A high-voltage insulating sleeve defect detection device and method

Abstract

The application belongs to the technical field of high-voltage insulation test, and discloses a high-voltage insulation sleeve defect detection device and method. A highly relevant mathematical model is established through historical evaluation data, and then the measured data of the high-voltage insulation sleeve to be detected are substituted into the mathematical model to obtain the deterioration state of the high-voltage insulation sleeve to be detected. The detection corrects the systematic or accidental errors of the measured data by using a software algorithm, is accurate in judgment, and is suitable for popularization in various high-voltage insulation sleeve state tests.

Description

Technical Field

[0001] This invention belongs to the field of high-voltage insulation testing technology, and specifically discloses a device and method for detecting defects in high-voltage insulating bushings. Background Technology

[0002] High-voltage insulating bushings are crucial accessories for electrical equipment, used to insulate the high-voltage leads of transformers, reactors, and other electrical equipment from their metal casings. They are an important component of the power system, and their insulation performance directly affects the safety, stability, and economical operation of the power grid. Insulation faults in high-voltage bushings develop gradually, and their insulation performance deteriorates over time. Currently, the most common methods for monitoring the insulation performance of high-voltage bushings are by measuring insulation resistance, capacitance, and dielectric loss. Existing bushing testing methods each have their own characteristics and are highly targeted; however, they present the following problems in practical applications:

[0003] Insulation resistance testing takes place in complex environments. Stray currents and the interaction of strong electromagnetic fields make test signals highly susceptible to interference from strong electric fields, leading to inaccurate test results. Capacitance and dielectric loss monitoring methods fail to reflect the gradual expansion of local defects in bushings because individual local defects do not significantly alter the overall dielectric loss tangent. Furthermore, their accuracy is relatively low. Therefore, condition assessment personnel urgently need a diagnostic method and system capable of quantitatively assessing the deterioration state of high-voltage insulating bushings. Summary of the Invention

[0004] To address the problems in the background art, the present invention provides a high-voltage insulating bushing defect detection device, the specific technical solution of which is as follows:

[0005] A high-voltage insulating bushing defect detection device includes a signal generation circuit, a signal acquisition circuit, and a detection module. The output of the signal acquisition circuit is communicatively connected to the detection module. The signal generation circuit is connected to both ends of a programmable AC power supply via a series power resistor connected to a conductor. The conductor is partially covered by a high-voltage insulating bushing. Multiple temperature sensor probes are axially spaced on the outer surface of the high-voltage insulating bushing. The temperature sensor probes are electrically connected to a temperature-current transmitter module from their input ends. A current sensor is installed on the portion of the conductor not covered by the high-voltage insulating bushing. The signal acquisition circuit includes a signal conditioning module, an A / D conversion module, and an FPGA data acquisition module, which are communicatively connected in sequence according to the signal transmission direction. The output ends of the temperature-current transmitter module and the current sensor are communicatively connected to the input end of the signal conditioning module. The detection module has a built-in multi-dimensional database and a correlation mathematical model establishment module.

[0006] Preferably, the programmable AC power supply has a total three-phase capacity of 12000VA, and the power resistor is an RXG20 type corrugated resistor with a resistance of 100Ω and a rated power of 10kW.

[0007] Preferably, the signal conditioning module includes an amplifier circuit module that amplifies the output voltage range from 0.6V-3V to 0-5V.

[0008] Preferably, the detection module further includes a signal calibration module, used to detect and calibrate nonlinear errors in the received signal using a piecewise fitting algorithm.

[0009] This invention also provides a method for detecting defects in high-voltage insulating bushings, comprising the following steps:

[0010] S1. Convert the temperature signal of the reference high-voltage insulating bushing obtained by the temperature sensor probe into a current signal, and convert the analog signal formed by conditioning the current signal and the current signal obtained by the current sensor at the same time point into a digital signal.

[0011] S2. Collect and organize the data of the digital signal, and upload the organized data to the multidimensional database;

[0012] S3. Determine the defect type of the reference high-voltage insulating bushing and fill it into the corresponding cell in the multidimensional database;

[0013] S4. Extract multiple sets of temperature data measured by the temperature sensor at different positions of the reference high-voltage insulating bushing at the same time point from the multidimensional database, high-frequency harmonic characteristic values ​​regularized from the current data measured by the current sensor, and the defect type, and establish a mathematical model through correlation fitting calculation.

[0014] S5. Replace the reference high-voltage insulating bushing with the high-voltage insulating bushing to be tested, repeat steps S1-S2 above, and substitute the measured data into the mathematical model described in step S4 to obtain the defect type of the high-voltage insulating bushing to be tested.

[0015] Preferably, the signal conditioning module in step S1 amplifies the output voltage range from 0.6V-3V to 0-5V.

[0016] Furthermore, the sorting process described in step S2 includes detecting and calibrating nonlinear errors in the received signal using a piecewise fitting algorithm.

[0017] The method for detecting defects in high-voltage insulating bushings using the aforementioned apparatus has the following advantages:

[0018] By establishing a database and mathematical model through experiments, real-time quantitative detection can be achieved, and the degradation state of high-voltage insulating bushings can be scientifically evaluated. The obtained high-voltage bushing temperature and high-frequency harmonic data are directly related to the degree of degradation of the high-voltage bushing. Furthermore, the mathematical model proposed in this application is more conducive to revealing the degradation state of high-voltage insulating bushings through the combined effect of the above two types of data.

[0019] Adding a step to detect and calibrate the nonlinear error in the received signal using a piecewise fitting algorithm during data processing can effectively eliminate systematic errors in the measuring device and random errors during the testing process, making the data more accurate.

[0020] Expanding the output voltage range from 0.6V-3V to 0-5V makes it easier for subsequent signal receiving devices to identify the signal.

[0021] The programmable AC power supply in the signal generation circuit of the device has a total capacity of 12000VA and uses RXG20 type corrugated resistors with a resistance of 100Ω and a rated power of 10kW. It has been proven that the above configuration generates the most stable signal and is more conducive to propagation. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a high-voltage insulating bushing defect detection device in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of high-voltage insulating bushing defect detection in an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the amplifier circuit module in an embodiment of the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely a part of the embodiments of this invention, and not all of them. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0026] Several high-voltage insulating bushings with defects such as local overheating, partial discharge, cracks and metal particles, as well as those that are completely normal, are selected as a reference group for high-voltage insulating bushings.

[0027] An embodiment of a high-voltage insulating bushing defect detection device:

[0028] according to Figure 1-2The signal generation circuit, signal acquisition circuit, and detection module are connected as shown. The output of the signal acquisition circuit is communicatively connected to the detection module, which is located in the host computer. The signal generation circuit is connected to the two ends of a programmable AC power supply via a series power resistor connected in series with a wire. The wire is covered with a high-voltage insulating sleeve, and multiple temperature sensor probes are installed at axial intervals on the outer surface of the high-voltage insulating sleeve. The probes are made of platinum resistance thermometers. The temperature sensor probes are electrically connected to the temperature-current transmitter module from the input end. The part of the wire without the high-voltage insulating sleeve is covered with a current sensor. The signal acquisition circuit includes a signal conditioning module, an A / D conversion module, and an FPGA data acquisition module that are communicatively connected in sequence according to the signal transmission direction. The output ends of the temperature-current transmitter module and the current sensor are communicatively connected to the input end of the signal conditioning module. The detection module has a built-in multidimensional database and a correlation mathematical model establishment module.

[0029] The programmable AC power supply is model Chroma 61705, with a total three-phase capacity of 12000VA. It can achieve a maximum phase voltage of 300V and a frequency range from 15Hz to 1.2kHz. The power resistor is an RXG20 corrugated resistor with a resistance of 100Ω and a rated power of 10kW. Its main function is to limit the circuit current and prevent the programmable power supply from overloading.

[0030] The signal conditioning module refers to the amplification circuit module. After resistor-to-current conversion, the output voltage range is 0.6V to 3V, and the final output voltage is 0 to 5V. Therefore, ordinary operational amplifiers cannot achieve the desired output value. This design uses the AD623 instrumentation amplifier from Analog Devices (ADI). With external resistors, its gain can reach up to 1000 times, exhibiting excellent DC characteristics and common-mode rejection ratio, with a bandwidth of 800kHz (G=1). The AD623 has a wide input common-mode range and provides full-scale output from a single power supply (+3V to +12V). It can replace discrete instrumentation amplifier designs, offering excellent linearity, temperature stability, and reliability.

[0031] Figure 3 This is a block diagram of the amplifier circuit module. +IN and -IN represent the sensor signal and the external adjustment signal, respectively. Since the 0.6V~3V voltage needs to be converted to the required 0V~5V output, R28 = 19.1K and R29 = 6.04K. REC is provided by a 2.5V regulator LM136. +VS uses a single 5V power supply, and -VS (negative power supply) and the reference voltage are both grounded. Pin -6 is the OUT output signal. The input-output relationship is as follows:

[0032]

[0033] In the formula RG Select a resistor for gain, where the value R is... G =100KΩ / (G-1), where G is the gain factor, and the gain in this design is 100.

[0034] After the acquired signal passes through the A / D converter circuit, errors in the operational amplifier, temperature drift, and nonlinearity of the A / D converter all affect the acquired signal. To address this issue, this invention uses a software algorithm in the built-in detection module of the host computer to adjust for nonlinear errors in the circuit, and employs a piecewise fitting method to improve measurement accuracy while maximizing resolution.

[0035] Using the above-described device to test the deterioration state of the high-voltage insulating bushing according to the following steps constitutes another embodiment of the present invention, "a method for detecting defects in high-voltage insulating bushings".

[0036] High-voltage insulating bushings were taken out one by one from the reference group. Figure 1 The device is connected to the detection device. The temperature signal of the reference high-voltage insulating bushing obtained by the temperature sensor probe is converted into a current signal by the temperature-current transmitter module. The current signal and the current signal obtained by the current sensor at the same time are input into the signal conditioning module. The signal conditioning module amplifies the output voltage range from 0.6V-3V to 0-5V. The analog signal formed after conditioning is converted into a digital signal by the A / D conversion module and then input into the FPGA data acquisition module.

[0037] The FPGA data acquisition module collects the digital signal data, detects and calibrates the nonlinear error in the received signal through a piecewise fitting algorithm, and uploads the processed data to the multidimensional database.

[0038] Identify the defect type of the high-voltage insulating bushing for reference and fill it into the corresponding cell in the multidimensional database;

[0039] Multiple sets of temperature data measured by the temperature sensor probe at different positions of the reference high-voltage insulating bushing at the same time point are extracted from the multidimensional database, along with the high-frequency harmonic characteristic values ​​and the defect type from the current data measured by the current sensor. A mathematical model is then established through correlation fitting calculation.

[0040] Replace the reference high-voltage insulating bushing with the high-voltage insulating bushing to be tested, repeat the measurement steps in the above process, substitute the measured data into the mathematical model, and obtain the defect type of the high-voltage insulating bushing to be tested.

[0041] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for detecting defects in high-voltage insulating bushings, implemented using the following apparatus, characterized in that, The device includes a signal generation circuit, a signal acquisition circuit, and a detection module. The output of the signal acquisition circuit is communicatively connected to the detection module. The signal generation circuit is connected to both ends of a programmable AC power supply via a series power resistor connected in series with a wire. The wire is partially covered with a high-voltage insulating sleeve. Multiple temperature sensor probes are axially spaced on the outer surface of the high-voltage insulating sleeve. The temperature sensor probes are electrically connected to a temperature-current transmitter module from their input ends. A current sensor is installed on the portion of the wire not covered with the high-voltage insulating sleeve. The signal acquisition circuit includes a signal conditioning module, an A / D conversion module, and an FPGA data acquisition module, which are communicatively connected in sequence according to the signal transmission direction. The output ends of the temperature-current transmitter module and the current sensor are communicatively connected to the input end of the signal conditioning module. The detection module has a built-in multidimensional database and a correlation mathematical model establishment module. The method includes the following steps: S1. Convert the temperature signal of the reference high-voltage insulating bushing obtained by the temperature sensor probe into a current signal, and convert the analog signal formed by conditioning the current signal and the current signal obtained by the current sensor at the same time point into a digital signal. S2. Collect and organize the data of the digital signal, and upload the organized data to the multidimensional database; S3. Determine the defect type of the reference high-voltage insulating bushing and fill it into the corresponding cell in the multidimensional database; S4. Extract multiple sets of temperature data measured by temperature sensors at different locations of the reference high-voltage insulating bushing at the same time point from the multidimensional database, high-frequency harmonic characteristic values ​​regularized from the current data measured by the current sensor, and the defect type, and establish a mathematical model through correlation fitting calculation. S5. Replace the reference high-voltage insulating bushing with the high-voltage insulating bushing to be tested, repeat steps S1-S2 above, and substitute the measured data into the mathematical model described in step S4 to obtain the defect type of the high-voltage insulating bushing to be tested.

2. The method for detecting defects in high-voltage insulating bushings as described in claim 1, characterized in that: The programmable AC power supply has a total three-phase capacity of 12000VA, and the power resistor is an RXG20 type corrugated resistor with a resistance of 100Ω and a rated power of 10kW.

3. The method for detecting defects in high-voltage insulating bushings as described in claim 2, characterized in that: The signal conditioning module includes an amplifier circuit module that amplifies the output voltage range from 0.6V-3V to 0-5V.

4. The method for detecting defects in high-voltage insulating bushings as described in claim 3, characterized in that: The detection module also includes a signal calibration module, which is used to detect and calibrate nonlinear errors in the received signal using a piecewise fitting algorithm.

5. The method for detecting defects in high-voltage insulating bushings as described in claim 4, characterized in that, The signal conditioning module described in step S1 amplifies the output voltage range from 0.6V-3V to 0-5V.

6. The method for detecting defects in high-voltage insulating bushings as described in claim 5, characterized in that, The sorting process described in step S2 includes detecting nonlinear errors in the received signal and performing calibration using a piecewise fitting algorithm.

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