Active protection method and system for internal fault of converter transformer on-load tap changer

Abstract

An active protection method and system for internal faults in an on-load tap changer of a converter transformer includes: determining the start time of on-load tap changer operation and then extending the time interval; identifying ultra-high frequency (UHF) and high frequency (HF) pulse signals and discharge pulse times exceeding a set threshold within the extended time interval; identifying whether the on-load tap changer is adjusting a polarity-crossing or non-polarity-crossing tap position; determining the internal abnormality of the on-load tap changer based on the UHF and HF pulse signals and their pulse times during operation; and further issuing "general alarm," "serious alarm," or even "protection trip" signals based on the severity of the internal partial discharge detected by the UHF and HF signals. This invention fundamentally avoids false alarms and trips in monitoring or protection devices caused by discharge during normal tap changer operation. Furthermore, it achieves a leap from "passively preventing false operation" to "actively detecting faults," proactively preventing damage to the on-load tap changer itself or even transformer explosions caused by its faults.

Description

Technical Field

[0001] This invention belongs to the field of high voltage direct current transmission and power equipment protection technology, specifically relating to a method and system for monitoring and actively protecting internal faults in on-load tap changers of converter transformers. Background Technology

[0002] Converter transformers are core equipment in high-voltage direct current (HVDC) transmission systems. Their on-load changers (OLTCs) stabilize DC voltage by dynamically adjusting the winding turns ratio. They are characterized by frequent operation, high voltage regulation capabilities, and high operating temperatures, with a maximum switching frequency of approximately 20 times per day during load fluctuations. During operation, spark discharges are inevitable when the tap changer switches contacts. These discharge signals are captured by partial discharge monitoring devices on the transformer body (such as high-frequency pulse current (HFCT) and ultra-high frequency (UHF) sensors). Frequent switching can cause a drop in the transformer oil breakdown voltage, and under long-term operating conditions, discharges occurring on the bare metal surface of the OLTC can lead to serious accidents.

[0003] Currently, active protection devices used for monitoring internal faults in converter transformers mainly rely on the amplitude, frequency, and phase characteristics of partial discharge signals for fault identification. However, the strong discharge pulse groups generated during the normal operation of tap changers have signal characteristics similar to fault discharges caused by internal insulation deterioration or poor contact, which can easily lead to misjudgments by protection devices, causing unnecessary alarms or even false trips, seriously affecting the reliable operation of the DC system.

[0004] Existing solutions typically involve setting simple thresholds or delays in the monitoring logic. On one hand, to avoid spark discharges generated during normal tap changer operation, a high threshold may fail to identify switch faults. On the other hand, lowering the threshold to identify faults could lead to misjudgments of normal operation and false tripping. Therefore, existing methods struggle to accurately distinguish between normal operation discharges and genuine fault discharges, posing risks of both false tripping and failure to trip. Thus, there is an urgent need for an active protection method capable of accurately identifying the tap changer's operating state and implementing intelligent discrimination logic within that timeframe to effectively differentiate between normal operation interference and genuine internal faults in the on-load tap changer. Summary of the Invention

[0005] The technical problem to be solved by this invention is to overcome the problem of "false operation" and "failure to operate" caused by the inability of existing active protection devices for converter transformers to effectively distinguish between normal operation discharge and internal fault discharge of on-load tap changers, and to provide a reliable active protection method for identifying internal discharge faults in on-load tap changers of converter transformers.

[0006] The technical solution of this invention is as follows: The core is to introduce the hard contact signal of "on-load switch operation" as the time reference for key state blocking and intelligent judgment, and transform the operation process of the tap changer from an "interference source" into an "identifiable state window". Within this window, a diagnostic method and system are adopted to effectively distinguish between normal operation interference of the on-load tap changer and the actual internal fault of the switch. When the tap changer is abnormal, a general alarm, a serious alarm and a protection trip are issued according to the graded action strategy.

[0007] The present invention adopts the following technical solution.

[0008] In a first aspect, the present invention discloses an active protection method for internal faults in the on-load tap changer of a converter transformer, the method comprising: Step 1: Determine the start time of on-load tap changer operation After that, proceed The time is extended, and the extension time is detected in real time. The discharge pulse signal is received, and then proceed to step 2; Step 2: Receive the on-load tap changer operation status signal via communication, and identify whether the on-load tap changer is adjusting the tap position with or without polarity. If it is identified as adjusting the tap position without polarity, proceed to Step 3; otherwise, proceed to Step 4. Step 3: Determine if the discharge pulse signal is greater than the high-frequency signal threshold. And greater than the ultra-high frequency signal threshold All discharge pulse moments ; when Only in [ , During the period and / or in ( , During the period and / or ( , If the discharge pulse is within the specified time period, it is determined to be interference with normal operation, and no alarm signal is issued or the protection action is activated. when If the fault occurs outside the three time periods mentioned above, it is determined that a fault may have occurred inside the on-load tap changer. Further assessment is needed to issue an alarm signal or activate the protection trip signal. ; Step 4: Determine if the discharge pulse signal is greater than the high-frequency signal threshold. And greater than the ultra-high frequency signal threshold All discharge pulse moments ; when Only in [ , During the period and / or ( , If the discharge pulse is within the specified time period, it is determined to be interference with normal operation, and no alarm signal is issued or the protection action is activated. when If the fault occurs outside of the two time periods mentioned above, it is determined that a fault may have occurred inside the on-load tap changer. Further judgment is needed to issue an alarm signal or activate the protection trip signal.

[0009] More preferably, In step 1, the hard contact status signal during on-load tap changer operation is acquired in real time from the on-load tap changer operating mechanism box, or the on-load tap changer operation status signal is obtained through communication to determine the start time of the on-load tap changer operation. .

[0010] More preferably, The stretching time The setting should include a predetermined margin after at least covering the on-load tap changer operating time range.

[0011] More preferably, The predetermined margin is set to 0.5 seconds.

[0012] More preferably, In step 3, the high-frequency signal threshold The value should be at least twice the background noise during normal operation; The ultra-high frequency signal threshold The value should be at least twice the background noise level during normal operation.

[0013] More preferably,

[0014] in, The time it takes for the moving contact of the tap selector to start moving and leave the fixed contact. The time between the tap selector leaving the fixed contact and before it contacts another fixed contact. The time it takes for the moving contact of the tap selector to contact another fixed contact. The time between the end of the tap selector's operation and the start of the switching operation. This refers to the switching action time.

[0015] More preferably, In step 3, when Only in [ , During the specified time period, the discharge pulse is determined to be a normal discharge signal generated by the breakdown of the contact gap due to the floating potential formed by the tap selector contact changing from closed to open. when Only in ( , During the specified time period, the discharge pulse is determined to be a normal discharge signal generated by the breakdown of the contact gap when the tap selector contacts are switched from open to closed, creating a floating potential. when Only in ( , During the specified time period, if the switching switch is operating normally, arcing occurs between the moving and stationary contacts, and the contact gap breaks down under the voltage level, generating a discharge pulse signal.

[0016] More preferably, In step 3, when the discharge pulse occurs ( , During the time period: If the discharge pulse time Continuing to occur Within 100ms of the start of the time, if the tap selector is found to be malfunctioning, a "general alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 200ms of the start of the event, if the tap selector is found to be malfunctioning and the situation is deemed serious, a "serious alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 300ms of the start of the time, if the tap selector is found to be malfunctioning or seriously malfunctioning, a "protection trip" signal will be issued.

[0017] More preferably, In step 3, when the discharge pulse occurs ( , During the time period: If the discharge pulse time Continuing to occur Within 100ms of the start of the time, if the tap selector is found to be malfunctioning, a "general alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 200ms of the start of the event, if the tap selector is found to be malfunctioning and the situation is deemed serious, a "serious alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 300ms of the start of the time, if the tap selector is found to be malfunctioning or seriously malfunctioning, a "protection trip" signal will be issued.

[0018] More preferably, In step 3, when the discharge pulse occurs Subsequent extension period Internal time: If the discharge pulse time Continuing to occur Within 100ms of the start of the event, if the switch is found to be malfunctioning, a "general alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 200ms of the start of the event, if the switch action is deemed abnormal and serious, a "serious alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 300ms of the start of the event, if the switch action is deemed abnormal or serious, a "protection trip" signal will be issued.

[0019] More preferably, In step 4, when the discharge pulse occurs ( , During the time period: If the discharge pulse time Continuing to occur Within 100ms of the start of the time, if the tap selector is found to be malfunctioning, a "general alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 200ms of the start of the event, if the tap selector is found to be malfunctioning and the situation is deemed serious, a "serious alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 300ms of the start of the event, if the tap selector is found to be malfunctioning, and the malfunction is deemed serious, a "protection trip" signal will be issued.

[0020] More preferably, In step 4, when the discharge pulse occurs Subsequent extension period Internal time: If the discharge pulse time Continuing to occur Within 100ms of the start of the event, if the switch is found to be malfunctioning, a "general alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 200ms of the start of the event, if the switch action is deemed abnormal and serious, a "serious alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 300ms of the start of the event, if the switch action is deemed abnormal or serious, a "protection trip" signal will be issued.

[0021] Secondly, the present invention discloses an active protection system for internal faults of on-load tap changers in converter transformers based on the aforementioned active protection method, including an on-load tap changer operation start time judgment module, an on-load tap changer tap position adjustment mode judgment module, a discharge pulse identification module, a fault judgment module, an alarm output and protection action module; The on-load tap changer operation start time determination module is used to determine the start time of on-load tap changer operation and to assign a grace period after the start time begins. ; The discharge pulse recognition module is used to identify the spread time. All discharge pulse signals exceeding the set threshold and the timing of the discharge pulses ; The on-load tap changer position adjustment mode determination module is used to identify whether the on-load tap changer is adjusting the polarity of the tap or the non-polarity of the tap. The fault diagnosis module uses ultra-high frequency and high frequency pulse signals and discharge pulse timings under different on-load tap changer adjustment modes. Determine the internal fault condition of the on-load tap changer; The alarm output and protection action modules are used to issue "general alarm", "serious alarm" and "protection trip" signals in different levels according to the severity of the internal fault of the on-load tap changer as determined by the fault judgment module.

[0022] 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 protection method for internal faults of the on-load tap changer of the converter transformer.

[0023] Fourthly, the present invention also discloses a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the active protection method for internal faults of the on-load tap changer of the converter transformer.

[0024] Compared with the prior art, the present invention has the following beneficial technical effects: 1. Significantly reduce the false trip rate: By accurately blocking interference during operation through hard contact signals, the false alarms and false trips of protection devices caused by normal operation discharge are fundamentally avoided, thus improving the reliability of DC system operation.

[0025] 2. Achieve early warning of tap changer anomalies: This not only prevents erroneous operation but, more importantly, enables intelligent identification of subtle anomalies in the internal state of the tap changer during this critical testing period. By comparing changes in operational discharge characteristics, potential faults such as contact wear, poor contact, and insulation degradation can be detected early, achieving a leap from "passively preventing erroneous operation" to "actively detecting faults."

[0026] 3. High adaptability and easy engineering implementation: It provides flexible hardware signal access or communication access methods, and fully considers the actual site conditions of equipment from different manufacturers and at different times, so that the protection strategy can be universally applied to various converter transformer projects, and the modification and implementation plan is clear and feasible.

[0027] 4. Clear logic and high reliability: It utilizes existing, highly reliable mechanical / electrical hard contacts and the discharge characteristics of tap changers during normal operation as state criteria, making the logic simple and clear. Attached Figure Description

[0028] Figure 1 Action logic block diagram of active protection method for internal discharge fault of on-load tap changer of converter transformer; Figure 2 A graph showing the difference in UHF signal changes during polarity and non-polarity tap adjustment in the normal operation of an on-load tap changer. 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] During operation, the on-load tap changer of the converter transformer will generate spark discharges in the switching switch and selector contacts. High-frequency pulse current and ultra-high frequency sensors will detect large discharge signals. Therefore, it is necessary to introduce the on-load tap changer operation signal contacts for relevant protection logic judgment.

[0031] To accurately and quickly distinguish between normal operation discharge and internal fault discharge of on-load tap changers, the specific implementation scheme adopted in this invention is as follows: Figure 1 As shown: Step 1: Determine the start time of on-load tap changer operation After that, proceed The time is extended, and the extension time is detected in real time. The discharge pulse signal is received, and then proceed to step 2; On-load tap changer status signal acquisition: The active protection system acquires the "On-load tap changer in operation" hard contact status signal from the on-load tap changer operating mechanism box in real time, or acquires the on-load tap changer operation status signal through communication. At the moment this signal changes, which is the moment on-load tap changer operation begins, a time extension T is applied, and the following steps are all performed within this time period. The stretching time The setting should include at least a 0.5-second margin after covering the on-load tap changer operating time range. The typical value selected in this invention is 6 seconds.

[0032] Step 2: Receive the on-load tap changer operation status signal via communication, and identify whether the on-load tap changer is adjusting the tap position with or without polarity. If it is identified as adjusting the tap position without polarity, proceed to Step 3; otherwise, proceed to Step 4. By judging the signal (communication / multi-parameter signal) received during on-load tap changer operation, it is possible to identify whether the tap position adjustment is normal (i.e., non-over-polarity) or over-polarity (e.g.) Figure 2 As shown), the tap selector is used to distinguish between two different types of gear adjustment methods to identify and differentiate abnormalities. Step 3: Determine if the discharge pulse signal is greater than the high-frequency signal threshold. And greater than the ultra-high frequency signal threshold All discharge pulse moments ; when Only in [ , During the period and / or in ( , During the period and / or ( , If the discharge pulse is within the specified time period, it is determined to be interference with normal operation, and no alarm signal is issued or the protection action is activated. when If the fault occurs outside the three time periods mentioned above, it is determined that a fault may have occurred inside the on-load tap changer. Further assessment is needed to issue an alarm signal or activate the protection trip signal. ; The frequency range of the high-frequency signal described in this invention is 500kHz-30MHz, and the frequency range of the ultra-high frequency signal is 300MHz-1.5GHz.

[0033] The high-frequency signal threshold The value should be at least twice the noise floor during normal operation; the ultra-high frequency signal threshold. The value should be at least twice the background noise level during normal operation.

[0034] In this invention,

[0035] in, The time it takes for the moving contact of the tap selector to start moving and leave the fixed contact. The time between the tap selector leaving the fixed contact and before it contacts another fixed contact. The time it takes for the moving contact of the tap selector to contact another fixed contact. The time between the end of the tap selector's operation and the start of the switching operation. This refers to the switching action time.

[0036] when Only in [ , During the specified time period, the discharge pulse is determined to be a normal discharge signal generated by the breakdown of the contact gap due to the floating potential formed by the tap selector contact changing from closed to open. when Only in ( , During the specified time period, the discharge pulse is determined to be a normal discharge signal generated by the breakdown of the contact gap when the tap selector contacts are switched from open to closed, creating a floating potential. when Only in ( , During the specified time period, if the switching switch is operating normally, arcing occurs between the moving and stationary contacts, and the contact gap breaks down under the voltage level, generating a discharge pulse signal.

[0037] When the discharge pulse occurs ( , During the time period: If the discharge pulse time Continuing to occur Within 100ms of the start of the time, if the tap selector is found to be malfunctioning, a "general alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 200ms of the start of the event, if the tap selector is found to be malfunctioning and the situation is deemed serious, a "serious alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 300ms of the start of the time, if the tap selector is found to be malfunctioning or seriously malfunctioning, a "protection trip" signal will be issued.

[0038] When the discharge pulse occurs ( , During the time period: If the discharge pulse time Continuing to occur Within 100ms of the start of the time, if the tap selector is found to be malfunctioning, a "general alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 200ms of the start of the event, if the tap selector is found to be malfunctioning and the situation is deemed serious, a "serious alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 300ms of the start of the time, if the tap selector is found to be malfunctioning or seriously malfunctioning, a "protection trip" signal will be issued.

[0039] When the discharge pulse occurs Subsequent extension period Internal time: If the discharge pulse time Continuing to occur Within 100ms of the start of the event, if the switch is found to be malfunctioning, a "general alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 200ms of the start of the event, if the switch action is deemed abnormal and serious, a "serious alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 300ms of the start of the event, if the switch action is deemed abnormal or serious, a "protection trip" signal will be issued.

[0040] Step 4: Determine if the discharge pulse signal is greater than the high-frequency signal threshold. And greater than the ultra-high frequency signal threshold All discharge pulse moments ; The frequency range of the high-frequency signal described in this invention is 500kHz-30MHz, and the frequency range of the ultra-high frequency signal is 300MHz-1.5GHz.

[0041] The high-frequency signal threshold The value should be at least twice the noise floor during normal operation; the ultra-high frequency signal threshold. The value should be at least twice the background noise level during normal operation.

[0042] when Only in [ , During the period and / or ( , If the discharge pulse is within the specified time period, it is determined to be interference with normal operation, and no alarm signal is issued or the protection action is activated. when If the fault occurs outside of the two time periods mentioned above, it is determined that a fault may have occurred inside the on-load tap changer. Further judgment is needed to issue an alarm signal or activate the protection trip signal.

[0043] When the discharge pulse occurs ( , During the time period: If the discharge pulse time Continuing to occur Within 100ms of the start of the time, if the tap selector is found to be malfunctioning, a "general alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 200ms of the start of the event, if the tap selector is found to be malfunctioning and the situation is deemed serious, a "serious alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 300ms of the start of the time, if the tap selector is found to be malfunctioning or seriously malfunctioning, a "protection trip" signal will be issued.

[0044] When the discharge pulse occurs Subsequent extension period Internal time: If the discharge pulse time Continuing to occur Within 100ms of the start of the event, if the switch is found to be malfunctioning, a "general alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 200ms of the start of the event, if the switch action is deemed abnormal and serious, a "serious alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 300ms of the start of the event, if the switch action is deemed abnormal or serious, a "protection trip" signal will be issued.

[0045] The present invention also discloses an active protection system for internal faults of on-load tap changers in converter transformers based on the active protection method, including an on-load tap changer operation start time judgment module, an on-load tap changer tap position adjustment mode judgment module, a discharge pulse identification module, a fault judgment module, an alarm output and protection action module; The on-load tap changer operation start time determination module is used to determine the start time of on-load tap changer operation and to assign a grace period after the start time begins. ; The discharge pulse recognition module is used to identify the spread time. All discharge pulse signals exceeding the set threshold and the timing of the discharge pulses ; The on-load tap changer position adjustment mode determination module is used to identify whether the on-load tap changer is adjusted to a polarity-crossing position or a non-polarity-crossing position. The fault diagnosis module uses ultra-high frequency and high frequency pulse signals and discharge pulse timings under different on-load tap changer adjustment modes. Determine the internal fault condition of the on-load tap changer; The alarm output and protection action modules are used to issue "general alarm", "serious alarm" and "protection trip" signals in different levels according to the severity of the internal fault of the on-load tap changer as determined by the fault judgment module.

[0046] The present invention also discloses a computer device, including a memory, a processor, and a computer program stored in the memory; wherein the processor executes the computer program to implement the steps of an active protection method for internal faults of on-load tap changers of converter transformers.

[0047] The present invention also discloses a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of an active protection method for internal faults of on-load tap changers in converter transformers.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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. An active protection method for internal faults in the on-load tap changer of a converter transformer, characterized in that, The method includes: Step 1: Determine the start time of on-load tap changer operation After that, proceed The time is extended, and the extension time is detected in real time. The discharge pulse signal is received, and then proceed to step 2; Step 2: Receive the on-load tap changer operation status signal via communication, and identify whether the on-load tap changer is adjusting the tap position with or without polarity. If it is identified as adjusting the tap position without polarity, proceed to Step 3; otherwise, proceed to Step 4. Step 3: Determine if the discharge pulse signal is greater than the high-frequency signal threshold. And greater than the ultra-high frequency signal threshold All discharge pulse moments ; when Only in [ , During the period and / or in ( , During the period and / or ( , If the discharge pulse is within the specified time period, it is determined to be interference with normal operation, and no alarm signal is issued or the protection action is activated. when If the fault occurs outside the three time periods mentioned above, it is determined that a fault may have occurred inside the on-load tap changer. Further assessment is needed to issue an alarm signal or activate the protection trip signal. ; Step 4: Determine if the discharge pulse signal is greater than the high-frequency signal threshold. And greater than the ultra-high frequency signal threshold All discharge pulse moments ; when Only in [ , During the period and / or ( , If the discharge pulse is within the specified time period, it is determined to be interference with normal operation, and no alarm signal is issued or the protection action is activated. when If the fault occurs outside of the two time periods mentioned above, it is determined that a fault may have occurred inside the on-load tap changer. Further judgment is needed to issue an alarm signal or activate the protection trip signal.

2. The active protection method for internal faults of the on-load tap changer of a converter transformer according to claim 1, characterized in that: In step 1, the hard contact status signal during on-load tap changer operation is acquired in real time from the on-load tap changer operating mechanism box, or the on-load tap changer operation status signal is obtained through communication to determine the start time of the on-load tap changer operation. .

3. The active protection method for internal faults of the on-load tap changer of a converter transformer according to claim 2, characterized in that: The stretching time The setting should include a predetermined margin after at least covering the on-load tap changer operating time range.

4. The active protection method for internal faults of the on-load tap changer of the converter transformer according to claim 3, characterized in that: The predetermined margin is set to 0.5 seconds.

5. The active protection method for internal faults of the on-load tap changer of a converter transformer according to claim 1, characterized in that: In step 3, the high-frequency signal threshold The value should be at least twice the background noise during normal operation; The ultra-high frequency signal threshold The value should be at least twice the background noise level during normal operation.

6. The active protection method for internal discharge faults of the on-load tap changer of a converter transformer according to claim 1, characterized in that: in, The time it takes for the moving contact of the tap selector to start moving and leave the fixed contact. The time between the tap selector leaving the fixed contact and before it contacts another fixed contact. The time it takes for the moving contact of the tap selector to contact another fixed contact. The time between the end of the tap selector's operation and the start of the switching operation. This refers to the switching action time.

7. The active protection method for internal faults of the on-load tap changer of a converter transformer according to claim 1 or 5, characterized in that: In step 3, when Only in [ , During the specified time period, the discharge pulse is determined to be a normal discharge signal generated by the breakdown of the contact gap due to the floating potential formed by the tap selector contact changing from closed to open. when Only in ( , During the specified time period, the discharge pulse is determined to be a normal discharge signal generated by the breakdown of the contact gap when the tap selector contacts are switched from open to closed, creating a floating potential. when Only in ( , During the specified time period, if the switching switch is operating normally, arcing occurs between the moving and stationary contacts, and the contact gap breaks down under the voltage level, generating a discharge pulse signal.

8. The active protection method for internal discharge faults of the on-load tap changer of a converter transformer according to claim 1 or 5, characterized in that: In step 3, when the discharge pulse occurs ( , During the time period: If the discharge pulse time Continuing to occur Within 100ms of the start of the time, if the tap selector is found to be malfunctioning, a "general alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 200ms of the start of the event, if the tap selector is found to be malfunctioning and the situation is deemed serious, a "serious alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 300ms of the start of the time, if the tap selector is found to be malfunctioning or seriously malfunctioning, a "protection trip" signal will be issued.

9. The active protection method for internal discharge faults of the on-load tap changer of a converter transformer according to claim 8, characterized in that: In step 3, when the discharge pulse occurs ( , During the time period: If the discharge pulse time Continuing to occur Within 100ms of the start of the time, if the tap selector is found to be malfunctioning, a "general alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 200ms of the start of the event, if the tap selector is found to be malfunctioning and the situation is deemed serious, a "serious alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 300ms of the start of the time, if the tap selector is found to be malfunctioning or seriously malfunctioning, a "protection trip" signal will be issued.

10. The active protection method for internal discharge faults of the on-load tap changer of a converter transformer according to claim 9, characterized in that: In step 3, when the discharge pulse occurs Subsequent extension period Internal time: If the discharge pulse time Continuing to occur Within 100ms of the start of the event, if the switch is found to be malfunctioning, a "general alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 200ms of the start of the event, if the switch action is deemed abnormal and serious, a "serious alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 300ms of the start of the event, if the switching action is deemed abnormal or serious, a "protection trip" signal will be issued.

11. The active protection method for internal faults of the on-load tap changer of a converter transformer according to claim 1 or 5, characterized in that: In step 4, when the discharge pulse occurs ( , During the time period: If the discharge pulse time Continuing to occur Within 100ms of the start of the time, if the tap selector is found to be malfunctioning, a "general alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 200ms of the start of the event, if the tap selector is found to be malfunctioning and the situation is deemed serious, a "serious alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 300ms of the start of the time, if the tap selector is found to be malfunctioning or seriously malfunctioning, a "protection trip" signal will be issued.

12. The active protection method for internal discharge faults of on-load tap changers in converter transformers according to claim 11, characterized in that: In step 4, when the discharge pulse occurs Subsequent extension period Internal time: If the discharge pulse time Continuing to occur Within 100ms of the start of the event, if the switch is found to be malfunctioning, a "general alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 200ms of the start of the event, if the switch action is deemed abnormal and serious, a "serious alarm" signal will be issued. If the discharge pulse time Continuing to occur Within 300ms of the start of the event, if the switching action is deemed abnormal or serious, a "protection trip" signal will be issued.

13. An active protection system for internal faults of on-load tap changers in converter transformers based on the active protection method described in any one of claims 1-12, comprising an on-load tap changer operation start time determination module, an on-load tap changer tap position adjustment mode determination module, a discharge pulse identification module, a fault determination module, and an alarm output and protection action module; characterized in that: The on-load tap changer operation start time determination module is used to determine the start time of on-load tap changer operation and to assign a grace period after the start time begins. ; The discharge pulse recognition module is used to identify the spread time. All discharge pulse signals exceeding the set threshold and the timing of the discharge pulses ; The on-load tap changer position adjustment mode determination module is used to identify whether the on-load tap changer is adjusted to a polarity-crossing position or a non-polarity-crossing position. The fault diagnosis module uses ultra-high frequency and high frequency pulse signals and discharge pulse timings under different on-load tap changer adjustment modes. Determine the internal fault condition of the on-load tap changer; The alarm output and protection action modules are used to issue "general alarm", "serious alarm" and "protection trip" signals in different levels according to the severity of the internal fault of the on-load tap changer as determined by the fault judgment module.

14. 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 1-12.

15. 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 1-12.

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