A multi-source on-site automatic calibration system and method for an on-line transformer monitoring device

Abstract

The application discloses a transformer on-line monitoring device multi-source field automatic calibration system and method, relates to the technical field of on-line monitoring of power equipment, and comprises the following units: an ultrasonic array consistency calibration unit, a high-frequency non-disassembly type calibration unit, an ultrahigh-frequency calibration unit, a synchronous state node output unit, a timing control and communication unit and a main control unit; the ultrasonic array consistency calibration unit outputs an excitation signal to a calibrated ultrasonic sensor; the high-frequency non-disassembly type calibration unit injects an excitation signal into a grounding wire through a clamp-type openable high-frequency excitation sensor and generates a reverse coupling pulse; the ultrahigh-frequency calibration unit outputs an excitation signal to a calibrated ultrahigh-frequency sensor; the synchronous state node output unit synchronously outputs a state node signal; the timing control and communication unit triggers calibration and receives a response reading; and the main control unit controls each unit to execute a calibration process according to the response reading. The application realizes automatic closed-loop calibration without a reference for a transformer on-line monitoring device.

Description

Technical Field

[0001] This application relates to the field of online monitoring technology for power equipment, and in particular to a multi-source on-site automatic verification system and method for online monitoring devices of transformers. Background Technology

[0002] Transformers are core equipment in power systems, and online partial discharge monitoring is a crucial means of assessing their insulation status. Current mainstream online partial discharge monitoring devices for transformers typically integrate a comprehensive monitoring host, an array of ultrasonic sensors (operating frequencies typically 20kHz~300kHz, mainly used for discharge location), high-frequency current sensors (operating frequencies typically 1MHz~100MHz, mainly used for quantitative discharge assessment), and ultra-high frequency sensors (operating frequencies typically 300MHz~3GHz, mainly used for discharge type identification and anti-interference detection). These three types of sensors correspond to three different signal physical forms: mechanical waves, conducted current, and spatial electromagnetic waves, respectively, collectively forming a multi-source joint monitoring system for transformer partial discharge. However, during long-term operation, due to on-site electromagnetic interference, changes in the external environment, and the influence of installation techniques, the stability and accuracy of the integrated monitoring host's data acquisition system may change. Problems such as loosening, surface contamination, and rust may also occur at the sensor terminals, ultimately leading to deviations in the accuracy and validity of the monitoring data from the online monitoring device.

[0003] Existing ultrasonic testing devices for transformers can only test a single sensor and cannot simultaneously test an array of multiple spatially distributed sensors in the field. When the amplitude or phase responses of the channels in the sensor array are inconsistent, the monitoring data from the online monitoring device will produce significant errors.

[0004] High-frequency sensor field verification may also face physical limitations: installed high-frequency current sensors are typically secured to the core and clamp grounding wire using tooling brackets, making on-site disassembly difficult and prone to disrupting the original installation. Furthermore, some high-frequency current sensors have very small gaps between the sensor and grounding wire after installation, making it difficult to verify the sensor and device using through-core coupling. Simultaneously, the surface of the transformer core or clamp grounding wire is coated with insulating varnish, preventing the application of high-frequency excitation signals to the grounding wire through breaking the varnish or direct contact. Existing through-core coupling and direct injection methods have significant limitations for on-site verification. Although some existing technologies mention "excitation sensors coupled with excitation signals via grounding wires," they do not identify or resolve the difficulties associated with the aforementioned through-core coupling and direct injection methods, nor do they disclose a high-frequency verification scheme that simultaneously achieves non-disassembly, bypasses insulating varnish, and uses reverse coupling pulses. Meanwhile, existing technologies provide a field calibration system and method for high-frequency current sensors. Although it does not require power outages for disassembly, it requires an independent high-frequency calibration sensor and calibration unit. The hardware cost is high, the algorithm is complex, and it is a single-channel calibration, which cannot meet the requirements of multi-channel consistency calibration. In addition, the calibration device and the calibrated device have a one-way data relationship, which cannot achieve closed-loop calibration and automatic periodic calibration.

[0005] Meanwhile, in existing technologies, the verification device cannot achieve automatic verification at regular intervals, often requiring manual on-site verification of the online monitoring device of the transformer under test, which is time-consuming, labor-intensive, and inefficient. Moreover, during the verification process, the online monitoring device of the transformer under test may simultaneously collect real partial discharge signals or environmental interference. Existing technologies cannot clearly distinguish which signals are excitation signals actively injected by the verification system, which can easily lead to misjudgments (such as misreporting a strong amplitude verification pulse as a sudden partial discharge). Summary of the Invention

[0006] The purpose of this application is to provide a multi-source on-site automatic calibration system and method for transformer online monitoring devices, which can realize reference-free automatic closed-loop on-site calibration of three parameters: ultrasonic, high frequency, and ultra-high frequency.

[0007] To achieve the above objectives, this application provides the following solution: In a first aspect, this application provides a multi-source on-site automatic calibration system for transformer online monitoring devices, used for on-site calibration of an online monitoring device for a transformer under calibration that integrates an ultrasonic sensor, a high-frequency sensor, and an ultra-high-frequency sensor under calibration. The system includes: an ultrasonic array consistency calibration unit, a high-frequency non-detachable calibration unit, an ultra-high-frequency calibration unit, a synchronous status node output unit, a timing control and communication unit, and a main control unit.

[0008] The ultrasonic array consistency verification unit is used to output a standard ultrasonic excitation signal to the ultrasonic sensor under calibration; the standard ultrasonic excitation signal is transmitted to the ultrasonic sensor under calibration through the transformer tank wall.

[0009] The high-frequency non-detachable calibration unit is used to inject a high-frequency pulse excitation signal into the grounding wire through a clamp-on openable high-frequency excitation sensor, generate a reverse coupling pulse on the grounding wire, and transmit it to the high-frequency sensor being calibrated.

[0010] The ultra-high frequency verification unit is used to radiate a standard ultra-high frequency excitation signal to the ultra-high frequency sensor being calibrated.

[0011] The synchronous status node output unit is used to synchronously output a status node signal to the online monitoring device of the transformer under test during the output excitation signals of the ultrasonic array consistency verification unit, the high-frequency non-detachable verification unit and the ultra-high frequency verification unit.

[0012] The timing control and communication unit is used to preset single or periodic verification tasks and automatically trigger the verification process; it is also used to receive the response reading fed back by the online monitoring device of the transformer under test after collecting the excitation signal; and it is also used to interact with the online monitoring device of the transformer under test through the communication interface.

[0013] The main control unit is used to control the ultrasonic array consistency verification unit, the high-frequency non-disassembly verification unit, the ultra-high frequency verification unit, the synchronization status node output unit, and the timing control and communication unit to execute the verification process based on the response readings fed back by the online monitoring device of the transformer under test.

[0014] Secondly, this application provides a multi-source on-site automatic verification method for transformer online monitoring devices, using the system described above, the method comprising: The ultrasonic array consistency verification unit outputs a standard ultrasonic excitation signal to the ultrasonic sensor under calibration; the standard ultrasonic excitation signal is transmitted to the ultrasonic sensor under calibration through the transformer tank wall.

[0015] The clamp-on openable high-frequency excitation sensor in the high-frequency non-detachable calibration unit injects a high-frequency pulse excitation signal into the grounding wire, generating a reverse coupling pulse on the grounding wire and transmitting it to the high-frequency sensor being calibrated.

[0016] The UHF calibration unit radiates a standard UHF excitation signal to the UHF sensor being calibrated.

[0017] During the output excitation signals of the ultrasonic array consistency verification unit, the high-frequency non-detachable verification unit, and the ultra-high frequency verification unit, the synchronous status node output unit synchronously outputs a status node signal to the online monitoring device of the transformer under test.

[0018] The timing control and communication unit presets single or periodic verification tasks and automatically triggers the verification process. It receives the response readings fed back by the online monitoring device of the transformer under test after collecting the excitation signal, and interacts with the online monitoring device of the transformer under test through the communication interface.

[0019] The main control unit controls the ultrasonic array consistency verification unit, the high-frequency non-detachable verification unit, the ultra-high frequency verification unit, the synchronization status node output unit, and the timing control and communication unit to execute the verification process based on the response readings fed back by the online monitoring device of the transformer under test.

[0020] According to the specific embodiments provided in this application, this application has the following technical effects: This application provides a multi-source on-site automatic calibration system and method for transformer online monitoring devices. The system includes: an ultrasonic array consistency calibration unit, a high-frequency non-detachable calibration unit, an ultra-high-frequency calibration unit, a synchronous status node output unit, a timing control and communication unit, and a main control unit. The ultrasonic array consistency calibration unit synchronously outputs a standard ultrasonic excitation signal to the ultrasonic sensor under calibration. The standard ultrasonic excitation signal is transmitted to the ultrasonic sensor under calibration via the transformer tank wall. It can simultaneously perform on-site calibration of an array composed of multiple spatially distributed ultrasonic sensors under calibration. The high-frequency non-detachable calibration unit injects a high-frequency pulse excitation signal into the grounding wire through a clamp-on openable high-frequency excitation sensor, generating a reverse coupling pulse on the grounding wire and transmitting it to the high-frequency sensor under calibration. This unit does not require disassembling the installed high-frequency sensor under calibration, nor does it require breaking or polishing the insulating varnish on the grounding wire surface. It generates a reverse coupling pulse on the grounding wire through electromagnetic induction, bypassing the physical limitations of existing through-core coupling and direct injection methods. The UHF verification unit radiates a standard UHF excitation signal to the UHF sensor being calibrated. This enables on-site verification of the UHF channel and sensor performance of the online monitoring device for the transformer under calibration. Together with ultrasonic array verification and high-frequency non-detachable verification, it forms a multi-parameter coverage, providing a more comprehensive verification method for evaluating the overall performance of the transformer online monitoring system. The synchronous status node output unit outputs a status node signal to the online monitoring device of the transformer under calibration during the excitation signal output periods of the ultrasonic array consistency verification unit, high-frequency non-detachable verification unit, and UHF verification unit. This unit clearly distinguishes between the verification excitation period and the on-site monitoring period, marking the signal collected during the verification period as the verification excitation signal, fundamentally avoiding misinterpreting strong amplitude verification pulses as sudden partial discharges in the transformer. The timing control and communication unit is used to preset single or periodic verification tasks and automatically trigger the verification process; it is also used to receive the response readings fed back by the online monitoring device of the transformer under test after collecting the excitation signal; and it is used to interact with the online monitoring device of the transformer under test through the communication interface. This unit has a built-in real-time clock and communication interface, and can preset single or periodic verification tasks and automatically trigger the verification process according to the preset plan, realizing unattended timed automatic verification. The main control unit is used to control the ultrasonic array consistency verification unit, high-frequency non-disassembly verification unit, ultra-high frequency verification unit, synchronous status node output unit, and timing control and communication unit to execute the verification process based on the response readings fed back by the online monitoring device of the transformer under test. This unit does not rely on any external calibration benchmark or independent calibration unit, and can perform verification using only the system's own response readings. It is the first to have a benchmark-free self-comparison verification logic, which greatly reduces algorithm complexity and hardware cost. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This application provides an overall architecture block diagram of a multi-source on-site automatic verification system for transformer online monitoring devices, as provided in one embodiment. Figure 2 A schematic diagram of the high-frequency excitation sensor structure in a multi-source on-site automatic verification system for an online transformer monitoring device provided in an embodiment of this application; Figure 3 A schematic diagram of the timing relationship between the synchronous status node output unit and the excitation signal in a multi-source field automatic verification system for an online transformer monitoring device provided in an embodiment of this application; Figure 4 This is a flowchart illustrating a multi-source on-site automatic verification method for an online transformer monitoring device provided in one embodiment of this application.

[0023] Reference numerals: 1-Upper housing; 2-Lower housing; 3-Openable hinge; 4-Locking mechanism; 5-Excitation signal input interface (BNC type); 6-Shielded outer shell; 7-Grounding wire through hole. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] In one exemplary embodiment, such as Figure 1 As shown, a multi-source on-site automatic verification system for transformer online monitoring devices is provided. In this embodiment, the system includes: an ultrasonic array consistency verification unit, a high-frequency non-disassembly verification unit, an ultra-high frequency verification unit, a synchronous status node output unit, a timing control and communication unit, and a main control unit.

[0027] The ultrasonic array consistency verification unit is used to output a standard ultrasonic excitation signal to the ultrasonic sensor under calibration; the standard ultrasonic excitation signal is transmitted to the ultrasonic sensor under calibration through the transformer tank wall.

[0028] The high-frequency non-detachable calibration unit is used to inject a high-frequency pulse excitation signal into the grounding wire through a clamp-on openable high-frequency excitation sensor, generate a reverse coupling pulse on the grounding wire, and transmit it to the high-frequency sensor being calibrated.

[0029] The ultra-high frequency verification unit is used to radiate a standard ultra-high frequency excitation signal to the ultra-high frequency sensor being calibrated.

[0030] The synchronous status node output unit is used to synchronously output a status node signal to the online monitoring device of the transformer under test during the output excitation signals of the ultrasonic array consistency verification unit, the high-frequency non-detachable verification unit and the ultra-high frequency verification unit.

[0031] The timing control and communication unit is used to preset single or periodic verification tasks and automatically trigger the verification process; it is also used to receive the response reading fed back by the online monitoring device of the transformer under test after collecting the excitation signal; and it is also used to interact with the online monitoring device of the transformer under test through the communication interface.

[0032] The main control unit is used to control the ultrasonic array consistency verification unit, the high-frequency non-disassembly verification unit, the ultra-high frequency verification unit, the synchronization status node output unit, and the timing control and communication unit to execute the verification process based on the response readings fed back by the online monitoring device of the transformer under test.

[0033] In existing technologies, some high-frequency current sensor field calibration systems adopt a three-stage architecture consisting of a calibration device, a high-frequency calibration current sensor, and a calibration unit. The calibration sensor includes a dual-coil structure comprising a magnetic core, a calibration coil, and a calibration coil. The system needs to output multiple sets of pulse excitation signals of different amplitudes to the calibration sensor, acquire the returned calibration electrical signals, and obtain a reference electrical signal by calculating parameters such as loss correction coefficients and magnetic flux, finally performing fitting and comparison. This type of solution requires a calibration unit, making the system complex and costly; it requires acquiring feedback signals and calculating multiple parameters, resulting in complex algorithms; and it is mostly single-channel calibration, unable to meet the requirements of multi-sensor synchronous calibration (general knowledge: online monitoring devices for transformers under calibration typically install one high-frequency sensor each on the core grounding wire and the clamp grounding wire, with the number of high-frequency acquisition channels generally ≥2); furthermore, this type of calibration device can only perform a single test, failing to meet the requirements of timed automatic calibration, and there is no status information output during calibration, making it impossible for the online monitoring device for the transformer under calibration to automatically distinguish between the calibration period and the normal monitoring period, requiring manual confirmation.

[0034] Some solutions employ a three-section architecture: a central control module, a transmitting unit, and a calibration unit. The transmitting unit includes a high-frequency transmitting unit and a current transmitting unit, while the calibration unit includes a high-frequency calibration unit and a current calibration unit, connected to a high-frequency calibration sensor and a current calibration sensor, respectively. The calibration unit accurately acquires and analyzes the signals output by the transmitting unit to provide a reference. This type of solution also relies on calibration sensors and calibration units for reference, supports only two parameters (high frequency and current), does not involve ultrasound or ultra-high frequency, and remains a single-channel calibration without multi-channel synchronization capability.

[0035] Furthermore, existing ultrasonic calibration devices typically employ an architecture of excitation sensors plus calibration sensors, performing calibration on a point-by-point basis for each sensor. This approach also relies on calibration sensors and calibration units for reference, resulting in low efficiency for single-channel point-by-point calibration, lack of multi-channel synchronous output capability, and inability to verify the amplitude and phase consistency of an array composed of multiple spatially distributed sensors.

[0036] To address the shortcomings of the existing technology, this application provides a multi-source on-site automatic verification system and method for transformer online monitoring devices, achieving the corresponding technical effects through the following technical solutions: The aforementioned system, through the collaborative operation of an ultrasonic array consistency verification unit, a high-frequency non-detachable verification unit, an ultra-high-frequency verification unit, a synchronous status node output unit, a timing control and communication unit, and a main control unit, can achieve reference-free automatic closed-loop on-site verification of the ultrasonic, high-frequency, and ultra-high-frequency parameters of the online monitoring device for the transformer under test. It eliminates the need to disassemble installed sensors or use external calibration benchmarks, automatically determining the consistency, proportional trend, and long-term drift of multi-source sensor channels. This solves the problems of existing technologies that rely on calibration units, have complex calculation methods, and cannot simultaneously verify multiple sources. Furthermore, this application allows for modular configuration of each verification unit, enabling the use of only some units as needed on-site for independent verification of a single type of sensor. In this system, the main control unit does not rely on any external standard reference source or independent calibration instrument. It performs single-channel proportional trend comparison, multi-channel lateral consistency comparison, and time-domain stability self-comparison solely based on the response readings from the online monitoring device of the transformer under test to the system's own output excitation signal, forming a reference-free self-comparison verification. Simultaneously, the main control unit generates verification control commands based on the response readings and adjusts the output parameters of each verification unit in real time, forming an automatic closed-loop verification. This application does not require additional calibration units, does not collect any reference electrical signals, and does not perform complex parameter calculations and fitting comparisons. It only utilizes the proportional accuracy of the verification system itself, without relying on any external reference benchmarks. Through proportional trend analysis, it can verify the online monitoring device of the transformer under verification on site. The engineering operation is simple, highly feasible, and more adaptable.

[0037] Compared with existing technologies, this application has the following core innovative effects: First, in terms of system architecture, this application completely eliminates the calibration unit, does not require the acquisition of any reference electrical signals, and does not perform complex parameter calculations and fitting comparisons. It only utilizes the proportional accuracy of the calibration system itself and achieves calibration judgment through the pioneering benchmark-free triple comparison logic (single-channel proportional trend comparison, multi-channel lateral consistency comparison, and time-domain stability self-comparison), which fundamentally simplifies the system structure and reduces hardware costs and algorithm complexity.

[0038] Secondly, regarding the high-frequency calibration method, this application uses a clamp-on openable high-frequency excitation sensor containing a single excitation coil. It generates a reverse coupling pulse on the grounding wire through electromagnetic induction. This eliminates the need to disassemble the installed high-frequency sensor being calibrated, and eliminates the need to break or polish the insulating varnish on the grounding wire surface. Furthermore, the sensor's output signal is not collected or used for any calculations or comparisons; it serves only as an excitation transmitting element. This is fundamentally different from the dual-coil calibration sensors in the prior art that require the collection of feedback signals.

[0039] Third, in terms of ultrasonic verification method, this application synchronously outputs standard ultrasonic excitation signals with the same amplitude, waveform and phase through multiple ultrasonic standard signal output channels, which can perform multi-channel consistency field verification on an ultrasonic array composed of multiple spatially distributed sensors at one time, filling the gap of existing technology that can only perform point-by-point single-channel verification.

[0040] Fourth, regarding the signal differentiation mechanism, this application uses a synchronous status node output unit to output a status node signal that is strictly synchronized with the excitation signal to the online monitoring device of the transformer under test during the verification excitation signal output period. This enables the online monitoring device of the transformer under test to mark the signal collected during the verification period as the verification mode, thereby fundamentally avoiding misjudging the verification pulse as a sudden partial discharge of the transformer.

[0041] Fifth, in terms of multi-parameter coverage, this application integrates ultrasonic array consistency verification, high-frequency non-disassembly verification, and ultra-high frequency verification into the same system for the first time, realizing multi-channel synchronous verification of ultrasonic, high-frequency, and ultra-high frequency three parameters. The verification coverage and system integration are significantly better than existing solutions with single or dual parameters.

[0042] Sixth, in terms of automation, this application achieves unattended, timed automatic verification by using a timed control and communication unit to preset single or periodic verification tasks and automatically trigger the verification process according to a preset plan, combined with the closed-loop control of the main control unit.

[0043] In another exemplary embodiment of this application, in order to perform multi-channel consistency field verification of the ultrasonic sensor array in the online monitoring device of the transformer under test, the ultrasonic array consistency verification unit includes several magnetically adsorbed ultrasonic excitation sensors and multiple ultrasonic standard signal output channels; each ultrasonic standard signal output channel is connected to a magnetically adsorbed ultrasonic excitation sensor; the magnetically adsorbed ultrasonic excitation sensor is adsorbed on the transformer tank wall at a preset distance from the ultrasonic sensor under test.

[0044] In this embodiment, the ultrasonic excitation sensor has a magnetic adsorption base that is adsorbed onto the transformer tank wall at a preset distance (e.g., 10cm) from the ultrasonic sensor being calibrated.

[0045] In another exemplary embodiment of this application, in order to perform non-disassembly on-site verification of the high-frequency sensor of the online monitoring device of the transformer under test, the above-mentioned high-frequency non-disassembly verification unit includes multiple high-frequency excitation signal output channels; each high-frequency excitation signal output channel is connected to a clamp-type openable high-frequency excitation sensor; the clamp-type openable high-frequency excitation sensor is provided with an excitation signal input interface and contains a single excitation coil; the clamp-type openable high-frequency excitation sensor is clamped onto the transformer core or clamp grounding wire.

[0046] In this embodiment, the clamp-on openable high-frequency excitation sensor is equipped with a dedicated excitation signal input BNC interface. During use, the sensor is clipped onto the grounding wire of the transformer core or clamp. A high-frequency pulse excitation signal is injected into the excitation signal interface of the clamp-on openable high-frequency excitation sensor through the high-frequency output channel of the calibration unit. The clamp-on openable high-frequency excitation sensor generates a reverse coupling pulse on the grounding wire. The high-frequency sensor being calibrated receives this pulse and outputs it to the high-frequency channel of the online monitoring device for the calibrated transformer for acquisition. The clamp-on openable high-frequency excitation sensor contains only a single excitation coil (not a dual-coil structure), resulting in a simple structure and low cost. It requires no calibration unit, does not acquire any reference electrical signals, and does not perform complex parameter calculations or fitting comparisons. It only utilizes the proportional accuracy of the calibration system itself to achieve on-site verification of the performance of the online monitoring device for the calibrated transformer.

[0047] like Figure 2As shown, the high-frequency excitation sensor adopts an openable clamp-like structure, including an upper housing 1, a lower housing 2, an openable hinge 3, a locking mechanism 4, an excitation signal input interface (BNC type) 5, a shielding shell 6, and a grounding wire through hole 7. An upper semi-annular magnetic core is installed inside the upper housing 1, and a lower semi-annular magnetic core is installed inside the lower housing 2. An excitation coil is wound on the lower semi-annular magnetic core, and this excitation coil is electrically connected to the excitation signal input interface (BNC type) 5. The upper housing 1 and the lower housing 2 are connected by the openable hinge 3, and the clamp-like opening and closing is achieved through the locking mechanism 4. In use… Open the locking mechanism 4, pass the grounding wire of the transformer core or clamp through the grounding wire hole 7, close the upper and lower half-ring housings and lock them, so that the magnetic core tightly surrounds the grounding wire; the excitation signal input interface (BNC type) 5 is connected to the high-frequency signal generation unit through a coaxial cable. When the pulse excitation signal is injected into the excitation coil inside the lower housing 2 through the excitation signal interface (BNC type) 5, an alternating magnetic field is generated in the magnetic core. According to the law of electromagnetic induction, a reverse coupling pulse signal is induced on the grounding wire passing through the grounding wire hole 7; the shielding shell 6 is grounded as a whole to suppress external interference.

[0048] The fundamental difference between this structure and existing high-frequency current sensors used for detection is that existing sensors only receive high-frequency pulse signals from the grounding wire, lacking both an internal excitation coil and an excitation signal input interface. Furthermore, existing high-frequency calibration sensors employ a dual-coil structure with a calibration coil and a verification coil; the verification signal relies on the combined magnetic field generated by the dual coils, resulting in complex calculations, requiring feedback signal acquisition, and relying on a calibration unit. The high-frequency excitation sensor of this application contains only a single excitation coil and an excitation signal input interface, eliminating the need for a calibration unit. The high-frequency excitation sensor contains only a single excitation coil and does not include a verification coil or any other feedback coil for acquiring or returning verification signals, simplifying the structure and reducing engineering application costs. Simultaneously, the high-frequency non-detachable calibration unit does not receive any feedback signals from the high-frequency excitation sensor, and its calibration judgment does not depend on the acquisition and comparison of any output signals from the high-frequency excitation sensor.

[0049] In another exemplary embodiment of this application, in order to perform on-site verification of the UHF sensor of the online monitoring device for the transformer under test, the above-mentioned UHF verification unit includes multiple UHF output channels; each UHF output channel is connected to a UHF excitation sensor.

[0050] In another exemplary embodiment of this application, in order to simultaneously meet the on-site verification requirements of multiple monitoring channels for partial discharge of transformers, including ultrasonic, high-frequency, and ultra-high-frequency signals, the ultrasonic array consistency verification unit includes at least eight ultrasonic standard signal output channels; the high-frequency non-detachable verification unit includes at least two high-frequency excitation signal output channels; and the ultra-high-frequency verification unit includes two ultra-high-frequency output channels.

[0051] In another exemplary embodiment of this application, in order to achieve precise synchronization between the excitation signal output and the acquisition time of the online monitoring device of the transformer under test, the above-mentioned status node signal is a passive dry node signal; the start time of the status node signal is synchronized with the output start time of the excitation signal, and the end time is synchronized with the stop time of the excitation signal; the status node signal is transmitted to the digital input interface of the online monitoring device of the transformer under test through an independent signal line.

[0052] The synchronous state node output unit is also used to output valid state node information at the same time as the verification system starts outputting the excitation signal under the control of the main control unit, and to stop the state node output and restore the invalid state after the verification is completed.

[0053] In this embodiment, Figure 3 This diagram illustrates the timing relationship between the synchronous state node output unit and the excitation signal in this application. From top to bottom, the diagram shows: excitation output state (high level indicates a verification excitation signal is output); state node output signal (low impedance state, strictly synchronized with the excitation output); and data markers collected by the online monitoring device of the transformer under test (verification mode / monitoring mode). During the valid period of the state node (low impedance state), the monitoring device marks the collected signal as a "verification excitation signal," stores it in a dedicated verification buffer, and does not participate in the partial discharge alarm logic. During the invalid period of the state node (high impedance state), it is marked as a "field signal," and normal partial discharge monitoring and diagnosis are performed. Through state node synchronization, it is ensured that the verification process does not affect the normal operation of online monitoring, while avoiding the misreporting of strong amplitude verification pulses as sudden partial discharge.

[0054] State node-based verification-monitoring collaborative steps: U1: When the verification system starts outputting the standard verification excitation signal, it enables the synchronous status node output unit to output valid status node information to the online monitoring device of the transformer under test.

[0055] U2: After the online monitoring device of the transformer being checked detects that the status node is valid, it marks all sensor signals collected now and subsequently as "verification excitation signals" and stores them in a dedicated verification buffer. They are not involved in the partial discharge alarm logic.

[0056] U3: After the verification system completes the excitation signal output, it immediately stops the output of the status node and restores it to the invalid state.

[0057] U4: After the online monitoring device of the transformer under test detects that the status node is invalid, it will restore the subsequent collected signals to the normal monitoring mode.

[0058] U5: The online monitoring device of the transformer under test will automatically compare the data in the "verification excitation signal" buffer with the standard output value and the preset threshold to generate the verification result.

[0059] In another exemplary embodiment of this application, in order to realize the timing synchronization control and data interaction between the verification system and the online monitoring device of the transformer under test, the timing control and communication unit includes a real-time clock and an RS485 communication interface.

[0060] The timing control and communication unit is also used to interact with the online monitoring device of the transformer under test via RS485 bus and receive control commands from the online monitoring device of the transformer under test.

[0061] In another exemplary embodiment of this application, in order to achieve closed-loop control and adaptive adjustment of the output parameters of each verification unit, the main control unit is further configured to generate a first verification control command and output it to the ultrasonic array consistency verification unit based on the standard ultrasonic excitation signal and the response reading fed back by the online monitoring device of the transformer under test after acquiring the standard ultrasonic excitation signal.

[0062] Based on the high-frequency pulse excitation signal and the response reading fed back by the online monitoring device of the transformer under test after acquiring the high-frequency pulse excitation signal, a second verification control command is generated and output to the high-frequency non-detachable verification unit.

[0063] Based on the standard UHF excitation signal and the response readings fed back by the online monitoring device of the transformer under test after acquiring the standard UHF excitation signal, a third verification control command is generated and output to the UHF verification unit.

[0064] The main control unit is also used to adjust the output parameters of the ultrasonic array consistency verification unit, the high-frequency non-detachable verification unit, and the ultra-high frequency verification unit according to the control command; the output parameters include the excitation signal output amplitude, the signal output interval time, and the signal repetition frequency.

[0065] In another exemplary embodiment of this application, in order to perform multi-dimensional performance evaluation and anomaly determination on each monitoring channel of the online monitoring device for the transformer under test, the main control unit is further configured to perform at least one of single-channel proportional trend comparison, multi-channel lateral consistency comparison and time-domain stability self-comparison based on the response reading.

[0066] The single-channel proportional trend comparison includes: controlling the ultrasonic array consistency verification unit, the high-frequency non-detachable verification unit, and the ultra-high frequency verification unit to output corresponding excitation signals according to a preset known fixed proportional relationship; calculating the actual proportional relationship between each response based on the response readings fed back by the online monitoring device of the transformer under test after acquiring the excitation signals; comparing the actual proportional relationship with the known fixed proportional relationship; and determining that the channel is abnormal if the deviation exceeds the proportional deviation threshold.

[0067] The multi-channel horizontal consistency comparison includes: calculating the consistency deviation coefficient of each channel's response reading by comparing the response readings of each channel in the same verification unit; if the deviation of a certain channel exceeds the consistency deviation threshold, the channel is determined to be abnormal; the consistency deviation coefficient is the percentage deviation of each channel's response reading from the average value of all channel response readings.

[0068] The time-domain stability self-comparison includes: controlling the ultrasonic array consistency verification unit, the high-frequency non-detachable verification unit, and the ultra-high frequency verification unit to periodically output excitation signals with fixed amplitudes; calculating the average response value of the current verification cycle based on the response readings collected by the online monitoring device of the transformer under test under multiple excitations; comparing the average response value of the current verification cycle with the historical baseline average value; and determining that the online monitoring device of the transformer under test has a long-term drift problem if the deviation exceeds the drift judgment threshold.

[0069] In this embodiment, the online monitoring device for the transformer under test determines whether the currently acquired signal is an excitation signal actively injected by the verification system based on the signal of the status node. This function eliminates the need for the online monitoring device to rely on signal amplitude, waveform, or other characteristics to distinguish the verification signal from actual partial discharge pulses or interference signals, fundamentally avoiding misjudging the verification excitation signal as transformer partial discharge, and also preventing the misidentification of random interference in the field as a verification response.

[0070] Based on the same inventive concept, this application also provides a method for multi-source automatic field verification of a transformer online monitoring device using the above-described multi-source automatic field verification system. The solution provided by this method is similar to the implementation described in the above system; therefore, the specific limitations in one or more embodiments of the multi-source automatic field verification method for a transformer online monitoring device provided below can be found in the limitations of the multi-source automatic field verification system for a transformer online monitoring device described above.

[0071] In one exemplary embodiment, such as Figure 4 As shown, a multi-source on-site automatic verification method for transformer online monitoring devices is provided, including the following steps: A1: The ultrasonic array consistency verification unit outputs a standard ultrasonic excitation signal to the ultrasonic sensor under calibration; the standard ultrasonic excitation signal is transmitted to the ultrasonic sensor under calibration through the transformer tank wall.

[0072] A2: A high-frequency pulse excitation signal is injected into the grounding wire through the clamp-on openable high-frequency excitation sensor in the high-frequency non-detachable calibration unit, generating a reverse coupling pulse on the grounding wire and transmitting it to the high-frequency sensor being calibrated.

[0073] A3: The UHF calibration unit radiates and outputs a standard UHF excitation signal to the UHF sensor being calibrated.

[0074] A4: During the output excitation signals of the ultrasonic array consistency verification unit, the high-frequency non-detachable verification unit, and the ultra-high frequency verification unit, the synchronous status node output unit synchronously outputs a status node signal to the online monitoring device of the transformer under test.

[0075] A5: Through the timing control and communication unit, a single or periodic verification task is preset and the verification process is automatically triggered. The response reading fed back by the online monitoring device of the transformer under test after collecting the excitation signal is received, and data interaction is performed with the online monitoring device of the transformer under test through the communication interface.

[0076] A6: The main control unit controls the ultrasonic array consistency verification unit, the high-frequency non-detachable verification unit, the ultra-high frequency verification unit, the synchronous status node output unit, and the timing control and communication unit to execute the verification process based on the response readings fed back by the online monitoring device of the transformer under test.

[0077] In one specific implementation, the verification process includes the following steps: S1: The verification system automatically outputs a standard verification excitation signal with known characteristics at regular intervals.

[0078] S2: The standard verification excitation signal is transmitted to the sensor under test via the corresponding path; when performing ultrasonic array verification, the standard verification excitation signal is transmitted to the ultrasonic sensor under test via the transformer tank wall through the magnetic adsorption ultrasonic excitation sensor; when performing high frequency verification, the standard verification excitation signal is transmitted to the high frequency sensor under test through the reverse coupling pulse generated on the grounding wire by the clamp-on openable high frequency excitation sensor via electromagnetic induction; when performing ultra-high frequency verification, the standard verification excitation signal is radiated out in the form of electromagnetic waves by the ultra-high frequency excitation sensor and received by the ultra-high frequency sensor under test.

[0079] S3: After receiving the standard verification excitation signal, the sensor under test (including the ultrasonic sensor under test, the high-frequency sensor under test, and the ultra-high-frequency sensor under test) generates a response signal. The online monitoring device of the transformer under test collects the response signal and obtains the response reading. During the verification, the synchronous status node output unit outputs a valid status node, so that the online monitoring device of the transformer under test marks the collected signal as "verification mode".

[0080] S4: The verification system determines the performance status of the online monitoring device and sensors of the transformer under test based on at least one of the following three comparison logics: Comparison Logic 1 (Single Channel Proportional Trend Comparison): The verification system outputs a standard verification excitation signal according to a preset known fixed proportional relationship (e.g., 1:2:4). The verification system calculates the actual proportional relationship between each response based on the response readings of the online monitoring device of the transformer under test. The actual proportional relationship is compared with the known fixed proportional relationship. If the deviation exceeds a preset threshold, it is determined that there is an anomaly in the channel.

[0081] The amplitude ratio of the output standard excitation signal is verified. For example: the response reading of the online monitoring device for the transformer under test. , , ; Calculate the actual proportionality coefficient: , (Theoretical values ​​are all 2); Calculate the percentage deviation: , ;like or The system determines that there is an abnormality in the online monitoring device channel or sensor of the transformer under test.

[0082] Comparison Logic 2 (Multi-channel Horizontal Consistency Comparison): By comparing the response readings of different channels with the same parameter, the consistency deviation coefficient of the response readings of each channel is calculated. If the deviation of a certain channel exceeds the preset threshold, it is determined that the channel is abnormal.

[0083] It has The first isoparametric sensor channel, the... The response readings for each channel are Calculate the average of all channel response readings. ; Calculate the first Consistency deviation coefficient of each channel ;like The system determines that there is an abnormality in the online monitoring device channel or sensor of the transformer under test.

[0084] Comparison Logic 3 (Time Domain Stability Self-Comparison): The verification system periodically and automatically sends a standard verification excitation signal with a fixed amplitude. The online monitoring device of the transformer under test collects multiple response readings under multiple excitations and calculates the stability index of the multiple response readings. If the stability index exceeds a preset threshold, it is determined that the online monitoring device of the transformer under test has a long-term drift problem.

[0085] The calibration system repeatedly outputs a fixed amplitude. Second-rate( Standard verification excitation signal: collected by the online monitoring device of the transformer under test. Under the incentive Response readings ; Calculate the average value Based on The average value calculated from repeated excitations This is the average value over the time dimension, and is based on the aforementioned calculation of consistency deviation for each channel. The average spatial dimension calculated for each channel These are different calculation dimensions and do not interfere with each other. The current average is compared with the historical baseline average; if the deviation is >10%, a long-term drift problem is identified.

[0086] This application also provides an application scenario in which the above-described multi-source on-site automatic verification method for transformer online monitoring devices is applied. Specifically, the multi-source on-site automatic verification method for transformer online monitoring devices provided in this embodiment can be applied in power equipment condition monitoring and intelligent operation and maintenance scenarios. This application scenario includes the deployment of the online monitoring device for the transformer under test, the operation of the multi-source sensor channel, and the on-site verification stage. After the online monitoring device for the transformer under test is deployed in the substation or converter station, its ultrasonic sensor array, high-frequency current sensor, and ultra-high frequency sensor enter the daily monitoring operation state, periodically or in a controlled manner triggering the on-site verification stage. Specifically, in the verification process of the online monitoring device for partial discharge of transformers, the multi-source sensing channels of the online monitoring device of the transformer under test can be automatically closed-loop verified based on the collaborative work of the main control unit, the ultrasonic array consistency verification unit, the high-frequency non-detachable verification unit, the ultra-high frequency verification unit, and the synchronous status node output unit. This means that verification control commands are generated for each channel of the online monitoring device of the transformer under test, standard excitation signals are output and response readings are collected, and then single-channel proportional trend comparison, multi-channel lateral consistency comparison and time-domain stability self-comparison are performed to determine whether there are any abnormalities or long-term drifts in each monitoring channel.

[0087] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0088] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the 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.

[0089] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A multi-source on-site automatic calibration system for an online transformer monitoring device, used for on-site calibration of an online monitoring device for a transformer under calibration that integrates an ultrasonic sensor, a high-frequency sensor, and an ultra-high-frequency sensor, characterized in that, The system includes: an ultrasonic array consistency verification unit, a high-frequency non-disassembly verification unit, an ultra-high frequency verification unit, a synchronous status node output unit, a timing control and communication unit, and a main control unit; The ultrasonic array consistency verification unit is used to output a standard ultrasonic excitation signal to the ultrasonic sensor under calibration; the standard ultrasonic excitation signal is transmitted to the ultrasonic sensor under calibration through the transformer tank wall. The high-frequency non-detachable calibration unit is used to inject a high-frequency pulse excitation signal into the grounding wire through a clamp-on openable high-frequency excitation sensor, generate a reverse coupling pulse on the grounding wire and transmit it to the high-frequency sensor being calibrated. The ultra-high frequency verification unit is used to radiate and output a standard ultra-high frequency excitation signal to the ultra-high frequency sensor being calibrated. The synchronous status node output unit is used to synchronously output a status node signal to the online monitoring device of the transformer under test during the output excitation signals of the ultrasonic array consistency verification unit, the high-frequency non-detachable verification unit and the ultra-high frequency verification unit. The timing control and communication unit is used to preset single or periodic verification tasks and automatically trigger the verification process; it is also used to receive the response reading fed back by the online monitoring device of the transformer under test after collecting the excitation signal; and it is also used to interact with the online monitoring device of the transformer under test through the communication interface. The main control unit is used to control the ultrasonic array consistency verification unit, the high-frequency non-disassembly verification unit, the ultra-high frequency verification unit, the synchronization status node output unit, and the timing control and communication unit to execute the verification process based on the response readings fed back by the online monitoring device of the transformer under test.

2. The multi-source on-site automatic verification system for transformer online monitoring devices according to claim 1, characterized in that, The ultrasonic array consistency verification unit includes several magnetically adsorbed ultrasonic excitation sensors and multiple ultrasonic standard signal output channels; each ultrasonic standard signal output channel is connected to a magnetically adsorbed ultrasonic excitation sensor; the magnetically adsorbed ultrasonic excitation sensor is adsorbed on the transformer tank wall at a preset distance from the ultrasonic sensor being calibrated.

3. The multi-source on-site automatic verification system for transformer online monitoring devices according to claim 2, characterized in that, The high-frequency non-detachable verification unit includes multiple high-frequency excitation signal output channels; each high-frequency excitation signal output channel is connected to a clamp-type openable high-frequency excitation sensor; the clamp-type openable high-frequency excitation sensor is provided with an excitation signal input interface and contains a single excitation coil; the clamp-type openable high-frequency excitation sensor is clamped onto the transformer core or clamp grounding wire.

4. The multi-source on-site automatic verification system for transformer online monitoring devices according to claim 3, characterized in that, The ultra-high frequency verification unit includes multiple ultra-high frequency output channels; each ultra-high frequency output channel is connected to an ultra-high frequency excitation sensor.

5. The multi-source on-site automatic verification system for transformer online monitoring devices according to claim 4, characterized in that, The ultrasonic array consistency verification unit includes at least eight ultrasonic standard signal output channels; the high-frequency non-detachable verification unit includes at least two high-frequency excitation signal output channels; and the ultra-high frequency verification unit includes two ultra-high frequency output channels.

6. The multi-source on-site automatic verification system for transformer online monitoring devices according to claim 1, characterized in that, The status node signal is a passive dry node signal; the start time of the status node signal is synchronized with the output start time of the excitation signal, and the end time is synchronized with the stop time of the excitation signal; the status node signal is transmitted to the digital input interface of the online monitoring device of the transformer under test through an independent signal line. The synchronous state node output unit is also used to output valid state node information at the same time as the verification system starts outputting the excitation signal under the control of the main control unit, and to stop the state node output and restore the invalid state after the verification is completed.

7. The multi-source on-site automatic verification system for transformer online monitoring devices according to claim 1, characterized in that, The timing control and communication unit includes a real-time clock and an RS485 communication interface; The timing control and communication unit is also used to interact with the online monitoring device of the transformer under test via RS485 bus and receive control commands from the online monitoring device of the transformer under test.

8. The multi-source on-site automatic verification system for transformer online monitoring devices according to claim 1, characterized in that, The main control unit is also used to generate a first verification control command and output it to the ultrasonic array consistency verification unit based on the standard ultrasonic excitation signal and the response reading fed back by the online monitoring device of the transformer under test after acquiring the standard ultrasonic excitation signal. Based on the high-frequency pulse excitation signal and the response reading fed back by the online monitoring device of the transformer under test after acquiring the high-frequency pulse excitation signal, a second verification control command is generated and output to the high-frequency non-detachable verification unit. Based on the standard UHF excitation signal and the response readings fed back by the online monitoring device of the transformer under test after acquiring the standard UHF excitation signal, a third verification control command is generated and output to the UHF verification unit. The main control unit is also used to adjust the output parameters of the ultrasonic array consistency verification unit, the high-frequency non-detachable verification unit, and the ultra-high frequency verification unit according to the control command; the output parameters include the excitation signal output amplitude, the signal output interval time, and the signal repetition frequency.

9. The multi-source on-site automatic verification system for transformer online monitoring devices according to claim 1, characterized in that, The main control unit is also used to perform at least one of single-channel proportional trend comparison, multi-channel lateral consistency comparison and time-domain stability self-comparison based on the response reading; The single-channel proportional trend comparison includes: controlling the ultrasonic array consistency verification unit, the high-frequency non-detachable verification unit, and the ultra-high frequency verification unit to output corresponding excitation signals according to a preset known fixed proportional relationship; calculating the actual proportional relationship between each response based on the response readings fed back by the online monitoring device of the transformer under test after acquiring the excitation signals; comparing the actual proportional relationship with the known fixed proportional relationship; and determining that the channel is abnormal if the deviation exceeds the proportional deviation threshold. The multi-channel horizontal consistency comparison includes: calculating the consistency deviation coefficient of each channel's response reading by comparing the response readings of each channel in the same verification unit; if the deviation of a certain channel exceeds the consistency deviation threshold, the channel is determined to be abnormal; the consistency deviation coefficient is the percentage deviation of each channel's response reading from the average value of all channel response readings. The time-domain stability self-comparison includes: controlling the ultrasonic array consistency verification unit, the high-frequency non-detachable verification unit, and the ultra-high frequency verification unit to periodically output excitation signals with fixed amplitudes; calculating the average response value of the current verification cycle based on the response readings collected by the online monitoring device of the transformer under test under multiple excitations; comparing the average response value of the current verification cycle with the historical baseline average value; and determining that the online monitoring device of the transformer under test has a long-term drift problem if the deviation exceeds the drift judgment threshold.

10. A multi-source on-site automatic verification method for an online transformer monitoring device, characterized in that, The method, using the system as described in any one of claims 1-9, comprises: The ultrasonic array consistency verification unit outputs a standard ultrasonic excitation signal to the ultrasonic sensor under calibration; the standard ultrasonic excitation signal is transmitted to the ultrasonic sensor under calibration via the transformer tank wall. A high-frequency pulse excitation signal is injected into the grounding wire through the clamp-on openable high-frequency excitation sensor in the high-frequency non-detachable calibration unit, generating a reverse coupling pulse on the grounding wire and transmitting it to the high-frequency sensor being calibrated. The UHF calibration unit radiates and outputs a standard UHF excitation signal to the UHF sensor being calibrated. During the output excitation signals of the ultrasonic array consistency verification unit, the high-frequency non-detachable verification unit, and the ultra-high frequency verification unit, the synchronous status node output unit synchronously outputs a status node signal to the online monitoring device of the transformer under test. Through the timing control and communication unit, a single or periodic verification task is preset and the verification process is automatically triggered. The unit receives the response reading fed back by the online monitoring device of the transformer under test after collecting the excitation signal, and interacts with the online monitoring device of the transformer under test through the communication interface. The main control unit controls the ultrasonic array consistency verification unit, the high-frequency non-detachable verification unit, the ultra-high frequency verification unit, the synchronization status node output unit, and the timing control and communication unit to execute the verification process based on the response readings fed back by the online monitoring device of the transformer under test.

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