A method and system for detecting mechanical jamming faults of split-type on-load tap-changers

Abstract

The present invention relates to the field of high-voltage direct current (HVDC) transmission technology and discloses a method and system for detecting mechanical stuck faults in split-type on-load tap changers. The method comprises: determining whether a transition resistor is missing in a switch switching module based on first current data; collecting the gear switching delay time and the gear shift instruction response status during the gear switching process; obtaining second current data from the converter transformer at several gear switching point monitoring locations, and determining, based on the second current data, whether the switch switching module has excessive mechanical friction resistance, causing a short-circuit current peak to exceed the limit; obtaining third current data from the converter transformer in the operating module, and performing comparative analysis on the third current data to obtain a fault mode classification result for the switch switching module; and collaboratively processing the fault mode classification result and the gear shift instruction response status to obtain a target alarm signal. The present invention can achieve accurate identification and timely protection of mechanical stuck faults in complex and changing operating environments.

Description

Technical Field

[0001] The present invention relates to the technical field of high-voltage direct current transmission, and in particular to a method and system for detecting mechanical sticking faults of a split-type on-load tap changer. Background Art

[0002] As a key voltage regulator, the on-load tap-changer (OLC) of the converter transformer in UHVDC transmission maintains stable power transmission in the DC system at both rated and low voltages by dynamically adjusting the converter transformer's gear position. Based on their structure, OLTCs can be categorized as either integrated or split types, both consisting of a switch selection section and a switch switching section.

[0003] The performance of split-type on-load tap-changers is crucial to system stability and reliability. However, in actual operation, mechanical jamming of the switch switching section can easily occur, leading to gear switching failures and even serious consequences. Traditional fault detection methods have several drawbacks. First, they can only disconnect the fault circuit when the fault expands and triggers the converter transformer protection, which often causes significant damage to the converter transformer. Second, traditional fault detection methods have difficulty accurately identifying different types of mechanical jamming faults, especially those involving interstage short circuits caused by transition resistors. This makes it difficult to accurately respond to protective measures, affecting system efficiency. Moreover, mechanical jamming faults are transient. Therefore, how to quickly and accurately detect mechanical jamming faults in complex power environments has become an urgent problem. Summary of the Invention

[0004] In response to the above problems, the present invention provides a method and system for detecting mechanical sticking faults of a split-type on-load tap changer.

[0005] In a first aspect, an embodiment of the present invention provides a method for detecting a mechanical jam fault of a split-type on-load tap changer. The split-type on-load tap changer is applied to a converter transformer and includes a switch switching module, a switch selection module, a flange, and an operating module. The flange is disposed between the switch switching module and the switch selection module, and the operating module is configured to drive the switch switching module and the switch selection module to implement gear switching.

[0006] The method for detecting a mechanical stuck fault of a split-type on-load tap changer comprises:

[0007] During the operation of the converter transformer, first current data of a plurality of loops of the converter transformer are obtained, and based on the first current data, whether a transition resistance of the switch module is missing is determined;

[0008] receiving a shift instruction sent by a converter control system, controlling the converter transformer to execute a shift switching process based on the shift instruction, and collecting a shift switching delay time and a shift instruction response status during the shift switching process;

[0009] obtaining second current data of the converter transformer at a plurality of gear switching point monitoring positions within an inter-stage short circuit detection window corresponding to the gear switching delay time, and determining, based on the second current data, whether the switching module has excessive mechanical friction resistance causing a short circuit current peak value to exceed a limit;

[0010] During the gear switching process of the converter transformer, third current data of the converter transformer in the operation module is obtained, and the third current data is compared and analyzed to obtain a fault mode classification result of the switch switching module;

[0011] The fault mode classification result and the gear shift instruction response status are collaboratively processed to obtain a target alarm signal, wherein the target alarm signal includes the fault location information of the switch switching module.

[0012] Preferably, after collaboratively processing the fault mode classification result and the gear shift instruction response status to obtain a target alarm signal, the method further includes:

[0013] acquiring real-time operating status data of the split on-load tap changer, and determining whether the split on-load tap changer is at risk of sticking based on the real-time operating status data, and if so, shutting down the split on-load tap changer, wherein the real-time operating status data includes real-time temperature data and real-time vibration frequency;

[0014] Acquiring contact wear data of the split on-load tap changer, and determining based on the contact wear data whether the split on-load tap changer has persistent mechanical jamming caused by contact wear, and if so, taking protective action on the converter transformer.

[0015] Preferably, during the operation of the converter transformer, obtaining first current data of a plurality of loops of the converter transformer, and judging whether the switch module has a missing transition resistor based on the first current data, includes:

[0016] During the operation of the converter transformer, obtaining a first current signal of the primary circuit of the converter transformer and a second current signal of the secondary circuit of the converter transformer;

[0017] performing spectrum feature extraction on the first current signal to obtain a high-frequency component of the first current signal;

[0018] It is determined whether the amplitude of the high-frequency component is greater than a first preset threshold and whether the second current signal is less than a second preset threshold. If so, it is determined that a transition resistor is missing in the switch switching module.

[0019] Preferably, the collecting of the gear switching delay time and the gear shift instruction response status during the gear switching process includes:

[0020] Recording the start time and end time of the gear switching process, and representing the difference between the end time and the start time as the gear switching delay time;

[0021] After executing the gear shifting process, a real-time mechanical operating state of the split on-load tap changer is acquired, and the real-time mechanical operating state is characterized as a gear shifting instruction response state.

[0022] Preferably, the acquiring of second current data of the converter transformer at a plurality of gear switching point monitoring positions, and judging based on the second current data whether the switch switching module has excessive mechanical friction resistance causing a short-circuit current peak value to exceed a limit, includes:

[0023] Acquire a third current signal of the converter transformer at a first gear switching point monitoring position and a fourth current signal of the converter transformer at a second gear switching point monitoring position;

[0024] It is determined whether the third current signal and the fourth current signal are both greater than a third preset threshold value. If so, it is determined that the switch switching module has excessive mechanical friction resistance, causing the short-circuit current peak value to exceed the limit.

[0025] Preferably, the operation module includes a motor and a transmission unit, and the acquiring of the third current data of the converter transformer in the operation module and the comparative analysis of the third current data to obtain the fault mode classification result of the switch switching module include:

[0026] Acquiring a fifth current signal and a sixth current signal of the converter transformer at both ends of the motor;

[0027] Acquire a seventh current signal of the converter transformer at a first detection point of the transmission unit and an eighth current signal of the converter transformer at a second detection point of the transmission unit;

[0028] performing comparative analysis on the fifth current signal, the sixth current signal, the seventh current signal, and the eighth current signal based on a fourth preset threshold to obtain a first fault mode classification result of the switch switching module;

[0029] Dynamically adjusting the fourth preset threshold to obtain a dynamic current threshold, and optimizing the first fault mode classification result based on the dynamic current threshold to obtain a second fault mode classification result;

[0030] The second failure mode classification result is characterized as a failure mode classification result of the switch switching module.

[0031] Preferably, the coordinated processing of the fault mode classification result and the gear shift instruction response status to obtain a target alarm signal includes:

[0032] generating an initial alarm signal based on the failure mode classification result;

[0033] determining whether the gear shift instruction response state matches a preset mechanical operating state, and if so, generating an intermediate alarm signal based on the initial alarm signal;

[0034] Performing cluster analysis on the intermediate alarm signal to obtain fault location information of the switch switching module;

[0035] Based on the fault location information, a decision tree algorithm is used to optimize the intermediate alarm signal to obtain a target alarm signal.

[0036] Preferably, the acquiring of real-time operating status data of the split on-load tap changer, and judging based on the real-time operating status data whether the split on-load tap changer has a risk of getting stuck, and if so, shutting down the split on-load tap changer, comprises:

[0037] Acquiring real-time temperature data and real-time vibration frequency of the split on-load tap-changer;

[0038] determining whether the real-time temperature data exceeds a preset temperature threshold or whether the real-time vibration frequency is greater than a preset frequency threshold, and if so, determining that the split on-load tap changer has a risk of getting stuck and generating a sticking warning;

[0039] An electrical locking protection action is taken based on the jam warning to prohibit the operation of the split on-load tap changer.

[0040] Preferably, the determining, based on the contact wear degree data, whether the split on-load tap changer has contact wear causing persistent mechanical jamming, and if so, taking protective action on the converter transformer, includes:

[0041] It is determined whether the contact wear degree data exceeds a preset wear range. If so, it is determined that contact wear of the split on-load tap changer causes continuous mechanical jamming, and a tripping protection operation is performed on the converter transformer.

[0042] In a second aspect, an embodiment of the present invention provides a split-type on-load tap changer mechanical sticking fault detection system, which is applied to the split-type on-load tap changer mechanical sticking fault detection method described above. The split-type on-load tap changer mechanical sticking fault detection system includes:

[0043] a first judgment module, configured to obtain first current data of a plurality of circuits of the converter transformer during operation of the converter transformer, and judge whether a transition resistance of the switch switching module is missing based on the first current data;

[0044] a data acquisition module, configured to receive a shift instruction sent by a converter control system, control the converter transformer to execute a shift switching process based on the shift instruction, and acquire a shift switching delay time and a shift instruction response status during the shift switching process;

[0045] a second judgment module, configured to obtain second current data of the converter transformer at a plurality of gear switching point monitoring positions within an inter-stage short-circuit detection window corresponding to the gear switching delay time, and judge, based on the second current data, whether there is excessive mechanical friction resistance in the switching module, causing a short-circuit current peak value to exceed a limit;

[0046] a fault mode classification module, configured to obtain third current data of the converter transformer in the operation module during the gear switching process of the converter transformer, and perform comparative analysis on the third current data to obtain a fault mode classification result of the switch switching module;

[0047] An alarm generation module is used to collaboratively process the fault mode classification result and the gear shift instruction response status to obtain a target alarm signal, wherein the target alarm signal includes the fault location information of the switch switching module.

[0048] Compared with the prior art, the embodiment of the present invention provides a method and system for detecting mechanical jamming faults of a split-type on-load tap changer. The beneficial effects are as follows: by obtaining the first current data of several loops to determine the absence of transition resistance in the switch switching module, abnormalities of key components can be discovered in a timely manner, serious problems such as current mutation caused by the absence of transition resistance can be avoided, and the safety of the tap changer switching operation can be ensured; the gear switching delay time and the gear adjustment instruction response status are collected, and combined with the second current data of several gear switching point monitoring positions in the inter-stage short-circuit detection window, it can be accurately determined whether the switch switching module has exceeded the short-circuit current peak due to excessive mechanical friction resistance, effectively preventing the expansion of short-circuit faults caused by mechanical failures, and maintaining the stable operation of the converter transformer and even the entire power system; not only can the fault mode be accurately identified, but the fault location can also be quickly located, which greatly shortens the fault processing time and improves the operational reliability and safety of the split-type on-load tap changer. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a flow chart of a method for detecting a mechanical stuck fault of a split-type on-load tap-changer according to an embodiment of the present invention;

[0050] Figure 2 This is a structural diagram of a split-type on-load tap changer according to an embodiment of the present invention;

[0051] Figure 3 This is a schematic structural diagram of a flange according to an embodiment of the present invention;

[0052] Figure 4 1 is a flow chart of collaborative processing to obtain a target alarm signal according to an embodiment of the present invention;

[0053] Figure 5 This is another flow chart of a method for detecting a mechanical sticking fault of a split-type on-load tap-changer according to an embodiment of the present invention;

[0054] Figure 6 This is a structural diagram of a split-type on-load tap-changer mechanical jam fault detection system according to an embodiment of the present invention;

[0055] Reference numerals:

[0056] 1. Switch switching module; 2. Switch selection module; 3. Flange; 4. Current transformer; H0~H4, terminal blocks. DETAILED DESCRIPTION

[0057] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0058] In the description of the present invention, it should be understood that the terms "first" and "second" etc. are used in the present invention to distinguish different objects rather than to describe a specific order.

[0059] In describing the present invention, it should be noted that, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0060] like Figure 1 As shown, an embodiment of the present invention provides a method for detecting a mechanical stuck fault of a split-type on-load tap changer, comprising the steps of:

[0061] It should be noted that the split on-load tap-changer is applied to the converter transformer, and the converter transformer is applied to the high-voltage direct current transmission system, which also includes a converter and a converter control system.

[0062] The split-type on-load tap-changer consists of a switching module, a switch selector module, a flange, and an operating module. The flange is located between the switching module and the switch selector module, and the operating module is used to drive the switching module and the switch selector module to achieve gear switching.

[0063] like Figure 2 As shown, the split on-load tap changer includes a switch switching module 1 and a switch selection module 2. The bottom of the switch switching module is connected to one end of a flange 3 through a current-carrying conductor, and the other end of the flange 3 is connected to the switch selection module through a current-carrying conductor.

[0064] like Figure 2 or Figure 3 As shown, several current transformers 4 are set in the flange. Figure 3 As shown, the flange is equipped with five terminals: H0, H1, H2, H3, and H4. Terminal H0 is not connected to the current transformer (shown in gray). Terminals H1 and H2 are the odd and even terminals of the converter transformer voltage regulator I, respectively. Terminals H3 and H4 are the odd and even terminals of the converter transformer voltage regulator II, respectively. The switch switching module is installed in the converter transformer auxiliary oil tank, and the switch selection module is installed in the converter transformer main oil tank. The auxiliary and main oil tanks are completely isolated from each other. It is understood that the operating module is mounted on the outer wall of the converter transformer oil tank and connected to the switch body through relevant components to actuate the switch.

[0065] The following is a detailed description of a method for detecting a mechanical stuck fault of a split-type on-load tap changer provided by an embodiment of the present invention:

[0066] S1. During operation of the converter transformer, obtaining first current data of multiple circuits of the converter transformer, and determining whether a transition resistance of a switching module is missing based on the first current data;

[0067] Specifically, step S1 includes:

[0068] 1) During the operation of the converter transformer, a first current signal of the converter transformer in the primary circuit and a second current signal of the converter transformer in the secondary circuit are obtained;

[0069] During converter transformer operation, sensors collect real-time current signals from the primary and secondary circuits of the converter transformer. The primary circuit is the main circuit in the converter transformer, directly used for transmitting and converting electrical energy. The secondary circuit is primarily used for controlling, protecting, measuring, and transmitting signals to the primary circuit. By monitoring and controlling the electrical parameters of the primary circuit, the safe and stable operation of the converter transformer is ensured.

[0070] 2) extracting spectrum features of the first current signal to obtain a high-frequency component of the first current signal;

[0071] The first current signal is subjected to spectral feature extraction using a fast Fourier transform to obtain a high-frequency component and a low-frequency component of the first current signal. The low-frequency component may reflect a normal operating state, and the high-frequency component may include abnormal fluctuations.

[0072] 3) Determine whether the amplitude of the high-frequency component is greater than a first preset threshold and whether the second current signal is less than a second preset threshold. If so, determine that a transition resistor is missing in the switch module.

[0073] The high-frequency component amplitude is determined to be greater than a first preset threshold. If so, it indicates abnormal fluctuations. The second current signal is further determined to be less than a second preset threshold. If so, it indicates that the current has not reached the expected level, and a transition resistor is determined to be missing in the switching module. It is understood that poor contact or aging of components can also lead to missing transition resistors.

[0074] S2. Receive a shift command sent by a converter control system, control the converter transformer to execute a shift switching process based on the shift command, and collect a shift switching delay time and a shift command response status during the shift switching process;

[0075] Specifically, the converter control system monitors parameters such as DC voltage, and issues instructions to the converter transformer to adjust the gear according to the needs and operating conditions of the HVDC transmission system, so that the trigger angle of the converter valve thyristor is within the appropriate range, ensuring the stable operation of the HVDC transmission system.

[0076] Furthermore, step S2 includes:

[0077] 1) Record the start and end time of the gear switching process, and represent the difference between the end and start time as the gear switching delay time;

[0078] The time difference between the start and completion of the gear switching is recorded using a timestamp to obtain the gear switching delay time.

[0079] 2) After the gear shifting process is executed, the real-time mechanical operating state of the split on-load tap changer is obtained, and the real-time mechanical operating state is represented as a gear shifting instruction response state.

[0080] The real-time mechanical operating status of the split on-load tap changer includes, but is not limited to, the motor speed. In one specific embodiment, the converter control system issues a speed reduction command. After executing the gear shift process, the real-time motor speed of the split on-load tap changer is obtained and represented as the gear shift command response status.

[0081] S3. Acquire second current data of the converter transformer at several gear switching point monitoring positions within the inter-stage short-circuit detection window corresponding to the gear switching delay time, and determine, based on the second current data, whether there is excessive mechanical friction resistance in the switch switching module, causing the short-circuit current peak to exceed the limit;

[0082] Specifically, when the converter transformer switches gears, the split on-load tap-changer operates with certain risks, such as poor contact and insulation damage, which can lead to interstage short circuits. The interstage short circuit detection window monitors relevant electrical quantities in real time during this time period to promptly detect and determine whether an interstage short circuit has occurred.

[0083] Furthermore, step S3 includes:

[0084] 1) obtaining a third current signal of the converter transformer at a monitoring position of a first gear switching point and a fourth current signal of the converter transformer at a monitoring position of a second gear switching point;

[0085] The current distribution within the converter transformer varies at different locations, especially during gear switching. The current variation characteristics at different locations have different value in fault diagnosis. By setting up monitoring points at multiple locations, more comprehensive and detailed current information can be obtained.

[0086] Specifically, the present invention sets two gear switching point monitoring positions inside the converter transformer, namely the first gear switching point monitoring position and the second gear switching point monitoring position. By monitoring the current changes at the corresponding positions, it can reflect the current size, change trend, etc. at the corresponding position at the moment of gear switching and for a period of time thereafter.

[0087] 2) Determine whether the third current signal and the fourth current signal are both greater than a third preset threshold value. If so, determine that the switch module has excessive mechanical friction resistance, causing the short-circuit current peak value to exceed the limit.

[0088] The current change during gear switching should be within a certain range. If the mechanical friction resistance exceeds the standard, it may cause the switching process to be abnormal, which in turn may cause the short-circuit current peak to exceed the normal range. By monitoring and comparing these current signals, it is possible to indirectly determine whether the mechanical friction resistance exceeds the standard and whether it has caused the short-circuit current peak to exceed the limit. Therefore, when both the third current signal and the fourth current signal are greater than the third preset threshold, it can be determined that the switching module has excessive mechanical friction resistance, causing the short-circuit current peak to exceed the limit.

[0089] S4. During the gear switching process of the converter transformer, obtaining third current data of the converter transformer in the operation module, and performing comparative analysis on the third current data to obtain a fault mode classification result of the switch switching module;

[0090] The operating module serves as the power source for the switch action and is equipped with necessary auxiliary devices such as limit switches, safety interlocks, position indicators, counters, and signal generators. Specifically, the operating module includes a motor and a transmission unit.

[0091] Furthermore, step S4 includes:

[0092] 1) obtaining a fifth current signal and a sixth current signal of the converter transformer at both ends of the motor;

[0093] During the gear switching process of the converter transformer, a fifth current signal and a sixth current signal at both ends of the motor are acquired through sensors.

[0094] 2) obtaining a seventh current signal of the converter transformer at a first detection point of the transmission unit and an eighth current signal of the converter transformer at a second detection point of the transmission unit;

[0095] During the gear switching process of the converter transformer, a seventh current signal of the converter transformer at the first detection point of the transmission unit and an eighth current signal of the converter transformer at the second detection point of the transmission unit are obtained through sensors.

[0096] 3) performing comparative analysis on the fifth current signal, the sixth current signal, the seventh current signal, and the eighth current signal based on a fourth preset threshold value to obtain a first fault mode classification result of the switching module;

[0097] Specifically, in this embodiment, the fifth current signal obtained is 5A, the sixth current signal is 4.8A, the seventh current signal is 6A, and the eighth current signal is 5.5A. A comparison reveals that the seventh and eighth current signals differ significantly and are generally higher, indicating a possible transmission unit load anomaly. Furthermore, considering the fourth preset threshold of 5.2A, and determining that both the seventh and eighth current signals are greater than the fourth preset threshold, the first fault mode classification result of the switching module is determined to be abnormal transmission resistance.

[0098] 4) Dynamically adjusting the fourth preset threshold to obtain a dynamic current threshold, and optimizing the first fault mode classification result based on the dynamic current threshold to obtain a second fault mode classification result;

[0099] It should be noted that because the first fault mode classification result may be inaccurate due to environmental interference, a dynamically adjusted threshold is adopted. In this embodiment, the fourth preset threshold is dynamically adjusted based on real-time temperature data to obtain a dynamic current threshold of 5.3A. It is determined that both the seventh current signal and the eighth current signal are greater than the dynamic current threshold. The first fault mode classification result is optimized based on the dynamic current threshold, resulting in a second fault mode classification result of mechanical sticking.

[0100] 5) The second fault mode classification result is characterized as the fault mode classification result of the switch switching module.

[0101] After eliminating the current fluctuation caused by temperature, this embodiment determines that the failure mode classification result of the switch module is mechanical sticking.

[0102] S5. Coordinate processing of the fault mode classification result and the gear shift instruction response status to obtain a target alarm signal.

[0103] Specifically, if Figure 4 As shown, step S5 includes:

[0104] S501, generating an initial alarm signal based on the failure mode classification result;

[0105] Features are extracted from the fault mode classification results, and an initial alarm signal is generated based on these features, such as "a spike reaches 15A and lasts for more than 3 seconds." This signal can be a simple flashing light, with different colors representing different alarm priorities. Red indicates a high-priority alarm, providing a direct reflection of the classification result.

[0106] S502, determining whether the gear shift instruction response state matches the preset mechanical operation state, and if so, generating an intermediate alarm signal based on the initial alarm signal;

[0107] In one specific embodiment, the converter control system issues a speed reduction command. After the gear shift process, the motor speed of the split-type on-load tap changer should decrease from 1000 rpm to 800 rpm. The real-time motor speed of the split-type on-load tap changer, i.e., the gear shift command response state, is 810 rpm. This is close to the preset mechanical operating state of 800 rpm, and a match is determined. This match determination effectively confirms the device's ability to respond to commands and avoids false alarms. Furthermore, an intermediate alarm signal is generated based on the initial alarm signal. Compared to the initial alarm signal, the intermediate alarm signal carries more fault information, such as "current overload, duration 5 seconds."

[0108] S503, performing cluster analysis on the intermediate alarm signal to obtain fault location information of the switch module;

[0109] Clustering algorithm is used to extract fault location features from the intermediate alarm signal to obtain the fault location information of the switch module.

[0110] S504 , optimizing the intermediate alarm signal using a decision tree algorithm based on the fault location information to obtain a target alarm signal.

[0111] The intermediate alarm signal is optimized using a decision tree algorithm in combination with the fault location information to obtain a target alarm signal in the final output form. It is understandable that the target alarm signal includes the fault location information of the switch module.

[0112] It should be noted that steps S1 to S5 reflect the process of detecting the mechanical jam fault of the switch switching module of the split-type on-load tap changer. Figure 5 As shown, the method for detecting a mechanical stuck fault of a split on-load tap changer according to the embodiment of the present invention further includes the following steps after step S5:

[0113] S6. Acquire real-time operating status data of the split on-load tap changer, and determine whether the split on-load tap changer has a risk of sticking based on the real-time operating status data. If so, shut down the split on-load tap changer.

[0114] Specifically, step S6 includes:

[0115] 1) Obtain real-time temperature data and vibration frequency of the split-type on-load tap-changer;

[0116] The real-time operating status data of the split-type on-load tap-changer, namely the real-time temperature data and the real-time vibration frequency, is obtained through sensors.

[0117] 2) Determine whether the real-time temperature data exceeds the preset temperature threshold or whether the real-time vibration frequency is greater than the preset frequency threshold. If so, it is determined that there is a risk of the split on-load tap-changer getting stuck and a sticking warning is generated;

[0118] Real-time temperature data reflects the heating status of the split on-load tap-changer, while real-time vibration frequency reflects its operational stability. In this embodiment, the preset temperature threshold is 60°C and the preset frequency threshold is 10Hz. If the real-time temperature exceeds 60°C or the real-time vibration frequency exceeds 10Hz, the split on-load tap-changer is determined to be at risk of sticking and a sticking warning is generated.

[0119] 3) Based on the jam warning, an electrical locking protection action is taken to prohibit the operation of the split-type on-load tap-changer.

[0120] Based on the jam warning, a relay is used to cut off the power supply path of the split on-load tap-changer, thereby preventing the split on-load tap-changer from updating its operating status. This protective action can ensure the safety of the equipment in the event of a mechanical jam fault.

[0121] Furthermore, if it is determined based on the real-time operating status data that the split on-load tap changer no longer has a risk of being stuck, the prohibition on the split on-load tap changer operation is released.

[0122] S7. Obtain contact wear data of the split on-load tap changer, and determine based on the contact wear data whether the split on-load tap changer has contact wear causing persistent mechanical jamming. If so, take protective action on the converter transformer.

[0123] The contact wear degree data of the split on-load tap-changer is obtained through the sensor to determine whether the contact wear degree data exceeds the preset wear range. If so, it is determined that the split on-load tap-changer has contact wear causing mechanical jamming to continue, and a tripping protection operation is taken for the converter transformer.

[0124] Specifically, the contact wear data can be contact wear depth. Determining whether the contact wear data exceeds a preset wear range depends on setting a reasonable threshold. In this embodiment, the preset wear range is 0 to 0.2 mm. If the contact wear data is 0.25 mm, which exceeds the preset wear range, it is determined that the split-type on-load tap changer has sustained mechanical jamming caused by contact wear, and a protective tripping operation is implemented for the converter transformer. This includes tripping the converter transformer incoming circuit breaker within the circuit breaker tripping time and shutting off the cooler operation, thereby ensuring the safety of the converter transformer.

[0125] The embodiment of the present invention provides a method for detecting a mechanical jam fault of a split-type on-load tap changer. By acquiring first current data of several loops to determine whether a transition resistance of a switch switching module is missing, abnormalities of key components can be discovered in a timely manner, serious problems such as current mutation caused by the missing transition resistance can be avoided, and the safety of the tap changer switching operation can be ensured. The gear switching delay time and the gear adjustment instruction response status are collected, and combined with the second current data of several gear switching point monitoring positions within the inter-stage short-circuit detection window, it can be accurately determined whether the switch switching module has exceeded the short-circuit current peak due to excessive mechanical friction resistance, effectively preventing the expansion of short-circuit faults caused by mechanical failures, and maintaining the stable operation of the converter transformer and even the entire power system. Not only can the fault mode be accurately identified, but the fault location can also be quickly located, which greatly shortens the fault processing time and improves the operational reliability and safety of the split-type on-load tap changer.

[0126] like Figure 6 As shown, an embodiment of the present invention provides a split-type on-load tap changer mechanical sticking fault detection system, which is applied to the split-type on-load tap changer mechanical sticking fault detection method described above.

[0127] Specifically, the split-type on-load tap-changer mechanical jam fault detection system includes:

[0128] The first judgment module 01 is used to obtain first current data of multiple circuits of the converter transformer during the operation of the converter transformer, and judge whether there is a missing transition resistor in the switch switching module based on the first current data;

[0129] Data acquisition module 02, used to receive the gear shifting instruction sent by the converter control system, control the converter transformer to execute the gear shifting process based on the gear shifting instruction, and collect the gear shifting delay time and gear shifting instruction response status during the gear shifting process;

[0130] The second judgment module 03 is configured to obtain second current data of the converter transformer at a plurality of gear switching point monitoring positions within an inter-stage short-circuit detection window corresponding to the gear switching delay time, and determine, based on the second current data, whether there is excessive mechanical friction resistance in the switch switching module, causing a short-circuit current peak value to exceed a limit;

[0131] The fault mode classification module 04 is configured to obtain the third current data of the converter transformer in the operation module during the gear switching process of the converter transformer, and perform comparative analysis on the third current data to obtain the fault mode classification result of the switch switching module;

[0132] The alarm generation module 05 is used to coordinately process the fault mode classification results and the gear shift instruction response status to obtain a target alarm signal, wherein the target alarm signal includes the fault location information of the switch switching module.

[0133] It should be noted that the various modules in the aforementioned split-type on-load tapchanger mechanical stuck fault detection system can be implemented in whole or in part through software, hardware, or a combination thereof. Each of these modules can be embedded in or independent of a processor in a computer device in hardware form, or stored in a computer device memory in software form, allowing the processor to call and execute the corresponding operations of each of these modules. For the specific definitions of the split-type on-load tapchanger mechanical stuck fault detection system, refer to the definitions of the split-type on-load tapchanger mechanical stuck fault detection method above. Both have the same functions and effects and are not further elaborated here.

[0134] In summary, the embodiment of the present invention provides a method and system for detecting mechanical jamming faults of split-type on-load tap changers. By acquiring first current data of several circuits to determine the absence of transition resistance in the switch switching module, abnormalities of key components can be discovered in a timely manner, serious problems such as current mutation caused by the absence of transition resistance can be avoided, and the safety of the tap changer switching operation can be ensured. By collecting the gear switching delay time and the gear adjustment instruction response status, and combining the second current data of several gear switching point monitoring positions within the inter-stage short-circuit detection window, it can be accurately determined whether the switch switching module has exceeded the short-circuit current peak due to excessive mechanical friction resistance, effectively preventing the expansion of short-circuit faults caused by mechanical failures, and maintaining the stable operation of the converter transformer and even the entire power system. Not only can the fault mode be accurately identified, but the fault location can also be quickly located, which greatly shortens the fault processing time and improves the operational reliability and safety of the split-type on-load tap changer.

[0135] Each embodiment in this specification is described in a progressive manner, and the same or similar parts of each embodiment can be directly referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. It should be noted that the various technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the various technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0136] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A method for detecting mechanical jamming faults of a split-type on-load tap-changer, characterized in that: The split on-load tap changer is applied to a converter transformer. The split on-load tap changer comprises a switch switching module, a switch selection module, a flange, and an operating module. The flange is arranged between the switch switching module and the switch selection module. The operating module is used to drive the switch switching module and the switch selection module to realize gear switching. The method for detecting a mechanical stuck fault of a split-type on-load tap changer comprises: During the operation of the converter transformer, first current data of a plurality of loops of the converter transformer are obtained, and based on the first current data, whether a transition resistance of the switch module is missing is determined; receiving a shift instruction sent by a converter control system, controlling the converter transformer to execute a shift switching process based on the shift instruction, and collecting a shift switching delay time and a shift instruction response status during the shift switching process; obtaining second current data of the converter transformer at a plurality of gear switching point monitoring positions within an inter-stage short circuit detection window corresponding to the gear switching delay time, and determining, based on the second current data, whether the switching module has excessive mechanical friction resistance causing a short circuit current peak value to exceed a limit; During the gear switching process of the converter transformer, third current data of the converter transformer in the operation module is obtained, and the third current data is compared and analyzed to obtain a fault mode classification result of the switch switching module; Coordinating the fault mode classification result and the gear shift instruction response state to obtain a target alarm signal, wherein the target alarm signal includes fault location information of the switch switching module; The method of obtaining first current data of a plurality of loops of the converter transformer during operation of the converter transformer and determining whether a transition resistance of the switch module is missing based on the first current data includes: During the operation of the converter transformer, obtaining a first current signal of the primary circuit of the converter transformer and a second current signal of the secondary circuit of the converter transformer; performing spectrum feature extraction on the first current signal to obtain a high-frequency component of the first current signal; It is determined whether the amplitude of the high-frequency component is greater than a first preset threshold and whether the second current signal is less than a second preset threshold. If so, it is determined that a transition resistor is missing in the switch switching module.

2. The method for detecting mechanical jamming fault of a split-type on-load tap-changer according to claim 1, characterized in that: After the fault mode classification result and the gear shift instruction response status are collaboratively processed to obtain a target alarm signal, the method further includes: acquiring real-time operating status data of the split on-load tap changer, and determining whether the split on-load tap changer is at risk of sticking based on the real-time operating status data, and if so, shutting down the split on-load tap changer, wherein the real-time operating status data includes real-time temperature data and real-time vibration frequency; Acquiring contact wear data of the split on-load tap changer, and determining based on the contact wear data whether the split on-load tap changer has persistent mechanical jamming caused by contact wear, and if so, taking protective action on the converter transformer.

3. The method for detecting mechanical jamming fault of a split-type on-load tap-changer according to claim 1, characterized in that: The collecting of the gear switching delay time and the gear shift instruction response status during the gear switching process includes: Recording the start time and end time of the gear switching process, and representing the difference between the end time and the start time as the gear switching delay time; After executing the gear shifting process, a real-time mechanical operating state of the split on-load tap changer is acquired, and the real-time mechanical operating state is characterized as a gear shifting instruction response state.

4. The method for detecting mechanical jamming fault of a split-type on-load tap-changer according to claim 1, characterized in that: The obtaining of second current data of the converter transformer at a plurality of gear switching point monitoring positions, and judging based on the second current data whether the switch switching module has excessive mechanical friction resistance causing a short-circuit current peak value to exceed a limit, includes: Acquire a third current signal of the converter transformer at a first gear switching point monitoring position and a fourth current signal of the converter transformer at a second gear switching point monitoring position; It is determined whether the third current signal and the fourth current signal are both greater than a third preset threshold value. If so, it is determined that the switch switching module has excessive mechanical friction resistance, causing the short-circuit current peak value to exceed the limit.

5. The method for detecting mechanical jamming fault of a split-type on-load tap-changer according to claim 1, characterized in that: The operation module includes a motor and a transmission unit. The acquiring of third current data of the converter transformer in the operation module and the comparative analysis of the third current data to obtain a fault mode classification result of the switch switching module include: Acquiring a fifth current signal and a sixth current signal of the converter transformer at both ends of the motor; Acquire a seventh current signal of the converter transformer at a first detection point of the transmission unit and an eighth current signal of the converter transformer at a second detection point of the transmission unit; performing comparative analysis on the fifth current signal, the sixth current signal, the seventh current signal, and the eighth current signal based on a fourth preset threshold to obtain a first fault mode classification result of the switch switching module; Dynamically adjusting the fourth preset threshold to obtain a dynamic current threshold, and optimizing the first fault mode classification result based on the dynamic current threshold to obtain a second fault mode classification result; The second failure mode classification result is characterized as a failure mode classification result of the switch switching module.

6. The method for detecting mechanical jamming fault of a split-type on-load tap-changer according to claim 1, characterized in that: The collaborative processing of the fault mode classification result and the gear shift instruction response state to obtain a target alarm signal includes: generating an initial alarm signal based on the failure mode classification result; determining whether the gear shift instruction response state matches a preset mechanical operating state, and if so, generating an intermediate alarm signal based on the initial alarm signal; Performing cluster analysis on the intermediate alarm signal to obtain fault location information of the switch switching module; Based on the fault location information, a decision tree algorithm is used to optimize the intermediate alarm signal to obtain a target alarm signal.

7. The method for detecting mechanical jamming fault of a split-type on-load tap-changer according to claim 2, characterized in that: The acquiring of real-time operating status data of the split on-load tap changer, and determining whether the split on-load tap changer has a risk of getting stuck based on the real-time operating status data, and if so, shutting down the split on-load tap changer, includes: Acquiring real-time temperature data and real-time vibration frequency of the split on-load tap-changer; determining whether the real-time temperature data exceeds a preset temperature threshold or whether the real-time vibration frequency is greater than a preset frequency threshold, and if so, determining that the split on-load tap changer has a risk of getting stuck and generating a sticking warning; An electrical locking protection action is taken based on the jam warning to prohibit the operation of the split on-load tap changer.

8. The method for detecting mechanical jamming fault of a split-type on-load tap-changer according to claim 2, characterized in that: The determining, based on the contact wear degree data, whether the split on-load tap changer has contact wear causing persistent mechanical jamming, and if so, taking protective action on the converter transformer, includes: It is determined whether the contact wear degree data exceeds a preset wear range. If so, it is determined that contact wear of the split on-load tap changer causes continuous mechanical jamming, and a tripping protection operation is performed on the converter transformer.

9. A split-type on-load tap-changer mechanical jam fault detection system, characterized in that: The split-type on-load tap changer mechanical sticking fault detection system is applied to the split-type on-load tap changer mechanical sticking fault detection method according to any one of claims 1 to 8, and the split-type on-load tap changer mechanical sticking fault detection system comprises: a first judgment module, configured to obtain first current data of a plurality of circuits of the converter transformer during operation of the converter transformer, and judge whether a transition resistance of the switch switching module is missing based on the first current data; a data acquisition module, configured to receive a shift instruction sent by a converter control system, control the converter transformer to execute a shift switching process based on the shift instruction, and acquire a shift switching delay time and a shift instruction response status during the shift switching process; a second judgment module, configured to obtain second current data of the converter transformer at a plurality of gear switching point monitoring positions within an inter-stage short-circuit detection window corresponding to the gear switching delay time, and judge, based on the second current data, whether there is excessive mechanical friction resistance in the switching module, causing a short-circuit current peak value to exceed a limit; a fault mode classification module, configured to obtain third current data of the converter transformer in the operation module during the gear switching process of the converter transformer, and perform comparative analysis on the third current data to obtain a fault mode classification result of the switch switching module; An alarm generation module is used to collaboratively process the fault mode classification result and the gear shift instruction response status to obtain a target alarm signal, wherein the target alarm signal includes the fault location information of the switch switching module.

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