Partial discharge detection method, device, partial discharge detection equipment and system for power cable

Abstract

This invention provides a method, apparatus, device, and system for partial discharge detection of power cables. The invention is simple to operate; it only requires inputting the desired partial discharge signal output discharge range to automatically output the discharge waveform within that range, thus achieving automatic partial discharge detection of power cables. Simultaneously, it features a preset function for the discharge interval; after setting, the voltage output between each discharge waveform can be continuously output according to that interval. This invention considers the aging and performance degradation of the circuit itself, performing self-calibration of the discharge quantity upon startup to determine the calibration coefficient for each run, ensuring the accuracy of the output waveform.

Description

Technical Field

[0001] This invention relates to the field of power grid technology, and in particular to a method, apparatus, equipment and system for detecting partial discharge in power cables. Background Technology

[0002] In today's rapidly developing world of science and technology, the power industry, as a fundamental national sector, is also growing stronger. The power industry occupies a vital position in people's lives; power outages can cause incalculable losses. Power cables, as important transmission equipment, are widely used in power grid construction. Common insulation materials used in daily cable laying include rubber insulation, polybutadiene rubber insulation, and cross-linked polyethylene (XLPE) insulation. Due to the superior physical and chemical properties of XLPE cables compared to other materials, low- and medium-voltage paper-insulated cables are gradually being replaced, and the number of high-voltage XLPE cables being laid is increasing year by year. Their large-scale production and application have promoted the development of my country's power industry.

[0003] With the widespread laying and prolonged use of cables, an increasing number of cables are exhibiting insulation defects of varying degrees, leading to power outages. To ensure the safe use of cables, partial discharge detection is necessary. Currently, partial discharge detection devices are generally manually adjustable. When outputting different partial discharge levels, the device must be manually switched to complete the next simulated partial discharge pulse output, increasing the overall operational complexity. Current partial discharge detection devices suffer from high complexity, long detection times, and low detection efficiency. Summary of the Invention

[0004] This invention provides a method, apparatus, equipment, and system for partial discharge detection of power cables. It can automatically generate partial discharge signals during partial discharge detection of power cables, realize automatic detection of partial discharge in power cables, reduce partial discharge detection time, and improve the detection efficiency of partial discharge detection devices.

[0005] In a first aspect, the present invention provides a method for partial discharge detection of power cables, applied to a partial discharge detection device, comprising: acquiring a control signal sent by a host computer; the control signal including a discharge interval and a discharge range; determining the number of detections and the pulse voltage during each detection based on the control signal; and controlling the partial discharge detection device to generate multiple partial discharge signals based on the number of detections and the pulse voltage during each detection, so as to realize automatic partial discharge detection of power cables.

[0006] In one possible implementation, determining the number of partial discharge detections and the pulse voltage for each detection based on a control signal includes: determining the number of partial discharge detections and the target discharge quantity for each detection based on a discharge interval and a discharge quantity range; and determining the pulse voltage for each detection based on the target discharge quantity for each detection.

[0007] In one possible implementation, before controlling the partial discharge detection device to generate multiple partial discharge signals based on the number of detections and the pulse voltage at each detection, to achieve automatic partial discharge detection of power cables, the method further includes: determining a calibration coefficient, which is used to calibrate the pulse voltage at each detection; and calibrating the pulse voltage at each detection based on the calibration coefficient.

[0008] In one possible implementation, determining the calibration coefficients includes: outputting a standard partial discharge signal to the calibration module, the standard partial discharge signal being a partial discharge signal of a standard discharge quantity; detecting the actual discharge quantity of the standard partial discharge signal in the calibration module; and determining the calibration coefficients based on the actual discharge quantity and the standard discharge quantity.

[0009] In one possible implementation, the partial discharge detection method further includes: during the automatic partial discharge detection process, for each discharge process, detecting the actual discharge amount of the partial discharge detection device on the device under test during that discharge process; calculating the error between the target discharge amount and the actual discharge amount on the device under test during that discharge process; and if the error is greater than the set error, re-determining the calibration coefficient.

[0010] Secondly, embodiments of the present invention provide a partial discharge detection device for power cables, applied to a partial discharge detection equipment. The partial discharge detection device includes: a communication module for acquiring control signals sent by a host computer; the control signals include a discharge interval and a discharge range; a processing module for determining the number of detections and the pulse voltage during each detection based on the control signals; and controlling the partial discharge detection equipment to generate multiple partial discharge signals based on the number of detections and the pulse voltage during each detection, so as to realize automatic partial discharge detection of power cables.

[0011] In one possible implementation, the processing module is specifically used to determine the number of detections and the target discharge amount for each detection during partial discharge detection based on the discharge interval and the discharge amount range; and to determine the pulse voltage for each detection based on the target discharge amount for each detection.

[0012] In one possible implementation, the processing module is further configured to determine a calibration coefficient, which is used to calibrate the pulse voltage during each detection; and to calibrate the pulse voltage during each detection based on the calibration coefficient.

[0013] In one possible implementation, the processing module is specifically used to output a standard partial discharge signal to the calibration module, the standard partial discharge signal being a partial discharge signal of a standard discharge quantity; detect the actual discharge quantity of the standard partial discharge signal in the calibration module; and determine the calibration coefficient based on the actual discharge quantity and the standard discharge quantity.

[0014] In one possible implementation, the processing module is further configured to, during the automatic partial discharge detection process, detect the actual discharge amount of the partial discharge detection device on the device under test for each discharge process; calculate the error between the target discharge amount and the actual discharge amount on the device under test for that discharge process; and if the error is greater than the set error, redetermine the calibration coefficient.

[0015] Thirdly, embodiments of the present invention provide a partial discharge detection device, comprising: a controller; the controller is used to acquire a control signal; the control signal includes a discharge interval and a discharge range; based on the control signal, the number of detections during partial discharge detection and the pulse voltage during each detection are determined; based on the number of detections and the pulse voltage during each detection, the partial discharge detection device is controlled to generate multiple partial discharge signals to realize automatic partial discharge detection of power cables.

[0016] In one possible implementation, the partial discharge detection device further includes a DC voltage source module and a pulse voltage generation module; the DC voltage source module and the pulse voltage generation module are respectively connected to a controller; the controller is specifically used to execute the following steps: Step 1: Determine the current pulse voltage to be output based on the pulse voltage sequence and the number of iterations; Step 2: Generate a first target signal and a second target signal based on the current pulse voltage to be output; Step 3: Output the first target signal to the DC voltage source module; Step 4: Output the second target signal to the pulse voltage generation module to instruct the pulse voltage generation module to output a pulse voltage; Step 5: Determine whether the termination condition is met. If yes, exit the partial discharge signal output process; if no, repeat steps 1 to 5 until exit the partial discharge signal output process; the termination condition is that the number of iterations is greater than the set number, or the current pulse voltage to be output is the highest level pulse voltage.

[0017] In one possible implementation, the partial discharge detection device further includes a calibration module; the calibration module is connected to the controller and is used to detect the actual discharge quantity on the device under test; the controller is also used to obtain the actual discharge quantity on the device under test during any test through the calibration module; based on the actual discharge quantity on the device under test during the test and the target discharge quantity corresponding to the pulse voltage during the test, the error between the actual discharge quantity and the target discharge quantity is determined; if the error is greater than the set error, the calibration coefficient is re-determined.

[0018] In one possible implementation, the controller includes a memory and a processor, the memory storing a computer program, the processor being configured to invoke and run the computer program stored in the memory to perform the steps of the method as described in the first aspect above and any possible implementation thereof.

[0019] Fourthly, embodiments of the present invention provide a partial discharge detection system, which includes a host computer and a partial discharge detection device as described in the third aspect above, and executes the steps of the method described in the first aspect and any possible implementation thereof to achieve automatic partial discharge detection.

[0020] Fifthly, embodiments of the present invention provide a computer-readable storage medium storing a computer program, characterized in that, when executed by a processor, the computer program implements the steps of the method as described in the first aspect and any possible implementation thereof.

[0021] This invention provides a method, apparatus, device, and system for partial discharge detection of power cables. The invention is simple to operate; it only requires inputting the desired partial discharge signal output discharge range to automatically output the discharge waveform within that range. This enables automatic generation of partial discharge signals during power cable partial discharge detection, reducing detection time and improving the detection efficiency of the device. Furthermore, it features a preset discharge interval function, allowing for continuous voltage output between discharge waveforms according to the set interval. The device considers circuit aging and performance degradation, performing self-calibration of the discharge quantity upon startup to determine the calibration coefficient for each run, ensuring the accuracy of the output waveform. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of a partial discharge detection device provided in an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the characteristic curves of the control voltage and output voltage of a DC voltage source module provided in an embodiment of the present invention;

[0025] Figure 3This is a schematic diagram of the structure of a pulse voltage generation module provided in an embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of the structure of a calibration module provided in an embodiment of the present invention;

[0027] Figure 5 This is a schematic flowchart of a partial discharge detection method for power cables provided in an embodiment of the present invention;

[0028] Figure 6 This is a flowchart illustrating another method for partial discharge detection of power cables provided in an embodiment of the present invention.

[0029] Figure 7 This is a flowchart illustrating another method for partial discharge detection of power cables provided in an embodiment of the present invention.

[0030] Figure 8 This is a flowchart illustrating a method of using a partial discharge detection device according to an embodiment of the present invention;

[0031] Figure 9 This is a schematic diagram of the structure of a partial discharge detection device for power cables provided in an embodiment of the present invention;

[0032] Figure 10 This is a schematic diagram of the structure of a controller provided in an embodiment of the present invention. Detailed Implementation

[0033] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0034] In the description of this invention, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The term "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. Furthermore, "at least one" and "more than one" refer to two or more. The terms "first," "second," etc., do not limit the quantity or order of execution, and "first," "second," etc., do not necessarily imply differences.

[0035] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner to facilitate understanding.

[0036] Furthermore, the terms "comprising" and "having," and any variations thereof, used in the description of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or modules is not limited to the steps or modules listed, but may optionally include other steps or modules not listed, or may optionally include other steps or modules inherent to such process, method, product, or device.

[0037] To make the objectives, technical solutions, and advantages of the present invention clearer, the following description will be provided in conjunction with the accompanying drawings and specific embodiments.

[0038] With the continuous advancement of urbanization in my country, more land resources are needed for power grid construction, leading to a conflict between land use for power equipment and urban development. Under the premise of ensuring both urban development and power grid construction, underground cables can alleviate the shortage of land resources to some extent. Cables are primarily installed underground in cities; reasonable laying methods and transmission routes can save above-ground space, reduce the use of overhead lines and cables, and beautify the urban environment. Secondly, underground cables are less affected by the external environment, are less prone to failure, and can safely transmit and distribute power for extended periods. Furthermore, underground cables can be used in conjunction with ring main units, junction boxes, and other devices, allowing multiple lines to coordinate and operate more flexibly, reducing the frequency and scope of power outages to some extent, thus ensuring the safety of power transmission from the grid.

[0039] Cross-linked polyethylene (XLPE) cables refer to cables with XLPE outer insulation material. Under normal operating conditions, the average lifespan of these cables is 20 to 30 years. However, the actual operating environment is never the same as the ideal environment, which leads to a shorter cable lifespan. Because they are laid underground, long-term contact with moist soil gradually reduces their insulation performance. Defects in manufacturing processes and materials also contribute to this decline, potentially causing power outages. With the widespread laying and prolonged use of underground cables, more and more cables are developing insulation defects of varying degrees, leading to power accidents. Previously, the method used to detect cable faults was post-accident repair—inspection and repair were only carried out after a power outage occurred, resulting in sudden economic losses for daily life and various industries. Therefore, to detect cable insulation defects earlier, many companies have adopted fixed-time periods for power cable inspection and maintenance, conducting unified inspections and repairs at regular intervals. This method still has shortcomings. It requires advance planning of maintenance schedules and coordination between different departments, which wastes manpower and resources and is not very targeted. Underground cable defects are highly concealed and random, and regular inspections generally cannot detect these defects in advance. With the expansion of the scale of underground cable laying and the rapid development of the cable manufacturing industry, early cable maintenance methods and testing standards are gradually no longer in line with the requirements for cable defect investigation and maintenance in China.

[0040] Partial discharge detection-based condition monitoring and assessment of power cables has become a reliable method in recent years, with extensive research and application by scholars and numerous enterprises both domestically and internationally. Partial discharge refers to the discharge phenomenon occurring within the insulation of a cable due to insulation defects, damage, stress bending, etc. Its development process further exacerbates the damage to the cable insulation, potentially leading to a breakdown fault in the entire cable. Based on this method, researchers in the power industry both domestically and internationally have developed numerous partial discharge detection devices. Their detection principles, depending on the type of sensor, can be categorized into capacitive detection and HFCT (High-Frequency Current Transformer) detection methods. The HFCT method allows for online detection, directly connected to the cable grounding wire for partial discharge detection. To calibrate partial discharge detectors from numerous manufacturers and models, a partial discharge signal generation device with standardized specifications and waveforms needs to be designed to calibrate various partial discharge detection equipment.

[0041] However, current pulse calibrators are generally in manual adjustment mode. When outputting partial discharge quantities at different levels, it is necessary to manually switch levels to complete the output of the next partial discharge simulation pulse, increasing the overall operational complexity of the device. To solve this problem, this invention designs a partial discharge signal source device that can automatically measure the data pulse discharge quantity and automatically adjust the level amplitude. It achieves continuous output of partial discharge calibration voltage waveforms. After the device is turned on, it can automatically output partial discharge simulation signals within the set discharge quantity range, reducing the operational complexity required for measurement and improving the calibration time of the device.

[0042] Figure 1 This is a schematic diagram of a partial discharge detection device provided in an embodiment of the present invention. The device includes a controller, a DC voltage source module, and a pulse voltage generation module. The controller controls the output pulse voltage, using the controller's DAC output port to output a variable DC voltage. This voltage enables the output of a DC voltage ranging from 0-500V, thereby completing the output of a partial discharge calibration voltage signal.

[0043] In some embodiments, the controller can be a microcontroller. The microcontroller selected is a model with serial communication and ADC output functions. In this invention, the model selected is the STM32L151C8T6 low-power microcontroller, whose main function is to receive voltage control signals sent by the host computer via serial communication, output a fixed amplitude 0-3.3V DC voltage, and control the DC voltage source module through this voltage.

[0044] In some embodiments, the DC voltage source module is selected as a voltage generating module with DC voltage control output amplitude, and the maximum output current should be greater than 10mA. In this invention, a DC voltage module manufactured by Tianjin Dongwen High Voltage Power Supply Co., Ltd. is selected, with parameters of a maximum output voltage of 500V and a maximum output current of 50mA. Its control voltage range is 0-3.3V, and within this range, the output voltage and control voltage are linearly controlled. The control voltage and output voltage characteristic curves of the DC voltage source module are shown below. Figure 2 As shown.

[0045] In some embodiments, the pulse voltage generation module can be a pulse generation circuit based on the Blumlein transmission line structure.

[0046] For example, such as Figure 3 As shown in the figure, an embodiment of the present invention provides a structural schematic diagram of a pulse voltage generation module. Figure 3 The DC voltage source module can be controlled by a controller to output a DC voltage of a fixed amplitude.

[0047] For example, the pulse voltage generation module may include a charging resistor, an impedance transmission line, and a reed high-voltage relay. The charging resistor R1 in the pulse generation circuit is a 100kΩ non-inductive resistor. The impedance transmission line has a length L and an impedance of 50Ω. A reed high-voltage relay is used as the switching device to achieve switching on high-voltage DC voltage. The relay's control signal comes from the controller, and the control level is TTL level. The relay is normally closed; it closes when the controller outputs a high TTL level. The load resistor R2 is a 50Ω non-inductive resistor, which serves as both a load and reduces signal reflection.

[0048] It should be noted that, Figure 1 The working principle of the partial discharge detection equipment shown is as follows.

[0049] First, the controller controls the DC voltage source module to generate a voltage signal of fixed amplitude and applies it to the transmission line. At this time, the relay remains in the open state. When the relay closes, according to the Blumlein transmission line principle, a voltage peak will be generated across the load resistor. The pulse voltage value is the partial discharge calibration voltage, and U is the output voltage value of the DC voltage source module. Its theoretical pulse duration is...

[0050]

[0051] Where L is the length of the 50-ohm impedance transmission line, and v is the wave velocity of the electromagnetic wave in the transmission line, approximately 2 × 10⁻⁶. 8 m / s.

[0052] As can be seen from the above principle, this circuit can generate pulse voltages of different amplitudes by changing the DC voltage source control signal, and the repetition frequency of the pulse voltage can be controlled by the controller. In the partial discharge calibration voltage waveform generated by this circuit, the pulse voltage rise time is about 8ns.

[0053] In some embodiments, the partial discharge detection device further includes a calibration module. The calibration module includes a discharge quantity measurement unit and a discharge quantity calculation unit.

[0054] It should be noted that the discharge quantity of the partial discharge calibration voltage is linearly related to its own amplitude. This is to achieve precise control of the partial discharge pulse discharge quantity. For example... Figure 4 As shown in the figure, an embodiment of the present invention provides a structural schematic diagram of a calibration module. Figure 4 The calibration module shown calculates the discharge amount of the output partial discharge calibration voltage in real time and feeds back the calculated actual discharge amount to the controller. Based on the feedback of the actual discharge amount and the target discharge amount, the controller adjusts the calibration coefficient, thereby achieving feedback regulation of the adjustable DC voltage.

[0055] Figure 5 This is a flowchart illustrating a partial discharge detection method for power cables according to an embodiment of the present invention. It is applied to a partial discharge detection device. The executing entity of this method is a partial discharge detection device for power cables. The partial discharge detection device can be a program unit within the controller of the partial discharge detection device. The method includes steps S101-S103.

[0056] S101. Obtain the control signal sent by the host computer.

[0057] In this embodiment, the control signal includes the discharge interval and the discharge range.

[0058] S102. Based on the control signal, determine the number of detections and the pulse voltage during each detection.

[0059] As one possible implementation, the partial discharge detection device can determine the pulse voltage for each detection based on steps S1021-S1022.

[0060] S1021. Based on the discharge interval and discharge range, determine the number of detections and the target discharge amount for each detection during partial discharge detection;

[0061] S1022. Determine the pulse voltage for each detection based on the target discharge amount at each detection.

[0062] S103. Based on the number of tests and the pulse voltage during each test, control the partial discharge detection equipment to generate multiple partial discharge signals to achieve automatic partial discharge detection of power cables.

[0063] It should be noted that the controller is used to acquire control signals; the control signals include the discharge interval and the discharge range; based on the control signals, the number of detections and the pulse voltage during each detection are determined; based on the number of detections and the pulse voltage during each detection, the controller controls the partial discharge detection equipment to generate multiple partial discharge signals to achieve automatic partial discharge detection of power cables.

[0064] For example, the partial discharge detection device further includes a DC voltage source module and a pulse voltage generation module; the DC voltage source module and the pulse voltage generation module are respectively connected to the controller;

[0065] Accordingly, the control is specifically used to perform the following steps to achieve automatic partial discharge detection.

[0066] Step 1: Determine the pulse voltage to be output based on the pulse voltage sequence and the number of iterations.

[0067] Step 2: Based on the current pulse voltage to be output, generate the first target signal and the second target signal.

[0068] Step 3: Output the first target signal to the DC voltage source module.

[0069] Step 4: Output a second target signal to the pulse voltage generation module to instruct the pulse voltage generation module to output a pulse voltage.

[0070] Step 5: Determine if the termination condition is met. If yes, exit the partial discharge signal output process; otherwise, repeat steps 1 to 5 until exiting the partial discharge signal output process. The termination condition is that the number of iterations is greater than the set number, or the current pulse voltage to be output is the highest level pulse voltage.

[0071] This invention provides a method for partial discharge detection of power cables. The invention is easy to operate; it only requires inputting the desired partial discharge signal output discharge range, and the device can automatically output the discharge waveform within that range. It also has a preset function for the discharge interval; after setting, the voltage output between each discharge waveform can be continuously output according to that interval. This device considers the aging and performance degradation of the circuit itself, and performs self-calibration of the discharge quantity upon startup, determining the calibration coefficient for each run to ensure the accuracy of the output waveform.

[0072] Optional, such as Figure 6 As shown, the partial discharge detection method for power cables provided in this embodiment of the invention further includes steps S201-S202 before step S103.

[0073] S201. Determine the calibration coefficient.

[0074] In some embodiments, the calibration coefficient is used to calibrate the pulse voltage at each test.

[0075] As one possible implementation, the partial discharge detection device can determine the calibration coefficient based on steps S2021-S2023.

[0076] S2021. Output standard partial discharge signal to the calibration module.

[0077] In some embodiments, the standard partial discharge signal is the partial discharge signal of the standard discharge level.

[0078] S2022, Detect the actual discharge amount of the standard partial discharge signal in the calibration module.

[0079] S2023. Determine the calibration coefficient based on the actual discharge amount and the standard discharge amount.

[0080] S202. Based on the calibration coefficient, calibrate the pulse voltage for each test.

[0081] Optional, such as Figure 7As shown, the partial discharge detection method for power cables provided in this embodiment of the invention further includes steps S301-S302 after step S103.

[0082] S301. During the automatic partial discharge detection process, for each discharge process, the actual discharge amount of the partial discharge detection equipment on the tested equipment is detected.

[0083] S302. Calculate the error between the target discharge amount and the actual discharge amount on the device under test during the discharge process.

[0084] S303. If the error is greater than the set error, the calibration coefficient shall be re-determined.

[0085] For example, a partial discharge detection device includes a calibration module; the calibration module is connected to a controller and is used to detect the actual discharge quantity on the device under test.

[0086] Accordingly, the controller is used to obtain the actual discharge quantity of the device under test during any test through the calibration module; based on the actual discharge quantity of the device under test during the test and the target discharge quantity corresponding to the pulse voltage during the test, the error between the actual discharge quantity and the target discharge quantity is determined; if the error is greater than the set error, the calibration coefficient is re-determined.

[0087] For example, such as Figure 4 As shown, calibration of partial discharge requires the use of a standard capacitor. After the pulse voltage output is connected to the standard capacitor C1, the discharge quantity can be calculated from the peak value of the pulse voltage applied to the standard capacitor. This calculation process requires first determining the pulse voltage peak value U0 and the standard capacitor C1; the discharge quantity Q can be expressed by the following formula.

[0088] Q = C1 × U0;

[0089] The measurement of the pulse voltage peak U0 is accomplished by the discharge measurement unit, namely the attenuation circuits R1 and R2 and the data acquisition card. The discharge quantity calculation unit then converts the discharge quantity to its actual value, which is compared with the target discharge quantity. When the actual discharge quantity is less than the target discharge quantity, the controller increases the output voltage amplitude of the DC voltage source module, thereby increasing the output pulse voltage. Conversely, when the actual discharge quantity is greater than the target discharge quantity, the controller does the opposite.

[0090] The aforementioned self-adjustment, or calibration function, runs every time the device is powered on and obtains the calibration coefficient K of the partial discharge detection equipment. The calibration coefficient K can be calculated using the following formula.

[0091]

[0092] Among them, Q 实际 Q represents the actual discharge quantity. 目标The target discharge amount.

[0093] After the coefficient K is calculated, the subsequent DC voltage can be adjusted according to the calibration coefficient K to ensure the accuracy of the subsequent actual discharge quantity.

[0094] like Figure 8 As shown in the diagram, this embodiment of the invention provides a schematic diagram of the power-on operation process of a partial discharge detection device. After power-on, the device first runs a self-test process, issuing a partial discharge calibration voltage with a discharge quantity of 100pC, and then... Figure 4 The discharge measurement unit shown measures the actual output voltage value. At this point, the standard capacitor C1 is selected with a capacitance of 100pF. If the partial discharge calibration voltage output by the system itself is without deviation, the measured output voltage amplitude should be 1V. However, in actual use, due to the influence of stray capacitance, inductance, and other parameters in the circuit, there is a deviation between the actual output value and the preset value. Furthermore, the wiring method will inevitably differ each time it is used, resulting in an error between the actual output value and the set value each time it is powered on. Assuming the actual voltage measured during the self-test after power-on is 0.8V, it indicates that the system needs adjustment and calibration for subsequent voltage outputs. The calibration coefficient K = 1 / 0.8 = 1.25. Therefore, for subsequent outputs, the coefficient K should be multiplied by the target value to determine the actual output voltage, and all subsequent output voltages should be corrected promptly.

[0095] Next, input the discharge interval and discharge range. For example, the discharge interval can be set to 100pC and the range can be set to 100pC-1nC. The system will then continuously output 11 sets of partial discharge calibration voltages at 100pC intervals: 100pC, 200pC, 300pC, 400pC, 500pC, 600pC, 700pC, 800pC, 900pC, and 1nC, to complete the signal output.

[0096] For example, an embodiment of the present invention provides a method for using a partial discharge detection device, as shown in steps A1-A5 below.

[0097] A1. Connect the partial discharge detection equipment to a capacitive load.

[0098] In some embodiments, the partial discharge-free capacitor serves as the load for the partial discharge calibration circuit, while the measuring terminal of the device under test is connected to the partial discharge-free capacitor.

[0099] A2. Start the partial discharge detection equipment and determine the adjustment coefficient K.

[0100] A3. Set the discharge output range and interval according to the performance of the device under test. For example, the discharge range can be set to 10pC-1nC with an interval of 10pC.

[0101] A4. After setting, turn on this device, and the device will start running continuously, emitting 10pC-1nC partial discharge simulated voltage waveforms at equal intervals.

[0102] A5. The device under test synchronously activates the partial discharge quantity detection function and records the measured value of partial discharge quantity for each set of simulated waveforms in real time. The measured value is compared with the actual value to obtain the discharge quantity measurement error value of the device under test.

[0103] This invention proposes an automatically adjustable partial discharge detection device. This invention enables automatic adjustment of the partial discharge calibration waveform, continuous generation of the partial discharge signal, automatic setting of the pulse output interval and automatic signal transmission, and self-calibration of the discharge quantity of the output signal waveform. This completes the automatic adjustment of the discharge quantity of the generated waveform, significantly improving the efficiency of the calibration process in the partial discharge detection device.

[0104] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0105] The following are device embodiments of the present invention. For details not described in detail, please refer to the corresponding method embodiments described above.

[0106] Figure 9 A schematic diagram of a partial discharge detection device for power cables according to an embodiment of the present invention is shown. Applied to partial discharge detection equipment, the partial discharge detection device 400 includes a communication module 401 and a processing module 402.

[0107] The communication module 401 is used to acquire control signals sent by the host computer; the control signals include the discharge interval and the discharge range.

[0108] The processing module 402 is used to determine the number of partial discharge detections and the pulse voltage during each detection based on the control signal; based on the number of detections and the pulse voltage during each detection, it controls the partial discharge detection equipment to generate multiple partial discharge signals to realize automatic partial discharge detection of power cables.

[0109] In one possible implementation, the processing module 402 is specifically used to determine the number of detections and the target discharge amount for each detection based on the discharge interval and the discharge amount range; and to determine the pulse voltage for each detection based on the target discharge amount for each detection.

[0110] In one possible implementation, the processing module 402 is further configured to determine a calibration coefficient, which is used to calibrate the pulse voltage during each detection; and to calibrate the pulse voltage during each detection based on the calibration coefficient.

[0111] In one possible implementation, the processing module 402 is specifically used to output a standard partial discharge signal to the calibration module, the standard partial discharge signal being a partial discharge signal of a standard discharge quantity; detect the actual discharge quantity of the standard partial discharge signal in the calibration module; and determine the calibration coefficient based on the actual discharge quantity and the standard discharge quantity.

[0112] In one possible implementation, the processing module 402 is further configured to, during the automatic partial discharge detection process, detect the actual discharge amount of the partial discharge detection device on the device under test for each discharge process; calculate the error between the target discharge amount and the actual discharge amount on the device under test for each discharge process; and if the error is greater than the set error, redetermine the calibration coefficient.

[0113] Figure 10 This is a schematic diagram of the structure of a controller provided in an embodiment of the present invention. Figure 10 As shown, the controller 500 of this embodiment includes: a processor 501, a memory 502, and a computer program 503 stored in the memory 502 and executable on the processor 501. When the processor 501 executes the computer program 503, it implements the steps in the above-described method embodiments, for example... Figure 5 Steps 101 to 103 are shown. Alternatively, when the processor 501 executes the computer program 503, it implements the functions of each module / unit in the above-described device embodiments, for example... Figure 9 The functions of the communication module 401 and the processing module 402 shown are illustrated.

[0114] For example, the computer program 503 can be divided into one or more modules / units, which are stored in the memory 502 and executed by the processor 501 to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program 503 in the controller 500. For example, the computer program 503 can be divided into... Figure 9 The communication module 401 and the processing module 402 are shown.

[0115] The processor 501 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0116] The memory 502 can be an internal storage unit of the controller 500, such as a hard disk or RAM of the controller 500. The memory 502 can also be an external storage device of the controller 500, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the controller 500. Furthermore, the memory 502 can include both internal storage units of the controller 500 and external storage devices. The memory 502 is used to store the computer program and other programs and data required by the terminal. The memory 502 can also be used to temporarily store data that has been output or will be output.

[0117] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0118] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0119] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0120] In the embodiments provided by this invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0121] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0122] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0123] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0124] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for detecting partial discharge in power cables, characterized in that, The partial discharge detection method is applied to partial discharge detection equipment and includes: Acquire control signals sent by the host computer; the control signals include the discharge interval and the discharge range. Based on the control signal, the number of detections and the pulse voltage during each detection are determined; Based on the number of detections and the pulse voltage during each detection, the partial discharge detection device is controlled to generate multiple partial discharge signals in order to achieve automatic partial discharge detection of power cables. During the automatic partial discharge detection process, for each discharge process, the actual discharge amount of the partial discharge detection device on the device under test is detected during that discharge process; the error between the target discharge amount and the actual discharge amount on the device under test is calculated; if the error is greater than the set error, the calibration coefficient is re-determined. Before controlling the partial discharge detection device to generate multiple partial discharge signals based on the number of detections and the pulse voltage at each detection to achieve automatic partial discharge detection of power cables, the method further includes: determining a calibration coefficient, including: outputting a standard partial discharge signal to a calibration module, wherein the standard partial discharge signal is a partial discharge signal with a standard discharge quantity; detecting the actual discharge quantity of the standard partial discharge signal in the calibration module; determining the calibration coefficient based on the actual discharge quantity and the standard discharge quantity; the calibration coefficient being used to calibrate the pulse voltage at each detection; and calibrating the pulse voltage at each detection based on the calibration coefficient.

2. The partial discharge detection method for power cables according to claim 1, characterized in that, The step of determining the number of detections and the pulse voltage for each detection based on the control signal includes: Based on the discharge interval and the discharge range, determine the number of partial discharge detections and the target discharge amount for each detection. The pulse voltage for each detection is determined based on the target discharge amount at each detection.

3. A partial discharge detection device for power cables, characterized in that, Applied to partial discharge detection equipment, the partial discharge detection device includes: The communication module is used to acquire control signals sent by the host computer; the control signals include the discharge interval and the discharge range. The processing module is used to determine the number of partial discharge detections and the pulse voltage during each detection based on the control signal; and to control the partial discharge detection equipment to generate multiple partial discharge signals based on the number of detections and the pulse voltage during each detection, so as to realize automatic partial discharge detection of power cables. The processing module is also used to, during the automatic partial discharge detection process, detect the actual discharge amount of the partial discharge detection device on the device under test for each discharge process; calculate the error between the target discharge amount and the actual discharge amount on the device under test for each discharge process; and if the error is greater than the set error, re-determine the calibration coefficient. The processing module is further configured to determine a calibration coefficient, including: outputting a standard partial discharge signal to a calibration module, wherein the standard partial discharge signal is a partial discharge signal with a standard discharge quantity; detecting the actual discharge quantity of the standard partial discharge signal in the calibration module; determining the calibration coefficient based on the actual discharge quantity and the standard discharge quantity; the calibration coefficient being used to calibrate the pulse voltage during each detection; and calibrating the pulse voltage during each detection based on the calibration coefficient.

4. A partial discharge detection device, characterized in that, include: Controller; The controller is used to acquire control signals; the control signals include discharge interval and discharge range. Based on the control signal, the number of detections and the pulse voltage during each detection are determined; Based on the number of detections and the pulse voltage during each detection, the partial discharge detection device is controlled to generate multiple partial discharge signals in order to achieve automatic partial discharge detection of power cables. The partial discharge detection device further includes a calibration module; the calibration module is connected to the controller and is used to detect the actual discharge quantity on the device under test; the controller is also used to obtain the actual discharge quantity on the device under test during any test through the calibration module; and to determine the error between the actual discharge quantity and the target discharge quantity based on the actual discharge quantity on the device under test during the test and the target discharge quantity corresponding to the pulse voltage during the test. If the error is greater than the set error, the calibration coefficient is re-determined; The controller is further configured to determine calibration coefficients, including: outputting a standard partial discharge signal to the calibration module, the standard partial discharge signal being a partial discharge signal with a standard discharge quantity; detecting the actual discharge quantity of the standard partial discharge signal in the calibration module; determining the calibration coefficients based on the actual discharge quantity and the standard discharge quantity; the calibration coefficients being used to calibrate the pulse voltage during each detection; and calibrating the pulse voltage during each detection based on the calibration coefficients.

5. The partial discharge detection device according to claim 4, characterized in that, The partial discharge detection device further includes a DC voltage source module and a pulse voltage generation module; the DC voltage source module and the pulse voltage generation module are respectively connected to the controller. The controller is specifically used to perform the following steps: Step 1: Determine the current pulse voltage to be output based on the pulse voltage sequence and the number of iterations; Step 2: Based on the current pulse voltage to be output, generate a first target signal and a second target signal; Step 3: Output the first target signal to the DC voltage source module; Step 4: Output the second target signal to the pulse voltage generation module to instruct the pulse voltage generation module to output the pulse voltage; Step 5: Determine whether the termination condition is met. If yes, exit the partial discharge signal output process; if no, repeat steps 1 to 5 until exiting the partial discharge signal output process. The termination condition is that the number of iterations is greater than the set number, or the current pulse voltage to be output is the highest level pulse voltage.

6. A partial discharge detection system, characterized in that, Includes: a host computer, and the partial discharge detection equipment as described in claim 4 or 5.

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