CN117928737A - Non-contact temperature detection device for dry-type transformer - Google Patents

Abstract

The application relates to a non-contact temperature detection device of a dry-type transformer, which comprises a main control unit and 5 infrared temperature measurement sensors; the 5 infrared temperature sensors monitor the temperatures of the upper early iron, the high-voltage winding, the low-voltage winding, the copper bar and the surrounding environment of the dry-type transformer respectively; the main control unit comprises a main chip, 5 paths of infrared receiving circuits, a display screen, a main chip and a communication module, wherein the 5 paths of infrared receiving circuits are in one-to-one correspondence with the 5 infrared temperature measuring sensors, are respectively used for receiving temperature information monitored by the 5 infrared temperature measuring sensors and converting the temperature information into temperature signals which can be processed by the main chip, and the main chip is used for processing the temperature signals output by the 5 paths of infrared receiving circuits to obtain temperature values of upper early-stage iron, a high-voltage winding, a low-voltage winding, a copper bar and the surrounding environment of the dry-type transformer, displaying the temperature values through the display screen and reporting to a cloud end through the communication module, so that remote monitoring is realized, and the efficiency, the accuracy and the convenience of temperature detection of the dry-type transformer are improved.

Description

A non-contact temperature detection device for dry-type transformer

Technical Field

The present application relates to the technical field of transformers, and in particular to a non-contact temperature detection device for dry-type transformers.

Background technique

The current temperature detection system of dry-type transformers mostly adopts contact measurement method, that is, PT100 platinum resistance thermometer, PTC130 resistance thermometer and other devices are used as temperature sensors, which are directly installed at 2/3 of the copper winding inside the transformer to realize transformer temperature measurement; however, although the traditional contact temperature monitoring method is simple and easy to use, it has some problems, such as the need to calibrate the sensor regularly, and the temperature sensor is easy to damage and cannot be replaced under power. When the power must be cut off to replace the temperature sensor, the economic cost of the operation is extremely high and there is a risk of power outage complaints from users.

Summary of the invention

The purpose of this application is to propose a non-contact temperature detection device for a dry-type transformer to improve the efficiency, accuracy and convenience of temperature detection of the dry-type transformer.

To achieve the above-mentioned purpose, an embodiment of the present application provides a non-contact temperature detection device for a dry-type transformer, comprising a main control unit and five infrared temperature sensors;

The five infrared temperature sensors respectively monitor the temperature of the upper iron, high-voltage winding, low-voltage winding, copper busbar and surrounding environment of the dry-type transformer;

The main control unit includes a main chip, 5-way infrared receiving circuits, a display screen, a main chip and a communication module. The 5-way infrared receiving circuits correspond to the 5 infrared temperature sensors one by one, and are respectively used to receive the temperature information monitored by the 5 infrared temperature sensors and convert it into a temperature signal that can be processed by the main chip. The main chip is used to process the temperature signals output by the 5-way infrared receiving circuits to obtain the temperature values of the upper iron, high-voltage winding, low-voltage winding, copper busbar and surrounding environment of the dry-type transformer, display the temperature values through the display screen, and report them to the cloud through the communication module to achieve remote monitoring.

Furthermore, the main chip is an STM32 chip, and the STM32 chip internally integrates a general timer, a serial communication interface, a serial port driver interface, an analog-to-digital converter, a general input/output and a temperature monitoring algorithm model, the serial communication interface is connected to the display screen, the serial port driver interface is connected to the communication module, the analog-to-digital converter is connected to the five infrared temperature sensors, and the temperature monitoring algorithm model is used to perform temperature prediction according to the temperature signal output by the analog-to-digital converter to obtain a temperature prediction value, and set an early warning threshold according to the temperature prediction value, when the temperature signal output by the analog-to-digital converter is greater than the early warning threshold, a corresponding alarm mechanism is triggered, and relevant personnel are notified through the communication module to perform inspection or maintenance.

Furthermore, the device also includes a humidity sensor and a load current detection module, wherein the humidity sensor is used to monitor the humidity information of the transformer, and the load current detection module is used to monitor the load current information of the transformer;

The main control unit also includes a humidity receiving circuit and a load current receiving circuit; the humidity receiving circuit is connected to the humidity sensor, and is used to receive the humidity information output by the humidity sensor and convert it into a humidity signal that can be processed by the main chip; the load current detection module is connected to the load current receiving circuit, and is used to receive the load current information output by the load current detection module and convert it into a load current signal that can be processed by the main chip;

The analog-to-digital converter is connected to the humidity receiving circuit and the load current receiving circuit;

The temperature monitoring algorithm model is specifically used to fit a temperature monitoring curve according to the temperature signal, humidity signal and load current signal output by the analog-to-digital converter, and obtain a temperature prediction value according to the fitted temperature monitoring curve.

Furthermore, the temperature monitoring algorithm model specifically adopts any one of polynomial fitting, least squares fitting, nonlinear fitting and statistical model fitting to fit the temperature monitoring curve.

Furthermore, the temperature monitoring algorithm model is used to read the temperature signal output by the analog-to-digital converter. If the temperature signal is read successfully, it is converted into a temperature value in a preset format and displayed on a display screen; if the temperature signal reading fails, a fault is displayed on the display screen and an alarm information is reported to the cloud.

Furthermore, the device also includes a buzzer for sounding an alarm when a corresponding alarm mechanism is triggered.

Furthermore, the device also includes a plurality of buttons, and different buttons realize different functions and call different interfaces.

The embodiments of the present application have the following beneficial effects:

The embodiments of the present application adopt non-contact temperature monitoring technology, which can solve the problems of limitations of traditional contact temperature monitoring methods. The use of non-contact temperature monitoring methods can solve some limitations of traditional contact temperature monitoring methods; traditional contact methods require placing temperature sensors on the monitored objects, which may cause damage to the monitored objects or interfere with their normal operation; while non-contact temperature monitoring methods can use infrared technology or other non-contact sensing technologies to obtain temperature data in real time and accurately, avoiding damage to the monitored objects.

The use of non-contact temperature monitoring technology can improve monitoring efficiency and accuracy. Traditional contact methods require manual installation and maintenance of temperature sensors, which may require downtime for maintenance and troubleshooting. The non-contact method can perform temperature monitoring without interfering with normal operation and can obtain temperature data in real time, improving monitoring efficiency and accuracy.

In addition, non-contact temperature monitoring technology is also convenient. Traditional contact methods often require investment of manpower and resources, while non-contact methods can monitor over a longer distance, reduce manpower investment, and improve monitoring convenience.

In summary, the use of non-contact temperature monitoring technology can solve the limitations of traditional methods, improve monitoring efficiency, accuracy and convenience, help ensure the safe and stable operation of equipment such as transformers, and reduce operation and maintenance costs.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

FIG1 is a structural diagram of a non-contact temperature detection device for a dry-type transformer in an embodiment of the present application.

FIG. 2 is a schematic diagram of five infrared temperature measurement sensors in an embodiment of the present application.

FIG3 is a main program operation logic diagram of the main chip in an embodiment of the present application.

FIG. 4 is a circuit diagram of a single-chip minimum system of a main chip in an embodiment of the present application.

FIG. 5 is a diagram of a 3.3V voltage stabilizing circuit of a main chip in an embodiment of the present application.

FIG. 6 is a diagram of a 3.9V voltage stabilizing circuit of a main chip in an embodiment of the present application.

FIG. 7 is a circuit diagram of a communication module in an embodiment of the present application.

FIG8 is a screen subroutine operation logic diagram of the main chip in an embodiment of the present application.

Detailed ways

The detailed description of the drawings is intended as an illustration of some current embodiments of the present application, and is not intended to represent the only form in which the present application can be implemented. It should be understood that the same or equivalent functions can be accomplished by different embodiments intended to be included within the scope of the present application.

1-2 , an embodiment of the present application provides a non-contact temperature detection device for a dry-type transformer, including a main control unit and five infrared temperature sensors;

The five infrared temperature sensors respectively monitor the temperature of the upper iron, high-voltage winding, low-voltage winding, copper busbar and surrounding environment of the dry-type transformer;

The main control unit includes a main chip, 5-way infrared receiving circuits, a display screen, a main chip and a communication module. The 5-way infrared receiving circuits correspond to the 5 infrared temperature sensors one by one, and are respectively used to receive the temperature information monitored by the 5 infrared temperature sensors and convert them into temperature signals that can be processed by the main chip. The main chip is used to process the temperature signals output by the 5-way infrared receiving circuits to obtain the temperature values of the upper iron, high-voltage winding, low-voltage winding, copper busbar and surrounding environment of the dry-type transformer, display the temperature values through the display screen, and report them to the cloud through the communication module to achieve remote monitoring.

The specific circuit structure of the infrared receiving circuit may vary according to different design requirements. The following is an example of a common infrared receiving circuit, including an infrared receiving head -> high-frequency amplifier -> limiter -> filter -> demodulator -> decoder -> output circuit; the output pin of the infrared receiving head is connected to the input pin of the high-frequency amplifier; the output pin of the high-frequency amplifier is connected to the input pin of the limiter; the output pin of the limiter is connected to the input pin of the filter; the output pin of the filter is connected to the input pin of the demodulator; the output pin of the demodulator is connected to the input pin of the decoder; the output pin of the decoder is connected to the output circuit;

Infrared Receiver Module, used to receive infrared signals and convert infrared light into electrical signals;

High-frequency amplifier: It is used to amplify the weak electrical signal output by the receiving head and increase the signal strength.

A clipper is used to limit the amplified signal waveform, clip and repair it into a fully rectangular signal;

Filter: used to filter out irrelevant frequency interference and noise and retain the frequency components of the infrared signal;

Demodulator, used to analyze and demodulate the filtered signal and restore the infrared signal to the original modulated signal;

Decoder: used to decode the demodulated signal, identify and extract the signal information contained, such as the command data sent by the infrared remote control;

The output circuit is used to output the decoded signal to the main chip for processing or control.

As shown in Figure 3, after the device is powered on, each functional module is initialized first, then the device control information is configured and the corresponding 4G network is connected to the cloud. After the connection is established, the network configuration code can be entered to bind the device.

Specifically, the cloud can communicate with the mobile phone APP, and remote monitoring can be achieved through the mobile phone APP. After the temperature data is uploaded to the cloud, the mobile phone APP can obtain the latest temperature information by connecting to the cloud server and display this information on the mobile phone. Operation and maintenance personnel can use the mobile phone APP to check the temperature of the transformer at any time, and can monitor the operating status of the transformer in real time no matter where they are. In this way, the mobile phone APP provides a convenient and fast way to remotely monitor the transformer, allowing operation and maintenance personnel to take timely measures to deal with abnormal temperature conditions and ensure the safe operation of the transformer.

Furthermore, the main chip is an STM32 chip, which internally integrates a general timer, a serial communication interface (USART, SPI, I2C, etc.), a serial port driver interface, an analog-to-digital converter (ADC), a general input/output (GPIO) and a temperature monitoring algorithm model (a program run by the STM32 chip processor). The serial communication interface is connected to the display screen, the serial port driver interface is connected to the communication module, and the analog-to-digital converter is connected to the five infrared temperature sensors. The temperature monitoring algorithm model is used to perform temperature prediction according to the temperature signal output by the analog-to-digital converter to obtain a temperature prediction value, and set a warning threshold according to the temperature prediction value. When the temperature signal output by the analog-to-digital converter is greater than the warning threshold, a corresponding alarm mechanism is triggered, and relevant personnel are notified through the communication module to perform inspection or maintenance.

Specifically, the general timer is a module integrated inside the chip, whose function is to generate various timers and counters for precise time delay, frequency measurement, pulse width modulation (PWM) and other operations. It can realize different timer functions by setting parameters such as interconnected timer clock source, pre-scaling, reload value, counting mode, etc.

A serial communication interface is an interface for serial data transmission between a chip and an external device. Common ones include USART, SPI, and I2C. USART (Universal Synchronous/Asynchronous Receiver/Transmitter) is a universal serial communication interface that supports synchronous and asynchronous transmission modes; SPI (Serial Peripheral Interface) is a high-speed serial communication interface that can connect multiple peripherals at the same time; I2C (Inter-Integrated Circuit) is a two-wire serial communication interface that is simple, low-cost, and has the characteristics of multiple devices sharing the bus.

The serial port driver interface is used to connect the communication module or other external devices. The serial port driver interface can realize data transmission and communication with other devices. The commonly used serial port is UART (Universal Asynchronous Receiver/Transmitter), which is a universal asynchronous serial communication interface.

An analog-to-digital converter is a device or module used to convert analog signals into digital signals. In embedded systems, analog-to-digital converters are often used to convert analog input signals (such as temperature, voltage, etc.) into corresponding digital representations for processing by the processor inside the chip.

General Purpose Input/Output, or GPIO for short, is a general-purpose programmable input/output interface used to connect and interact with external devices in embedded systems. Through the GPIO interface, you can set a pin to input mode to receive external signals; you can also set a pin to output mode to output specific signals. The GPIO interface is flexible and versatile in embedded systems and can adapt to different application scenarios and connection requirements.

Specifically, this embodiment uses a temperature monitoring algorithm model to predict the temperature according to the temperature signal output by the analog-to-digital converter, and obtains the predicted value of the future temperature. The predicted value can be used to judge the temperature trend and change, so as to make corresponding processing and decision. At the same time, according to the predicted value, a warning threshold is set. When the temperature signal output by the analog-to-digital converter exceeds the warning threshold, the alarm mechanism will be triggered. The alarm mechanism can be to send an alarm message to relevant personnel through a communication module to remind them that they need to perform maintenance or maintenance operations. Why do we need to predict? This is because the prediction of temperature changes can detect potential problems or anomalies in advance, so as to take corresponding measures to avoid accidents or losses. By predicting the temperature signal and setting the warning threshold, an alarm can be issued in time before the temperature exceeds the safe range to ensure the safety of equipment and personnel. Through the combination of temperature prediction and alarm mechanism, the accuracy and timeliness of temperature monitoring can be improved, thereby better providing support for the monitoring and protection of equipment conditions.

The STM32 chip processor includes a power supply circuit, a clock circuit and a reset circuit. As shown in Figure 4, the STM chip has 3 groups of digital power pins, 1 group of analog power pins and a clock power supply pin VBAT. The chip operating voltage is 1.61V-3.6V, and this system uses 3.3V power supply. Since this design uses the RTC clock function, the VBAT pin is connected to VCC. When designing the circuit, the main control chip power pin also needs to be added with a 0.1uF decoupling capacitor, and the decoupling capacitor should be as close to the pin as possible when the PCB is laid out.

The clock circuit of this embodiment uses an external 8MHz passive crystal oscillator to the crystal oscillator pin to provide a reference operating frequency for the system. The operating frequency of the microcontroller is multiplied to 72MHz through the internal phase-locked loop of the chip, ensuring that each module of the microcontroller can run in an orderly manner.

This embodiment provides 3.3V voltage for the system through 220V AC power, and converts 3V into 3.3V required for chip operation and 5V required for battery operation through 2 power conversions. As shown in Figure 5, the 3.3V voltage stabilizing circuit of this circuit uses the linear voltage stabilizing chip RS3236-3.3, which has the characteristics of simple peripheral circuit, stable operation and low price. The input voltage range of this chip is: 1.7V-7.5V, the output voltage is 3.3V, and the maximum output current is 1A, which can meet the power supply requirements of the back-stage circuit. The 2nd pin of the RS3236-3.3 chip is grounded, the 5th pin is the output end, and the 1st pin is the input end. In order to increase the stability of voltage conversion, 0.1uF and 22uF capacitors are connected to the input and output ends of the chip for decoupling and voltage stabilization respectively. When the PCB is laid out, the decoupling capacitor is as close as possible to the pins of the LDO chip.

The power module uses the MT2492 voltage regulator chip, which has a peak output current of up to 3A and a built-in power-off protection function. The maximum instantaneous drop voltage is 150mV. The 3.9V voltage regulator circuit is shown in Figure 6.

This embodiment uses the cloud 4G module LZ501 as the communication module. The module has an external antenna for communication. The chip has its own SIM_VDD as the SIM card power supply. The internal conversion output 1.8V voltage is used as the serial port voltage conversion, as shown in Figure 7.

Furthermore, the device also includes a humidity sensor and a load current detection module, wherein the humidity sensor is used to monitor the humidity information of the transformer, and the load current detection module is used to monitor the load current information of the transformer;

The main control unit also includes a humidity receiving circuit and a load current receiving circuit; the humidity receiving circuit is connected to the humidity sensor, and is used to receive the humidity information output by the humidity sensor and convert it into a humidity signal that can be processed by the main chip; the load current detection module is connected to the load current receiving circuit, and is used to receive the load current information output by the load current detection module and convert it into a load current signal that can be processed by the main chip;

The analog-to-digital converter is connected to the humidity receiving circuit and the load current receiving circuit;

The temperature monitoring algorithm model is specifically used to fit a temperature monitoring curve according to the temperature signal, humidity signal and load current signal output by the analog-to-digital converter, and obtain a temperature prediction value according to the fitted temperature monitoring curve.

Specifically, when considering the humidity signal and load current signal of the dry-type transformer, there are the following reasons:

Humidity has a certain impact on the temperature change of dry-type transformers. By incorporating humidity signals into the temperature monitoring algorithm model, the temperature change trend can be reflected more accurately. Changes in humidity will cause changes in heat conduction and heat dissipation, thereby affecting temperature changes.

Load current is an important parameter of dry-type transformers. Current will flow through the transformer during operation, and the current has a direct impact on temperature changes. As the load current changes, corresponding heat will be generated inside the transformer, resulting in temperature changes. Therefore, considering the load current signal can more comprehensively analyze and predict the temperature changes of dry-type transformers.

In summary, by using the temperature signal, humidity signal and load current signal of the dry-type transformer to fit the temperature monitoring curve and making temperature predictions based on the curve, the accuracy and reliability of the temperature change of the dry-type transformer can be improved, and it can help to take corresponding measures in time to ensure the normal operation and safety of the transformer.

Furthermore, the temperature monitoring algorithm model specifically adopts any one of the fitting methods of polynomial fitting, least squares fitting, nonlinear fitting and statistical model fitting to fit the temperature monitoring curve, or the temperature monitoring curves fitted by multiple fitting methods are weighted summed to obtain the final temperature monitoring curve. The temperature monitoring curve refers to the temperature change curve formed over time, which is obtained by real-time recording and drawing the temperature change over time. Usually, the temperature monitoring curve is a curve chart drawn with time as the horizontal axis and temperature value as the vertical axis. The weighting method can be determined according to the specific situation, and the weight can be assigned according to the corresponding fitting accuracy, credibility or other factors. In this way, the final temperature monitoring curve will more comprehensively reflect the trend of the overall temperature change.

Furthermore, after the device is powered on, the display screen program is initialized, and each functional module is initialized. The temperature monitoring algorithm model is used to read the temperature signal output by the analog-to-digital converter. If the temperature signal is read successfully, it is converted into a temperature value in a preset format and displayed on the display screen; if the temperature signal reading fails, a fault is displayed on the display screen, and an alarm message is reported to the cloud.

Furthermore, the device also includes a buzzer for sounding an alarm when a corresponding alarm mechanism is triggered.

Furthermore, the device also includes a plurality of buttons, and different buttons realize different functions and call different interfaces.

The embodiments of the present application have the following beneficial effects:

The embodiments of the present application adopt non-contact temperature monitoring technology, which can solve the problems of limitations of traditional contact temperature monitoring methods. The use of non-contact temperature monitoring methods can solve some limitations of traditional contact temperature monitoring methods; traditional contact methods require placing temperature sensors on the monitored objects, which may cause damage to the monitored objects or interfere with their normal operation; while non-contact temperature monitoring methods can use infrared technology or other non-contact sensing technologies to obtain temperature data in real time and accurately, avoiding damage to the monitored objects.

The use of non-contact temperature monitoring technology can improve monitoring efficiency and accuracy. Traditional contact methods require manual installation and maintenance of temperature sensors, which may require downtime for maintenance and troubleshooting. The non-contact method can perform temperature monitoring without interfering with normal operation and can obtain temperature data in real time, improving monitoring efficiency and accuracy.

In addition, non-contact temperature monitoring technology is also convenient. Traditional contact methods often require investment of manpower and resources, while non-contact methods can monitor over a longer distance, reduce manpower investment, and improve monitoring convenience.

In summary, the use of non-contact temperature monitoring technology can solve the limitations of traditional methods, improve monitoring efficiency, accuracy and convenience, help ensure the safe and stable operation of equipment such as transformers, and reduce operation and maintenance costs.

The embodiments of the present application have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims (7)

1. A non-contact temperature detection device for a dry-type transformer, characterized in that it comprises a main control unit and five infrared temperature sensors; The five infrared temperature sensors respectively monitor the temperature of the upper iron, high-voltage winding, low-voltage winding, copper busbar and surrounding environment of the dry-type transformer; The main control unit includes a main chip, 5-way infrared receiving circuits, a display screen, a main chip and a communication module. The 5-way infrared receiving circuits correspond to the 5 infrared temperature sensors one by one, and are respectively used to receive the temperature information monitored by the 5 infrared temperature sensors and convert it into a temperature signal that can be processed by the main chip. The main chip is used to process the temperature signals output by the 5-way infrared receiving circuits to obtain the temperature values of the upper iron, high-voltage winding, low-voltage winding, copper busbar and surrounding environment of the dry-type transformer, display the temperature values through the display screen, and report them to the cloud through the communication module to achieve remote monitoring. 2. The non-contact temperature detection device for dry-type transformer according to claim 1, characterized in that the main chip is an STM32 chip, and a universal timer, a serial communication interface, a serial port driver interface, an analog-to-digital converter, a general input/output and a temperature monitoring algorithm model are integrated inside the STM32 chip, the serial communication interface is connected to the display screen, the serial port driver interface is connected to the communication module, the analog-to-digital converter is connected to the 5 infrared temperature sensors, and the temperature monitoring algorithm model is used to perform temperature prediction according to the temperature signal output by the analog-to-digital converter to obtain a temperature prediction value, and an early warning threshold is set according to the temperature prediction value, when the temperature signal output by the analog-to-digital converter is greater than the early warning threshold, a corresponding alarm mechanism is triggered, and relevant personnel are notified by the communication module to perform maintenance or maintenance. 3. The non-contact temperature detection device for dry-type transformer according to claim 2, characterized in that the device further comprises a humidity sensor and a load current detection module, the humidity sensor is used to monitor the humidity information of the transformer, and the load current detection module is used to monitor the load current information of the transformer; The main control unit also includes a humidity receiving circuit and a load current receiving circuit; the humidity receiving circuit is connected to the humidity sensor, and is used to receive the humidity information output by the humidity sensor and convert it into a humidity signal that can be processed by the main chip; the load current detection module is connected to the load current receiving circuit, and is used to receive the load current information output by the load current detection module and convert it into a load current signal that can be processed by the main chip; The analog-to-digital converter is connected to the humidity receiving circuit and the load current receiving circuit; The temperature monitoring algorithm model is specifically used to fit a temperature monitoring curve according to the temperature signal, humidity signal and load current signal output by the analog-to-digital converter, and obtain a temperature prediction value according to the fitted temperature monitoring curve. 4. The non-contact temperature detection device for dry-type transformers according to claim 3 is characterized in that the temperature monitoring algorithm model specifically adopts any one of polynomial fitting, least squares fitting, nonlinear fitting and statistical model fitting to fit the temperature monitoring curve. 5. The non-contact temperature detection device for dry-type transformers according to claim 4 is characterized in that the temperature monitoring algorithm model is used to read the temperature signal output by the analog-to-digital converter. If the temperature signal is read successfully, it is converted into a temperature value in a preset format and displayed on a display screen; if the temperature signal reading fails, a fault is displayed on the display screen and an alarm information is reported to the cloud. 6. The non-contact temperature detection device for dry-type transformers according to claim 5, characterized in that the device also includes a buzzer for sounding an alarm when a corresponding alarm mechanism is triggered. 7. The non-contact temperature detection device for dry-type transformers according to claim 5, characterized in that the device further comprises a plurality of buttons, and different buttons realize different functions and call different interfaces.