Multi-parameter-based active defense method and system for discharge defect of oil-immersed transformer

Abstract

The invention discloses an oil-immersed transformer discharge defect active defense method and system based on multiple parameters. When the transformer runs, pulse current signals, ultrahigh-frequency signals and signals of the content of acetylene dissolved in oil are acquired, and the intensity and continuity of discharge are judged according to the comparison between the amplitude of the pulse current signals and the amplitude of the ultrahigh-frequency signals and different preset thresholds and whether signals higher than the thresholds are generated in a plurality of past time periods or not. Meanwhile, whether discharge defects exist in oil or not and the degradation condition of the defects are judged in an auxiliary mode according to the concentration of the dissolved acetylene. According to the invention, the discharge defect in the oil-immersed transformer can be identified, an alarm signal is sent out in time before the discharge defect develops into arc breakdown, an active protection means is prompted to be adopted, and an anti-error effect on even flash discharge or external interference is realized based on discharge continuity judgment.

Description

Technical Field

[0001] This invention belongs to the field of oil-immersed transformer discharge defect identification technology, specifically relating to an active defense method and system for oil-immersed transformer discharge defects based on multi-parameter signals.

[0002] Background Information Oil-immersed transformers are important electrical equipment in the transmission and conversion of electrical energy. If a discharge defect occurs inside the transformer and is not detected in time, it may quickly develop into an arc breakdown fault, causing the oil tank to crack due to the large amount of gas produced or even causing a deflagration accident.

[0003] When discharge defects develop, partial discharges generate pulse current signals and ultra-high frequency signals. Insulating materials affected by discharges also produce acetylene, which dissolves in oil. By detecting these characteristic physical quantities, internal discharge defects can be identified. Currently, ultra-high frequency and pulse current sensors used in engineering may be affected by interference such as no-load closing and external lightning strikes, resulting in short-term large amplitudes. Simply setting a threshold for the amplitude to determine whether to alarm is unreliable. Online dissolved acetylene gas detection devices may also experience data jumps, and using acetylene content alone for alarms is not reliable enough. Therefore, by comprehensively analyzing multiple parameter signals and applying certain continuity discrimination conditions, the influence of interference can be effectively eliminated, ensuring the reliability of discharge defect identification.

[0004] CN120511621A discloses an active protection method and system for oil-immersed transformers based on pulse current characteristics. It determines whether active protection should be activated based on whether the instantaneous value of the pulse current signal at the core grounding point reaches the protection activation threshold; it determines whether the current pulse cluster is an internal discharge abnormality pulse cluster based on the characteristics of three sets of pulse current signals; and it determines whether the protection should operate based on the number of abnormal discharge pulse clusters within a set period. However, this scheme simply sets a threshold for amplitude to determine internal discharge faults, which has insufficient reliability.

[0005] CN117872068A discloses a method and system for identifying severe discharge defects inside oil-immersed equipment. During equipment operation, it collects digital pulse current signals output by high-frequency pulse current sensors installed at the oil tank grounding wire and / or the bushing end screen grounding wire. The signal energy and the number of pulses contained are used to determine whether high-energy cluster discharge has occurred. The presence of a severe discharge defect inside the oil tank is determined based on whether the number of high-energy cluster discharges within a set time exceeds a preset threshold. However, this method only considers changes in signal energy to determine severity, ignoring the large pulse current signals caused by external interference signals during actual operation. Therefore, this method is prone to misjudgment due to large external discharges, resulting in insufficient accuracy. Summary of the Invention

[0006] To address the problems existing in the prior art, the purpose of this invention is to provide an active defense method for discharge defects in oil-immersed transformers based on multi-parameter signals. This method can reliably identify discharges inside the oil tank through pulse current, ultra-high frequency signals, and the content of dissolved acetylene gas in the oil. When a discharge defect occurs, it can promptly issue an alarm, reminding maintenance personnel to request equipment shutdown, thus achieving active defense against internal transformer faults.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: On one hand, the present invention discloses an active defense method for discharge defects in oil-immersed transformers based on multi-parameter signals, comprising the following steps: Step 1: Real-time detection of the transformer's pulse current signal UHF signal Dissolved acetylene content in oil ,in t The current time is recorded as the signal acquisition time. T 0; Step 2: If for all n =1,2, … , N All have , If yes, proceed to step 6; otherwise, proceed to step 3. For proactive defense time window, This indicates the number of time windows within the active defense cycle. Indicates the threshold value of the first pulse. Indicates the first ultra-high frequency amplitude threshold; Step 3: If for all n =1,2, … , N All have , If yes, proceed to step 5; otherwise, proceed to step 4. This indicates the second pulse amplitude threshold, which is greater than the first pulse amplitude threshold. This indicates a second UHF amplitude threshold that is greater than the first UHF amplitude threshold; Step 4: If If yes, proceed to step 5; otherwise, return to step 1. This indicates the dissolved acetylene content in the oil at the current moment. Indicates the threshold value for acetylene content; Step 5: If If yes, proceed to step 6; otherwise, return to step 1. This represents the pulse current signal at the current moment. This indicates a third pulse amplitude threshold that is greater than the second pulse amplitude threshold. Indicates the current UHF signal. This indicates a third UHF amplitude threshold that is greater than the second UHF amplitude threshold. Step 6: Determine if a discharge defect has occurred in the current transformer.

[0008] More preferably, In step 1, pulse current signals are obtained by acquiring the signals output from the high-frequency pulse current sensor, the ultra-high frequency sensor, and the oil dissolved acetylene gas concentration detection device installed on the transformer. UHF signal Dissolved acetylene content in oil .

[0009] More preferably, In step 2, the active defense time window t The value of 1 ranges from 100 to 500 ms; Number of time windows within the active defense cycle N The calculation method is as follows: ; This indicates the integer division operation.

[0010] More preferably, Active defense cycle T The value should be greater than the duration of the interference signal during no-load closing and external lightning strikes.

[0011] More preferably, First pulse amplitude threshold First UHF amplitude threshold The calculation method is as follows:

[0012]

[0013] In the formula, k 1 is the first reliability coefficient; This represents the maximum absolute value of the noise floor of the pulse current signal when there is no discharge. This represents the maximum absolute value of the UHF signal noise floor when there is no discharge.

[0014] More preferably, First reliability coefficient k 1 has a value of [5, 10).

[0015] More preferably, Second pulse amplitude threshold Second UHF amplitude threshold The calculation method is as follows:

[0016]

[0017] In the formula, k 2 is the second reliability coefficient; This represents the maximum absolute value of the noise floor of the pulse current signal when there is no discharge. This represents the maximum absolute value of the UHF signal noise floor when there is no discharge.

[0018] More preferably, Second reliability coefficient k 2 takes the value [10, 15].

[0019] More preferably, The third pulse amplitude threshold Third UHF amplitude threshold The calculation method is as follows:

[0020]

[0021] In the formula, k 3 is the third reliability coefficient; This represents the maximum absolute value of the noise floor of the pulse current signal when there is no discharge. This represents the maximum absolute value of the UHF signal noise floor when there is no discharge.

[0022] More preferably, The third reliability coefficient is set to [15, 20].

[0023] More preferably, The acetylene content range threshold The value range is 1-3 .

[0024] Secondly, this invention discloses an active defense system for discharge defects in oil-immersed transformers based on the aforementioned active defense method, comprising a multi-parameter signal acquisition module, an active defense cycle and time window setting module, and a discharge defect judgment module: The active defense cycle and time window setting module sets the active defense cycle. T and active defense time window t 1. Calculate the number of time windows within the active defense cycle. N ; During the active defense cycle, the multi-parameter signal acquisition module acquires pulse current signals. UHF signal Dissolved acetylene content in oil ; The discharge defect judgment module compares the pulse current signal and the ultra-high frequency signal with the corresponding preset amplitude threshold, and also uses the dissolved acetylene concentration to help determine whether the transformer has a discharge defect.

[0025] Thirdly, the present invention discloses a computer device, including a memory, a processor, and a computer program stored in the memory; the processor executes the computer program to implement the steps of the active defense method for discharge defects of oil-immersed transformers based on multi-parameter signals.

[0026] Fourthly, the present invention also claims protection for a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the active defense method for discharge defects of oil-immersed transformers based on multi-parameter signals.

[0027] Compared with the prior art, the present invention has the following beneficial technical effects: Currently, UHF and pulse current sensors used in engineering applications may experience short-term large amplitudes due to interference from no-load closing, external lightning strikes, etc. Simply setting a threshold for the amplitude to determine whether to alarm is unreliable. Online dissolved acetylene gas detection devices may also experience data jumps, and using acetylene content alone for alarms is not reliable enough. This invention combines three signals to achieve joint discrimination of dissolved gas information and high-frequency partial discharge signal. This ensures that when pulse current signal and UHF signal experience instantaneous large measurement value interference under external interference, or when the data output of online dissolved acetylene gas detection device jumps instantaneously, defect identification will not be misjudged, thus improving the reliability of internal discharge defect identification in oil-immersed transformers. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the active defense method for discharge defects in oil-immersed transformers based on multi-parameter signals according to the present invention. Figure 2 It is a time-domain waveform diagram of the pulse current signal during the development of internal discharge defects in a transformer; Figure 3 This is the time-domain waveform of the transformer pulse current signal when the circuit is closed under no-load conditions. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0030] like Figure 1As shown, this invention is an active defense method for discharge defects in oil-immersed transformers based on multi-parameter signals, comprising the following steps: Step 1: Acquire the signals output from the high-frequency pulse current sensor, the ultra-high frequency sensor, and the oil dissolved acetylene gas concentration detection device installed on the transformer to obtain the pulse current signal. UHF signal Dissolved acetylene content in oil ,in t The current time is the time difference between the current time and the program start time. Record the current time as... T 0; where the pulse current signal is a high-frequency signal. The signal is a high-frequency signal with a frequency range of 3M-30MHz, and the frequency range of the collected ultra-high frequency signal is 300M-1.5GHz.

[0031] Step 2: If for all n =1,2, … , N All have , If yes, proceed to step 6; otherwise, proceed to step 3. For proactive defense time window, This indicates the number of time windows within the active defense cycle. Indicates the threshold value of the first pulse. Indicates the first ultra-high frequency amplitude threshold; The symbol representing "for any" Symbol representing "always exist"; active defense cycle time T The value should be greater than the duration of the interference signal during no-load closing and external lightning strikes.

[0032] In this invention, an active defense time window t 1. The preferred value range is 100-500ms; active defense cycle time T The preferred value range is 1~5s.

[0033] Number of time windows within the active defense cycle N The calculation method is as follows: ; This represents the rounding operation. The first pulse amplitude threshold. First UHF amplitude threshold The calculation method is as follows:

[0034]

[0035] In the formula, k1 is the first reliability coefficient, with a value of [5, 10); This represents the maximum absolute value of the noise floor of the pulse current signal when there is no discharge. This represents the maximum absolute value of the UHF signal noise floor when there is no discharge.

[0036] Step 3: If for all n =1,2, … , N All have , If yes, proceed to step 5; otherwise, proceed to step 4. In a preferred embodiment of the present invention, the second pulse amplitude threshold Second UHF amplitude threshold The calculation method is as follows:

[0037]

[0038] In the formula, k 2 is the second reliability coefficient, with a value of [10, 15); This represents the maximum absolute value of the noise floor of the pulse current signal when there is no discharge. This represents the maximum absolute value of the UHF signal noise floor when there is no discharge. Step 4: If If yes, proceed to step 5; otherwise, proceed to step 1. In a preferred embodiment of the present invention, the acetylene content amplitude threshold The value range is 1-3 .

[0039] Step 5: If If yes, proceed to step 6; otherwise, proceed to step 1. In a preferred embodiment of the present invention, the third pulse amplitude threshold Third UHF amplitude threshold The calculation method is as follows:

[0040]

[0041] In the formula, k 3 is the third reliability coefficient, with a value of [15, 20]. This represents the maximum absolute value of the noise floor of the pulse current signal when there is no discharge. This represents the maximum absolute value of the UHF signal noise floor when there is no discharge. Step 6: A discharge defect has occurred in the transformer, triggering an alarm signal that prompts maintenance personnel to request equipment shutdown.

[0042] This invention requires acquiring analog signals from a high-frequency pulse current sensor, an ultra-high-frequency sensor, and a dissolved acetylene detection device installed on the transformer body during transformer operation, and obtaining digital pulse current signals. UHF signal Signal of dissolved acetylene content in oil Secondly, the intensity and continuity of the discharge are determined by comparing the amplitude of the pulse current signal and the ultra-high frequency signal with different preset thresholds, and by whether signals exceeding the threshold have been generated in the past several time periods. At the same time, the concentration of dissolved acetylene is used to help determine whether there is a discharge defect in the oil and the degree of defect deterioration. Finally, if the transformer is found to have a discharge defect, an alarm signal is output to remind the operation and maintenance personnel to stay away from the monitored equipment and apply for shutdown in a timely manner.

[0043] This invention discloses an active defense system for discharge defects in oil-immersed transformers that utilizes the aforementioned active defense method for discharge defects in oil-immersed transformers based on multi-parameter signals, including a multi-parameter signal acquisition module, an active defense cycle and time window setting module, and a discharge defect judgment module. The active defense cycle and time window setting module sets the active defense cycle. T and active defense time window t 1. Calculate the number of time windows within the active defense cycle. N ; During the active defense cycle, the multi-parameter signal acquisition module acquires pulse current signals. UHF signal Dissolved acetylene content in oil ; The discharge defect judgment module compares the pulse current signal and the ultra-high frequency signal with the corresponding preset amplitude threshold, and also uses the dissolved acetylene concentration to help determine whether the transformer has a discharge defect.

[0044] The feasibility of the method of the present invention is illustrated by taking the internal discharge defect of an oil-immersed transformer as an example. When a developing discharge defect occurs inside the transformer, the pulse current sensor installed at the transformer core grounding wire and the ultra-high frequency sensor installed on the transformer body wall can measure pulse signals with high amplitude and repeatability. Will Set to 100ms, T is set to 1s. Set to 200mV, Setting the voltage to 400mV, and following steps 1, 2, and 6, these signals can be used to determine if a discharge defect has occurred inside the transformer. Figure 2 As shown, the pulse signal and ultra-high frequency signal appear for a duration of more than 1 second.

[0045] However, during no-load closing, although the pulse current signal appeared to be much higher than the noise floor, its duration was short, less than 1 second, and no ultra-high frequency signal was generated. Figure 3 As shown, this invention can identify discharge defects and will not misjudge no-load closing interference, prompting maintenance personnel to take timely measures.

[0046] This disclosure can be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of this disclosure.

[0047] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination of the foregoing. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0048] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0049] Computer program instructions used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing the status information of the computer-readable program instructions to implement various aspects of this disclosure.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A method for active defense against discharge defects in oil-immersed transformers based on multi-parameter parameters, characterized in that: Includes the following steps: Step 1: Real-time detection of the transformer's pulse current signal UHF signal Dissolved acetylene content in oil ,in t The current time is recorded as the signal acquisition time. T 0; Step 2: If for all n =1,2, … , N All have , If yes, proceed to step 6; otherwise, proceed to step 3. For proactive defense time window, This indicates the number of time windows within the active defense cycle. Indicates the threshold value of the first pulse. Indicates the first ultra-high frequency amplitude threshold; Step 3: If for all n =1,2, … , N All have , If yes, proceed to step 5; otherwise, proceed to step 4. This indicates the second pulse amplitude threshold, which is greater than the first pulse amplitude threshold. This indicates a second UHF amplitude threshold that is greater than the first UHF amplitude threshold; Step 4: If If yes, proceed to step 5; otherwise, return to step 1. This indicates the dissolved acetylene content in the oil at the current moment. Indicates the threshold value for acetylene content; Step 5: If If yes, proceed to step 6; otherwise, return to step 1. This represents the pulse current signal at the current moment. This indicates a third pulse amplitude threshold that is greater than the second pulse amplitude threshold. This indicates the current UHF signal. This indicates a third UHF amplitude threshold that is greater than the second UHF amplitude threshold. Step 6: Determine if a discharge defect has occurred in the current transformer.

2. The active defense method for discharge defects in oil-immersed transformers based on multi-parameter parameters as described in claim 1, characterized in that, In step 1, pulse current signals are obtained by acquiring the signals output from the high-frequency pulse current sensor, the ultra-high frequency sensor, and the oil dissolved acetylene gas concentration detection device installed on the transformer. UHF signal Dissolved acetylene content in oil .

3. The active defense method for discharge defects in oil-immersed transformers based on multi-parameter parameters as described in claim 1, characterized in that, In step 2, the active defense time window t The value of 1 ranges from 100 to 500 ms; Number of time windows within the active defense cycle N The calculation method is as follows: ； This indicates the integer division operation.

4. The active defense method for discharge defects in oil-immersed transformers based on multi-parameter parameters as described in claim 3, characterized in that, Active defense cycle T The value should be greater than the duration of the interference signal during no-load closing and external lightning strikes.

5. The active defense method for discharge defects in oil-immersed transformers based on multi-parameter parameters as described in claim 1, characterized in that, First pulse amplitude threshold First UHF amplitude threshold The calculation method is as follows: In the formula, k 1 represents the first reliability coefficient; This represents the maximum absolute value of the noise floor of the pulse current signal when there is no discharge. This represents the maximum absolute value of the UHF signal noise floor when there is no discharge.

6. The active defense method for discharge defects in oil-immersed transformers based on multi-parameter parameters as described in claim 5, characterized in that, First reliability coefficient k 1 has a value of [5, 10).

7. The active defense method for discharge defects in oil-immersed transformers based on multi-parameter parameters as described in claim 1 or 6, characterized in that, Second pulse amplitude threshold Second UHF amplitude threshold The calculation method is as follows: In the formula, k 2 is the second reliability coefficient; This represents the maximum absolute value of the noise floor of the pulse current signal when there is no discharge. This represents the maximum absolute value of the UHF signal noise floor when there is no discharge.

8. The active defense method for discharge defects in oil-immersed transformers based on multi-parameter parameters as described in claim 7, characterized in that, Second reliability coefficient k 2 takes the value [10, 15].

9. The active defense method for discharge defects in oil-immersed transformers based on multi-parameter parameters as described in claim 1 or 8, characterized in that, The third pulse amplitude threshold Third UHF amplitude threshold The calculation method is as follows: In the formula, k 3 is the third reliability coefficient; This represents the maximum absolute value of the noise floor of the pulse current signal when there is no discharge. This represents the maximum absolute value of the UHF signal noise floor when there is no discharge.

10. The active defense method for discharge defects in oil-immersed transformers based on multi-parameter parameters as described in claim 8, characterized in that, The third reliability coefficient is set to [15, 20].

11. The active defense method for discharge defects in oil-immersed transformers based on multi-parameter parameters as described in claim 1, characterized in that, The acetylene content range threshold The value range is 1-3 .

12. An active defense system for discharge defects in an oil-immersed transformer based on the method of any one of claims 1-11, comprising a multi-parameter signal acquisition module, an active defense cycle and time window setting module, and a discharge defect criterion module, characterized in that: The active defense cycle and time window setting module sets the active defense cycle. T and active defense time window t 1. Calculate the number of time windows within the active defense cycle. N ; During the active defense cycle, the multi-parameter signal acquisition module acquires pulse current signals. UHF signal Dissolved acetylene content in oil ; The discharge defect judgment module compares the pulse current signal and the ultra-high frequency signal with the corresponding preset amplitude threshold, and also uses the dissolved acetylene concentration to help determine whether the transformer has a discharge defect.

13. A computer device comprising a memory, a processor, and a computer program stored in the memory; characterized in that: The processor executes the computer program to implement the steps of the method according to any one of claims 1-11.

14. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the steps of the method according to any one of claims 1-11.

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