A power transformer fault detection device based on power line carrier

Abstract

This utility model discloses a power transformer fault detection device based on power line carrier wave, including a monitoring host, a temperature and gas detection module, and a carrier communication module. The monitoring host and one or more temperature and gas detection modules are connected in series on a low-voltage power line through the carrier communication module, enabling the monitoring host to communicate with one or more temperature and gas detection modules via power line carrier wave. The monitoring host communicates with a host computer via wired or wireless means. This detection system analyzes power transformer faults by measuring changes in temperature and gas. Through ingenious circuit design, it completes the conversion from analog to digital quantities without using an A / D conversion circuit or a reference standard power supply. It also uses a low-voltage power line to achieve communication via carrier wave, resulting in a simple structure, compact size, and convenient maintenance.

Description

Technical Field

[0001] This utility model relates to the field of power maintenance technology, and in particular to a power transformer fault detection device based on power line carrier wave. Background Technology

[0002] In today's society, electricity has permeated every aspect of life, becoming an indispensable commodity for all industries. Power outages caused by electrical equipment malfunctions not only damage the reputation of power companies but also negatively impact public life. Therefore, accurately and in real-time monitoring of transformers and ensuring their efficient operation to guarantee a stable energy supply is a fundamental social responsibility and mission of energy companies.

[0003] In existing technologies, sensors are generally used to directly acquire transformer temperature and gas information. Finally, the collected information is converted from digital to analog by a digital-to-analog converter circuit and sent to the back-end terminal wirelessly or via wired means. Each sensor requires a digital-to-analog converter circuit, which is costly and complex in structure. Moreover, the conversion circuit is easily affected by the natural environment, resulting in large errors. In addition, a separate communication system is required, which involves a large amount of construction and investment. Utility Model Content

[0004] To solve the above-mentioned technical problems, this utility model provides a power transformer fault detection based on power line carrier. Through ingenious circuit design, it completes the conversion of analog to digital quantities without the need for A / D conversion circuit and reference standard power supply. Furthermore, it utilizes existing low-voltage power lines for carrier, resulting in a simple structure and cost savings.

[0005] To solve the above-mentioned technical problems, the present invention provides a technical solution: a power transformer fault detection device based on power line carrier, characterized in that: it includes a monitoring host, a temperature and gas detection module, and a carrier communication module. The monitoring host and one or more sets of temperature and gas detection modules are connected in series on a low-voltage power line through the carrier communication module, so that the monitoring host and one or more sets of temperature and gas detection modules can communicate via power line carrier. The monitoring host communicates with a host computer via wired or wireless means.

[0006] The temperature and gas detection module includes a microcontroller and a temperature acquisition circuit and a gas acquisition circuit electrically connected to the microcontroller. The temperature acquisition circuit includes a thermistor Rx, a resistor R1 and a capacitor C1. The two ends of the thermistor Rx are connected to the RA0 and RA2 ports of the microcontroller, respectively. The two ends of the resistor R1 are connected to the RA1 and RA2 ports of the microcontroller, respectively. The RA2 port of the microcontroller is grounded through the capacitor C1.

[0007] The gas acquisition circuit includes a capacitive gas sensor Cx, resistors R2, R3, R4, R5, and a 555 timer chip. One end of the capacitive gas sensor Cx and one end of resistor R2 are grounded, and the other end is electrically connected to the second, fifth, and sixth ports of the 555 timer chip, respectively. The two ends of resistor R3 are electrically connected to the second, third, and seventh ports of the 555 timer chip, respectively. One end of resistors R4 and R5 is electrically connected to the third port of the 555 timer chip, and the other end is electrically connected to the power supply and the RA3 port of the microcontroller.

[0008] Furthermore, resistors R1, R2, R3, R4, and R5 are all constant-value resistors.

[0009] Furthermore, the monitoring host is electrically connected to the alarm device.

[0010] Furthermore, the carrier communication module includes an SC1128 chip, a power amplifier, a coupler, a bandpass filter, and a preamplifier. The SC1128 chip modulates the information to be transmitted and then transmits it to the existing low-voltage power line through the power amplifier and coupler. The information transmitted on the existing low-voltage power line is processed by the coupler, bandpass filter, and preamplifier before entering the SC1128 chip for demodulation.

[0011] The beneficial effects of this utility model are as follows:

[0012] 1. This application analyzes power transformer faults by detecting changes in transformer temperature and gas. Through ingenious circuit design, it completes the conversion from analog to digital quantities without the need for A / D conversion circuits and reference standard power supplies. This not only saves costs but also features a simple structure and compact size. Furthermore, the communication circuit utilizes existing low-voltage power lines for carrier communication, avoiding the construction of communication cables. This not only saves on construction work and investment but also makes maintenance more convenient.

[0013] 2. This application achieves the conversion from analog to digital signals using a non-A / D converter, while avoiding the need to set a standard reference voltage. It utilizes the threshold voltage of the microcontroller as a reference point. Although different chips may differ, the voltage of the same chip remains constant. This allows for the determination of the charging time of a 1kΩ resistor and the division of it with the charging time of a thermistor to obtain parameters for a temperature table. This method not only simplifies the circuit structure but also improves the accuracy of temperature detection. Furthermore, since both the 1kΩ resistor and the thermistor are affected by the same temperature, their ratio can eliminate the influence of temperature, further improving the accuracy of temperature measurement.

[0014] 3. The monitoring host of this application has the ability to receive and parse temperature and gas reading data, and can generate management commands. It also has an independent operation mode, that is, when it leaves the network environment of the upper-level machine, it can be used for digital display, button operation and sending management commands. In this way, even if there is a problem with the upper-level equipment or communication network, the monitoring system can be ensured to operate normally.

[0015] To make the above and other objects, features and advantages of this utility model more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only five of the drawings in this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a structural block diagram of this application.

[0018] Figure 2 This is a block diagram of the monitoring host structure.

[0019] Figure 3 This is a block diagram illustrating the principle of SC1128 carrier communication.

[0020] Figure 4 This is a schematic diagram of a temperature acquisition circuit.

[0021] Figure 5 This is a schematic diagram of a gas sampling circuit. Detailed Implementation

[0022] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. While some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0023] The names of the messages or information exchanged between the various devices, systems, equipment, and modules in this utility model embodiment are for illustrative purposes only and are not intended to limit the scope of these messages or information. Example

[0024] like Figure 1-5As shown, a power transformer fault detection device based on power line carrier communication includes a monitoring host, a temperature and gas detection module, and a carrier communication module. The monitoring host and one or more temperature and gas detection modules are connected in series on a low-voltage power line through the carrier communication module, enabling the monitoring host to communicate with one or more temperature and gas detection modules via power line carrier communication. The monitoring host communicates with a host computer via wired or wireless means.

[0025] The temperature and gas detection module includes a microcontroller and a temperature acquisition circuit and a gas acquisition circuit electrically connected to the microcontroller. The temperature acquisition circuit includes a thermistor Rx, a resistor R1 and a capacitor C1. The two ends of the thermistor Rx are connected to the RA0 and RA2 ports of the microcontroller, respectively. The two ends of the resistor R1 are connected to the RA1 and RA2 ports of the microcontroller, respectively. The RA2 port of the microcontroller is grounded through the capacitor C1.

[0026] The gas acquisition circuit includes a capacitive gas sensor Cx, resistors R2, R3, R4, R5, and a 555 timer chip. One end of the capacitive gas sensor Cx and one end of resistor R2 are grounded, and the other end is electrically connected to the second, fifth, and sixth ports of the 555 timer chip, respectively. The two ends of resistor R3 are electrically connected to the second, third, and seventh ports of the 555 timer chip, respectively. One end of resistors R4 and R5 is electrically connected to the third port of the 555 timer chip, and the other end is electrically connected to the power supply and the RA3 port of the microcontroller.

[0027] The microcontroller in the temperature and gas detection module is a Microchip PIC16C57, while the temperature sensor still uses a traditional, inexpensive thermistor. Through circuit optimization, the traditional A / D conversion circuit is no longer used in the temperature acquisition process; instead, the PIC16C57 microcontroller is employed. In gas measurement, the gas sensing element is capacitance, which is measured using a 555 timer circuit. Again, A / D conversion is not used; the 555 chip digitizes the signal from the capacitive gas sensor, thus creating a low-cost, simple, high-performance, and intelligent gas instrument.

[0028] Furthermore, resistors R1, R2, R3, R4, and R5 are all constant-value resistors.

[0029] The carrier communication module uses the SC1128 chip, specially developed by Beijing ZYLH Microelectronics Technology Co., Ltd. This chip employs new technologies such as direct sequence spread spectrum, digital signal processing, and direct digital frequency synthesis, exhibiting excellent anti-interference and anti-fading performance. It integrates multiple functions, including spread spectrum / despread, modulation / demodulation, D / A and A / D conversion, a built-in electronic meter, output driver, input signal amplification, watchdog timer, operating voltage detection, and serial communication with a microcontroller. Compared to other spread spectrum communication carrier chips, the SC1128 chip offers two output forms: one is a sine wave buffer output after a D / A converter, resulting in fewer harmonic components; the other is an output through a high-voltage open-drain buffer, which is less expensive. Furthermore, the chip also features an input signal amplifier, a built-in watchdog circuit, a built-in voltage monitor, a built-in electronic meter circuit, and a built-in serial half-duplex synchronous transmission communication interface. The typical data rate is 6.0 kb / s (maximum 20 kb / s), the capture threshold can be set by software, and it has a built-in 64×8 SRAM memory (supporting power-down operation).

[0030] Furthermore, the monitoring host uses the AT89C52 microcontroller manufactured by Atmel. This chip integrates an 8KB electrically erasable programmable EEPROM on-chip program storage unit and 256 8-bit RAM modules, eliminating the need for additional external program storage devices, thereby reducing the overall system size and weight and improving its stability.

[0031] The memory is not used frequently; its main function is to store various temperature and gas data collected. This information is constantly changing and will be lost if the monitoring equipment loses power, but it can be retrieved upon the next restart.

[0032] Because some critical values ​​must remain unchanged when the power is off, we chose to use the Microchip 24LC04 chip with 4K-bit electrically erasable serial EEPROM functionality to store these important parameters. This product is presented in an 8-pin configuration and achieves its communication capability through a two-wire serial connection, while also supporting the I2C protocol.

[0033] The host has the ability to receive and parse temperature and gas reading data, and can generate management commands. It also has an independent operation mode, which means that when it leaves the network environment of the upper-level machine, it can be used for digital display, button operation, and sending management commands. In this way, even if there are problems with the upper-level equipment or communication network, the monitoring system can still be ensured to operate normally.

[0034] Temperature and gas play complementary roles in transformer fault detection, exhibiting a close intrinsic relationship. When a problem occurs within a transformer, the primary impact is an increase in temperature. As the temperature rises, the insulating material gradually decomposes and releases gases. Various types of faults trigger different levels of temperature increases, causing the insulating material to decompose in various ways and release different chemical elements and gases in varying amounts. Therefore, by combining temperature and gas detection and analysis, we can more deeply and accurately identify the type of transformer fault and its severity.

[0035] This application is based on a monitoring host and multiple temperature and gas detection modules. These devices are responsible for monitoring the temperature and gas conditions of the transformer and converting the data into digital information. The monitoring host then uses this data to identify potential problems with the transformer. No special connecting cables are required; the connection can be achieved using low-voltage power line carrier technology on existing low-voltage power lines, avoiding the need for communication cables.

[0036] The overall technical solution formed by the above technical features is used as follows:

[0037] Step S1: The temperature and gas detection module is installed on the transformer to acquire the transformer's temperature and gas information and convert the analog signal into a digital signal;

[0038] Step S2: The temperature and gas detection module sends the obtained temperature and gas data to the existing low-voltage power line according to the carrier communication module;

[0039] Step S3: The monitoring host obtains the temperature and gas data transmitted on the low-voltage power line through the carrier communication module, displays the measured values ​​of each temperature and gas detection module, and can also transmit the measured values ​​of each temperature and gas detection module to the host computer.

[0040] In step S1, the temperature information is obtained as follows: first, the RA2 port of the microcontroller is set to a low voltage state to allow capacitor C1 to release energy. After capacitor C1 is completely discharged, the RA2 port is switched to receiving mode, and the high voltage generated by the RA1 port is used to charge capacitor C1 through resistor R1. Then, the built-in timer of the microcontroller is used to calculate this charging time. Once it is found that the RA2 port is fully charged, the timing is stopped immediately. This is the time required for resistor R1 to charge.

[0041] The charging time of the thermistor Rx is obtained using the same method.

[0042] The charging times of resistor R1 and thermistor Rx were obtained respectively. The microcontroller divided the two times to obtain a ratio that varies with the thermistor value. The actual temperature value was then obtained by referring to the temperature value table that was pre-determined and programmed.

[0043] In step S1, the temperature information is obtained as follows: the capacitive gas sensor Cx changes its output capacitance according to the gas concentration in the surrounding environment. The signal generated by the third port of the 555 chip changes frequency with the change in the capacitance of Cx. The Cx capacitance-gas relationship table, which is pre-determined and programmed, is consulted to obtain the specific relationship between the capacitance and the corresponding gas concentration. The microcontroller can calculate the corresponding gas concentration based on this frequency.

[0044] In step S2, the temperature and gas data sent contains the address code of the temperature and gas detection module.

[0045] In step S2, the temperature and gas data transmission process is as follows: the data is first output by the microcontroller, modulated by the SC1128 chip, and then transmitted to the existing low-voltage power line through a power amplifier and coupler.

[0046] In step S3, the temperature and gas data receiving process is as follows: the received data is transmitted through a low-voltage power line, and after being processed by a coupler, a bandpass filter, and a preamplifier, it enters the SC1128 chip for demodulation and is finally transmitted to the microcontroller.

[0047] In step S3, each temperature gas detection module is given a unique address code. The monitoring host reads, converts, and stores the detection values ​​of the connected temperature gas detection modules through the unique address codes.

[0048] This application, through ingenious circuit design, achieves analog-to-digital conversion without the need for A / D conversion circuits and reference standard power supplies, saving costs and resulting in a simple and compact structure. Furthermore, the communication circuit utilizes existing low-voltage power lines for carrier communication, eliminating the need for communication cables. This not only saves on construction work and investment but also makes maintenance more convenient.

[0049] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A power transformer fault detection device based on power line carrier wave, characterized in that: It includes a monitoring host, a temperature and gas detection module, and a carrier communication module. The monitoring host and one or more temperature and gas detection modules are connected in series on a low-voltage power line through the carrier communication module, so that the monitoring host and one or more temperature and gas detection modules can communicate via power line carrier. The monitoring host communicates with a host computer via wired or wireless means. The temperature and gas detection module includes a microcontroller and a temperature acquisition circuit and a gas acquisition circuit electrically connected to the microcontroller. The temperature acquisition circuit includes a thermistor Rx, a resistor R1 and a capacitor C1. The two ends of the thermistor Rx are connected to the RA0 and RA2 ports of the microcontroller, respectively. The two ends of the resistor R1 are connected to the RA1 and RA2 ports of the microcontroller, respectively. The RA2 port of the microcontroller is grounded through the capacitor C1. The gas acquisition circuit includes a capacitive gas sensor Cx, resistors R2, R3, R4, R5, and a 555 timer chip. One end of the capacitive gas sensor Cx and one end of resistor R2 are grounded, and the other end is electrically connected to the second, fifth, and sixth ports of the 555 timer chip, respectively. The two ends of resistor R3 are electrically connected to the second, third, and seventh ports of the 555 timer chip, respectively. One end of resistors R4 and R5 is electrically connected to the third port of the 555 timer chip, and the other end is electrically connected to the power supply and the RA3 port of the microcontroller.

2. The power transformer fault detection device based on power line carrier as described in claim 1, characterized in that: The resistors R1, R2, R3, R4, and R5 are all constant value resistors.

3. The power transformer fault detection device based on power line carrier as described in claim 1, characterized in that: The monitoring host is electrically connected to the alarm device.

4. The power transformer fault detection device based on power line carrier as described in claim 1, characterized in that: The carrier communication module includes an SC1128 chip, a power amplifier, a coupler, a bandpass filter, and a preamplifier. The SC1128 chip modulates the information to be transmitted and then transmits it to the existing low-voltage power line through the power amplifier and coupler. The information transmitted on the existing low-voltage power line is processed by the coupler, bandpass filter, and preamplifier before entering the SC1128 chip for demodulation.

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