Generator outlet side voltage transformer insulation state on-line monitoring system

Abstract

The application provides an online monitoring system for insulation state of a generator outlet side voltage transformer. The online monitoring system for insulation state of the generator outlet side voltage transformer comprises a front-end sensing module, which extracts original electrical signals from the voltage transformer body and related circuits in a non-invasive installation mode, does not change the original main circuit structure and electrical parameters of the device, and provides an electrical quantity signal source for insulation diagnosis. The online monitoring system for insulation state of the generator outlet side voltage transformer can synchronously identify slow melting faults of high-voltage fuses, expands the fault coverage range, can timely issue early warnings in the early stage of defect development, guides maintenance personnel to carry out targeted maintenance, effectively avoids equipment damage and unit abnormal shutdown caused by insulation faults, improves the reliability and safety of generator operation, reduces the number of unnecessary power-off test times, reduces the equipment operation and maintenance cost, and has significant practical value and economic benefits.

Description

Technical Field

[0001] This invention relates to the field of generator outlet side voltage monitoring technology, and more particularly to an online monitoring system for the insulation status of generator outlet side voltage transformers. Background Technology

[0002] Colored polyester filament is a functional fiber made by blending colorants with polyester melt and then spinning it. The finished product can be used directly for weaving without subsequent dyeing processing, which can significantly shorten the textile production process and reduce wastewater discharge. It is an environmentally friendly fiber variety that the textile industry is currently promoting.

[0003] The integrated cooling process for colored polyester filament production combines the cooling and solidification stage with the spinning and extrusion stage into one spinning process. Unlike traditional separate cooling devices, its core feature is that the cooling and shaping of the filament is completed directly at the spinning outlet, reducing the path length of the filament exposed to the ambient temperature environment and improving the controllability of the cooling process.

[0004] Currently, most colored polyester filament production uses a split structure with a spinning box and independent side-blowing cooling. After the high-temperature molten colored filament is extruded from the spinneret, it needs to pass through a natural cooling zone without temperature control before entering the cooling air field. The surface of the filament cools down quickly while the interior cools down slowly, which easily leads to uneven dispersion of the masterbatch, resulting in color differences between the inside and outside of the filament and inconsistent color across the cross section. At the same time, the single-side blowing cooling method easily causes uneven circumferential cooling of the filament, resulting in large deviations in the fineness of the single filament and a high breakage rate during stretching. Furthermore, the cooling air is directly discharged without being recycled, resulting in high overall production energy consumption, which makes it difficult to meet the mass production needs of high-quality colored polyester filament.

[0005] Therefore, it is necessary to provide an online monitoring system for the insulation status of the voltage transformer on the generator output side to solve the above-mentioned technical problems. Summary of the Invention

[0006] This invention provides an online monitoring system for the insulation status of voltage transformers on the generator outlet side, which solves the problems of uneven cooling in the production of colored polyester yarn, which easily leads to color difference and breakage, as well as high energy consumption.

[0007] To solve the above-mentioned technical problems, the online monitoring system for the insulation status of the generator outlet side voltage transformer provided by the present invention includes: a front-end sensing module, an oil medium characteristic acquisition module, a signal acquisition and processing module, and a diagnostic output module; The front-end sensing module extracts the original electrical signals from the voltage transformer body and related circuits in a non-intrusive installation manner without changing the original main circuit structure and electrical parameters of the equipment, providing an electrical signal source for insulation diagnosis. The oil dielectric characteristic acquisition module relies on the original spare interface of the voltage transformer oil tank to collect the dielectric characteristic parameters of the insulating oil, reflecting the aging and moisture degree of the insulating oil, without the need for invasive modification of the equipment body. The signal acquisition and processing module performs filtering, conditioning, synchronous sampling, reference correction and feature extraction on the two front-end input analog signals, and outputs standardized feature parameters to eliminate measurement deviations caused by operating condition fluctuations. The diagnostic output module determines the insulation status and identifies faults based on the processed multi-dimensional feature parameters, and outputs graded early warnings and diagnostic opinions to provide maintenance personnel with repair guidance.

[0008] Preferably, the front-end sensing module includes a voltage acquisition unit, a power frequency current acquisition unit, and a high-frequency current acquisition unit. The voltage acquisition unit is connected in parallel to the secondary side circuit of the voltage transformer to acquire the voltage waveform and amplitude signal output from the secondary side in real time, which serves as the voltage parameter input for calculating the excitation current. The power frequency current acquisition unit is connected in series to the secondary side circuit of the voltage transformer to accurately acquire the power frequency current signal from the secondary side, which serves as the current parameter input for synthesizing the excitation current. The high-frequency current acquisition unit is mounted on the grounding lead of the primary side of the voltage transformer to extract the high-frequency partial discharge current signal generated during insulation degradation, which serves as an auxiliary judgment signal source for unstable inter-turn short circuits. The voltage acquisition unit and the power frequency current acquisition unit are both installed inside the junction box on the secondary side of the voltage transformer. The high frequency current acquisition unit is installed 20 centimeters above the grounding end of the primary side grounding lead. The signal cables of each unit are all bundled and laid along the transformer body bracket to the monitoring cabinet.

[0009] Preferably, the oil medium characteristic acquisition module includes a permeable gas sampling unit, an oil micro-water sampling unit, and an oil temperature compensation unit. The permeable gas sampling unit is installed at the spare oil inlet on the side wall of the voltage transformer tank. It adopts a semi-permeable membrane gas chamber structure to contact the oil cavity, allowing only the characteristic fault gas dissolved in the oil to permeate into the gas chamber. The gas chamber contains a gas sensing element that outputs the corresponding gas concentration signal. The oil micro-water sampling unit is installed at the drain valve interface at the bottom of the tank. It uses a capacitive micro-water sensing probe immersed in the insulating oil to collect the trace moisture content signal in the oil in real time. The oil temperature compensation unit is installed in the middle of the side wall of the tank. It has a built-in temperature sensor to collect the real-time temperature of the insulating oil. On the one hand, it is used to correct the temperature of the gas sample and micro-water measurement values, and on the other hand, it provides temperature parameters for electrical quantity reference calibration.

[0010] Preferably, the signal acquisition and processing module includes a signal conditioning unit, a synchronous acquisition unit, a dual-parameter reference calibration unit, and a feature extraction unit. The signal conditioning unit filters, amplifies, and impedance-matches each original analog signal to suppress background noise interference from the strong electromagnetic environment at the generator outlet and improves the signal-to-noise ratio of weak insulation characteristic signals. The synchronous acquisition unit performs synchronous analog-to-digital conversion on the conditioned electrical quantity signals and oil medium signals to ensure complete time-phase alignment of multiple signals, providing time-consistent digital data for subsequent vector operations and correlation analysis. The dual-parameter reference calibration unit includes a load impedance calculation subunit and a temperature correction subunit, which are connected upstream. The secondary voltage, secondary current, and oil temperature signals output by the synchronous acquisition unit are connected to the downstream feature extraction unit and diagnostic module. The load impedance calculation subunit calculates the total load impedance on the secondary side using the real-time acquired secondary voltage and current data. The temperature correction subunit generates a temperature correction coefficient by combining real-time oil temperature data, and outputs the load offset and temperature correction coefficient together. The feature extraction unit synthesizes and calculates the vector sum of the excitation current based on the ampere-turn balance theory of the voltage transformer, extracts the phase change feature value of the excitation current, and simultaneously extracts the amplitude and frequency characteristics of the high-frequency partial discharge signal and the characteristic parameters of the oil medium. It also completes the reference correction of the feature parameters by combining the correction data output by the dual-parameter reference correction unit.

[0011] Preferably, the diagnostic output module includes an insulation condition diagnostic unit, a multi-source fusion diagnostic unit, an early warning output unit, and a data storage unit. The insulation condition diagnostic unit employs dynamic threshold judgment logic, using the phase change characteristic difference coefficient of the excitation current as the core criterion to determine the degree of inter-turn short circuit and early insulation defects. It combines high-frequency partial discharge signals to identify early inter-turn short circuit faults with strong instability and non-metallic characteristics, while simultaneously identifying slow-blow faults in high-voltage fuses. The electrical quantity characteristic parameters and oil medium characteristic parameters output by the upstream docking feature extraction unit of the multi-source fusion diagnostic unit are used to combine the oil medium deterioration characteristics with electrical quantities. The insulation characteristics are correlated and analyzed. The slow deterioration trend of the oil medium is combined to predict the insulation aging process. The sudden change characteristics of electrical quantities are combined to identify the inter-turn insulation defects that have occurred. The two dimensions are mutually verified to output a comprehensive insulation status assessment result. When the early warning output unit detects that the characteristic parameters exceed the normal threshold, it will issue a graded early warning signal in a timely manner, and at the same time output the corresponding diagnostic opinions and fault attention points to clarify the type and approximate location of the defect. The data storage unit stores the historical data and fault records of the entire monitoring process, supports historical trend query and retrospective analysis, and provides data support for equipment status assessment and maintenance plan formulation.

[0012] Preferably, the front-end sensing module, the oil medium characteristic acquisition module, the signal acquisition and processing module, and the diagnostic output module constitute an online monitoring device; An online monitoring device is installed on the top of a base frame, a mounting shell is installed on the top of the base frame, a connecting structure is installed on one side of the mounting shell, and a display screen is installed on the top of the mounting shell; The mounting housing covers the online monitoring equipment, and the connection structure is an external connector for easy wiring. The base frame is fixed in the corresponding position with fasteners, and the display screen can display monitoring data.

[0013] Preferably, a docking assembly is installed on the top of the mounting shell, and threaded holes are provided on both the front and back sides of the mounting shell near the bottom. A threaded hole passes through the mounting housing for mounting the housing on top of the base frame.

[0014] Preferably, the mounting housing includes a housing and a plurality of heat exchange bars, the plurality of heat exchange bars being mounted on the front and back of the housing; Both the shell and the heat exchange bars are made of materials with high thermal conductivity.

[0015] Preferably, the docking assembly includes a magnetic frame, a card frame, a magnetic edge, and a cover plate. The magnetic frame is installed on the top of the mounting shell, the card frame is snapped into the bottom of the magnetic frame, and the cover plate is installed on the top of the magnetic frame.

[0016] Preferably, the base frame includes a base plate, a buffer pad, fixing bolts, and a limiting frame. The buffer pad is installed at the bottom of the base plate, the limiting frame is installed at the top of the base plate, and the fixing bolts pass through the housing and are threadedly connected to the limiting frame. The outer surface of the limiting frame is covered with sealing material to ensure a good seal.

[0017] Compared with related technologies, the online monitoring system for the insulation status of the generator outlet side voltage transformer provided by the present invention has the following advantages: This invention provides an online monitoring system for the insulation status of voltage transformers on the generator outlet side. This system solves the problems of traditional offline insulation testing, which cannot monitor insulation in real time and has a low detection rate for early insulation defects. Based on the excitation current-phase characteristic determination method, it has higher detection sensitivity for early inter-turn insulation defects with few short-circuit turns and high instability, achieving a detection accuracy down to the single-turn level, far exceeding conventional detection methods. By adding an oil dielectric characteristic acquisition module and a multi-source fusion diagnostic unit, it compensates for the inability of single electrical quantity monitoring to detect the degradation trend of the insulating oil dielectric, realizing an extension from post-fault diagnosis to proactive prediction during the degradation process. The two dimensions of characteristics mutually verify each other, effectively reducing the probability of misjudgment and missed detection in strong electromagnetic environments. The dual-parameter reference correction unit, through secondary load and oil... The dynamic benchmark adjustment based on temperature and humidity eliminates the drift of characteristic parameters caused by operating condition fluctuations, significantly reducing the probability of false alarms when the unit load changes or the ambient temperature fluctuates, and improving the operational reliability of the monitoring device. At the same time, the solution adopts a non-intrusive installation method, which does not require modification of the original main structure of the voltage transformer and can be deployed while the unit is running. It can also simultaneously identify slow-blow faults of high-voltage fuses, expanding the fault coverage. It can issue early warnings in the early stage of defect development, guide maintenance personnel to carry out targeted maintenance, effectively avoid equipment damage and abnormal unit shutdown caused by insulation faults, improve the reliability and safety of generator operation, reduce the number of unnecessary power outage tests, and reduce equipment operation and maintenance costs, which has significant practical value and economic benefits. Attached Figure Description

[0018] Figure 1 A schematic diagram of the first embodiment of the online monitoring system for the insulation status of the generator outlet side voltage transformer provided by the present invention; Figure 2 A schematic diagram of the front-end sensing module is provided for this invention; Figure 3 A schematic diagram of the oil medium feature acquisition module provided for this invention; Figure 4 A schematic diagram of the signal acquisition and processing module provided for this invention; Figure 5 A schematic diagram of the diagnostic output module provided for this invention; Figure 6 A schematic diagram of a second embodiment of the online monitoring system for the insulation status of a generator outlet-side voltage transformer provided by the present invention; Figure 7 This is a schematic diagram of the structure of the base frame of the present invention; Figure 8 Provided for the present invention Figure 7 An enlarged view of point A shown; Figure 9 Provided for the present invention Figure 7 A magnified view of point B shown.

[0019] The following are the labels in the diagram: 1. Base frame, 101. Base plate, 102. Buffer pad, 103. Fixing bolt, 104. Limiting frame, 2. Mounting shell, 201. Shell, 202. Heat exchange strip, 3. Docking assembly, 301. Magnetic frame, 302. Clip frame, 303. Magnetic edge, 304. Cover plate, 4. Connection structure, 5. Online monitoring equipment, 6. Display screen. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments. Example

[0021] Please refer to the following: Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 ,in, Figure 1 A schematic diagram of the first embodiment of the online monitoring system for the insulation status of the generator outlet side voltage transformer provided by the present invention; Figure 2 A schematic diagram of the front-end sensing module is provided for this invention; Figure 3 A schematic diagram of the oil medium feature acquisition module provided for this invention; Figure 4 A schematic diagram of the signal acquisition and processing module provided for this invention; Figure 5 A schematic diagram of the diagnostic output module is provided for this invention. The online monitoring system for the insulation status of the generator outlet-side voltage transformer includes: a front-end sensing module, an oil medium characteristic acquisition module, a signal acquisition and processing module, and a diagnostic output module; The front-end sensing module extracts the original electrical signals from the voltage transformer body and related circuits in a non-intrusive installation manner without changing the original main circuit structure and electrical parameters of the equipment, providing an electrical signal source for insulation diagnosis. The oil dielectric characteristic acquisition module relies on the original spare interface of the voltage transformer oil tank to collect the dielectric characteristic parameters of the insulating oil, reflecting the aging and moisture degree of the insulating oil, without the need for invasive modification of the equipment body. The signal acquisition and processing module performs filtering, conditioning, synchronous sampling, reference correction and feature extraction on the two front-end input analog signals, and outputs standardized feature parameters to eliminate measurement deviations caused by operating condition fluctuations. The diagnostic output module performs insulation status determination and fault identification based on the processed multi-dimensional feature parameters, and outputs graded early warnings and diagnostic opinions to provide maintenance personnel with maintenance guidance. The four functional modules are arranged in layers inside the vertical monitoring cabinet according to the signal transmission sequence. The modules are physically connected through shielded cabling inside the cabinet. The entire cabinet is fixed to the local support column next to the voltage transformer. All external interfaces of the modules are centrally located on the same side wall of the cabinet.

[0022] The front-end sensing module includes a voltage acquisition unit, a power frequency current acquisition unit, and a high-frequency current acquisition unit. The voltage acquisition unit is connected in parallel to the secondary side circuit of the voltage transformer to acquire the voltage waveform and amplitude signal output from the secondary side in real time, which serves as the voltage parameter input for calculating the excitation current. The power frequency current acquisition unit is connected in series to the secondary side circuit of the voltage transformer to accurately acquire the power frequency current signal from the secondary side, which serves as the current parameter input for synthesizing the excitation current. The high-frequency current acquisition unit is mounted on the grounding lead of the primary side of the voltage transformer to extract the high-frequency partial discharge current signal generated during the insulation degradation process, which serves as an auxiliary judgment signal source for unstable inter-turn short circuits. The voltage acquisition unit and the power frequency current acquisition unit are both installed inside the junction box on the secondary side of the voltage transformer. The high frequency current acquisition unit is installed 20 centimeters above the grounding end of the primary side grounding lead. The signal cables of each unit are all bundled and laid along the transformer body bracket to the monitoring cabinet.

[0023] The oil medium characteristic acquisition module includes a permeable gas sampling unit, an oil micro-water sampling unit, and an oil temperature compensation unit. The permeable gas sampling unit is installed at the spare oil inlet on the side wall of the voltage transformer tank. It adopts a semi-permeable membrane gas chamber structure to contact the oil cavity, allowing only the characteristic fault gas dissolved in the oil to permeate into the gas chamber. The gas chamber contains a gas sensing element that outputs the corresponding gas concentration signal. The oil micro-water sampling unit is installed at the drain valve interface at the bottom of the tank. It uses a capacitive micro-water sensing probe immersed in the insulating oil to collect the signal of trace moisture content in the oil in real time. The oil temperature compensation unit is installed in the middle of the side wall of the tank. It has a built-in temperature sensor to collect the real-time temperature of the insulating oil. On the one hand, it is used to correct the temperature of the gas sample and micro-water measurement values, and on the other hand, it provides temperature parameters for electrical quantity reference calibration. The permeable gas sampling unit is connected to the spare oil intake port in the upper middle part of the side wall of the oil tank. The oil micro water sampling unit is connected to the reserved interface on the side of the oil drain valve at the bottom of the oil tank. The oil temperature compensation unit is embedded in the reserved screw hole in the middle of the side wall of the oil tank. The signal lines of the three units are all routed downwards along the oil tank wall and connected to the cabinet.

[0024] The signal acquisition and processing module includes a signal conditioning unit, a synchronous acquisition unit, a dual-parameter reference calibration unit, and a feature extraction unit. The signal conditioning unit filters, amplifies, and impedance-matches the raw analog signals to suppress background noise interference from the strong electromagnetic environment at the generator outlet and improves the signal-to-noise ratio of weak insulation characteristic signals. The synchronous acquisition unit performs synchronous analog-to-digital conversion on the conditioned electrical signals and oil medium signals to ensure complete time-phase alignment of multiple signals, providing time-consistent digital data for subsequent vector calculations and correlation analysis. The dual-parameter reference calibration unit includes a load impedance calculation subunit and a temperature correction subunit, with upstream synchronous connection. The secondary voltage, secondary current, and oil temperature signals output by the acquisition unit are connected to the downstream feature extraction unit and diagnostic module. The load impedance calculation subunit calculates the total load impedance on the secondary side using the real-time acquired secondary voltage and current data. The temperature correction subunit generates a temperature correction coefficient by combining the real-time oil temperature data, and outputs the load offset and temperature correction coefficient together. The feature extraction unit synthesizes and calculates the vector sum of the excitation current based on the ampere-turn balance theory of the voltage transformer, extracts the phase change feature value of the excitation current, and simultaneously extracts the amplitude and frequency characteristics of the high-frequency partial discharge signal and the oil medium characteristic parameters. It also completes the reference correction of the feature parameters by combining the correction data output by the dual-parameter reference correction unit. The signal conditioning unit, synchronous acquisition unit, dual-parameter reference calibration unit, and feature extraction unit are arranged sequentially on the same main control circuit board according to the signal flow direction. The board is horizontally installed in the middle partition of the monitoring cabinet, and the units are connected to each other through the printed circuits on the board.

[0025] The diagnostic output module includes an insulation condition diagnostic unit, a multi-source fusion diagnostic unit, an early warning output unit, and a data storage unit. The insulation condition diagnostic unit uses dynamic threshold judgment logic, with the phase change characteristic difference coefficient of the excitation current as the core criterion, to determine the degree of inter-turn short circuit and early insulation defects. It combines high-frequency partial discharge signals to identify early inter-turn short circuit faults with strong instability and non-metallicity, and simultaneously identifies slow-blow faults of high-voltage fuses. The multi-source fusion diagnostic unit connects the upstream docking feature extraction unit with the electrical quantity characteristic parameters and oil medium characteristic parameters, and performs correlation analysis between the oil medium degradation characteristics and electrical quantity insulation characteristics. It combines the slow degradation trend of the oil medium to predict the insulation aging process, and combines the sudden change characteristics of electrical quantities to identify existing inter-turn insulation defects. The two dimensions are mutually verified to output a comprehensive insulation condition assessment result. When the early warning output unit detects that the characteristic parameters exceed the normal threshold, it promptly issues a graded early warning signal, and simultaneously outputs corresponding diagnostic opinions and fault concern points, clarifying the type and approximate location of the defect. The data storage unit stores historical data and fault records of the entire monitoring process, supports historical trend query and retrospective analysis, and provides data support for equipment condition assessment and maintenance plan formulation. The insulation status diagnostic unit and the multi-source fusion diagnostic unit are integrated in the rear computing area of ​​the main control circuit board. The external terminal block of the early warning output unit is located on the side wall of the lower part of the cabinet. The data storage unit is embedded in the side slot of the main control board. The display component is installed in the upper area of ​​the front panel of the cabinet.

[0026] The working principle of the online monitoring system for the insulation status of the generator outlet side voltage transformer provided by this invention is as follows: This system operates based on the ampere-turn balance theory and the equivalent circuit model of inter-turn short circuits of voltage transformers. Each acquisition unit of the front-end sensing module synchronously acquires the voltage and power frequency current signals of the secondary side of the voltage transformer, as well as the high-frequency current signal of the primary side grounding circuit. The oil medium characteristic acquisition module obtains the concentration of dissolved characteristic gases and trace moisture content in the oil through a permeable gas sampling unit and an oil micro-water sampling unit, respectively. Combined with temperature data from the oil temperature compensation unit, it performs preliminary correction of the oil medium measurement values. The two raw signals undergo filtering, amplification, and anti-interference processing by the signal conditioning unit, and then are synchronously converted from analog to digital by the synchronous acquisition unit to ensure phase consistency of the multiple signals. The dual-parameter reference correction unit calculates the total load impedance of the secondary side based on real-time secondary voltage and current, and dynamically adjusts the feature calculation reference and diagnostic threshold based on the real-time oil temperature and the generated temperature correction coefficient. The feature extraction unit uses vector operations... The excitation current of the transformer is calculated, and the phase change characteristic value of the excitation current is extracted. At the same time, the characteristic parameters of the high-frequency partial discharge signal and the oil dielectric signal are extracted, and the reference correction of the characteristic parameters is completed by combining the correction data. The insulation condition diagnosis unit uses the phase change characteristic difference coefficient of the excitation current as the core judgment basis, and combines the dynamic threshold to determine the degree of insulation defects between winding turns. At the same time, it combines the high-frequency partial discharge signal to identify unstable inter-turn short circuit faults and simultaneously identify slow-blow faults of high-voltage fuses. The multi-source fusion diagnosis unit performs correlation analysis between the oil dielectric deterioration characteristics and the electrical insulation characteristics. It predicts the development trend of insulation aging through oil dielectric parameters and accurately identifies the insulation defects that have occurred through electrical parameters. The two complement and verify each other. Finally, the early warning output unit outputs the corresponding level of early warning and diagnosis opinions based on the comprehensive diagnosis results, realizing uninterrupted online monitoring of the insulation condition of the voltage transformer.

[0027] Compared with related technologies, the online monitoring system for the insulation status of the generator outlet side voltage transformer provided by the present invention has the following advantages: This system solves the problems of traditional offline insulation testing, such as the inability to monitor in real time and the low detection rate of early insulation defects. Based on the excitation current-phase characteristic judgment method, it has higher detection sensitivity for early inter-turn insulation defects with few short-circuit turns and high instability, achieving a detection accuracy at the single-turn level, far exceeding conventional detection methods. By adding an oil medium characteristic acquisition module and a multi-source fusion diagnostic unit, it compensates for the inability of single electrical quantity monitoring to detect the degradation trend of the insulating oil medium, realizing an extension from post-fault diagnosis to advanced prediction during the degradation process. The two dimensions of characteristics mutually verify each other, effectively reducing the probability of misjudgment and missed detection in strong electromagnetic environments. The dual-parameter reference correction unit eliminates the need for dynamic reference adjustment based on two factors: secondary load and oil temperature. Besides reducing the drift of characteristic parameters caused by operating condition fluctuations, the system significantly reduces the probability of false alarms when the unit load changes or the ambient temperature fluctuates, thus improving the operational reliability of the monitoring device. Furthermore, the overall solution adopts a non-intrusive installation method, requiring no modification to the original main structure of the voltage transformer. Deployment can be completed while the unit is running. It can also simultaneously identify slow-blow faults in high-voltage fuses, expanding the fault coverage. It can issue timely warnings in the early stages of defect development, guiding maintenance personnel to conduct targeted repairs. This effectively avoids equipment damage and abnormal unit shutdowns caused by insulation faults, improving the reliability and safety of generator operation, reducing unnecessary power outage tests, and lowering equipment maintenance costs. It possesses significant practical value and economic benefits. Example

[0028] Please refer to the following: Figures 6-7 - Figures 8-9 , Figure 6 A schematic diagram of a second embodiment of the online monitoring system for the insulation status of a generator outlet-side voltage transformer provided by the present invention; Figure 7 This is a schematic diagram of the structure of the base frame of the present invention; Figure 8 Provided for the present invention Figure 7 An enlarged view of point A shown; Figure 9 Provided for the present invention Figure 7 The enlarged view at point B shows an online monitoring system for the insulation status of a generator outlet-side voltage transformer, based on the first embodiment of this application. The second embodiment of this application proposes another online monitoring system for the insulation status of a generator outlet-side voltage transformer. The second embodiment is merely a preferred embodiment of the first embodiment, and its implementation will not affect the independent implementation of the first embodiment.

[0029] Specifically, the difference between the online monitoring system for the insulation status of the generator outlet side voltage transformer provided in the second embodiment of this application is that the front-end sensing module, the oil medium characteristic acquisition module, the signal acquisition and processing module, and the diagnostic output module constitute the online monitoring device 5; Online monitoring device 5, the online monitoring device 5 is installed on the top of the base frame 1, the top of the base frame 1 is equipped with a mounting shell 2, a connecting structure 4 is installed on one side of the mounting shell 2, and a display screen 6 is installed on the top of the mounting shell 2; The mounting shell 2 covers the online monitoring device 5, the connection structure 4 is an external connector for easy wiring, the base frame 1 is fixed in the corresponding position by fasteners, and the display screen 6 can display monitoring data.

[0030] The top of the mounting shell 2 is equipped with a docking component 3, and threaded holes are provided on the front and back of the mounting shell 2 near the bottom. A threaded hole passes through the mounting housing for mounting the mounting housing 2 on top of the base frame 1.

[0031] The mounting housing 2 includes a housing 201 and a plurality of heat exchange bars 202, the plurality of heat exchange bars 202 being installed on the front and back of the housing 201; Both the shell 201 and the heat exchange bar 202 are made of materials with high thermal conductivity.

[0032] The docking assembly 3 includes a magnetic frame 301, a clip frame 302, a magnetic edge 303, and a cover plate 304. The magnetic frame 301 is installed on the top of the mounting shell 2, the clip frame 302 is inserted into the bottom of the magnetic frame 301, and the cover plate 304 is installed on the top of the magnetic frame 301. The card frame 302 is inserted into the magnetic frame 301, and the magnetic edge 303 and the magnetic frame 301 attract each other, increasing the stability of the connection.

[0033] The base frame 1 includes a base plate 101, a buffer pad 102, a fixing bolt 103, and a limiting frame 104. The buffer pad 102 is installed at the bottom of the base plate 101, and the limiting frame 104 is installed at the top of the base plate 101. The fixing bolt 103 passes through the housing 201 and is threadedly connected to the limiting frame 104. The outer surface of the limit frame 104 is covered with sealing material to ensure a sealing effect.

[0034] Compared with related technologies, the online monitoring system for the insulation status of the generator outlet side voltage transformer provided by the present invention has the following advantages: First, the mounting shell 2 is fixed to the top of the base plate 101 using the fixing bolts 103 in the base frame 1. The mounting shell 2 is equipped with an online monitoring device 5 consisting of a front-end sensing module, an oil medium characteristic acquisition module, a signal acquisition and processing module, and a diagnostic output module. The connection structure 4 facilitates the wiring connection. The heat exchange strip 202 on the outer surface of the mounting shell 2 assists in the heat dissipation of the device. The display screen 6 on the top of the mounting shell 2 is protected by the docking component 3. During operation, the front-end sensing module and the oil medium characteristic acquisition module synchronously acquire the electrical quantity and oil medium characteristic signal of the voltage transformer. After the signal acquisition and processing module completes the benchmark correction and feature extraction, the diagnostic output module completes the multi-source fusion insulation diagnosis. It can realize real-time monitoring and graded early warning of insulation status on-site, without the need for network wiring. The installation does not change the main structure of the equipment, effectively improving the accuracy of early insulation defect detection, reducing the false alarm rate caused by operating condition fluctuations, and adapting to the scenario of scattered modification of single equipment.

[0035] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. An online monitoring system for the insulation status of a voltage transformer on the generator output side, characterized in that, include: Front-end sensing module, oil medium characteristic acquisition module, signal acquisition and processing module, and diagnostic output module; The front-end sensing module extracts the original electrical signals from the voltage transformer body and related circuits in a non-intrusive installation manner without changing the original main circuit structure and electrical parameters of the equipment, providing an electrical signal source for insulation diagnosis. The oil dielectric characteristic acquisition module relies on the original spare interface of the voltage transformer oil tank to collect the dielectric characteristic parameters of the insulating oil, reflecting the aging and moisture degree of the insulating oil, without the need for invasive modification of the equipment body. The signal acquisition and processing module performs filtering, conditioning, synchronous sampling, reference correction and feature extraction on the two front-end input analog signals, and outputs standardized feature parameters to eliminate measurement deviations caused by operating condition fluctuations. The diagnostic output module determines the insulation status and identifies faults based on the processed multi-dimensional feature parameters, and outputs graded early warnings and diagnostic opinions to provide maintenance personnel with repair guidance.

2. The online monitoring system for the insulation status of the generator outlet-side voltage transformer according to claim 1, characterized in that, The front-end sensing module includes a voltage acquisition unit, a power frequency current acquisition unit, and a high-frequency current acquisition unit. The voltage acquisition unit is connected in parallel to the secondary side circuit of the voltage transformer to acquire the voltage waveform and amplitude signal output from the secondary side in real time, which serves as the voltage parameter input for calculating the excitation current. The power frequency current acquisition unit is connected in series to the secondary side circuit of the voltage transformer to accurately acquire the power frequency current signal from the secondary side, which serves as the current parameter input for synthesizing the excitation current. The high-frequency current acquisition unit is mounted on the grounding lead of the primary side of the voltage transformer to extract the high-frequency partial discharge current signal generated during insulation degradation, which serves as an auxiliary judgment signal source for unstable inter-turn short circuits.

3. The online monitoring system for the insulation status of the generator outlet-side voltage transformer according to claim 1, characterized in that, The oil medium characteristic acquisition module includes a permeable gas sampling unit, an oil micro-water sampling unit, and an oil temperature compensation unit. The permeable gas sampling unit is installed at the spare oil inlet on the side wall of the voltage transformer tank. It adopts a semi-permeable membrane gas chamber structure to contact the oil cavity, allowing only the characteristic fault gas dissolved in the oil to permeate into the gas chamber. The gas chamber contains a gas sensing element that outputs the corresponding gas concentration signal. The oil micro-water sampling unit is installed at the drain valve interface at the bottom of the tank. It uses a capacitive micro-water sensing probe immersed in the insulating oil to collect the signal of trace moisture content in the oil in real time. The oil temperature compensation unit is installed in the middle of the side wall of the tank. It has a built-in temperature sensor to collect the real-time temperature of the insulating oil. This is used to correct the temperature of the gas sample and micro-water measurement values, and to provide temperature parameters for electrical quantity reference calibration.

4. The online monitoring system for the insulation status of the generator outlet-side voltage transformer according to claim 1, characterized in that, The signal acquisition and processing module includes a signal conditioning unit, a synchronous acquisition unit, a dual-parameter reference correction unit, and a feature extraction unit. The signal conditioning unit filters, amplifies, and performs impedance matching on each original analog signal to suppress background noise interference from the strong electromagnetic environment at the generator outlet and improve the signal-to-noise ratio of weak insulation characteristic signals. The synchronous acquisition unit performs synchronous analog-to-digital conversion on the conditioned electrical quantity signals and oil medium signals to ensure that the time phase of multiple signals is completely aligned, providing time-consistent digital data for subsequent vector operations and correlation analysis. The dual-parameter reference correction unit includes a load impedance calculation subunit and a temperature correction subunit. It connects upstream to the secondary voltage, secondary current, and oil temperature signals output by the synchronous acquisition unit and downstream to the feature extraction unit and diagnostic module. The load impedance calculation subunit calculates the total load impedance on the secondary side by collecting real-time secondary voltage and current data. The temperature correction subunit generates a temperature correction coefficient by combining real-time oil temperature data, and outputs the load offset and temperature correction coefficient together. The feature extraction unit synthesizes and calculates the vector sum of the excitation current based on the ampere-turn balance theory of the voltage transformer, extracts the phase change feature value of the excitation current, and extracts the amplitude and frequency features of the high-frequency partial discharge signal and the oil medium feature parameters. It also completes the reference correction of the feature parameters by combining the correction data output by the dual-parameter reference correction unit.

5. The online monitoring system for the insulation status of the generator outlet-side voltage transformer according to claim 1, characterized in that, The diagnostic output module includes an insulation condition diagnostic unit, a multi-source fusion diagnostic unit, an early warning output unit, and a data storage unit. The insulation condition diagnostic unit employs dynamic threshold judgment logic, using the phase change characteristic difference coefficient of the excitation current as the core criterion to determine the degree of inter-turn short circuits and early insulation defects. It combines high-frequency partial discharge signals to identify early inter-turn short circuit faults with strong instability and non-metallic characteristics, while simultaneously identifying slow-blow faults in high-voltage fuses. The multi-source fusion diagnostic unit connects upstream to the feature extraction unit, using electrical quantity characteristic parameters and oil medium characteristic parameters to correlate oil medium degradation characteristics with electrical quantity insulation characteristics. It predicts the insulation aging process based on the slow degradation trend of the oil medium and identifies existing inter-turn insulation defects based on abrupt changes in electrical quantities. These two dimensions mutually verify each other, outputting a comprehensive insulation condition assessment result. When the early warning output unit detects characteristic parameters exceeding normal thresholds, it promptly issues graded early warning signals and outputs corresponding diagnostic opinions and fault focus points, clarifying the type and approximate location of the defect. The data storage unit stores historical data and fault records from the entire monitoring process, supporting historical trend queries and retrospective analysis, providing data support for equipment condition assessment and maintenance plan formulation.

6. The online monitoring system for the insulation status of the generator outlet-side voltage transformer according to claim 1, characterized in that, The front-end sensing module, oil medium characteristic acquisition module, signal acquisition and processing module and diagnostic output module constitute the online monitoring device (5); An online monitoring device (5) is installed on the top of a base frame (1). A mounting shell (2) is installed on the top of the base frame (1). A connecting structure (4) is installed on one side of the mounting shell (2). A display screen (6) is installed on the top of the mounting shell (2).

7. The online monitoring system for the insulation status of the generator outlet-side voltage transformer according to claim 6, characterized in that, The mounting housing (2) is equipped with a docking component (3) on its top, and threaded holes are provided on the front and back of the mounting housing (2) near the bottom.

8. The online monitoring system for the insulation status of the generator outlet-side voltage transformer according to claim 6, characterized in that, The mounting housing (2) includes a housing (201) and a plurality of heat exchange strips (202), which are mounted on the front and back of the housing (201).

9. The online monitoring system for the insulation status of the generator outlet-side voltage transformer according to claim 6, characterized in that, The docking assembly (3) includes a magnetic frame (301), a card frame (302), a magnetic edge (303), and a cover plate (304). The magnetic frame (301) is installed on the top of the mounting shell (2), the card frame (302) is inserted into the bottom of the magnetic frame (301), and the cover plate (304) is installed on the top of the magnetic frame (301).

10. The online monitoring system for the insulation status of the generator outlet-side voltage transformer according to claim 6, characterized in that, The base frame (1) includes a base plate (101), a buffer pad (102), a fixing bolt (103), and a limiting frame (104). The buffer pad (102) is installed at the bottom of the base plate (101), and the limiting frame (104) is installed at the top of the base plate (101). The fixing bolt (103) passes through the housing (201) and the limiting frame (104) and is threadedly connected.

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