Device and method for detecting diffusion process of oil-soluble gas under partial discharge condition

Abstract

The invention relates to a device and a method for detecting an oil-soluble gas diffusion process under a partial discharge condition, and the device comprises a high-voltage generator which provides a high-voltage condition for the oil-soluble gas diffusion under the partial discharge condition; the test box is used for simulating a partial discharge process according to the high-voltage condition output by the high-voltage generator, providing a detection signal and generating partial discharge quantity and diffusion gas under the partial discharge condition; the partial discharge gas analyzer is used for detecting the gas concentration of diffusion gas in the test box and obtaining a gas diffusion coefficient generated by partial discharge; and the data analysis system is used for processing the detection data obtained from the partial discharge gas analyzer and the oscilloscope, establishing the relationship between the diffusion coefficient of the oil-soluble gas and the partial discharge amount under the partial discharge condition, and representing the partial discharge process by using the diffusion coefficient of the oil-soluble gas. Compared with the prior art, the method has the advantages of judging the partial discharge degree, improving the detection sensitivity and the like.

Description

Technical Field

[0001] The invention relates to the technical field of partial discharge in high-voltage insulating transformers, and in particular to a detection device and method for an oil-soluble gas diffusion process under partial discharge conditions. Background Art

[0002] Power transformers are important equipment in electrical systems. Transformer accidents will not only cause damage to the transformer itself and its ancillary equipment, but also cause huge economic losses to social production due to the interruption of power supply. The main insulation inside the transformer is oil-paper insulation, and partial discharge is one of the main causes of insulation failure inside the transformer. Under the action of electrical stress, thermal stress and even mechanical stress, the oil-paper insulation will inevitably decompose, and then produce characteristic gases such as low molecular hydrocarbons and H2, which will dissolve in the transformer oil. The types and volume fractions of gases produced by different types of partial discharges and partial discharges of different severity are different. According to the volume fraction of characteristic gases in the oil obtained by gas chromatography analysis in oil, the fault condition of the transformer is judged, that is, the dissolved gas analysis method (DGA) in transformer oil, which has been widely used to judge internal faults of transformers. Therefore, it is very meaningful to study the gas generation characteristics of partial discharge in transformers and understand the partial discharge situation inside transformers through gas generation characteristics for the safe and stable operation of transformers.

[0003] However, the existing transformer partial discharge gas generation characteristic detection device determines whether the transformer is discharged based on the result of detecting whether the transformer produces diffused gas, but cannot determine the degree of transformer discharge, resulting in low transformer working efficiency and limited application scope.

[0004] How to detect the partial discharge degree of transformers has become a technical problem that needs to be solved. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a detection device and method for the oil-soluble gas diffusion process under partial discharge conditions.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] According to one aspect of the present invention, a device for detecting the diffusion process of oil-soluble gas under partial discharge conditions is provided, the device comprising:

[0008] High voltage generator, which provides high voltage conditions for the diffusion of oil-soluble gas under partial discharge conditions;

[0009] A test box, used to simulate the process of partial discharge according to the high voltage condition output by the high voltage generator and provide a detection signal, generate the amount of partial discharge and the diffusion gas under the partial discharge condition;

[0010] Partial discharge gas analyzer, used to detect the gas concentration of the diffused gas in the test box and obtain the gas diffusion coefficient generated by partial discharge;

[0011] Oscilloscope, used to obtain voltage data of partial discharge from the high voltage generator and partial discharge data from the test box;

[0012] The data analysis system is used to process the detection data obtained from the partial discharge gas analyzer and the oscilloscope, establish the relationship between the oil-soluble gas diffusion coefficient and the partial discharge amount under the partial discharge condition, and use the oil-soluble gas diffusion coefficient to characterize the partial discharge process.

[0013] Preferably, the test box comprises electrodes, transformer oil, an oil inlet valve, an oil outlet valve, a pressure gauge, a pressure release valve and a gas channel;

[0014] The electrodes are placed in a test box;

[0015] The transformer oil is injected into the test box through the oil inlet valve and discharged from the test box through the oil outlet valve;

[0016] The pressure gauge and the pressure relief valve are installed at one end of the test box;

[0017] The gas channel is installed on a side of the test box close to the ground, and the gas generated by partial discharge diffuses through the gas channel.

[0018] More preferably, the electrode is subjected to a voltage generated by a high voltage generator, so that the electrode undergoes local discharge and generates gas;

[0019] The electrodes include needle electrodes, insulating paperboard and plate electrodes;

[0020] The insulating paperboard is installed on the plate electrode and is located between the needle electrode and the plate electrode;

[0021] When the applied voltage reaches the set voltage threshold, the electric field strength near the needle electrode causes the insulating oil and insulating cardboard to ionize, resulting in partial discharge;

[0022] The plate electrode is used to collect charged particles generated by ionization of the needle electrode and maintain charge balance.

[0023] More preferably, the test box further comprises a first detection point and a second detection point, wherein the first detection point is located at one end of the gas channel close to the electrode, and the second detection point is located at one end of the gas channel far from the electrode;

[0024] The first detection point and the second detection point are both connected to a partial discharge gas analyzer;

[0025] The first detection point is an initial detection point where the gas generated by the partial discharge passes through the gas channel, and the gas concentration detected by the partial discharge gas analyzer at the first detection point is the initial gas concentration of the partial discharge;

[0026] The gas concentration detected by the partial discharge gas analyzer at the second detection point is the current gas concentration detected after the gas generated by the partial discharge diffuses in the channel for a set time.

[0027] More preferably, the distance between the first detection point and the second detection point is at least 1000 mm.

[0028] Preferably, the process of obtaining the gas diffusion coefficient generated by the partial discharge comprises:

[0029] The partial discharge analyzer detects the gas concentration difference Δc at two detection points installed on the gas channel.

[0030] Δc=c1-c2

[0031] Wherein, c1 represents the initial gas concentration of partial discharge; c2 represents the gas concentration detected after the gas generated by partial discharge diffuses in the channel for a set time;

[0032] According to the calculated gas concentration difference Δc, the oil-soluble gas diffusion coefficient D under partial discharge conditions is obtained by data fitting:

[0033]

[0034] Where k represents the Boltzmann constant; m represents the mass of the diffusing gas, and π represents the pi constant.

[0035] Preferably, the establishing of the relationship between the oil-soluble gas diffusion coefficient and the local discharge amount under the local discharge condition comprises:

[0036] The voltage amplitude of the voltage applied to the test box starts from zero and is increased at a uniform rate in a step-by-step manner until the insulating cardboard breaks down. The data analysis system collects the voltage and current data at each breakdown moment based on the oscilloscope and calculates the partial discharge amount W. PD :

[0037]

[0038] Where U represents the peak value of the applied voltage, q i Indicates the amount of partial discharge charge; represents the partial discharge discharge phase; t represents the breakdown duration;

[0039] Diffusion coefficient D and partial discharge amount W PD Linear fitting was performed to obtain the oil-soluble gas diffusion coefficient D and the local discharge amount W under partial discharge conditions. PDRelationship:

[0040] D=F(W PD ,T,μ,P)

[0041] Among them, T represents the temperature of transformer oil, μ represents the viscosity of transformer oil, and P represents the pressure in the transformer test box.

[0042] Preferably, the device further comprises a high voltage stabilizer connected to the high voltage generator,

[0043] The high voltage stabilizer is used to suppress electromagnetic interference in the high voltage generator and adjust the voltage output by the high voltage generator to be in a stable state.

[0044] Preferably, the device further comprises a voltage stabilizer protector respectively connected to the test box and the oscilloscope; the voltage stabilizer protector is used to protect various devices in the device to avoid device failure due to excessive discharge voltage.

[0045] According to another aspect of the present invention, a method for detecting the diffusion process of oil-soluble gas under partial discharge conditions is provided, the method comprising:

[0046] Step S1, assembling insulating cardboard: sandwiching a layer of cardboard with a hole between two pieces of insulating cardboard and bonding them together using epoxy resin insulating glue, and installing the assembled insulating cardboard on the electrodes of the test box;

[0047] Step S2, using a step-by-step voltage-boosting method to adjust the voltage of the high-voltage generator, measuring the starting voltage of partial discharge and the breakdown voltage of the electrode, and recording the voltage data of the high-voltage generator and the voltage data of partial discharge of the electrode; measuring and recording the gas concentrations at two monitoring points during the development process of partial discharge;

[0048] Step S3, calculating the oil-soluble gas diffusion coefficient based on the recorded gas concentration, and calculating the partial discharge amount based on the partial discharge voltage data;

[0049] Step S4, linearly fitting the diffusion coefficient and the local discharge amount, establishing the relationship between the diffusion coefficient of the oil-soluble gas and the local discharge amount under the local discharge condition, and characterizing the local discharge process by the diffusion coefficient.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] 1) The present invention simulates partial discharge and analyzes the gas diffusion coefficient and partial discharge amount generated by partial discharge, thereby establishing a corresponding relationship between the partial discharge process and the gas diffusion process, and using the oil-soluble gas diffusion coefficient to characterize the partial discharge process, thereby solving the problem that the existing transformer partial discharge gas production characteristic detection device cannot judge the discharge degree of the transformer, and can more accurately evaluate the severity and development trend of partial discharge faults, providing a basis for maintenance decisions; accurate fault diagnosis and timely maintenance can significantly improve the operating reliability and safety of power equipment, and reduce the risk and loss of unexpected power outages.

[0052] 2) The present invention establishes a correspondence between the local discharge process and the gas diffusion process. The research and application of this relationship can help monitor and locate local discharge defects, thereby timely discovering early signs of insulation faults, enhancing the ability to identify early faults, and helping to improve the sensitivity and reliability of local discharge detection technology. It solves the problem that the existing detection devices cannot determine the discharge degree of the transformer, resulting in low transformer working efficiency and limited application scope. It can help power system operators formulate more scientific equipment maintenance and replacement strategies based on the gas diffusion coefficient.

[0053] 3) The present invention constructs a corresponding relationship between the local discharge process and the gas diffusion process. The study of this relationship helps to deeply understand the physical process of local discharge and the aging mechanism of insulating materials, and promotes the development of related theories. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a structural schematic diagram of the detection device in the present invention;

[0055] Figure 2 It is a structural schematic diagram of the connection part of the high voltage generator, the high voltage stabilizer and the oscilloscope in the present invention;

[0056] Figure 3 It is a structural schematic diagram of the connection part of the test box, voltage stabilizer protector, partial discharge gas analyzer, oscilloscope and data analysis system in the present invention;

[0057] Figure 4 It is a curve showing the relationship between the diffusion coefficient of oil-soluble gas and the discharge amount under the partial discharge condition in the present invention;

[0058] In the attached drawings, 1. high voltage generator; 2. high voltage stabilizer; 3. test box; 4. voltage stabilizer protector; 5. partial discharge gas analyzer; 6. oscilloscope; 7. data analysis system; 8. power supply; 9. step-up transformer; 10. protection resistor; 11. resistor-capacitor voltage divider; 12. coupling capacitor; 13. electrode; 14. transformer oil; 15. oil inlet valve; 16. oil outlet valve; 17. pressure gauge; 18. pressure release valve; 19. gas channel; 20. first detection point; 21. second detection point; 22. needle electrode; 23. insulating cardboard; 24. plate electrode; 25. resistor-capacitor protector; 26. filter. DETAILED DESCRIPTION

[0059] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0060] The present invention designs a detection device for the diffusion process of oil-soluble gas under partial discharge conditions, which solves the technical problem that the existing detection device for the partial discharge gas production characteristics of the transformer judges whether the transformer is discharged based on the result of detecting whether the transformer produces diffused gas, but cannot judge the discharge degree of the transformer, resulting in low transformer working efficiency and limited application scope.

[0061] Example 1

[0062] This embodiment relates to a detection device for the diffusion process of oil-soluble gas under partial discharge conditions, such as Figure 1 , including: a high voltage generator 1, a high voltage stabilizer 2, a test box 3, a voltage stabilizer protector 4, a partial discharge gas analyzer 5, an oscilloscope 6 and a data analysis system 7.

[0063] The high voltage generator 1 is connected to the high voltage stabilizer 2, the high voltage stabilizer 2 is connected to the test box 3 and the oscilloscope 6, the test box 3 is respectively connected to the voltage stabilizer protector 4 and the partial discharge gas analyzer 5, the voltage stabilizer protector 4 is connected to the oscilloscope 6, and the partial discharge gas analyzer 5 and the oscilloscope 6 are respectively connected to the data analysis system 7.

[0064] The high voltage generator 1 provides high voltage conditions for the diffusion of oil-soluble gas under partial discharge conditions;

[0065] The high voltage stabilizer 2 is used to suppress electromagnetic interference in the high voltage generator 1, adjust the voltage output by the high voltage generator 1 to be in a stable state, extend the service life of the high voltage generator 1 and obtain more accurate and reliable high voltage data;

[0066] Test box 3, simulating the process of partial discharge for the detection result, generating the amount of partial discharge and the diffusion gas under the condition of partial discharge, and providing the detection signal for the detection;

[0067] The voltage stabilizer protector 4 is used to protect the equipment, avoid equipment failure due to excessive discharge voltage, extend the service life of the equipment, and improve the reliability of the test results while ensuring stable operation of the device;

[0068] The partial discharge analyzer 5 is used to detect the gas concentrations at the first detection point 20 and the second detection point 21 in the test box 3, so as to obtain the gas diffusion coefficient generated by the partial discharge.

[0069] Oscilloscope 6, for obtaining high voltage data during partial discharge and discharge voltage data during partial discharge;

[0070] The oscilloscope 6 is preferably a dual-trace oscilloscope. Modern dual-trace oscilloscopes usually have built-in mathematical operations and measurement tools, which can further analyze the displayed signal, such as calculating the signal's frequency, period, amplitude, rise time and other parameters.

[0071] The data analysis system 7 processes the detection data obtained by the partial discharge analyzer 5 and the oscilloscope 6, establishes the relationship between the oil-soluble gas diffusion coefficient and the discharge amount under the partial discharge condition, and can more accurately diagnose the insulation status and internal faults of high-voltage electrical equipment such as transformers.

[0072] Among them, the relationship between the diffusion coefficient of oil-soluble gas and the discharge amount under partial discharge conditions is established as follows:

[0073] The diffusion coefficient of oil-soluble gas under partial discharge conditions is obtained by detecting the gas concentration difference (Δc) of two detection points (first detection point 20 and second detection point 21) installed on the gas channel 19 by the partial discharge analyzer 5:

[0074] Δc=c1-c2

[0075] Wherein, c1 represents the gas concentration detected by the first detection point 20; c2 represents the gas concentration detected by the second detection point 21;

[0076] The diffusion coefficient (D) is calculated as:

[0077]

[0078] Where k is the Boltzmann constant and m is the mass of the diffusing gas.

[0079] In order to establish the relationship between the diffusion coefficient of oil-soluble gas and the discharge amount under partial discharge conditions, the voltage amplitude of the external voltage starts from zero and is increased at a uniform rate in a step-by-step manner until the insulation cardboard breaks down, and the voltage and current data at each breakdown moment are collected. The partial discharge amount (W) is obtained based on the data obtained by the oscilloscope 5. PD ):

[0080]

[0081] Where U represents the peak value of the applied voltage; q i Indicates the amount of partial discharge charge; represents the partial discharge discharge phase; t represents the breakdown duration.

[0082] The data obtained from the above two formulas (diffusion coefficient D and partial discharge amount W PD ) can be linearly fitted to obtain the relationship between the oil-soluble gas diffusion coefficient and the discharge amount under partial discharge conditions:

[0083] D=F(W PD ,T,μ,P)

[0084] Wherein, T represents the temperature of transformer oil; μ represents the viscosity of transformer oil; and P represents the pressure in the transformer test box.

[0085] After obtaining the curve of gas concentration variation with time at the detection point and the local discharge amount within the period of time, the oil-soluble gas diffusion coefficient is obtained by data fitting through the gas concentration curve; the diffusion coefficient is corresponded to the local discharge energy, and the relationship between the oil-soluble gas diffusion coefficient and the discharge amount under the local discharge condition is established according to the formula obtained by data fitting. Since the local discharge energy can characterize the local discharge process, the local discharge process can be characterized by testing the oil-soluble gas diffusion coefficient under the local discharge condition.

[0086] Example 2

[0087] This embodiment also relates to a detection device for the diffusion process of oil-soluble gas under partial discharge conditions, such as Figure 2 The high voltage generator 1 includes a power supply 8 and a step-up transformer 9; the high voltage stabilizer 2 includes a protection resistor 10, a resistor-capacitor voltage divider 11 and a coupling capacitor 12.

[0088] The primary winding of the step-up transformer 9 is connected to the power supply 8 , the secondary winding is connected to the protection resistor 10 of the high voltage stabilizer 2 , the protection resistor 10 is connected to the RC voltage divider 11 , the RC voltage divider 11 is connected to the coupling capacitor 12 and the oscilloscope 6 , and the coupling capacitor 12 is connected to the test box 3 .

[0089] The power source 8 inputs electric energy by connecting to the primary winding of the step-up transformer 9, and the step-up transformer 9 generates a higher voltage at the secondary winding through the principle of electromagnetic induction to meet the voltage requirements of the present invention;

[0090] The step-up transformer 9 is used to provide the necessary high voltage to simulate the voltage state of the equipment under actual operating conditions, and to obtain the detection result of the oil-soluble gas diffusion process under partial discharge conditions based on the relationship between the oil-soluble gas diffusion and the discharge amount under partial discharge conditions.

[0091] The step-up transformer 9 is preferably an AC step-up transformer, which can efficiently convert a low AC voltage into a high AC voltage and keep the energy loss in the electric energy conversion process low.

[0092] The protective resistor 10 is used to limit the current in the loop.

[0093] The protective resistor 10 is preferably a carbon composite high-voltage resistor and a ceramic composite high-voltage resistor, which have the advantages of very low inductance, good high-voltage performance, and excellent anti-pulse performance.

[0094] The RC voltage divider 11 is used to measure the transformer output voltage in addition to maintaining the stability and safety of the transformer.

[0095] The RC voltage divider 11 is preferably an FRC RC voltage divider, which has the advantages of high precision and high stability, and safe and convenient operation when measuring industrial frequency AC high voltage and DC high voltage.

[0096] The coupling capacitor 12 is used to maintain the stability of the transmission of the high-voltage signal, ensuring that the high-voltage signal displayed by the oscilloscope is the high-voltage signal actually transmitted to the test box, making the detection result of the present invention more reliable.

[0097] The coupling capacitor 12 is preferably A series of high voltage capacitors featuring stable performance under different temperature conditions and excellent insulation design.

[0098] Example 3

[0099] This embodiment also relates to a detection device for the diffusion process of oil-soluble gas under partial discharge conditions, such as Figure 3The test box 3 includes an electrode 13, transformer oil 14, an oil inlet valve 15, an oil outlet valve 16, a pressure gauge 17, a pressure release valve 18, a gas channel 19, a first detection point 20 and a second detection point 21; the voltage stabilizer 4 includes a resistor-capacitor protector 25 and a filter 26; the transformer oil 14 is injected into the test box 3 by the oil inlet valve 15 and discharged from the test box 3 by the oil outlet valve 16, the electrode 13 is connected to the high-voltage stabilizer 2 and the resistor-capacitor protector 25 of the voltage stabilizer 4, and is placed in the test box 3, and the pressure The gauge 17 and the pressure release valve 18 are installed at the upper end of the test box 3, the gas channel 19 is installed at the lower right corner of the test box 3, the first detection point 20 and the second detection point 21 are installed on the gas channel 19, and the first detection point 20 is located at the end of the gas channel 19 close to the electrode 13, and the second detection point 21 is located at the end of the gas channel 19 away from the electrode 13; the resistor-capacitor protector 25 of the voltage stabilizer is connected to the filter 26; the filter 26 is connected to the oscilloscope 6, and the oscilloscope 6 is connected to the data analysis system 7.

[0100] The electrode 13 is used to simulate an electrical fault under a very non-uniform field, and local discharge occurs through the high voltage generator electrode 13 and generates gas;

[0101] For clarification, see Figure 3 As shown, the electrode 13 includes a needle electrode 22 , an insulating paperboard 23 and a plate electrode 24 .

[0102] The needle electrode 22 is connected to the high voltage stabilizer 2. When the applied voltage reaches a certain value, the electric field strength near the needle tip is sufficient to ionize the insulating oil and the insulating cardboard, resulting in partial discharge.

[0103] The insulating paperboard 23 is placed on the plate electrode 24 and installed under the needle electrode 22. When the external voltage reaches a certain value, the electric field strength near the needle tip is much higher than that of the surrounding medium. The insulating paperboard 23 will inevitably decompose, thereby producing characteristic gases such as low molecular hydrocarbons and H2, which will dissolve in the transformer oil.

[0104] The plate electrode 24 is connected to the voltage stabilizer 4. During the discharge process, the plate electrode 24 serves as a counter electrode for collecting charges, and can collect charged particles generated by the ionization of the needle electrode 22. While maintaining the charge balance, the plate electrode 24 is connected to a measuring device, such as an oscilloscope 6, through the voltage stabilizer 2 to detect and analyze the current and voltage data during the discharge process.

[0105] In this embodiment, the electrode 13 is preferably: the needle electrode 22 is φ1mm×40mm at the top, the plate electrode 24 is φ30mm×24mm, and the middle insulating paperboard 23 is 90mm×90mm×1mm (thickness), where φ represents the diameter.

[0106] The oil inlet valve 15 completes the injection process of the transformer oil 14 in the test box 3 , and the oil outlet valve 16 completes the discharge process of the transformer oil 14 in the test box 3 .

[0107] The pressure gauge 17 displays the current pressure in the test box 3 and issues an alarm when the pressure is too high.

[0108] The pressure relief valve 18 is used to release the pressure when the pressure in the test box 3 is too high.

[0109] The gas passage 19 is used for diffusion of gas generated by the local discharge of the electrode 13 caused by the high voltage generator 1 through the gas passage 19 .

[0110] In this embodiment, the gas channel 19 is preferably a 2000 mm×φ60 mm steel pipe, wherein φ represents the diameter.

[0111] The first detection point 20 is the initial detection point where the gas generated by the partial discharge passes through the gas channel 19, and the detected gas concentration is the initial gas concentration of the partial discharge;

[0112] The second detection point 21 detects the current gas concentration after the gas generated by the partial discharge diffuses in the channel for a period of time, and is combined with the first detection point 20 to obtain the diffusion coefficient of the gas generated by the partial discharge.

[0113] In this embodiment, the first detection point 20 and the second detection point 21 are at least 1000 mm apart, and preferably 1000 mm apart in this embodiment.

[0114] The RC protector 25 can prevent problems such as unreliable detection results or equipment failure due to excessive discharge current.

[0115] The filter 26 makes the electrical signal detected by the oscilloscope 6 a noise-reduced electrode partial discharge signal, thereby improving the accuracy and reliability of the detection result.

[0116] Example 4

[0117] This embodiment relates to a method for detecting an oil-soluble gas diffusion process under partial discharge conditions, comprising:

[0118] Step S1, assembling insulating paperboard: sandwich a layer of paperboard with a φ30mm hole between two pieces of insulating paperboard 23, glue them together with epoxy resin insulating glue, dry them at 115°C for 24 hours, and then vacuum immerse them in oil at 70°C for 24 hours; polish the paperboard in advance to avoid sharp corners or burrs to avoid partial discharge. Install the treated insulating paperboard 23 on the plate electrode 24 of the electrode 13.

[0119] Step S2, measuring the starting voltage of partial discharge and the electrode breakdown voltage: the step-up transformer 9 first measures the starting voltage of partial discharge and the electrode breakdown voltage by a step-up method. After placing the assembled insulating paperboard 23, the voltage is evenly and slowly increased, and the voltage is increased by 0.5kV every 10s. As soon as the discharge pulse appears on the oscilloscope 6, the data analysis system 7 records the current voltage data of the high-voltage generator 1 and the current voltage data of the partial discharge of the electrode 13. At this time, the current voltage data of the partial discharge of the electrode 13 is the starting discharge voltage U0 of the electrode 13. After obtaining the starting voltage of partial discharge, the voltage of the high-voltage generator 1 is continued to be increased to measure the breakdown voltage of the electrode 13. If the oscilloscope 6 has a pulse that is significantly higher than other discharge pulses or observes the breakdown of the electrode 13, the current voltage data of the high-voltage generator 1 and the current voltage data of the partial discharge of the electrode 13 are recorded. At this time, the current voltage data of the partial discharge of the electrode 13 is the breakdown voltage U1 of the discharge model.

[0120] Step S3, measuring the gas concentration during the development of partial discharge: the high voltage generator 1 directly increases the voltage to about 120% to 160% of the starting voltage, but less than the breakdown voltage. Then the voltage is kept stable, and after the voltage is pressed for a period of time, the partial discharge analyzer 5 starts to collect the gas concentration of the first detection point 20 and the second detection point 21 installed on the gas channel 19, and the data analysis system 7 records it. During the development of partial discharge, the partial discharge analyzer 5 collects the gas concentration of the first detection point 20 and the second detection point 21 installed on the gas channel 19 at regular intervals, and the data analysis system 7 records it.

[0121] Step S4, based on the gas concentration recorded by the data analysis system 7, establish the relationship between the oil-soluble gas diffusion coefficient and the discharge amount under the partial discharge condition, and fit the detected data, and characterize the partial discharge process by the diffusion coefficient, specifically: according to the concentration of each gas component in the oil sample, obtain the characteristic gas concentration change curve during the development of partial discharge. The data analysis system 7 records the characteristic gas concentration change curve during the development of partial discharge, and obtains the characteristic gas diffusion coefficient of oil-paper insulation under partial discharge conditions by data fitting through the characteristic gas concentration change curve. Figure 4 As shown in the figure, the diffusion coefficient corresponds to the local discharge energy, and the relationship between the oil-soluble gas diffusion coefficient and the discharge amount under the local discharge condition is established. The local discharge energy can characterize the local discharge process, thereby obtaining the corresponding relationship between the oil-soluble gas diffusion and the local discharge process, that is, the oil-soluble gas diffusion coefficient under the local discharge condition can be used to characterize the local discharge process.

[0122] In the several embodiments provided in the present application, it should be understood that the disclosed devices and systems can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0123] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0124] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0125] The electronic device of the present invention includes a central processing unit (CPU), which can perform various appropriate actions and processes according to computer program instructions stored in a read-only memory (ROM) or loaded from a storage unit into a random access memory (RAM). In the RAM, various programs and data required for device operation can also be stored. The CPU, ROM and RAM are connected to each other via a bus. An input / output (I / O) interface is also connected to the bus.

[0126] Multiple components in the device are connected to the I / O interface, including: input units, such as keyboards, mice, etc.; output units, such as various types of displays, speakers, etc.; storage units, such as disks, optical disks, etc.; and communication units, such as network cards, modems, wireless communication transceivers, etc. The communication unit allows the device to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunication networks.

[0127] The processing unit performs the various methods and processes described above, such as methods S1 to S4. For example, in some embodiments, methods S1 to S4 may be implemented as a computer software program, which is tangibly contained in a machine-readable medium, such as a storage unit. In some embodiments, part or all of the computer program may be loaded and / or installed on the device via a ROM and / or a communication unit. When the computer program is loaded into the RAM and executed by the CPU, one or more steps of methods S1 to S4 described above may be performed. Alternatively, in other embodiments, the CPU may be configured to execute methods S1 to S4 in any other appropriate manner (e.g., by means of firmware).

[0128] The functions described above herein may be performed at least in part by one or more hardware logic components. For example, without limitation, exemplary types of hardware logic components that may be used include: field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), complex programmable logic devices (CPLDs), and the like.

[0129] The program code for implementing the method of the present invention can be written in any combination of one or more programming languages. These program codes can be provided to a processor or controller of a general-purpose computer, a special-purpose computer or other programmable data processing device, so that the program code, when executed by the processor or controller, enables the functions / operations specified in the flow chart and / or block diagram to be implemented. The program code can be executed entirely on the machine, partially on the machine, partially on the machine as a stand-alone software package and partially on a remote machine, or entirely on a remote machine or server.

[0130] In the context of the present invention, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or equipment. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or equipment, or any suitable combination of the foregoing. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0131] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A detection device for oil-soluble gas diffusion process under partial discharge conditions, characterized in that: The device includes: A high voltage generator (1) provides high voltage conditions for diffusion of oil-soluble gas under partial discharge conditions; A test box (3) is used to simulate the process of partial discharge according to the high voltage condition output by the high voltage generator (1) and provide a detection signal, and to generate a partial discharge amount and a diffusion gas under the partial discharge condition; A partial discharge gas analyzer (5) is used to detect the gas concentration of the diffusion gas in the test box (3) and obtain the gas diffusion coefficient generated by the partial discharge; An oscilloscope (6) is used to obtain voltage data during partial discharge from the high voltage generator (1) and to obtain data on the amount of partial discharge from the test box (3); The data analysis system (7) is used to process the detection data obtained from the partial discharge gas analyzer (5) and the oscilloscope (6), establish the relationship between the oil-soluble gas diffusion coefficient and the partial discharge amount under the partial discharge condition, and use the oil-soluble gas diffusion coefficient to characterize the partial discharge process.

2. The detection device for oil-soluble gas diffusion process under partial discharge conditions according to claim 1 is characterized in that: The test box (3) comprises an electrode (13), transformer oil (14), an oil inlet valve (15), an oil outlet valve (16), a pressure gauge (17), a pressure release valve (18) and a gas channel (19); The electrode (13) is placed in the test box (3); The transformer oil (14) is injected into the test box (3) through the oil inlet valve (15) and discharged from the test box (3) through the oil outlet valve (16); The pressure gauge (17) and the pressure relief valve (18) are installed at one end of the test box (3); The gas channel (19) is installed on a side of the test box (3) close to the ground, and the gas generated by partial discharge is diffused through the gas channel (19).

3. The detection device for oil-soluble gas diffusion process under partial discharge conditions according to claim 2 is characterized in that: The electrode (13) generates a voltage through the high voltage generator (1), causing the electrode to locally discharge and generate gas; The electrode (13) comprises a needle electrode (22), an insulating paperboard (23) and a plate electrode (24); The insulating paperboard (23) is installed on the plate electrode (24) and is located between the needle electrode (22) and the plate electrode (24); When the externally applied voltage reaches a set voltage threshold, the electric field strength near the needle electrode (22) causes the insulating oil and the insulating paperboard (23) to ionize, thereby generating local discharge; The plate electrode (24) is used to collect charged particles generated by ionization of the needle electrode (22) to maintain charge balance.

4. The detection device for oil-soluble gas diffusion process under partial discharge conditions according to claim 2 is characterized in that: The test box (3) further comprises a first detection point (20) and a second detection point (21), wherein the first detection point (20) is located at one end of the gas channel (19) close to the electrode (13), and the second detection point (21) is located at one end of the gas channel (19) far from the electrode (13); The first detection point (20) and the second detection point (21) are both connected to a partial discharge gas analyzer (5); The first detection point (20) is an initial detection point where the gas generated by the partial discharge passes through the gas channel (19), and the gas concentration detected by the partial discharge gas analyzer (5) at the first detection point (20) is the initial gas concentration of the partial discharge; The gas concentration detected by the partial discharge gas analyzer (5) at the second detection point (21) is the current gas concentration detected after the gas generated by the partial discharge diffuses in the gas channel (19) for a set time.

5. The detection device for oil-soluble gas diffusion process under partial discharge conditions according to claim 4 is characterized in that: The distance between the first detection point (20) and the second detection point (21) is at least 1000 mm.

6. The detection device for oil-soluble gas diffusion process under partial discharge conditions according to claim 1 is characterized in that: The process of obtaining the gas diffusion coefficient generated by partial discharge includes: The partial discharge analyzer (5) detects the gas concentration difference Δc between two detection points installed on the gas channel (19), Δc=c1-c2 Wherein, c1 represents the initial gas concentration of partial discharge; c2 represents the gas concentration detected after the gas generated by partial discharge diffuses in the channel for a set time; According to the calculated gas concentration difference Δc, the oil-soluble gas diffusion coefficient D under partial discharge conditions is obtained by data fitting: Where k represents the Boltzmann constant; m represents the mass of the diffusing gas, and π represents the pi constant.

7. The detection device for oil-soluble gas diffusion process under partial discharge conditions according to claim 1 is characterized in that: The relationship between the oil-soluble gas diffusion coefficient and the local discharge amount under the local discharge condition is established as follows: The voltage amplitude of the voltage applied to the test box (3) starts from zero and is increased at a uniform rate in a step-by-step manner until the insulating paperboard breaks down. The data analysis system (7) collects the voltage and current data at each breakdown moment according to the oscilloscope (5) to calculate the partial discharge amount W. PD : Where U represents the peak value of the applied voltage, q i Indicates the amount of partial discharge charge; represents the partial discharge discharge phase; t represents the breakdown duration; Diffusion coefficient D and partial discharge amount W PD Linear fitting was performed to obtain the oil-soluble gas diffusion coefficient D and the local discharge amount W under partial discharge conditions. PD Relationship: D=F(W PD ,T,μ,P) Among them, T represents the temperature of transformer oil, μ represents the viscosity of transformer oil, and P represents the pressure in the transformer test box.

8. The detection device for oil-soluble gas diffusion process under partial discharge conditions according to claim 1 is characterized in that: The device also includes a high-voltage stabilizer (2) connected to the high-voltage generator (1), The high-voltage stabilizer (2) is used to suppress electromagnetic interference in the high-voltage generator (1) and to adjust the voltage output by the high-voltage generator (1) to be in a stable state.

9. The detection device for oil-soluble gas diffusion process under partial discharge conditions according to claim 1 is characterized in that: The device also includes a voltage stabilizer protector (4) connected to the test box (3) and the oscilloscope (6) respectively; the voltage stabilizer protector (4) is used to protect various devices in the device to avoid device failure due to excessive discharge voltage.

10. A method for detecting the oil-soluble gas diffusion process under partial discharge conditions using the device according to any one of claims 1 to 9, the method comprising: Step S1, assembling insulating cardboard: sandwiching a layer of cardboard with a hole between two pieces of insulating cardboard and bonding them together using epoxy resin insulating glue, and installing the assembled insulating cardboard on the electrodes of the test box; Step S2, using a step-by-step voltage-boosting method to adjust the voltage of the high-voltage generator, measuring the starting voltage of partial discharge and the breakdown voltage of the electrode, and recording the voltage data of the high-voltage generator and the voltage data of partial discharge of the electrode; measuring and recording the gas concentrations at two monitoring points during the development process of partial discharge; Step S3, calculating the oil-soluble gas diffusion coefficient based on the recorded gas concentration, and calculating the partial discharge amount based on the partial discharge voltage data; Step S4, linearly fitting the diffusion coefficient and the local discharge amount, establishing the relationship between the diffusion coefficient of the oil-soluble gas and the local discharge amount under the local discharge condition, and characterizing the local discharge process by the diffusion coefficient.

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