Method and system for identifying GIS partial discharge signal and interference signal

Abstract

The invention discloses a method for identifying a GIS partial discharge signal and an interference signal. The method comprises the following steps: 100, acquiring a voltage signal of the partial discharge signal; 200, integrating the acquired voltage signal twice to obtain the charge quantity of partial discharge; 300, obtaining to-be-evaluated characteristic impedance of the partial discharge based on the charge quantity of the partial discharge; and 400, comparing the to-be-evaluated characteristic impedance with known partial discharge characteristic impedance so as to identify whether the partial discharge signal is an interference signal. Correspondingly, the invention also provides a system for identifying the GIS partial discharge signal and the interference signal. According to the method, the partial discharge signals and the interference signals can be effectively distinguished, and the problem that the partial discharge signals and the interference signals are difficult to distinguish in a complex environment in the prior art is solved.

Description

Technical Field

[0001] This invention relates to a signal processing method and system, and more particularly to a method and system for distinguishing GIS partial discharge signals from interference signals. Background Technology

[0002] With the development of power systems, GIS has been widely used in high-voltage transmission and distribution systems due to its advantages such as small size, high reliability and low maintenance.

[0003] However, partial discharge in GIS can lead to gradual deterioration of insulation materials, eventually causing insulation failures and seriously affecting the safe operation of the power system. To ensure the reliability of GIS operation, accurate detection of partial discharge signals is necessary.

[0004] Existing PD detection technologies mainly rely on ultra-high frequency (UHF) antenna methods to identify partial discharges by detecting electromagnetic waves.

[0005] However, due to the complex environment in which GIS operates, external electromagnetic interference signals are difficult to completely eliminate, leading to frequent misjudgments and false alarms, affecting the accuracy of detection results. Especially in high-voltage direct current (HVDC) systems, partial discharge signals and interference signals have very similar characteristics, making it difficult for traditional detection methods to effectively distinguish them. Furthermore, existing methods typically rely on vast amounts of historical data and complex algorithm models, increasing the complexity and cost of the detection system. Summary of the Invention

[0006] One of the objectives of this invention is to provide a method for identifying partial discharge signals and interference signals in GIS. This method estimates the partial discharge charge by measuring the voltage of the partial discharge signal and performing two integrations, thereby effectively distinguishing between partial discharge and interference signals and solving the problem in the prior art that it is difficult to distinguish between PD and interference signals in complex environments.

[0007] In accordance with the aforementioned objective, this invention proposes a method for identifying partial discharge signals and interference signals in GIS (Gas Injection Geological Survey), comprising the following steps:

[0008] 100: Voltage signal used to acquire partial discharge signals;

[0009] 200: The acquired voltage signal is integrated twice to obtain the charge amount of partial discharge;

[0010] 300: Obtain the characteristic impedance of the partial discharge to be evaluated based on the charge amount of the partial discharge;

[0011] 400: Compare the characteristic impedance to be evaluated with the known partial discharge characteristic impedance to identify whether the partial discharge signal is an interference signal.

[0012] Furthermore, in the method for identifying GIS partial discharge signals and interference signals according to the present invention, step 100 further includes: amplifying, filtering and correcting the collected voltage data.

[0013] Furthermore, in the method for identifying GIS partial discharge signals and interference signals described in this invention:

[0014] In step 100, the voltage signal includes a first voltage signal obtained based on a first sensor and a second voltage signal obtained based on a second sensor;

[0015] In step 200, the first voltage signal is integrated twice to obtain the first charge; the second voltage signal is integrated twice to obtain the second charge.

[0016] In step 300, the characteristic impedance to be evaluated is obtained based on the ratio of the first charge quantity and the second charge quantity.

[0017] Furthermore, in the method for identifying GIS partial discharge signals and interference signals according to the present invention, the first sensor includes an electrical sensor, and the second sensor includes a magnetic sensor.

[0018] Furthermore, in step 200 of the method for identifying GIS partial discharge signals and interference signals according to the present invention, the integration time of the two integrations is selected before the second zero-crossing point of the partial discharge signal.

[0019] Another objective of this invention is to provide a system for identifying partial discharge signals and interference signals in GIS. This system estimates the partial discharge charge by measuring the voltage of the partial discharge signal and performing two integrations, thereby effectively distinguishing between partial discharge and interference signals and solving the problem in the prior art of difficulty in distinguishing PD and interference signals in complex environments.

[0020] In accordance with the aforementioned objective, this invention proposes a system for identifying partial discharge signals and interference signals in GIS (Gas Injection Geological Survey), comprising:

[0021] The signal acquisition module acquires the voltage signal of the partial discharge signal;

[0022] The dual integration module integrates the acquired voltage signal twice to obtain the charge amount of partial discharge;

[0023] Characteristic impedance module, which obtains the characteristic impedance of the partial discharge to be evaluated based on the charge amount of the partial discharge;

[0024] The identification module compares the characteristic impedance to be evaluated with the known partial discharge characteristic impedance to identify whether the partial discharge signal is an interference signal.

[0025] Furthermore, in the system for identifying GIS partial discharge signals and interference signals described in this invention, the signal acquisition module also amplifies, filters, and corrects the acquired voltage data.

[0026] Furthermore, in the system for identifying GIS partial discharge signals and interference signals described in this invention:

[0027] The voltage signal acquired by the signal acquisition module includes a first voltage signal obtained based on a first sensor and a second voltage signal obtained based on a second sensor;

[0028] The dual integration module integrates the first voltage signal twice to obtain the first charge; and integrates the second voltage signal twice to obtain the second charge.

[0029] The characteristic impedance module obtains the characteristic impedance to be evaluated based on the ratio of the first charge and the second charge.

[0030] Furthermore, in the system for identifying GIS partial discharge signals and interference signals according to the present invention, the first sensor includes an electrical sensor, and the second sensor includes a magnetic sensor.

[0031] Furthermore, in the system for identifying GIS partial discharge signals and interference signals described in this invention, the integration time of the dual integration module is selected before the second zero-crossing point of the partial discharge signal when performing two integrations.

[0032] The method and system described in this invention estimate the partial discharge charge by measuring the voltage of the partial discharge signal and performing two integrations, thereby effectively distinguishing between partial discharge and interference signals and solving the problem in the prior art that it is difficult to distinguish between PD and interference signals in complex environments.

[0033] The method and system described in this invention can be applied to high-voltage power transmission and distribution systems, enabling accurate measurement and analysis of partial discharge signals, thereby enhancing the operational reliability and maintenance efficiency of GIS. Attached Figure Description

[0034] Figure 1 The schematic diagram illustrates the steps of one embodiment of the method for identifying partial discharge signals and interference signals in GIS according to the present invention.

[0035] Figure 2 The system architecture of the system for identifying partial discharge signals and interference signals in GIS according to the present invention is shown in one embodiment. Detailed Implementation

[0036] The method and system for identifying partial discharge signals and interference signals in GIS will be further explained and described below with reference to the accompanying drawings and specific embodiments. However, this explanation and description do not constitute an undue limitation on the technical solution of the present invention.

[0037] Figure 1 The schematic diagram illustrates the steps of one embodiment of the method for identifying partial discharge signals and interference signals in GIS according to the present invention.

[0038] like Figure 1 As shown, in some embodiments of the present invention, the method for identifying GIS partial discharge signals and interference signals may include the following steps:

[0039] 100: The voltage signal used to acquire partial discharge signals.

[0040] In some more specific embodiments, the acquired voltage signal includes a first voltage signal obtained based on a first sensor and a second voltage signal obtained based on a second sensor.

[0041] In some more specific embodiments, the first sensor includes an electrical sensor, and the second sensor includes a magnetic sensor.

[0042] Based on the above setup, an electrical sensor can be used to capture the first voltage signal V generated by partial discharge. eo (t). A magnetic sensor can be used to capture the current signal generated by partial discharge and output a second voltage signal V. mo (t).

[0043] In a specific example, the electrical sensor could be an ultra-high frequency (UHF) electrical sensor, model FDU 1000. This sensor operates in the frequency range of 300MHz to 1.5GHz, and features high sensitivity and wide bandwidth, enabling it to accurately capture voltage changes caused by partial discharge.

[0044] The magnetic sensor can be a high-frequency flexible current sensor (flexible Rogowski coil) of model CWT Mini 50B. This sensor features fast high-frequency response and high sensitivity, and can accurately measure current changes caused by partial discharge.

[0045] In some more specific implementations, to ensure accurate measurement of partial discharge signals, the electrical sensor can be installed near the high-voltage port of a switchgear, circuit breaker, or transformer, locations where the strongest partial discharge (PD) signals can be captured. The electrical sensor can be secured in the selected location using a mounting bracket or insulating tape to ensure that the sensor does not move or loosen during operation.

[0046] Furthermore, in some more specific embodiments, the magnetic sensor can be installed on the outside of the cable or conductor in the GIS, close to the path of the PD current. For example, it can be installed on the surface of a cable joint, terminal box, or conductor through which the current flows. The magnetic sensor can be secured to the cable or conductor using magnetic clamps, cable ties, or mounting brackets to ensure that the sensor is in close contact with the cable or conductor being measured for accurate current measurement.

[0047] After the electrical and magnetic sensors are installed, they can be connected to the data processing unit using shielded cables, and relevant tests should be performed to ensure system reliability. The specific steps are as follows:

[0048] Cable Connections: Connect the electrical sensor to the data processing unit via a shielded coaxial cable to ensure stable signal transmission. Ensure the coaxial cable's shield is properly grounded to prevent electromagnetic interference. Connect the magnetic sensor to the data processing unit via a shielded twisted-pair cable to minimize the impact of electromagnetic interference.

[0049] Grounding: Ensure that the shielding layer of the shielded cable and the sensor housing are properly grounded, with a grounding resistance R. g Meet the specifications to avoid external electromagnetic interference; ensure that the grounding potential between the sensor and the data processing unit is consistent.

[0050] Signal transmission test: Use a signal generator to input a known test signal V in (t) to the sensor, the oscilloscope detects the output signal V at the input of the data processing unit. out (t); Verify V out (t) and V in (t) Consistency in amplitude, frequency and waveform to ensure no distortion during signal transmission.

[0051] Functional test: The initial signal V output by the sensor is acquired through the data processing unit. s (t), analyze its integrity and stability; put the GIS into normal operation state, collect and analyze the output signals V of the electrical and magnetic sensors. e,s (t) and V m,s (t), to verify whether its amplitude, frequency and phase meet expectations.

[0052] System calibration: The data processing unit is calibrated using a standard signal, with a known amplitude V input. std and frequency f std Adjust the system gain G and filter parameter F to match the output signal with the standard signal.

[0053] In some preferred embodiments, the acquired voltage signal is amplified, filtered, and corrected. Specifically:

[0054] In some implementations, the acquired first voltage signal V eo (t) and the second voltage signal V mo (t) is amplified to obtain the amplified first voltage signal V. e,amp (t) and the second voltage signal V m,amp (t). The amplifier parameters can be adjusted according to the sensor's output characteristics to ensure adequate signal strength.

[0055] The amplified first and second voltage signals are filtered to remove low-frequency noise and high-frequency interference, retaining the effective frequency band of the partial discharge signal, resulting in the filtered first voltage signal V. e,filt (t) and the second voltage signal V m,filt (t). In some more specific implementations, the filter used may include a bandpass filter designed to cover the main frequency components of the partial discharge signal.

[0056] Then, based on the transfer function H of the electrical sensor e (s) and the transfer coefficient H of the magnetic sensor m (s) is used to correct the filtered first and second voltage signals. The transfer function describes the relationship between the sensor's output signal and input signal. The transfer function H of an electrical sensor... e (s) describes the response characteristics of the voltage signal, as shown in the following formula:

[0057]

[0058] Among them, V eo (s) represents the Laplace transform of the output voltage of the electrical sensor, V pd (s) represents the Laplace transform of the first voltage signal of partial discharge, C1 and C2 are the parameters of the electrical sensor, and R is the resistance.

[0059] The transfer function H of a magnetic sensor m (s) describes the response characteristics of the current signal, as shown in the following formula:

[0060]

[0061] Among them, V mo (s) represents the Laplace transform of the magnetic sensor output voltage, I pd (s) represents the Laplace transform of the partial discharge current signal, where M is the mutual inductance coefficient, L is the inductance, and R is the resistance.

[0062] Using the transfer function, the filtered first voltage signal V e,filt (t) and the second voltage signal V m,filt(t) is corrected. Through transfer function correction, the nonlinear effects of the sensor can be eliminated, and the corrected first and second voltage signals are obtained as V0 and V1, respectively. e,c (t) and V m,c (t).

[0063] In some implementations, the corrected first voltage signal V can also be... e,c (t) and the second voltage signal V m,c (t) is used for storage. The stored data may include timestamps and signal amplitudes to ensure the accuracy and timing consistency of subsequent analysis. The data storage format can adopt a standard time series data format for easy subsequent processing and analysis.

[0064] 200: The acquired voltage signal is integrated twice to obtain the charge amount of partial discharge.

[0065] In some more specific embodiments, the first voltage signal V from the self-electric sensor is acquired. e,c (t) is integrated twice to obtain the first charge; the second voltage signal V from the self-magnetic sensor is then obtained. m,c (t) is integrated twice to obtain the second charge. Specifically:

[0066] For an electrical sensor, the first charge Q is obtained by performing two integrations based on the following formula. e :

[0067]

[0068] Where C1 is the capacitance of the electrical sensor, R is the resistance, Z1 is the characteristic impedance of the electrical sensor, and t0 is the integration time. For the electrical sensor, k = C1·R·Z1, where k is the coupling constant.

[0069] For a magnetic sensor, the second charge Q can be obtained by performing two integrations based on the following formula. m :

[0070]

[0071] Where M is the mutual inductance coefficient of the magnetic sensor, and t0 is the integration time. For the magnetic sensor, the coupling constant k = M (unit: Ω·s). The coupling constant eliminates the influence of sensor characteristics, unifies the measurement results of different sensors, and thus improves the accuracy and reliability of partial discharge signal detection and analysis.

[0072] In some preferred embodiments, in order to reduce the accumulation of noise during integration, the integration time t0 can be selected before the second zero-crossing point of the partial discharge pulse. This can avoid introducing noise and other irrelevant signals into the integration result, ensure the accuracy of the partial discharge charge, help improve the accuracy and reliability of the integration calculation, and avoid the impact of noise accumulation on the result.

[0073] 300: Obtain the characteristic impedance of the partial discharge to be evaluated based on the amount of charge in the partial discharge.

[0074] In some more specific implementations, based on the first charge Q e Second charge Q m The ratio is used to obtain the characteristic impedance Z0 to be evaluated:

[0075]

[0076] This formula utilizes the voltage signals from both electrical and magnetic sensors, and calculates the characteristic impedance Z0 of the GIS to be evaluated by integrating the charge ratio. This calculation process relies only on the coupling constant, and not on other electrical parameters or the accuracy of the sensor model, making the measurement process simpler and more reliable.

[0077] 400: Compare the characteristic impedance to be evaluated with the known partial discharge characteristic impedance to identify whether the partial discharge signal is an interference signal.

[0078] For a real partial discharge signal, the calculated characteristic impedance value Z0 to be evaluated should be close to the known characteristic impedance of the GIS. The characteristic impedance of the GIS is usually within a specific range. If the calculated result Z0 falls within this range, the signal can be determined to be a partial discharge signal. This indicates that the signal propagation characteristics are consistent with the normal operating state of the GIS, and the characteristic impedance of the partial discharge signal matches the known characteristic impedance of the GIS, proving that the signal is a partial discharge signal.

[0079] For external interference signals, due to their different propagation characteristics compared to PD signals, the calculated characteristic impedance Z0 to be evaluated will significantly deviate from the known GIS characteristic impedance range. The characteristic impedance of external interference signals may be significantly higher or lower than the known range. Therefore, these interference signals can be identified and distinguished based on the degree of deviation of the ratio. When the characteristic impedance value Z0 significantly deviates from the known GIS characteristic impedance range, it indicates that the signal is an external interference signal, and the characteristic impedance of the interference signal does not match the known characteristic impedance of the GIS, proving that the signal is an interference signal.

[0080] In another embodiment of the present invention, a system for identifying partial discharge signals and interference signals in GIS is also provided.

[0081] Figure 2 The system architecture of the system for identifying partial discharge signals and interference signals in GIS according to the present invention is shown in one embodiment.

[0082] like Figure 2 As shown, in this embodiment, the system may include:

[0083] The signal acquisition module 202 acquires the voltage signal of the partial discharge signal;

[0084] The dual integration module 204 integrates the acquired voltage signal twice to obtain the charge amount of the partial discharge.

[0085] Characteristic impedance module 206 obtains the characteristic impedance to be evaluated of the partial discharge based on the charge amount of the partial discharge;

[0086] The identification module 208 compares the characteristic impedance to be evaluated with the known partial discharge characteristic impedance to identify whether the partial discharge signal is an interference signal.

[0087] In some more specific implementations, the signal acquisition module 202 also amplifies, filters, and corrects the acquired voltage data.

[0088] In some more specific embodiments, the voltage signal acquired by the signal acquisition module 202 includes a first voltage signal obtained based on a first sensor and a second voltage signal obtained based on a second sensor; the dual integration module 204 integrates the first voltage signal twice to obtain a first charge; integrates the second voltage signal twice to obtain a second charge; and the characteristic impedance module 206 obtains the characteristic impedance to be evaluated based on the ratio of the first charge and the second charge.

[0089] In some more specific embodiments, the first sensor may include an electrical sensor, and the second sensor may include a magnetic sensor.

[0090] In some more specific implementations, the dual integration module 204 selects the integration time as before the second zero-crossing point of the partial discharge signal when performing two integrations.

[0091] In this invention, the signal acquisition module 202, the dual integration module 204, the characteristic impedance module 206, and the identification module 208 can be implemented in any suitable manner. For example, they can take the form of a microprocessor or processor and a computer-readable medium storing computer-readable program code (e.g., software or firmware) executable by the (micro)processor, logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers, and embedded microcontrollers. Examples of controllers include, but are not limited to, the following microcontrollers: ARC 625D, Atmel AT91SAM, Microchip PIC18F26K20, and Silicon Labs C8051F320.

[0092] Furthermore, those skilled in the art will recognize that, besides implementing the controller using purely computer-readable program code, the method steps can be logically programmed to enable the modules to perform the same function in the form of logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers (PLCs), and embedded microcontrollers. Therefore, such a module can be considered a hardware component, and the devices included within it for implementing various functions can also be considered structures within that hardware component. Alternatively, the devices for implementing various functions can be considered as both software modules implementing the method and structures within a hardware component.

[0093] To verify the credibility and robustness of this invention, cross-validation was used for data analysis. The specific steps are as follows:

[0094] Data Grouping: Experimental data is divided into training and test sets, used for model training and validation, respectively. Each set contains signals collected under different conditions, covering partial discharge signals of varying intensities and various types of external interference signals. Random sampling is used for data grouping to ensure the representativeness and diversity of data from each experiment.

[0095] Cross-validation method: The experiment uses k-fold cross-validation, where k is set to 10. Specifically, the experimental data is randomly divided into 10 subsets. In each iteration, 9 subsets are used as the training set, and the remaining subset is used as the test set. This process is repeated 10 times. During each cross-validation iteration, the classification accuracy of the model on the test set is calculated, and the classification results and error range for each experiment are recorded.

[0096] Results Statistics and Analysis: The results of each cross-validation were summarized, and the overall classification accuracy and error range were calculated. Specific statistics included the mean measured value, standard deviation, classification accuracy, and error range. The results show that the method of this invention can effectively distinguish between partial discharge signals and external interference signals. Specific results are listed in Table 1:

[0097] Table 1

[0098]

[0099]

[0100] Among them, the average measured value of the partial discharge signal in 100 experiments was within the known characteristic impedance range of GIS (50-60Ω), indicating that the method accurately identifies the partial discharge signal with a classification accuracy of 97%.

[0101] For external interference signals, the average measurement value in 100 experiments deviated significantly from the known characteristic impedance range of GIS, indicating that the method effectively identifies external interference signals with a classification accuracy of 95%.

[0102] The experimental results above demonstrate that the method and system for identifying partial discharge signals and interference signals in GIS according to the present invention have high accuracy and reliability. This method and system can effectively distinguish partial discharge signals from external interference signals in complex environments, providing solid technical support for GIS fault detection and maintenance.

[0103] It should be noted that the prior art portion of the protection scope of this invention is not limited to the embodiments given in this invention document. All prior art that does not contradict the solution of this invention, including but not limited to prior patent documents, prior publications, prior public uses, etc., can be included in the protection scope of this invention.

[0104] Furthermore, the combination of the technical features in this case is not limited to the combination methods described in the claims of this case or the combination methods described in the specific embodiments. All technical features described in this case can be freely combined or combined in any way, unless they contradict each other.

[0105] It should also be noted that the embodiments listed above are merely specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and similar changes or modifications made thereto are those that can be directly derived or easily conceived by those skilled in the art from the content disclosed in the present invention, and should all fall within the protection scope of the present invention.

Claims

1. A method for identifying GIS partial discharge signals from interference signals, characterized in that, Includes the following steps: 100: Acquire the voltage signal of the partial discharge signal; 200: The acquired voltage signal is integrated twice to obtain the charge amount of partial discharge; 300: Obtain the characteristic impedance of the partial discharge to be evaluated based on the charge amount of the partial discharge; 400: Compare the characteristic impedance to be evaluated with the known partial discharge characteristic impedance to identify whether the partial discharge signal is an interference signal.

2. The method of claim 1, wherein the GIS partial discharge signal is identified from the interference signal by, Step 100 also includes: amplifying, filtering, and correcting the acquired voltage data.

3. The method for identifying partial discharge signals and interference signals in GIS as described in claim 1, characterized in that: In step 100, the voltage signal includes a first voltage signal obtained based on a first sensor and a second voltage signal obtained based on a second sensor; In step 200, the first voltage signal is integrated twice to obtain the first charge amount; The second voltage signal is integrated twice to obtain the second charge quantity; In step 300, the characteristic impedance to be evaluated is obtained based on the ratio of the first charge quantity and the second charge quantity.

4. The method of claim 3, wherein the GIS partial discharge signal is identified from the interference signal by, The first sensor includes an electrical sensor, and the second sensor includes a magnetic sensor.

5. The method of claim 1, wherein the GIS partial discharge signal is identified from the interference signal by, In step 200, the integration time for the two integrations is selected before the second zero-crossing point of the partial discharge signal.

6. A system for identifying GIS partial discharge signals from interference signals, characterized in that, include: The signal acquisition module acquires the voltage signal of the partial discharge signal; The dual integration module integrates the acquired voltage signal twice to obtain the charge amount of partial discharge; Characteristic impedance module, which obtains the characteristic impedance of the partial discharge to be evaluated based on the charge amount of the partial discharge; The identification module compares the characteristic impedance to be evaluated with the known partial discharge characteristic impedance to identify whether the partial discharge signal is an interference signal.

7. The system for discriminating between GIS partial discharge signals and interference signals of claim 6, wherein, The signal acquisition module also amplifies, filters, and corrects the acquired voltage data.

8. The system for identifying partial discharge signals and interference signals in GIS as described in claim 6, characterized in that: The voltage signal acquired by the signal acquisition module includes a first voltage signal obtained based on a first sensor and a second voltage signal obtained based on a second sensor; The dual integration module integrates the first voltage signal twice to obtain the first charge. The second voltage signal is integrated twice to obtain the second charge quantity; The characteristic impedance module obtains the characteristic impedance to be evaluated based on the ratio of the first charge and the second charge.

9. The system for discriminating between GIS partial discharge signals and interference signals of claim 8, wherein, The first sensor includes an electrical sensor, and the second sensor includes a magnetic sensor.

10. The system for discriminating between GIS partial discharge signals and interference signals of claim 6, wherein, When performing two integrations, the integration time of the dual integration module is selected to be before the second zero-crossing point of the partial discharge signal.

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