Transformer turn-to-turn short circuit fault diagnosis system based on DSP

Abstract

The utility model provides a transformer turn-to-turn short circuit fault diagnosis system based on a DSP (Digital Signal Processor), which is used for solving the problems that a traditional diagnosis system cannot quickly process a large amount of data and is low in diagnosis accuracy. The system comprises a transformer, a current sensor, a signal conditioning module, an A / D conversion module, a DSP, a communication module, a buzzer, an LED indicating lamp, a display screen and a power supply module. The current sensor is connected in series on a transformer bus and collects nine paths of currents on the high side, the middle side and the low side, current signals are processed through the signal conditioning module and then enter the A / D conversion module, analog signals are converted into digital signals, then the digital signals are transmitted to the DSP to be processed, the operation state of the transformer is obtained, and the operation state of the transformer is displayed through the LED indicator lamp, the buzzer and the display screen. Meanwhile, the diagnosis result is sent to the master control room through the communication module, the practicability of the system is enhanced, and real-time transmission of information is ensured.

Description

Technical Field

[0001] The utility model belongs to the technical field of power systems, and in particular relates to a transformer inter-turn short circuit fault diagnosis system based on DSP. Background Art

[0002] Transformers are a vital component of the power grid, and their safe and stable operation is crucial to its reliability. Turn-to-turn short circuits are one of the most common transformer faults. Failure to detect and address them promptly can lead to more serious failures or even equipment damage, resulting in significant losses to the power grid and the national economy. Traditional electrical equipment inspection and fault diagnosis rely primarily on manual inspections and empirical judgment. This approach is inefficient and error-prone, making it inadequate for the inspection needs of modern, complex electrical equipment. Currently, transformer turn-to-turn short circuit fault diagnosis results can only be displayed in the control room, failing to promptly alert on-site maintenance personnel. To improve the accuracy and real-time performance of transformer status detection and fault diagnosis, a QPSO-LSSVM model is employed to automatically process and analyze large amounts of data, determine the operating status of the transformer windings, and display diagnostic information in real time through various means. Substations are equipped with at least two transformers. When one transformer is out of service, the remaining transformer, taking into account overload conditions, can meet the power supply needs of Class I and II loads, ensuring power supply continuity. Class I and II loads typically account for 70-80% of the total load. Therefore, an effective electrical equipment fault diagnosis system can not only accurately identify faults, but also quickly notify on-site operation and maintenance personnel to ensure that timely measures can be taken to ensure stable operation of the power grid. Summary of the Invention

[0003] In response to the technical problems existing in the above-mentioned background technology, the present invention proposes a DSP-based transformer inter-turn short-circuit fault diagnosis system, which solves the problems that traditional diagnostic technology cannot quickly process large amounts of data, has low diagnostic accuracy, and the diagnostic results can only be viewed on the main control room display. It is beneficial for on-site operation and maintenance personnel to timely grasp and view the operating status of the transformer winding.

[0004] In order to achieve the above object, the technical solution of the present invention is achieved as follows:

[0005] A DSP-based transformer inter-turn short-circuit fault diagnosis system includes a transformer, a current sensor, a signal conditioning module, an A / D conversion module, a DSP, a buzzer, an LED indicator, a display, and a power module. The current sensor is connected in series to the transformer busbar to collect a total of 9 currents on the high, medium, and low sides. The current signal is processed by the signal conditioning module and then enters the A / D conversion module, which converts the analog signal into a digital signal. The signal is then transmitted to the DSP for processing to obtain the transformer operating status. At the same time, the transformer operating status is displayed through the LED indicator, the buzzer, and the display. The power module supplies power to the DSP, the signal conditioning module, and the A / D conversion module respectively.

[0006] Preferably, the transformer operating status includes: normal, minor fault, general fault, serious fault and severe fault; at the same time, the DSP drives the indicator light and buzzer to issue differentiated alarms according to the fault type, and directly displays the fault type through the on-site display screen.

[0007] Preferably, a communication module is included, and the DSP monitors the operating status of the transformer in real time, obtains the diagnosis result, and sends the diagnosis result to the main control room through the communication module.

[0008] Preferably, the main control room is equipped with a monitoring host, a server and a monitoring screen; after the monitoring host receives the diagnosis result, it displays the diagnosis result on the monitoring screen and sends the diagnosis result to the server at the same time. The server acts as a data center and centrally manages the diagnosis results from multiple monitoring hosts.

[0009] Preferably, the signal conditioning module includes an operational amplifier, the reverse input terminal of the operational amplifier is connected to the output terminal of the operational amplifier after passing through resistor R14 and sliding rheostat R15, and capacitor C8 is connected in parallel at both ends of resistor R14; the reverse input terminal of the operational amplifier is grounded in turn through resistor R13 and resistor R12, both ends of resistor R12 are connected in parallel with resistor R11, and both ends of resistor R11 are connected in parallel with capacitor C9; the positive input terminal of the operational amplifier is connected to the reverse input terminal of the operational amplifier through a bidirectional voltage regulator diode composed of D6 and D7, and the positive input terminal of the operational amplifier is grounded.

[0010] Preferably, the communication module includes a transceiver chip, a transient voltage suppression tube and an isolated non-regulated DC-DC chip; the pin +VIN of the isolated non-regulated DC-DC chip is connected to a 3.3V power supply, the pin -VIN of the isolated non-regulated DC-DC chip is grounded, the pin +VOUT of the isolated non-regulated DC-DC chip receives the pin VCC2 of the transceiver chip, and the pin -VOUT of the isolated non-regulated DC-DC chip receives the pin GND2 of the transceiver chip; the pin R of the transceiver chip is connected to the DSP through a filtering circuit composed of a resistor R16 and a capacitor C11; the pin RE and the pin DE of the transceiver chip are connected to the DSP through a filtering circuit composed of a resistor R17 and a capacitor C12; the pin D of the transceiver chip is connected to the DSP through a filtering circuit composed of a resistor R18 and a capacitor C13; one end of the transient voltage suppression tube is connected to pins A and B of the transceiver chip, and the other end of the transient voltage suppression tube is grounded.

[0011] Preferably, the A / D acquisition module model is AD7656; the operational amplifier model is LM324; the DSP model is TMS320F28335; the transceiver chip model is ISO15, the transient voltage suppression tube model is SM712, the isolated non-regulated DC-DC chip model is IB0303LS; and the display model is LCD1602 liquid crystal display.

[0012] The beneficial effects of the present invention include: collecting the current signal of a 110kV transformer through a current transformer, performing A / D conversion, and then performing fault diagnosis by a DSP using the QPSO-LSSVM transformer inter-turn short-circuit fault diagnosis model. The diagnostic results include: normal, minor fault, general fault, more serious fault, and severe fault. Depending on the fault type, an LED and buzzer are driven to issue differentiated alarms, which are directly displayed on the on-site display screen. The DSP transmits the diagnostic results to the main control room via a communication module, and uses multiple methods to display diagnostic information, thereby improving the efficiency and effectiveness of the alarm system, ensuring that key information can be quickly and accurately conveyed to operators, and enhancing the safety and reliability of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0014] Figure 1 This is a principle block diagram of the utility model.

[0015] Figure 2 This is a training flow chart of the transformer inter-turn short-circuit fault diagnosis model of the utility model.

[0016] Figure 3 This is a workflow diagram of the present utility model.

[0017] Figure 4 This is the DSP circuit diagram of the utility model.

[0018] Figure 5 This is the circuit diagram of the signal conditioning module of the present utility model.

[0019] Figure 6 This is the circuit diagram of the A / D conversion module of the utility model.

[0020] Figure 7 This is the circuit diagram of the communication module of the present utility model.

[0021] Figure 8 This is the circuit diagram of the power module of the utility model.

[0022] Figure 9 This is a circuit diagram of the display screen of the present utility model.

[0023] Figure 10 This is the circuit diagram of the LED indicator light of the present utility model.

[0024] Figure 11 This is the buzzer circuit diagram of the utility model. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0026] like Figure 1 As shown, the embodiment of the utility model provides a DSP-based transformer inter-turn short circuit fault diagnosis system, including a 110kV transformer, a current sensor, a signal conditioning module, an A / D conversion module, a DSP, a communication module, a buzzer, an LED indicator, a display screen, and a power module. The current sensor is connected in series to the 110kV transformer busbar to collect a total of 9 currents on the three sides of the transformer (high, medium, and low). The current signal is processed by the signal conditioning module and then enters the A / D conversion module, which converts the analog signal into a digital signal and then transmits it to the DSP for processing. In the DSP, the collected current signal is diagnosed using the QPSO-LSSVM transformer inter-turn short circuit fault diagnosis model to obtain the transformer operating status, including: normal, minor fault, general fault, more serious fault, and severe fault. At the same time, the indicator light and buzzer are driven to issue a differentiated alarm based on the fault type, and the fault type is directly displayed on the on-site display screen. The DSP monitors the transformer operating status in real time, obtains the judgment result, and sends the judgment result to the main control room via the communication module. In addition, the power module supplies power to the DSP, signal conditioning module, and A / D conversion module respectively.

[0027] The main control room is equipped with a monitoring host, a server and a monitoring screen. After receiving the diagnosis result, the monitoring host displays the diagnosis result on the local monitoring screen and sends the diagnosis result to the server. The server can serve as a data center to centrally manage the judgment results from multiple monitoring hosts.

[0028] The QPSO-LSSVM fault diagnosis model flow chart is as follows Figure 2As shown in the figure, first, current data of the transformer in normal state and during turn-to-turn short-circuit faults are collected, and severity levels for different numbers of short-circuit turns are defined. Second, the data is preprocessed to remove missing values ​​and obviously abnormal samples from the dataset. A standardization method is used to normalize the raw data to the interval [0, 1] to accelerate the convergence of the model. Third, the penalty factor C and kernel function parameter g in the LSSVM model are optimized using the QPSO algorithm, resulting in an optimal parameter LSSVM diagnostic model. Finally, the dataset is divided into a training set and a test set in a ratio of 7:3. The model is trained using samples from the training set, and tested using samples from the test set. This results in a QPSO-LSSVM turn-to-turn short-circuit fault diagnosis model with optimal classification performance.

[0029] The working principle of this embodiment is as follows Figure 3 As shown in the figure, the trained QPSO-LSSVM model parameters are first loaded into the DSP's memory. The DSP system initialization routine is then executed to ensure the proper functioning of all peripheral components and interfaces. The transformer bus current signal is collected via a current transformer, converted to digital form, and transmitted to the DSP. The DSP extracts characteristic factors relevant to fault diagnosis from this data. These extracted characteristic factors are then fed into the trained QPSO-LSSVM model, which then performs fault diagnosis inference and generates fault diagnosis results, including normal, minor, general, severe, and critical faults. The DSP continuously monitors the transformer's operating status and updates the diagnostic results in real time.

[0030] like Figure 4As shown, the DSP model used in this application is the TMS320F28335, a series of high-performance digital signal processors (DSPs) produced by Texas Instruments. It features a CPU clock frequency of up to 150MHz and uses 32-bit fixed-point or floating-point operations, providing high-performance mathematical computing capabilities. It has a rich set of peripheral resources, including multiple general-purpose timers, a watchdog timer, a compare unit, PWM outputs, and communication interfaces such as SPI, I2C, and UART. It provides analog input channels and supports ADC functions for acquiring analog signals. It also supports external memory interfaces, allowing connection to storage devices such as SDRAM, NOR Flash, and NAND Flash. VDDIO.1 to VDDIO.8 are digital I / O power pins, connected to a 3.3V power supply; VDD.1 to VDD.13 are CPU and logic digital power pins, connected to a 1.9V power supply. Pin XRS is the DSP device reset input pin and also serves as the reset output pin for the watchdog circuit. The initial position of the PC pointer is 0xFFFC0. When XRS is high, program execution begins at the location indicated by the PC. If a watchdog reset occurs, this pin is low. During a watchdog reset, the XRS pin is driven low for the duration of the watchdog reset (512 OSCCLK cycles). It is driven by an open-drain driver consisting of C55 and R47, along with the 3.3V power supply and GND. VSS.1 through VSS.22 are the DSP digital ground pins and are connected to GND. Pin X1 is the internal / external oscillator input, and pin X2 is the internal oscillator output. Connecting a crystal oscillator Y1 between pins X1 and X2, and connecting a 1.9V external oscillator to X1, requires that pin XCLKOUT be grounded. VDDA2 and VSSA2 are the ADC analog power supply pins, while VDD1A18, VDD2A18, VSS1AGND, and ASS2AGND are the ADC analog ground pins. Pin ADCLO is the common ground for the analog inputs and is connected to analog ground. Pin ADCREFIN is the external reference input. The ADCRESEXT pin is the ADC external current bias resistor. Connect a 22kΩ resistor to analog ground. The ADCRESEXT pin is the internal reference output and requires a 2.2μF ceramic resistor with low equivalent series resistance to bypass it to analog ground. The ADCREFP pin is the internal reference voltage positive output and requires a 2.2μF ceramic resistor with low equivalent series resistance to bypass it to analog ground.GPIO62 on the DSP is connected to the CONVESTA / B / C pins of two AD7656 chips to control simultaneous sampling. GPIO48-63 and GPIO64-79 are connected to two sets of DB0-15, respectively, to receive data from the two AD7656 chips. CPIO46 is connected to the RESET pins of the two chips to send a reset signal. GPIO44 is connected to the BUSY pins of the two chips. A high level indicates that the chip is in the process of converting, while a low level indicates that the conversion is complete and the result can be read. GPIO0 is connected to the RS pin of the LCD1602, GPIO01 is connected to the EN pin, and GPIO02-09 are connected to D0-D7, respectively. GPIO13 on the DSP controls the alarm bell, and GPIO14-18 control the LED indicators, activating the alarm if an abnormality occurs.

[0031] like Figure 5 As shown, the signal conditioning module includes an operational amplifier. Its inverting input is connected to its output via resistor R14 and rheostat R15, with capacitor C8 connected in parallel across resistor R14. The inverting input of the operational amplifier is connected to ground via resistors R13 and R12, followed by resistor R11, which is connected in parallel with capacitor C9. The positive input of the operational amplifier is connected to the inverting input of the operational amplifier via a bidirectional voltage regulator diode formed by diodes D6 and D7, and its positive input is grounded. The signal conditioning module converts the sensor's signal into a standard signal, involving amplification, filtering, isolation, and modulation and demodulation to ensure that the analog signal is properly processed and prepared before entering the A / D module. The output current signal of the AC transformer is fed into the signal conditioning circuit's CurrentA port. After passing through sampling resistors R11 and R12, the current signal is converted into a voltage signal. Capacitor C9 provides high-frequency decoupling to ensure the stability of the output voltage signal. The signal passes through the operational amplifier circuit, consisting of an LM324 operational amplifier, resistor R14, capacitor C8, and Zener diodes D6 and D7, which conditions the signal into a stable voltage signal for input into the A / D module. The positive input of the LM324 operational amplifier is connected to ground via a bidirectional Zener diode formed by D6 and D7. If a transient voltage spike causes the voltage to exceed the circuit's tolerance range, the bidirectional Zener diode will conduct, shunting the excess voltage and thus protecting the circuit. The negative input of the LM324 operational amplifier is connected to the output of the LM324 operational amplifier through resistor R14, capacitor C8, and a sliding rheostat R15. This combined circuit is used to adjust and optimize the signal amplitude, filter noise, stabilize the power supply, or provide necessary bias.

[0032] like Figure 6The A / D converter shown is the AD7656, a highly integrated, 6-channel, 16-bit successive approximation analog-to-digital converter (ADC) manufactured by Analog Devices. Using iCMOS process technology, it delivers high performance while significantly reducing power consumption and package size. This chip has a maximum throughput of 250kSPS and supports true bipolar analog inputs with a pin- or software-selectable ±5V analog input range. The AD7656 features an on-chip 2.5V reference and reference buffer, supporting both parallel and serial interfaces. It also includes a low-noise, wideband sample-and-hold amplifier capable of handling input frequencies up to 8MHz. Data pins DB0-DB15 connect directly to the DSP's data lines D0-D15 for parallel or serial data output. To sample nine current signals (high, medium, and low), the AD7656 has six analog input pins (V1-V6). Therefore, two chips are required: the first chip operates with all pins V1-V6, while the second chip operates with pins V1-V3. To ensure that analog data is collected simultaneously, CONVST pins 21-23 must be triggered simultaneously for analog-to-digital conversion. After receiving the start signal, the DSP activates the CS chip select signal to initiate CONVST and synchronize ADC sampling. After the conversion is complete, the BUSY pin generates an interrupt signal, which the DSP responds to and reads the data. The STBY pin is the standby mode input. When the STBY pin receives a 3.3V high signal, the chip operates normally; when the STBY pin receives a low signal, the chip enters standby mode. The VCC and VDD pins are connected to the -15V and +15V power supplies, respectively, and are decoupled via a 10μF capacitor. The RESCAPA, RESCAPB, and RESCAPC pins are reference voltage pins. Each pin should be connected to analog ground with a 0.1μF capacitor to filter high-frequency noise and stabilize the voltage of internal circuits. The REFIN pin is the reference voltage input / output, which enables the internal reference voltage.

[0033] like Figure 7As shown, the communication module includes a transceiver chip, a transient voltage suppression tube and an isolated non-regulated DC-DC chip; the pin +VIN of the isolated non-regulated DC-DC chip is connected to a 3.3V power supply, the pin -VIN of the isolated non-regulated DC-DC chip is grounded, the pin +VOUT of the isolated non-regulated DC-DC chip is connected to the pin VCC2 of the transceiver chip, and the pin -VOUT of the isolated non-regulated DC-DC chip is connected to the pin GND2 of the transceiver chip; the pin R of the transceiver chip and the filter circuit composed of resistor R16 and capacitor C11 are connected to the DSP; the pin RE and pin DE of the transceiver chip are connected to the DSP through the filter circuit composed of resistor R17 and capacitor C12; the pin D of the transceiver chip is connected to the DSP through the filter circuit composed of resistor R18 and capacitor C13; one end of the transient voltage suppression tube is connected to pins A and B of the transceiver chip, and the other end of the transient voltage suppression tube is grounded.

[0034] Due to the strong electromagnetic interference within the substation and the long distance between the on-site data acquisition and processing units and the host computer in the main control room, signal attenuation and data loss may occur. To ensure high data transmission reliability, this system selected the RS-485 serial bus as a data transmission solution. RS-485 uses two lines, A and B, for differential signal transmission, which helps reduce electromagnetic interference and improve the signal's anti-interference ability. It supports a maximum data transmission rate of up to 10Mbps and a standard maximum transmission distance of 1200 meters. The common-mode output voltage range is -7V to +12V, and the minimum receiver input impedance is 12kΩ. The bus can connect up to 32 devices, and can support more devices with the use of repeaters. This system uses TI's ISO15, an isolated half-duplex differential signal transceiver chip, to facilitate communication between the host and slave computers. The ISO15, manufactured by Texas Instruments, complies with the RS-485 standard, supports a data rate of 1 Mbps and 256 nodes. It features low capacitance, thermal protection, and fail-safe features, operating over a wide temperature range. Its reinforced isolation helps protect sensitive circuits from voltage transients. Because the DSP's SCI uses TTL-level signals, while the PC's serial port uses RS232-level signals, the ISO15 transceiver chip converts the DSP's TTL-level signals into RS485 differential signals. On the host computer side, a common RS232 / 485 converter is also required to convert the RS485 signals into RS232 signals for the PC to understand, thus completing data communication between the master and slave devices. VCC2 is the bus-side power pin, connected to a 3.3V power supply, and GND2 is connected to ground. Pin R is the receiver output pin and is connected to the DSP pin SCIB_RX through an RC filter circuit. Pins RE and DE are the receiver logic-low enable pins and are connected to the DSP pin SCIB_DIR through an RC filter circuit. Pin D is the data input pin and is connected to the DSP pin SCIB_TX through an RC low-pass filter. Pins A and B are connected to the host computer. To protect the device from damage caused by electrostatic discharge and lightning strikes, a transient voltage suppression (TVS) network consisting of SM712 semiconductor devices is added to the differential signal terminals of Pins A and B. To eliminate the influence of common-mode voltage, the system power supply is isolated from the RS-485 transceiver power supply using an unregulated DC-DC isolation chip IB0303LS.

[0035] like Figure 8 As shown, the power module provides 3.3V and 1.9V voltages to DSP28335. Figure 8This application uses the TPS767D301 power supply chip, a low-dropout linear regulator manufactured by Texas Instruments specifically designed for DSP applications. The OUT1 output voltage is adjustable (1.5V to 5.5V), while the OUT2 output voltage is fixed at 3.3V. The DSP core requires a 1.9V supply voltage. The design of R19 and R20 should follow the following rules: =1.1834V, so R19 = 18kΩ and R20 = 30kΩ. A 0.1μF capacitor and a 10μF electrolytic capacitor are added to the output to ensure voltage smoothing. High-frequency noise is filtered through ferrite beads L1 and L2, respectively, resulting in 1.9V and 3.3V analog power supplies. A 0.1μF capacitor and a 10μF electrolytic capacitor are also added to the input to ensure power supply stability. Pins 1RESET and 2RESET are connected to the DSP's XRSN pin. If either the 1.9V or 3.3V output voltage falls below the preset threshold, it activates a reset signal, resetting the DSP to ensure stable system operation.

[0036] The power module provides 15V power to the A / D module and operational amplifier, such as Figure 8 As shown in Figure b, this is provided by the WD5-24S15A1 chip. The INPUT 24V port is connected to the OUT+ pin, and the INPUT 0V port is connected to the OUT- pin, providing driver power. A 100uF / 35V capacitor C33 is connected between the two ports for filtering and decoupling. The IN+ pin outputs a 15V DC source, while the IN- pin is grounded. A 220uF capacitor C32 and a 1kΩ resistor R51 are connected between the two ports for voltage regulation and to reduce noise on the power line. The IN4747A Zener diode D12 protects the circuit from reverse voltage damage.

[0037] like Figure 9The display used is an LCD1602, capable of displaying two lines of 16 characters each. This is a dot-matrix LCD module specifically designed for displaying letters, numbers, and symbols. It's used for displaying DSP calculation outputs on-site. It consists of several 5x7 or 5x10 dot-matrix character positions. Pin VO is the LCD contrast adjustment pin, which adjusts the display brightness by adjusting the RJ1 potentiometer. Connecting it to the positive power supply minimizes contrast, while connecting it to ground maximizes contrast. Pin RS is the register select pin; a high level selects the data register and a low level selects the instruction register. Pin RW is connected high for read operations and low for write operations. Pin E is the enable pin; a transition from high to low (falling edge active) causes the LCD module to execute commands. Pins 7-14 are 8-bit bidirectional data lines connected to the DSP's GPIO interface. VDD is connected to the 5V power supply, while capacitor C10 is connected to GND to provide voltage regulation and filtering.

[0038] The alarm circuit consists of LED indicator and light buzzer, such as Figure 10 and Figure 11 As shown in the figure. If the diagnosis indicates a transformer interturn short circuit, the TMS320F28335's internal program pulls the previously high level of GPIO14 pin down. A 3.3V power supply is connected to digital ground via resistor R21, indicator D1, and GPIO14 pin, illuminating indicator D1. A low signal at GPIO13 turns on transistor TP6, creating a 3.3V power supply path through transistor TP6 and buzzer BZ1 to digital ground, driving buzzer BZ1 to generate an audible alarm. The combination of the LED and buzzer alerts maintenance personnel on-site of the transformer interturn short circuit. If the transformer is normal, the green LED will be on steadily without flashing, and the buzzer will remain silent; if a minor fault occurs, the blue LED will flash, with an interval set to 2 seconds (1 second on, 1 second off), and the buzzer will emit a 1-second prompt tone every 10 seconds; if a general fault occurs, the yellow LED will flash, with an interval set to 2 seconds (0.5 seconds on, 1.5 seconds off), and the buzzer will emit a 0.5-second prompt tone every 5 seconds; if a more serious fault occurs, the orange LED will flash quickly, with an interval set to 1 second (0.3 seconds on, 0.7 seconds off), and the buzzer will emit two 0.5-second alarm sounds every 2 seconds, with a 0.5-second interval in between; if a serious fault occurs, the red LED will flash rapidly, with an interval set to 0.5 seconds (0.2 seconds on, 0.3 seconds off), and the buzzer will continuously sound an alarm, with a brief pause of 0.2 seconds every 0.3 seconds to produce a rapid intermittent sound.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A DSP-based transformer turn-to-turn short circuit fault diagnosis system, characterized in that: It includes a transformer, a current sensor, a signal conditioning module, an A / D conversion module, a DSP, a buzzer, an LED indicator, a display and a power module; the current sensor is connected in series to the transformer bus to collect a total of 9 currents on the high, medium and low sides. The current signal is processed by the signal conditioning module and then enters the A / D conversion module to convert the analog signal into a digital signal, which is then transmitted to the DSP for processing to obtain the transformer operating status. At the same time, the transformer operating status is displayed through the LED indicator, buzzer and display; the power module supplies power to the DSP, signal conditioning module and A / D conversion module respectively.

2. The DSP-based transformer turn-to-turn short circuit fault diagnosis system according to claim 1, characterized in that: The transformer operating status includes: normal, minor fault, general fault, serious fault and severe fault; at the same time, the DSP drives the indicator light and buzzer to issue differentiated alarms according to the fault type, and directly displays the fault type on the on-site display screen.

3. The DSP-based transformer turn-to-turn short circuit fault diagnosis system according to claim 1, characterized in that: Including a communication module, the DSP monitors the operating status of the transformer in real time, obtains the diagnosis results, and sends the diagnosis results to the main control room through the communication module.

4. The DSP-based transformer turn-to-turn short circuit fault diagnosis system according to claim 3 is characterized in that: The main control room is equipped with a monitoring host, a server and a monitoring screen. After receiving the diagnosis results, the monitoring host displays the diagnosis results on the monitoring screen and sends the diagnosis results to the server. The server acts as a data center and centrally manages the diagnosis results from multiple monitoring hosts.

5. The DSP-based transformer turn-to-turn short circuit fault diagnosis system according to claim 1, characterized in that: The signal conditioning module includes an operational amplifier, the reverse input end of the operational amplifier is connected to the output end of the operational amplifier after passing through resistor R14 and sliding rheostat R15, and capacitor C8 is connected in parallel across resistor R14; the reverse input end of the operational amplifier is grounded via resistors R13 and R12 in sequence, resistor R11 is connected in parallel across resistor R12, and capacitor C9 is connected in parallel across resistor R11; the positive input end of the operational amplifier is connected to the reverse input end of the operational amplifier through a bidirectional voltage regulator diode composed of D6 and D7, and the positive input end of the operational amplifier is grounded.

6. The DSP-based transformer turn-to-turn short-circuit fault diagnosis system according to claim 3, characterized in that: The communication module includes a transceiver chip, a transient voltage suppression tube and an isolated non-regulated DC-DC chip; the pin +VIN of the isolated non-regulated DC-DC chip is connected to a 3.3V power supply, the pin -VIN of the isolated non-regulated DC-DC chip is grounded, the pin +VOUT of the isolated non-regulated DC-DC chip is connected to the pin VCC2 of the transceiver chip, and the pin -VOUT of the isolated non-regulated DC-DC chip is connected to the pin GND2 of the transceiver chip; the pin R of the transceiver chip is connected to the filter circuit composed of a resistor R16 and a capacitor C11 and is connected to the DSP; the pin RE and the pin DE of the transceiver chip are connected to the DSP through the filter circuit composed of a resistor R17 and a capacitor C12; the pin D of the transceiver chip is connected to the DSP through the filter circuit composed of a resistor R18 and a capacitor C13; one end of the transient voltage suppression tube is connected to the pins A and B of the transceiver chip, and the other end of the transient voltage suppression tube is grounded.

7. The DSP-based transformer turn-to-turn short-circuit fault diagnosis system according to claim 6, characterized in that: The A / D acquisition module model is AD7656; the operational amplifier model is LM324; the DSP model is TMS320F28335; the transceiver chip model is ISO15, the transient voltage suppression tube model is SM712, the isolated non-regulated DC-DC chip model is IB0303LS; and the display model is LCD1602 liquid crystal display.

Images