real time.

[0028] The current generator is used to generate a test current of the required magnitude and waveform according to the instructions of the internal host, and apply it to the explosion-proof electrical appliance under test through the test circuit.

[0029] The electrical parameter testing unit is used to monitor the test voltage and test current in the test circuit in real time and transmit them to the internal host.

[0030] The temperature anomaly alarm unit is used to receive temperature data and transmit it to the internal host. When the temperature data is detected to exceed the safety threshold, it triggers an audible and visual alarm. At the same time, it sends a power-off signal to the test circuit to cut off the test current.

[0031] The regulated power supply is connected to the power grid and is used to power the touch screen, current generator, electrical parameter testing unit, and temperature abnormality alarm unit.

[0032] Furthermore, the electrical parameter testing unit includes: a passive high-precision voltage transformer and a passive high-precision current transformer; wherein the passive high-precision voltage transformer is connected in parallel to the power input terminal of the test circuit for real-time monitoring of the test voltage of the test circuit; and the passive high-precision current transformer is connected in series in the test circuit for real-time monitoring of the test current of the test circuit.

[0033] The temperature anomaly alarm unit includes an alarm chip and a speaker. The alarm chip is configured to drive the speaker to emit an alarm sound and generate a power-off signal when the temperature exceeds a safety threshold.

[0034] On the other hand, this invention proposes a wireless testing method for overcurrent and temperature rise of explosion-proof electrical appliances based on ultrasonic communication, which is implemented using the aforementioned wireless testing system for overcurrent and temperature rise of explosion-proof electrical appliances based on ultrasonic communication. The method includes the following steps:

[0035] The explosion-proof electrical appliance under test is connected in series to the test circuit, and the installation and debugging of the wireless test system for overcurrent and temperature rise of the explosion-proof electrical appliance based on ultrasonic communication is completed on the explosion-proof electrical appliance under test.

[0036] Set the temperature rise test parameters using the digital display control panel, increase the current in the test circuit to the set target value, and start the temperature rise test.

[0037] The process of the temperature rise detection test includes:

[0038] The temperature data inside the explosion-proof electrical appliance and the ambient temperature and humidity data are collected in real time according to the preset interval, and the temperature data inside the explosion-proof electrical appliance and the ambient temperature change data are calculated.

[0039] When the ambient temperature change is greater than 2°C, the laboratory's temperature and humidity control system is activated; and when the temperature change is less than 1°C, the laboratory's temperature and humidity control system is shut down.

[0040] When the temperature data changes by more than 3°C, the temperature rise test of the explosion-proof electrical appliance shall be stopped.

[0041] When the ambient temperature change is less than 3℃, and the temperature change data of all temperature measuring points inside the explosion-proof electrical appliance are less than 1℃ for two consecutive measurements, it is determined that the temperature rise of the explosion-proof electrical appliance has reached a stable state, and the temperature rise test ends.

[0042] After the temperature rise test is completed, and the surface and internal temperatures of the explosion-proof electrical appliance have cooled to room temperature, the overcurrent protection test is started.

[0043] The process of the overcurrent protection test is as follows:

[0044] Measure the internal resistance of the explosion-proof electrical appliance, and calculate the target test voltage required for the overcurrent protection test based on the preset target overcurrent protection current value and the internal resistance.

[0045] The target test voltage is applied instantaneously to the test circuit, causing the current in the test circuit to instantaneously reach the target overcurrent value;

[0046] The overcurrent protection time acquisition device automatically monitors the test current and starts timing when the test current exceeds the threshold, and stops timing when the explosion-proof electrical appliance triggers the overcurrent protection action, thus obtaining the overcurrent protection time and ending the overcurrent protection test.

[0047] During the temperature rise detection test and overcurrent protection test, all test data of the temperature rise detection test and overcurrent protection test are saved in real time.

[0048] The beneficial effects of adopting the above technical solution are as follows:

[0049] This invention effectively overcomes the technical bottlenecks commonly found in traditional wired testing methods, such as cumbersome operation, limited accuracy, and difficulties in real-time data transmission. It also solves the technical challenge of wireless communication technology being unable to transmit data through thick metal walls. This significantly improves the spatial deployment flexibility of the testing device, enhances the anti-interference performance and testing accuracy of temperature measurement, and provides multi-node distributed monitoring capabilities through multi-channel data transmission, thereby greatly improving the overall efficiency of monitoring the internal temperature and overcurrent protection of explosion-proof electrical appliances.

[0050] Furthermore, this invention significantly saves testing time and economic costs, substantially reduces power consumption, and provides solid technical support for the research and development of new explosion-proof electrical products. This achievement helps promote the standardization and intelligent transformation of the inspection and testing process for explosion-proof electrical products, and has positive significance for the sustainable and healthy development of the testing and inspection field and the explosion-proof electrical industry. Attached Figure Description

[0051] Figure 1 This is a structural diagram of a wireless testing system for overcurrent and temperature rise of explosion-proof electrical appliances based on ultrasonic communication in this embodiment;

[0052] Figure 2 This is a schematic diagram illustrating the ultrasonic thick metal wall communication principle in this embodiment;

[0053] Figure 3 This is a schematic diagram of the overcurrent protection time acquisition device in this embodiment;

[0054] Figure 4 This is a schematic diagram of the data receiving and storage device in this embodiment;

[0055] Figure 5 This is a schematic diagram of the digital display control panel in this embodiment;

[0056] Figure 6 This is a flowchart of the closed-loop adjustment process for the control current of the electrical parameter unit in this embodiment;

[0057] Figure 7 This is a flowchart illustrating the temperature test completion determination process in this embodiment.

[0058] Figure 8 This is a flowchart of a wireless testing method for overcurrent and temperature rise of explosion-proof electrical appliances based on ultrasonic communication in this embodiment. Detailed Implementation

[0059] To facilitate understanding of this application, specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments. The following embodiments are illustrative of the invention but are not intended to limit its scope. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0060] Example 1

[0061] This embodiment presents a wireless testing system for overcurrent and temperature rise of explosion-proof electrical appliances based on ultrasonic communication, such as... Figure 1 As shown, the system includes:

[0062] A temperature acquisition device is used to acquire the internal temperature of explosion-proof electrical appliances and convert the temperature into a digital temperature signal;

[0063] An ultrasonic through-wall communication device is used to receive the digital temperature signal and modulate it into an ultrasonic signal, which is then wirelessly transmitted through the explosion-proof electrical enclosure. Simultaneously, the device receives and demodulates the ultrasonic signal and temperature data outside the explosion-proof electrical enclosure.

[0064] An overcurrent protection time acquisition device is used to acquire the input current of explosion-proof electrical appliances and record the overcurrent protection time of the explosion-proof electrical appliances;

[0065] A data receiving and storage device is used to receive, decode, and store the temperature data, the input current of the explosion-proof electrical appliance, and the overcurrent protection time of the explosion-proof electrical appliance;

[0066] A digital display control panel is used to provide a human-machine interface and perform at least one of the following functions: setting test parameters, controlling the test process, and real-time data display and processing.

[0067] The output of the temperature acquisition device is connected to the input of the ultrasonic through-wall communication device. The output of the ultrasonic through-wall communication device and the input of the data receiving and storage device are connected wirelessly. The output of the overcurrent protection time acquisition device is connected to the input of the data receiving and storage device. The data receiving and storage device is connected to the digital display console through a bidirectional data channel.

[0068] In this embodiment, the data receiving and storage unit is connected to the digital display console via a customized bidirectional data channel. The system uses thermocouples to collect the temperature at the test points, transmits the data wirelessly via ultrasonic signals, and simultaneously uses a current transformer to measure the overcurrent protection time of the explosion-proof electrical appliances. The data is then further processed and displayed, enabling wireless testing of the electrical overcurrent protection and temperature rise of the explosion-proof electrical appliances.

[0069] The temperature acquisition device includes a T-type thermocouple and a data transmission unit. The test end of the T-type thermocouple is fixed inside the explosion-proof electrical appliance at the test point to measure the temperature of the test point. The T-type thermocouple transmits the measured temperature to the data transmission unit via a wire connection. The data transmission unit converts the received analog temperature signal into a digital temperature signal, modulates the digital temperature signal at a preset modulation frequency via magnetic coupling communication, and transmits the resulting analog modulated signal to an ultrasonic through-wall communication device.

[0070] In this embodiment, the temperature acquisition device is relatively simple to arrange. It can be magnetically attached to a suitable location inside the explosion-proof electrical appliance. The test end of the T-type thermocouple is fixed to the temperature testing position inside the explosion-proof electrical appliance with glue or tape, utilizing the Seebeck effect of the thermocouple to achieve point-to-point temperature measurement. The thermocouple is connected to the data transmission unit via wires. Through magnetic coupling, the microcontroller simulates a 125Hz modulated signal to send the acquired temperature data to the next-level ultrasonic through-wall communication device. The temperature measurement and transmission device is powered by a button battery, facilitating replacement and maintenance.

[0071] The ultrasonic through-wall communication device includes: a transmitting end disposed inside the explosion-proof electrical appliance and a receiving end disposed on the outer shell of the explosion-proof electrical appliance.

[0072] The transmitting end includes: an electromagnetic signal acquisition module, a voltage follower, a signal amplifier, and an ultrasonic transducer.

[0073] The electromagnetic signal acquisition module is used to receive the analog modulation signal, convert the analog modulation signal into a digital signal using a digital signal converter, and then use a microcontroller to control a digital frequency synthesizer to modulate the digital signal at a specific frequency to generate a high-frequency analog signal, which is then transmitted to a voltage follower. The voltage follower is used to buffer and impedance transform the high-frequency analog signal and transmit the output analog signal to a signal amplifier. The signal amplifier is used to amplify the received analog signal and transmit it to an ultrasonic transducer. The ultrasonic transducer is used to convert the amplified analog signal into an ultrasonic signal and transmit it to the receiving end.

[0074] The receiving end includes: an ultrasonic receiving transducer, a preamplifier adaptive amplifier, a voltage follower, a voltage comparator, and a digital-to-analog converter.

[0075] The ultrasonic receiving transducer receives ultrasonic signals transmitted from the ultrasonic transmitting transducer and transmits them to a pre-adaptive amplifier; the pre-adaptive amplifier amplifies the received ultrasonic signals and transmits them to a voltage follower; the voltage follower buffers and performs impedance transformation on the amplified ultrasonic signals and transmits the output voltage signal to a voltage comparator; the voltage comparator compares the voltage signal with a reference voltage, shapes the voltage signal to generate a digital square wave signal, and transmits it to a digital-to-analog converter; the digital-to-analog converter converts the digital square wave signal into an analog signal as temperature data and transmits the temperature data to a data receiving and storage device.

[0076] In this embodiment, as Figure 2 As shown, the ultrasonic through-wall communication device mainly consists of a transmitter adsorbed inside the explosion-proof electrical appliance and a receiver adsorbed on the outer shell. The transmitter includes an electromagnetic signal acquisition module, a digital signal converter (ADC), a signal amplifier, a voltage follower, and an ultrasonic transmitting transducer. The receiver includes a receiving transducer, a pre-adaptive amplifier (AGC), a voltage follower, a voltage comparator, and a digital-to-analog converter (DAC). The electromagnetic signal acquisition module uses an STM32 microcontroller to control a digital frequency synthesizer (DDS) to convert the electromagnetic signal into a digital signal. After modulation and decoding, the signal is transmitted from the ultrasonic transmitting transducer to the receiving transducer. After receiving the data, it is filtered, amplified, and the stored signal is sent to the next-stage data receiving and storage unit. Both parts of the ultrasonic through-wall communication device are powered by button batteries for easy replacement and maintenance.

[0077] Both the ultrasonic transmitting transducer and the ultrasonic receiving transducer are oblique-type transducers; the ultrasonic transmitting surface or ultrasonic receiving surface of the oblique-type transducer is positioned at a predetermined angle with the normal of the metal wall of the explosion-proof electrical appliance, so that the ultrasonic wave propagates in the metal wall through a reflection path, thereby generating a horizontal offset between the exit point outside the metal wall and the incident point inside the metal wall; the reflection path is configured to overcome the echo interference generated by the direct penetration of the ultrasonic wave.

[0078] In this embodiment, the ultrasonic through-wall communication device uses an oblique-type transducer to achieve wireless communication across a thick metal wall. The oblique-type probe overcomes echo interference and improves penetration capability by deflecting the reflection path.

[0079] The overcurrent protection time acquisition device includes: a current transformer, an overcurrent protection recorder, and a signal transmitter; wherein the current transformer is used to acquire the input current flowing through the explosion-proof electrical appliance under test in the test circuit and transmit it to the overcurrent protection recorder; the overcurrent protection recorder is used to start timing when the input current exceeds a threshold and stop timing when the explosion-proof electrical appliance triggers overcurrent protection action, thereby obtaining the overcurrent protection time and transmitting it to the signal transmitter; the signal transmitter is used to transmit the input current and overcurrent protection time to a data receiving and storage device.

[0080] In this embodiment, as Figure 3 As shown, the overcurrent protection time acquisition device includes a current transformer, an overcurrent protection recorder, and a signal transmitter. The current transformer is installed on the input current conductor of the electrical appliance under test to acquire the input current value of the electrical appliance under test, and then transmits the data to the overcurrent protection recorder. The overcurrent protection recorder also records the time when the electrical appliance under test completes the overcurrent protection. Since the overcurrent protection time acquisition device is located outside the electrical appliance under test, the signal transmitter can transmit these two data to the data receiving and storage device wirelessly.

[0081] The test circuit includes a voltage regulator and a high-current generator; wherein the input terminal of the voltage regulator is connected to the power grid, and the output terminal of the voltage regulator is connected to the input terminal of the high-current generator; the output terminal of the high-current generator is connected to the power input terminal of the explosion-proof electrical appliance under test, for providing an adjustable test current to the explosion-proof electrical appliance.

[0082] The data receiving and storage device includes a data receiver, an ambient temperature and humidity sensor, and a data storage device. The data receiver receives temperature data from an ultrasonic through-wall communication device and input current and overcurrent protection time from an overcurrent protection time acquisition device, decodes the data to obtain the temperature, current, and overcurrent protection time of the explosion-proof electrical appliance, and transmits this data to the data storage device. The ambient temperature and humidity sensor collects and monitors the laboratory's ambient temperature and humidity in real time and transmits this data to the data storage device. The data storage device stores the temperature, current, and overcurrent protection time of the explosion-proof electrical appliance, as well as the laboratory's ambient temperature and humidity, and transmits this data to a digital display console via a data transmission channel. When the ambient temperature or humidity deviates from the set range, the data storage device controls the laboratory's constant temperature and humidity device to start or stop via commands.

[0083] In this embodiment, as Figure 4As shown, the data receiving and storage device is directly powered by the power grid via a three-prong plug. The output of the ambient temperature and humidity sensor is connected to the data storage device via a data cable to control the laboratory's constant temperature and humidity system, maintaining stable ambient temperature and humidity. The explosion-proof electrical internal temperature data receiving device receives and decodes signals sent by the ultrasonic through-wall communication device, connects to the data storage device via a data channel, records and stores internal and ambient temperature data, and can import and retrieve data at any time. The output of the data receiving and storage module is connected to the input of the digital display console, and outputs data to the digital display console via a data transmission channel.

[0084] The digital display control panel includes: an internal host, a touch screen display, a current generator, a temperature abnormality alarm unit, an electrical parameter testing unit, and a regulated power supply.

[0085] The internal host interacts with the touch screen via an internal bus, receiving instructions and displaying data; the internal host controls the output of the current generator according to the received instructions; the internal host receives feedback signals from the electrical parameter testing unit for closed-loop control; the internal host monitors the status of the temperature anomaly alarm unit and triggers protection actions; the internal host is connected to the data receiving and storage device via a bidirectional data channel.

[0086] The touch screen is used to provide a human-machine interface, allowing operators to set parameters, switch functions, and start and stop tests via touch, and to display system status, temperature rise detection test parameters, and overcurrent protection test parameters in real time.

[0087] The current generator is used to generate a test current of the required magnitude and waveform according to the instructions of the internal host, and apply it to the explosion-proof electrical appliance under test through the test circuit.

[0088] The electrical parameter testing unit is used to monitor the test voltage and test current in the test circuit in real time and transmit them to the internal host.

[0089] The electrical parameter testing unit includes: a passive high-precision voltage transformer and a passive high-precision current transformer; wherein the passive high-precision voltage transformer is connected in parallel to the power input terminal of the test circuit for real-time monitoring of the test voltage of the test circuit; and the passive high-precision current transformer is connected in series in the test circuit for real-time monitoring of the test current of the test circuit.

[0090] The temperature anomaly alarm unit is used to receive temperature data and transmit it to the internal host. When the temperature data is detected to exceed the safety threshold, it triggers an audible and visual alarm. At the same time, it sends a power-off signal to the test circuit to cut off the test current.

[0091] The temperature anomaly alarm unit includes an alarm chip and a speaker. The alarm chip is configured to drive the speaker to emit an alarm sound and generate a power-off signal when the temperature exceeds a safety threshold.

[0092] The regulated power supply is connected to the power grid and is used to power the touch screen, current generator, electrical parameter testing unit, and temperature abnormality alarm unit.

[0093] In this embodiment, as Figure 5 As shown, the digital display control panel consists of an internal host, a touch screen, a temperature anomaly alarm unit, an electrical parameter testing unit, a regulated power supply, and a current generator. The regulated power supply connects to the power grid to power all devices, and the current generator supplies the test current to the explosion-proof electrical equipment in the test circuit. The internal host operates the temperature rise test system and the overcurrent protection test system, enabling functions such as data channel switching, test current adjustment, test time setting, data processing, and temperature graph plotting. All these functions are displayed on the touch screen. The electrical parameter testing unit consists of a passive high-precision voltage transformer and a passive high-precision current transformer, used to test the maximum surface temperature test voltage and current of the explosion-proof electrical equipment. The voltage transformer is connected in parallel with the main circuit power input terminal of the explosion-proof electrical equipment (testing the main circuit voltage), and the current transformer is connected in series with the maximum surface temperature test circuit of the explosion-proof electrical equipment (measuring the test circuit current). Simultaneously, the temperature anomaly alarm unit monitors the temperature of the internal test points in real time. Upon detecting an abnormal test temperature, the alarm chip controls the speaker to emit an alarm sound and simultaneously cuts off the test current to ensure test safety.

[0094] In this embodiment, as Figure 6As shown, the overcurrent and temperature rise testing methods for explosion-proof electrical appliances are based on two core principles: Joule's law, which guides the temperature rise test; and a pre-calculated voltage loading method for rapid protection actions, which guides the overcurrent protection test. Specifically, the temperature rise test aims to verify the thermal stability of explosion-proof electrical appliances under long-term continuous operation. Its theoretical basis is Joule's law Q=I²Rt, which states that when current flows through a conductor, the conversion of electrical energy into heat energy is proportional to the square of the current. As the test duration increases, the current value in the test circuit will decrease due to the increased resistance, so the current value needs to be adjusted in real time during the experiment. This embodiment uses a simulated operating condition method to conduct the test, reproducing the maximum load current of the equipment during actual operation using a high-current generator. During the test, the three-phase conductive circuits of the explosion-proof electrical appliance are connected in series to the test circuit, and the thermal stability is verified through real-time monitoring and recording in this embodiment. To ensure constant test conditions, i.e., the current value, this system features real-time current monitoring and closed-loop regulation: the main control system within the digital display console continuously acquires the real-time current value fed back from the electrical parameter testing unit and compares it with the set value, thereby dynamically adjusting the output voltage of the voltage regulator to compensate for the current attenuation caused by increased resistance, thus maintaining the stability of the test current. The system also records the internal and surface temperatures of the explosion-proof electrical equipment in real time until the temperature change meets the stability criterion, such as a temperature rise not exceeding 3°C per hour, thus completing the verification of its thermal stability.

[0095] In this embodiment, as Figure 7 As shown, since the overcurrent protection time of most electrical appliances is designed to be within 500ms, while the time it takes for the current generator to adjust the current to reach the given current value is often longer than the overcurrent protection time, the electrical appliance under test may trigger overcurrent protection before reaching the required test current value. Therefore, in the overcurrent protection test, the internal resistance of the electrical appliance under test is measured first, then the required voltage value is calculated, and then a voltage that meets the test requirements is set and applied to the electrical appliance under test to reproduce the overload current during actual operation. At the instant the voltage is applied, the target overcurrent value is generated in the circuit. The overcurrent protection time acquisition device starts timing synchronously and stops timing when the protection device cuts off the circuit, thus accurately recording the protection action time under standard overcurrent conditions.

[0096] Example 2

[0097] This embodiment presents a wireless testing method for overcurrent and temperature rise of explosion-proof electrical appliances based on ultrasonic communication, such as... Figure 8 As shown, the method includes the following steps:

[0098] The explosion-proof electrical appliance under test is connected in series to the test circuit, and the installation and debugging of the ultrasonic communication-based wireless test system for overcurrent and temperature rise of explosion-proof electrical appliances are completed on the explosion-proof electrical appliance under test.

[0099] In this embodiment, the electrical appliance under test is connected in series to the test circuit, the power supply of the temperature acquisition device is turned on, the thermocouple terminals are attached to the position to be observed with tape or glue, the magnetic surface of the temperature acquisition device is attached to a suitable position, and the transmitting end and receiving end of the ultrasonic through-wall communication device are placed on the inner and outer walls of the explosion-proof electrical appliance respectively, to ensure that the oblique projection effect is achieved.

[0100] Set the temperature rise test parameters using the digital display control panel, increase the current in the test circuit to the set target value, and start the temperature rise test.

[0101] In this embodiment, the system automatically detects the operating status of the data transmission channel, opens the temperature rise test system through the human-machine interface of the touch screen, sets the temperature rise test parameters, and then sends a current adjustment command to the current generator. The current can be manually or automatically adjusted from zero to the set current value. The host system monitors the current data in real time and compares it with the set value. When the actual current reaches the test current, the current adjustment command output stops, and the temperature test power supply current adjustment stops.

[0102] The temperature rise detection test process includes:

[0103] The system collects temperature data inside the explosion-proof electrical appliance and ambient temperature and humidity data in real time according to preset intervals, and calculates the temperature data inside the explosion-proof electrical appliance and the changes in ambient temperature.

[0104] When the ambient temperature change exceeds 2°C, the laboratory's temperature and humidity control system is activated; and when the temperature change is less than 1°C, the system is shut down.

[0105] When the temperature data changes by more than 3°C, the temperature rise test of the explosion-proof electrical appliance shall be stopped.

[0106] When the ambient temperature change is less than 3℃, and the temperature change data of all temperature measuring points inside the explosion-proof electrical appliance are less than 1℃ for two consecutive measurements, it is determined that the temperature rise of the explosion-proof electrical appliance has reached a stable state, and the temperature rise test ends.

[0107] In this embodiment, the data receiving and storage unit collects and processes the internal temperature data and ambient temperature and humidity data of the explosion-proof electrical appliance in real time at preset intervals, and performs calculations and judgments: if the ambient temperature change is greater than 2°C, the host system will control the laboratory constant temperature and humidity device to start; if the temperature change is less than 1°C, the temperature and humidity control device will stop; if the temperature change exceeds 3°C, the temperature rise detection test of the explosion-proof electrical appliance will stop. When the ambient temperature change is less than 3°C, and the temperature data changes measured twice at 1-hour intervals are both less than 1°C, the temperature rise detection test of the explosion-proof electrical appliance is considered to be over.

[0108] After the temperature rise test is completed, and the surface and internal temperatures of the explosion-proof electrical appliance have cooled to room temperature, the overcurrent protection test is started.

[0109] The overcurrent protection test process is as follows:

[0110] Measure the internal resistance of the explosion-proof electrical appliance, and calculate the target test voltage required for the overcurrent protection test based on the preset target overcurrent protection current value and the internal resistance.

[0111] The target test voltage is applied instantaneously to the test circuit, causing the current in the test circuit to instantaneously reach the target overcurrent value;

[0112] The overcurrent protection time acquisition device automatically monitors the test current and starts timing when the test current exceeds the threshold until the explosion-proof electrical appliance triggers the overcurrent protection action, thus obtaining the overcurrent protection time and ending the overcurrent protection test.

[0113] In this embodiment, the surface and internal temperature of the electrical appliance under test are cooled to room temperature. The overcurrent protection test system is opened through the human-machine interface of the touch screen. The system first issues an instruction to measure the internal resistance of the electrical appliance under test, and then calculates the corresponding voltage value based on the fact that the input current of the test electrical appliance is 8-10 times the rated current. Then, it sends a voltage adjustment instruction to the voltage regulator at the front end of the current generator to carry out the test. When the electrical appliance triggers the overcurrent protection, the overcurrent protection test of the explosion-proof electrical appliance is considered to be over, and the overcurrent protection time acquisition device automatically records the data.

[0114] During the temperature rise detection test and overcurrent protection test, all test data of the temperature rise detection test and overcurrent protection test are saved in real time.

[0115] Example 3

[0116] This embodiment proposes a computer program product, including a computer program or instructions, which, when executed by a processor, implements the aforementioned wireless testing method for overcurrent and temperature rise of explosion-proof electrical appliances based on ultrasonic communication.

[0117] Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or part of the technical solution, can be embodied in the form of a computer program product.

[0118] The various embodiments in this application are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0119] The scope of protection of this application is not limited to the embodiments described above. Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from the scope and spirit of this disclosure. If such modifications and variations fall within the scope of this disclosure and its equivalents, then the intent of this disclosure also includes these modifications and variations.

Claims

1. A wireless testing system for overcurrent and temperature rise of explosion-proof electrical appliances based on ultrasonic communication, characterized in that, The system includes: a temperature acquisition device for acquiring the internal temperature of explosion-proof electrical appliances and converting the temperature into a digital temperature signal; An ultrasonic through-wall communication device is used to receive the digital temperature signal and modulate it into an ultrasonic signal, which is then wirelessly transmitted through the explosion-proof electrical enclosure. Simultaneously, the device receives and demodulates the ultrasonic signal and temperature data outside the explosion-proof electrical enclosure. An overcurrent protection time acquisition device is used to acquire the input current of explosion-proof electrical appliances and record the overcurrent protection time of the explosion-proof electrical appliances; A data receiving and storage device is used to receive, decode, and store the temperature data, the input current of the explosion-proof electrical appliance, and the overcurrent protection time of the explosion-proof electrical appliance; A digital display control panel is used to provide a human-machine interface and perform at least one of the following functions: setting test parameters, controlling the test process, and real-time data display and processing. The output of the temperature acquisition device is connected to the input of the ultrasonic through-wall communication device. The output of the ultrasonic through-wall communication device and the input of the data receiving and storage device are connected wirelessly. The output of the overcurrent protection time acquisition device is connected to the input of the data receiving and storage device. The data receiving and storage device is connected to the digital display console through a bidirectional data channel.

2. The wireless testing system for overcurrent and temperature rise of explosion-proof electrical appliances based on ultrasonic communication according to claim 1, characterized in that, The temperature acquisition device includes a T-type thermocouple and a data transmission unit. The test end of the T-type thermocouple is fixed inside the explosion-proof electrical appliance at the test point to measure the temperature of the test point. The T-type thermocouple transmits the measured temperature to the data transmission unit via a wire connection. The data transmission unit converts the received analog temperature signal into a digital temperature signal, modulates the digital temperature signal at a preset modulation frequency via magnetic coupling communication, and transmits the resulting analog modulated signal to an ultrasonic through-wall communication device.

3. The wireless testing system for overcurrent and temperature rise of explosion-proof electrical appliances based on ultrasonic communication according to claim 2, characterized in that, The ultrasonic through-wall communication device includes: a transmitting end disposed inside the explosion-proof electrical appliance and a receiving end disposed on the outer shell of the explosion-proof electrical appliance; The transmitting end includes: an electromagnetic signal acquisition module, a voltage follower, a signal amplifier, and an ultrasonic transducer; The electromagnetic signal acquisition module receives the analog modulated signal, converts it into a digital signal using a digital signal converter, and modulates the digital signal at a specific frequency using a digital frequency synthesizer controlled by a microcontroller to generate a high-frequency analog signal, which is then transmitted to a voltage follower. The voltage follower buffers and performs impedance transformation on the high-frequency analog signal and transmits the output analog signal to a signal amplifier. The signal amplifier amplifies the received analog signal and transmits it to an ultrasonic transducer. The ultrasonic transducer converts the amplified analog signal into an ultrasonic signal and transmits it to the receiving end. The receiving end includes: an ultrasonic receiving transducer, a preamplifier adaptive amplifier, a voltage follower, a voltage comparator, and a digital-to-analog converter; The ultrasonic receiving transducer receives ultrasonic signals transmitted from the ultrasonic transmitting transducer and transmits them to a pre-adaptive amplifier; the pre-adaptive amplifier amplifies the received ultrasonic signals and transmits them to a voltage follower; the voltage follower buffers and performs impedance transformation on the amplified ultrasonic signals and transmits the output voltage signal to a voltage comparator; the voltage comparator compares the voltage signal with a reference voltage, shapes the voltage signal to generate a digital square wave signal, and transmits it to a digital-to-analog converter; the digital-to-analog converter converts the digital square wave signal into an analog signal as temperature data and transmits the temperature data to a data receiving and storage device.

4. The wireless testing system for overcurrent and temperature rise of explosion-proof electrical appliances based on ultrasonic communication according to claim 3, characterized in that, Both the ultrasonic transmitting transducer and the ultrasonic receiving transducer are oblique-type transducers; the ultrasonic transmitting surface or ultrasonic receiving surface of the oblique-type transducer is positioned at a predetermined angle with the normal of the metal wall of the explosion-proof electrical appliance, so that the ultrasonic wave propagates in the metal wall through a reflection path, thereby generating a horizontal offset between the exit point outside the metal wall and the incident point inside the metal wall; the reflection path is configured to overcome the echo interference generated by the direct penetration of the ultrasonic wave.

5. The wireless testing system for overcurrent and temperature rise of explosion-proof electrical appliances based on ultrasonic communication according to claim 4, characterized in that, The overcurrent protection time acquisition device includes: a current transformer, an overcurrent protection recorder, and a signal transmitter; wherein the current transformer is used to acquire the input current of the explosion-proof electrical appliance and transmit it to the overcurrent protection recorder; the overcurrent protection recorder is used to start timing when the input current exceeds a threshold and stop timing when the explosion-proof electrical appliance triggers overcurrent protection action, thereby obtaining the overcurrent protection time and transmitting it to the signal transmitter; the signal transmitter is used to transmit the input current and overcurrent protection time to a data receiving and storage device.

6. The wireless testing system for overcurrent and temperature rise of explosion-proof electrical appliances based on ultrasonic communication according to claim 5, characterized in that, The test circuit includes a voltage regulator and a high-current generator; wherein the input terminal of the voltage regulator is connected to the power grid, and the output terminal of the voltage regulator is connected to the input terminal of the high-current generator; the output terminal of the high-current generator is connected to the power input terminal of the explosion-proof electrical appliance under test, for providing an adjustable test current to the explosion-proof electrical appliance.

7. The wireless testing system for overcurrent and temperature rise of explosion-proof electrical appliances based on ultrasonic communication according to claim 6, characterized in that, The data receiving and storage device includes a data receiver, an ambient temperature and humidity sensor, and a data storage device. The data receiver receives temperature data from an ultrasonic through-wall communication device and input current and overcurrent protection time from an overcurrent protection time acquisition device, decodes the data to obtain the temperature, current, and overcurrent protection time of the explosion-proof electrical appliance, and transmits this data to the data storage device. The ambient temperature and humidity sensor collects and monitors the laboratory's ambient temperature and humidity in real time and transmits this data to the data storage device. The data storage device stores the temperature, current, and overcurrent protection time of the explosion-proof electrical appliance, as well as the laboratory's ambient temperature and humidity, and transmits this data to a digital display console via a data transmission channel. When the ambient temperature or humidity deviates from the set range, the data storage device controls the laboratory's constant temperature and humidity device to start or stop via commands.

8. The wireless testing system for overcurrent and temperature rise of explosion-proof electrical appliances based on ultrasonic communication according to claim 7, characterized in that, The digital display control panel includes: an internal host, a touch screen display, a current generator, a temperature abnormality alarm unit, an electrical parameter testing unit, and a regulated power supply. The internal host interacts with the touch screen via an internal bus, receiving commands and displaying data; the internal host controls the output of the current generator according to the received commands; the internal host receives feedback signals from the electrical parameter testing unit for closed-loop control; the internal host monitors the status of the temperature anomaly alarm unit and triggers protection actions; the internal host is connected to a data receiving and storage device via a bidirectional data channel. The touch screen is used to provide a human-machine interface, allowing operators to set parameters, switch functions and start / stop tests via touch, and display system status, temperature rise detection test parameters and overcurrent protection test parameters in real time. The current generator is used to generate a test current of the required magnitude and waveform according to the instructions of the internal host, and apply it to the explosion-proof electrical appliance under test through the test circuit. The electrical parameter testing unit is used to monitor the test voltage and test current in the test circuit in real time and transmit them to the internal host. The temperature anomaly alarm unit is used to receive temperature data and transmit it to the internal host. When the temperature data is detected to exceed the safety threshold, it triggers an audible and visual alarm. At the same time, it sends a power-off signal to the test circuit to cut off the test current. The regulated power supply is connected to the power grid and is used to power the touch screen, current generator, electrical parameter testing unit, and temperature abnormality alarm unit.

9. The wireless testing system for overcurrent and temperature rise of explosion-proof electrical appliances based on ultrasonic communication according to claim 8, characterized in that, The electrical parameter testing unit includes: a passive high-precision voltage transformer and a passive high-precision current transformer; wherein the passive high-precision voltage transformer is connected in parallel to the power input terminal of the test circuit for real-time monitoring of the test voltage of the test circuit; and the passive high-precision current transformer is connected in series in the test circuit for real-time monitoring of the test current of the test circuit. The temperature anomaly alarm unit includes an alarm chip and a speaker. The alarm chip is configured to drive the speaker to emit an alarm sound and generate a power-off signal when the temperature exceeds a safety threshold.

10. A wireless testing method for overcurrent and temperature rise of explosion-proof electrical appliances based on ultrasonic communication, implemented using the wireless testing system for overcurrent and temperature rise of explosion-proof electrical appliances based on ultrasonic communication as described in any one of claims 1-9, characterized in that... This method includes the following steps: The explosion-proof electrical appliance under test is connected in series to the test circuit, and the installation and debugging of the wireless test system for overcurrent and temperature rise of the explosion-proof electrical appliance based on ultrasonic communication is completed on the explosion-proof electrical appliance under test. Set the temperature rise test parameters using the digital display control panel, increase the current in the test circuit to the set target value, and start the temperature rise test. The process of the temperature rise detection test includes: The temperature data inside the explosion-proof electrical appliance and the ambient temperature and humidity data are collected in real time according to the preset interval, and the temperature data inside the explosion-proof electrical appliance and the ambient temperature change data are calculated. When the ambient temperature change is greater than 2°C, the laboratory's temperature and humidity control system is activated; and when the temperature change is less than 1°C, the laboratory's temperature and humidity control system is shut down. When the temperature data changes by more than 3°C, the temperature rise test of the explosion-proof electrical appliance shall be stopped. When the ambient temperature change is less than 3℃, and the temperature change data of all temperature measuring points inside the explosion-proof electrical appliance are less than 1℃ for two consecutive measurements, it is determined that the temperature rise of the explosion-proof electrical appliance has reached a stable state, and the temperature rise test ends. After the temperature rise test is completed, and the surface and internal temperatures of the explosion-proof electrical appliance have cooled to room temperature, the overcurrent protection test is started. The process of the overcurrent protection test is as follows: Measure the internal resistance of the explosion-proof electrical appliance, and calculate the target test voltage required for the overcurrent protection test based on the preset target overcurrent protection current value and the internal resistance. The target test voltage is applied instantaneously to the test circuit, causing the current in the test circuit to instantaneously reach the target overcurrent value; The overcurrent protection time acquisition device automatically monitors the test current and starts timing when the test current exceeds the threshold, and stops timing when the explosion-proof electrical appliance triggers the overcurrent protection action, thus obtaining the overcurrent protection time and ending the overcurrent protection test. During the temperature rise detection test and overcurrent protection test, all test data of the temperature rise detection test and overcurrent protection test are saved in real time.

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