A transient ground potential spike real-time online monitoring system

Abstract

The application discloses a kind of transient ground net ground potential spike real-time online monitoring system, specifically including capture terminal selection determination module, the arrangement installation module of capture terminal, host parameter configuration module, field potential spike detection module and networking alarm module, the arrangement installation module of capture terminal specifically includes background noise confirmation unit, effective test point confirmation unit and key information consistency acquisition unit, the present application can be in real time before the front end condition of primary equipment failure, especially special operation mode such as high temperature, high humidity, heavy load, improve the safety and reliability of system, from passive treatment to active and initiative defense, strict control accident in the time, reduce the cost of failure maintenance in later period, provide technical support for the development of future comprehensive online monitoring system, and by terminal data trend analysis, judge the trend of failure in advance, intervene in time, break the impact of later period failure on power grid, improve the safety and stability of power grid.

Description

Technical Field

[0001] This invention relates to the field of substation monitoring technology, specifically to a real-time online monitoring system for transient grounding grid ground potential spikes. Background Technology

[0002] As a crucial energy distribution node in the power system, substations directly supply high-voltage switchgear to external users. The main components of this switchgear consist of circuit breakers, disconnectors, voltage transformers, current transformers, surge arresters, and various voltage-resistant insulating bushings. Because it is sealed within a metal armor, routine inspections and tests are physically limited. Within this confined space, the insulation conditions and levels of this highly integrated equipment are critical to the safety, stability, and reliability of the power system. In the new era, my country's power system has increasingly higher requirements for power quality, emphasizing not only stable and reliable power supply but also its safety. Metal-enclosed switchgear equipment is widely used in power systems. Therefore, the stability and reliability of high-voltage switchgear operation is a paramount concern for electrical equipment. During operation, it is subject to inherent technological limitations, high temperatures, high pressures, vibrations, and other chemical corrosion, leading to reduced insulation performance, partial discharge, and accelerated insulation aging, resulting in significant economic losses to the power system.

[0003] Currently, the management of this type of equipment relies on periodic on-site inspections by personnel using handheld devices. This method faces challenges such as the large number of devices, personnel responsibility, and the alignment of power grid load with inspection timeframes. In other words, there are equipment dead zones and time dead zones, making it impossible to understand and control the insulation status of the primary equipment inside the central switch cabinet in a real-time and timely manner. For the most important central switch cabinets that are directly in contact with users, the management has always been a passive approach rather than an active defense. Summary of the Invention

[0004] This invention provides a real-time online monitoring system for transient grounding grid ground potential spikes. It can effectively solve the problem mentioned in the background art that the current management of such equipment relies on periodic offline inspections by personnel using handheld devices. This method faces problems such as the large number of devices, personnel responsibility, and the alignment of grid load with inspection time points. In other words, there are equipment dead zones and time dead zones, making it impossible to understand and control the insulation status of the primary equipment inside the central grounding switch in real time. For the most important central grounding switch cabinets that are directly in contact with users, the management has always been a passive response rather than an active defense.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a real-time online monitoring system for ground potential spikes in transient grounding grids, characterized in that: it can understand the insulation status and operating conditions of various equipment in the central switch cabinet in real time, changing passive handling to active defense, providing strong technical support for predicting grid faults, ensuring reliable power supply, and curbing sudden uncontrollable faults;

[0006] Specifically, it includes a capture terminal selection and determination module, a capture terminal deployment and installation module, a host parameter configuration module, a field potential spike detection module, and a network alarm module;

[0007] The deployment and installation module of the capture terminal specifically includes a background noise confirmation unit, an effective test point confirmation unit, and a key information consistency acquisition unit;

[0008] The field potential spike detection module includes a ground power spike detection unit and an ultrasonic detection unit.

[0009] According to the above technical solution, when the capture terminal selection and determination module selects the transient grounding grid ground potential spike capture terminal, it adopts a composite TEV sensor and the contact part with the switch cabinet body is made of polytetrafluoroethylene material with good dielectric constant, with built-in receiving electrodes, forming a capacitor with the switch cabinet wall, which can couple the discharge signal inside the cabinet to the sensor for signal processing, ensuring that the partial discharge signal inside the switch cabinet is detected.

[0010] Composite TEV sensors detect partial discharge in electrical equipment. TEV stands for Transient Ground Voltage. When partial discharge occurs in electrical equipment, electromagnetic waves are generated. These electromagnetic waves induce a transient ground voltage signal on the metal casing of the equipment. By detecting this signal using composite TEV sensors, the partial discharge status of the electrical equipment can be monitored.

[0011] The measurement signals include ultrasonic signals and electrical signals. The ultrasonic measurement frequency band ranges from 20kHz to 120kHz, with a center frequency of 40kHz. The TEV measurement frequency band ranges from 10MHz to 100MHz.

[0012] According to the above technical solution, when the terminal detection of a partial discharge signal inside the switch cabinet is clear, the capture terminal selection and determination module needs to obtain the type of partial discharge and make a corresponding selection according to the type of partial discharge. The partial discharge specifically includes corona discharge, surface discharge, internal discharge and suspension discharge.

[0013] The corona discharge is a discharge phenomenon generated between a high-voltage conductor and the surrounding gas. Corona discharge exhibits the characteristics of a non-uniform electric field, which can produce a continuous discharge phenomenon.

[0014] The surface discharge is a phenomenon that occurs on the surface of an insulating medium, and it is a relatively special gas discharge phenomenon.

[0015] The internal discharge exists inside the insulating medium. During the production and processing of the insulating medium, design and manufacturing defects in materials and processes are inevitable, resulting in quality defects inside the insulating medium.

[0016] The floating discharge occurs because one of the conductor components in the high-voltage equipment has a design defect or poor contact at a certain part, causing the component to be located between the high-voltage electrode and the low-voltage electrode and receive a voltage division according to the impedance ratio of its position, resulting in a floating potential on the conductor component relative to ground.

[0017] According to the above technical solution, in the specific installation process of the capture terminal, the installation of the transient grounding grid ground potential spike capture terminal adopts a self-adhesive type and a connection method with the host. The system adopts multiple connection methods, and the terminal sensor and the host can switch between three methods: BNC, SMA interface, and optical fiber for easy use. The number of multiple distribution points is determined according to the background noise of the site and the specific situation of the central cabinet structure.

[0018] According to the above technical solution, the background noise confirmation unit is used because the operation of the substation is complex and the equipment in the substation is diverse, which will cause various kinds of background noise. Therefore, the background noise needs to be initialized and confirmed before commissioning and included in the judgment criteria. The background noise is specifically divided into air background and metal background.

[0019] The effective test point confirmation unit is because test points have a significant impact on test results. Therefore, the selection of test points should be based on the structure of the device under test, with multiple points installed, and a comprehensive evaluation should be made to confirm the effective test points. Valid test points include front middle, front lower, rear upper, rear middle, rear lower, side upper, side middle, and side lower.

[0020] Assume the effect of background noise is a constant C. b The validity of the test points is weighted by their distance and angle relative to the noise source, and the following formula is proposed:

[0021]

[0022] in:

[0023] N eff This is valid noise data;

[0024] n is the number of test points;

[0025] A i It is the position factor of the i-th test point, which can be the acoustic characteristics of the test point;

[0026] d i α is the distance from the i-th test point to the noise source, and α is the attenuation coefficient;

[0027] w i It is the weight of the i-th test point, which can be assigned a value based on the relative importance of the test point;

[0028] C b It is the background noise factor, representing the combined effect of air background noise and metallic background noise;

[0029] in

[0030]

[0031] This reflects the influence of the geometric position and angle of the test point;

[0032] α i (f) is the frequency-dependent sound absorption coefficient, which can take into account the sound absorption characteristics of the material at different frequencies;

[0033] s(X i ,θ) is the device noise radiation pattern predicted by machine learning;

[0034] The weight w for each test point i This represents the relative importance of the test point in the entire noise test. The weight can be allocated according to the location of the test point, its distance from the noise source, and the noise intensity that the test point can receive. Test points closer to the noise source usually receive stronger noise, so their weight is greater. The closer the test point is to the noise source, the greater the weight value should be. The weight of the test point can be proportional to the inverse of the distance, similar to the noise attenuation model.

[0035] Let the distance to test point i be d. i Then w can be calculated using the following formula. i :

[0036]

[0037] d i It is the distance between the i-th test point and the noise source;

[0038] γ is the attenuation coefficient of the weight, which is usually consistent with the noise attenuation model and takes a value of 2 or 3, indicating that the noise attenuates as the distance increases;

[0039] in:

[0040] C b =C total (f)×f c (f)×E f

[0041] C total(f) represents the background noise, indicating the overall background noise intensity at frequency f. This value can be obtained directly from actual measurements or from certain preset background noise standards.

[0042]

[0043] The frequency response function is used to describe the variation of background noise at different frequencies;

[0044] f0 is the characteristic frequency, representing the dominant frequency of the noise source;

[0045] σ is the width of the frequency response, which determines the sensitivity to noise changes;

[0046] E f =α T ×T+α H ×H

[0047] An environmental correction factor, taking into account the effects of temperature (T) and humidity (H), is used to dynamically adjust background noise.

[0048] α T and α H It is the influence coefficient of temperature and humidity on background noise, which is usually obtained through experimental data or experience.

[0049] According to the above technical solution, the key information consistency acquisition unit determines the information of the uploaded data. The data information specifically includes: temperature, humidity, load, and air background and metal background noise. The installation position of the same detection terminal in different central cabinets should be consistent so that relatively stable recorded values ​​can be read during detection.

[0050] Abnormal values ​​in ground wave detection results include the following:

[0051] A test value <10dB indicates no fault.

[0052] If 10dB < test value < 20dB, it indicates that attention is needed and the testing cycle should be shortened.

[0053] If the test value is greater than 20dB, it indicates that combined acoustic and electrical detection is required to determine the signal source.

[0054] Abnormal values ​​in ultrasound test results include the following:

[0055] The test value is greater than 6dB and there is a clear discharge sound, indicating that the obvious sound signal can be monitored through headphones.

[0056] According to the above technical solution, the host parameter configuration module, when configuring the host technical parameters, specifically includes configuring the measurement channel, measurement range, capacitance range of the testable items, voltage surge resistance, charging power supply, and built-in rechargeable battery;

[0057] The measurement channel selection includes 4 / 8 independent measurement channels, each channel supports optical and electrical dual input modes, supports Ethernet networking, sampling accuracy up to 12 bits, sampling rate of 60MHz per channel, and detection sensitivity of 1pC.

[0058] The measurement range is 1pC to 100nC, the nonlinear error of this range is ≤±5%, the capacitance range of the testable samples is 6pF to 250μF, and the voltage surge resistance is 2500V.

[0059] The charging power supply is AC220V±10%, frequency 50Hz, and power <50W;

[0060] Built-in rechargeable battery: 4 hours of continuous operation;

[0061] When the built-in rechargeable battery loses AC power and the battery level drops to 70%, it will automatically send an alarm to the main station.

[0062] According to the above technical solution, the grounding spike detection unit is a transient grounding grid potential spike detection unit. The partial discharge part of the medium-voltage switchgear is generally in the insulation layer of the switchgear, where electromagnetic waves will appear. Part of the electromagnetic waves will be shielded by the metal shell, and the remaining part of the electromagnetic waves will propagate out from the gas-insulated switch or the gap of the medium-voltage switchgear. At the same time, a grounding wave will be generated and will pass through the equipment shell to the main grounding grid.

[0063] At this time, there is an instantaneous ground potential in the grounding grid. The grounding grid potential spike exists for a very short time, only on the nanosecond level. The instantaneous ground potential spike can be captured when the switch cabinet is working; a special capacitive sensing probe can be used to capture it.

[0064] According to the above technical solution, the ultrasonic detection unit actually uses the principle of mechanical vibration to analyze energy discharge from the perspective of energy theory. The phenomenon of partial discharge energy burst and breakdown in the air gap is the whole discharge process.

[0065] Electrical energy is converted into thermal energy, causing the gas at the discharge center to expand. The expanding gas propagates in the form of sound waves, heating the surrounding gas during propagation to form a certain temperature zone. The temperature and environment around the isothermal zone are relatively higher. After a period of time, the gas cools and contracts, eventually producing a frequency band containing a certain frequency component, ranging from 10 Hz to 10 MHz. Frequency greater than 20 kHz is ultrasound. Therefore, partial discharge sound sources can be used for point source localization.

[0066] According to the above technical solution, the network alarm module is formed by networking between the intelligent gateway of the station control layer and the built-in host of the central cabinet, transmitting the alarm to the main station through the 5G network, and storing it in the cloud platform, which includes Alibaba and Baidu.

[0067] Alarm thresholds are set within the main station, and when the monitored values ​​reach the alarm thresholds, push notifications are sent to relevant monitoring terminals, including mobile apps and SMS messages.

[0068] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0069] 1. This invention enables real-time monitoring of the front-end status of primary equipment faults, especially under special operating conditions such as high temperature, high humidity, and heavy load, improving system safety and reliability. It transforms passive handling into proactive defense, addressing problems at the outset and preventing them before they occur, thus reducing later maintenance costs. It provides technical support for the future development of comprehensive online monitoring systems. Furthermore, by analyzing terminal data trends, it can predict fault trajectories in advance, intervene promptly, and mitigate the impact of later faults on the power grid, improving the safety and stability of the power grid. It can also assess equipment status, providing effective quality assessment criteria for State Grid equipment procurement. It provides strong technical guarantees for power grid fault prediction, power supply reliability, and the prevention of sudden and uncontrollable faults, which is of great significance to power grid safety and stability.

[0070] 2. By using real-time online monitoring, the monitoring capabilities of the insulation equipment of the medium-voltage switchgear are effectively improved. This real-time monitoring is seamless and eliminates blind spots, preventing problems before they occur. It reduces the actual workload and intensity of offline maintenance personnel, reduces equipment wear and tear failures, enables proactive handling, and minimizes equipment and property losses. At the same time, it significantly reduces power outages caused by equipment malfunctions, ensuring power supply services for the public. Furthermore, it can monitor user-directly supplied equipment in real time, improving the reliability of power distribution and ensuring the safety and reliability of power supply for user equipment, public service systems, and public services. It avoids low voltage and low power factor operation at the end of emergency supply modes, improves economic efficiency, and promotes innovative breakthroughs in related management technologies.

[0071] 3. By equivalently treating the noise source and flexibly correcting the environment, the dynamic adaptability of the background noise factor is ensured. At the same time, the calculation process is simplified, the evaluation efficiency and accuracy are improved, and the noise assessment is more practical and widely applicable. It is suitable for various equipment testing and environmental noise monitoring scenarios, improves calculation efficiency, and makes the evaluation process more intuitive, avoiding unnecessary complex calculations, while still accurately reflecting the noise level in the actual environment. Attached Figure Description

[0072] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0073] In the attached diagram:

[0074] Figure 1This is a flowchart of the real-time online monitoring system of the present invention;

[0075] Figure 2 This is a schematic diagram of the air background and metal background of the present invention;

[0076] Figure 3 This is a schematic diagram of the distribution of test points in the cabinet in this invention. Detailed Implementation

[0077] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0078] Example: Figure 1 As shown, the present invention provides a technical solution, a real-time online monitoring system for ground potential spikes in transient grounding grids, which can understand the insulation status and operating conditions of various equipment in the central switch cabinet in real time, changing passive handling to active defense, and providing strong technical support for predicting power grid faults, ensuring power supply reliability, and curbing sudden uncontrollable faults;

[0079] Specifically, it includes a capture terminal selection and determination module, a capture terminal deployment and installation module, a host parameter configuration module, a field potential spike detection module, and a network alarm module;

[0080] The deployment and installation module of the capture terminal specifically includes a background noise confirmation unit, a valid test point confirmation unit, and a key information consistency acquisition unit;

[0081] The field potential spike detection module includes a ground power spike detection unit and an ultrasonic detection unit.

[0082] Based on the above technical solution, when selecting the transient grounding grid ground potential spike capture terminal, the capture terminal selection and determination module adopts a composite TEV sensor. The contact part between the sensor and the switch cabinet body is made of polytetrafluoroethylene material with good dielectric constant. The sensor has a built-in receiving electrode and forms a capacitor with the switch cabinet wall. This can couple the discharge signal inside the cabinet to the sensor for signal processing, ensuring that the partial discharge signal inside the switch cabinet can be effectively detected.

[0083] Composite TEV sensors detect partial discharge in electrical equipment. TEV stands for Transient Ground Voltage. When partial discharge occurs in electrical equipment, electromagnetic waves are generated. These electromagnetic waves induce a transient ground voltage signal on the metal casing of the equipment. By detecting this signal using composite TEV sensors, the partial discharge status of the electrical equipment can be monitored.

[0084] The measurement signals include ultrasonic signals and electrical signals. The ultrasonic measurement frequency band ranges from 20kHz to 120kHz, with a center frequency of 40kHz. The TEV measurement frequency band ranges from 10MHz to 100MHz.

[0085] Based on the above technical solution, when the terminal selection and determination module determines that the terminal can detect the partial discharge signal inside the switch cabinet, it needs to obtain the type of partial discharge and make the corresponding selection according to the type of partial discharge. The partial discharge specifically includes corona discharge, surface discharge, internal discharge and floating discharge.

[0086] Corona discharge is a discharge phenomenon generated between a high-voltage conductor and the surrounding gas. Corona discharge is characterized by a non-uniform electric field, which can produce a continuous discharge phenomenon.

[0087] Surface discharge is a phenomenon that occurs on the surface of an insulating medium. This is a relatively special gas discharge phenomenon, commonly found at the top of the insulating bushing of power cables and at the windings of motors.

[0088] Internal discharge exists inside the insulating medium. During the production and processing of the insulating medium, design and manufacturing defects in materials and processes are inevitable, resulting in quality defects inside the insulating medium.

[0089] Floating discharge occurs when a conductor component in a high-voltage device has a design defect or poor contact at a certain point, causing the component to be located between the high-voltage and low-voltage electrodes and receive a voltage drop according to its impedance ratio at its position, resulting in a floating potential on the conductor component relative to ground.

[0090] Based on the above technical solution, in the specific installation process of the capture terminal, the installation of the transient grounding grid ground potential spike capture terminal adopts a self-adhesive type and a connection method with the host. The system adopts multiple connection methods, and the terminal sensor and the host can switch between three methods: BNC, SMA interface, and optical fiber for easy use. The number of multiple distribution points is determined according to the background noise of the site and the specific situation of the central cabinet structure to improve sensitivity.

[0091] like Figure 2 As shown, based on the above technical solution, the background noise confirmation unit is necessary because the operation of the substation is complex and the equipment in the substation is diverse, which will cause various kinds of background noise. Therefore, the background noise needs to be initialized and confirmed before commissioning and included in the judgment criteria. The background noise is specifically divided into air background and metal background.

[0092] like Figure 3 As shown, the valid test point confirmation unit is because test points have a significant impact on test results. Therefore, the selection of test points should be based on the structure of the device under test, with multiple points installed, and a comprehensive evaluation should be made to confirm the valid test points. Valid test points include front middle, front lower, rear upper, rear middle, rear lower, side upper, side middle, and side lower.

[0093] Assume the effect of background noise is a constant C.b The validity of the test points is weighted by their distance and angle relative to the noise source, and the following formula is proposed:

[0094]

[0095] in:

[0096] N eff It is valid noise data, that is, the test results after background noise adjustment;

[0097] n is the number of test points;

[0098] A i It is the position factor of the i-th test point, which can be the acoustic characteristics of the test point, such as material and geometry;

[0099] d i α is the distance from the i-th test point to the noise source, and α is the attenuation coefficient, usually 2 or 3, used to describe how the noise attenuates as the distance increases;

[0100] w i It is the weight of the i-th test point, which can be assigned a value according to the relative importance of the test point. For example, test points closer to the noise source have a larger weight.

[0101] C b It is the background noise factor, representing the combined effect of air background noise and metallic background noise;

[0102] in

[0103]

[0104] It reflects the influence of the geometric position and angle of the test point, making noise attenuation more flexible;

[0105] α i (f) is the frequency-dependent sound absorption coefficient, which can take into account the sound absorption characteristics of the material at different frequencies;

[0106] s(X i ,θ) is the device noise radiation pattern predicted by machine learning, which makes the directionality and intensity of device noise radiation more accurate;

[0107] Suppose we have a test point i, 3 ​​meters away from the noise source, located in front of and below the device (i.e., θ). i =30°, φ i =10°, Z i (i = 2 meters), the frequency response of the equipment noise is α. i(f) = 0.5 (at a test frequency of 1000Hz), assuming the device noise radiation pattern obtained through the machine learning model is s(X) i ,θ)=0.8;

[0108] A i = (1 / (3^2)×0.5×0.8) = 0.0444;

[0109] The weight w for each test point i This represents the relative importance of the test point in the overall noise test. The weight can be allocated based on the test point's location, its distance from the noise source, and the noise intensity it receives. Test points closer to the noise source typically receive stronger noise and therefore have a higher weight. The closer the test point is to the noise source, the greater its weight should be. The weight of a test point can be proportional to the inverse of its distance (similar to a noise attenuation model).

[0110] Assume the distance to test point i is d. i Then w can be calculated using the following formula. i :

[0111]

[0112] d i It is the distance between the i-th test point and the noise source;

[0113] γ is the attenuation coefficient of the weight, which is usually consistent with the noise attenuation model. It is usually 2 or 3, indicating that the noise attenuates as the distance increases.

[0114] in:

[0115] C b =C total (f)×f c (f)×E f

[0116] C total (f) represents the background noise, indicating the overall background noise intensity at frequency f. This value can be directly derived from actual measurements or certain preset background noise standards, without needing to distinguish between air and metallic noise.

[0117]

[0118] The frequency response function is used to describe the variation of background noise at different frequencies;

[0119] f0 is the characteristic frequency, representing the dominant frequency of the noise source.

[0120] σ is the width of the frequency response, which determines the sensitivity to noise changes.

[0121] Ef =α T ×T+α H ×H

[0122] An environmental correction factor, taking into account the effects of temperature (T) and humidity (H), is used to dynamically adjust background noise.

[0123] α T and α H It is the influence coefficient of temperature and humidity on background noise, which is usually obtained through experimental data or experience.

[0124] Based on the above technical solution, the key information consistency acquisition unit determines the information of the uploaded data. The data information specifically includes: temperature, humidity, load, and background noise of air and metal. The installation position of the same detection terminal in different central cabinets should be consistent so that relatively stable recorded values ​​can be read during detection.

[0125] Abnormal values ​​in ground wave detection results include the following:

[0126] A test value <10dB indicates no fault.

[0127] If 10dB < test value < 20dB, it indicates that attention is needed and the testing cycle should be shortened.

[0128] If the test value is greater than 20dB, it indicates that combined acoustic and electrical detection is required to determine the signal source.

[0129] Abnormal values ​​in ultrasound test results include the following:

[0130] The test value is greater than 6dB and there is a clear discharge sound, indicating that the obvious sound signal can be monitored through headphones.

[0131] Based on the above technical solution, the host parameter configuration module, when configuring the host technical parameters, specifically includes configuring the measurement channel, measurement range, capacitance range of testable items, voltage surge resistance, charging power supply, and built-in rechargeable battery;

[0132] The measurement channel selection includes 4 / 8 independent measurement channels, each channel supports optical and electrical dual input modes, supports Ethernet networking, sampling accuracy up to 12 bits, sampling rate of 60MHz per channel, and detection sensitivity of 1pC.

[0133] The measurement range is 1pC to 100nC, the nonlinear error of this range is ≤±5%, the capacitance range of the testable samples is 6pF to 250μF, and the voltage surge resistance is 2500V.

[0134] The charging power supply is AC220V±10%, frequency 50Hz, and power <50W;

[0135] Built-in rechargeable battery: 4 hours of continuous operation;

[0136] When the built-in rechargeable battery loses AC power and the battery level drops to 70%, it will automatically send an alarm to the main station.

[0137] Based on the above technical solution, the grounding spike detection unit is a transient grounding grid potential spike detection unit. The partial discharge part of the medium-voltage switchgear is generally in the insulation layer of the switchgear, where electromagnetic waves will appear. Part of these electromagnetic waves will be shielded by the metal shell, while the remaining electromagnetic waves will propagate out from the gas-insulated switch or the gap in the medium-voltage switchgear. At the same time, a grounding wave will be generated and will travel from the equipment shell to the main grounding grid.

[0138] At this time, there is an instantaneous ground potential in the grounding grid. The grounding grid potential spike exists for a very short time, only on the nanosecond level. The instantaneous ground potential spike can be captured when the switch cabinet is working; a special capacitive sensing probe can be used to capture it.

[0139] Based on the above technical solution, the ultrasonic detection unit actually uses the principle of mechanical vibration to analyze energy discharge from the perspective of energy theory. The phenomenon of partial discharge energy burst and breakdown in the air gap is the whole discharge process.

[0140] Electrical energy is converted into thermal energy, causing the gas at the discharge center to expand. The expanding gas propagates in the form of sound waves, heating the surrounding gas during propagation to form a certain temperature zone. The temperature and environment around the isothermal zone are relatively higher. After a period of time, the gas cools and contracts, eventually producing a frequency band containing a certain frequency component, ranging from 10 Hz to 10 MHz. Frequency greater than 20 kHz is ultrasound. Therefore, partial discharge sound sources can be used for point source localization.

[0141] Based on the above technical solution, the network alarm module connects the intelligent gateway at the station control layer with the built-in host in the central cabinet, transmits the alarm data to the main station via the 5G network, and stores it in the cloud platform, which includes Alibaba and Baidu.

[0142] Alarm thresholds are set within the main station, and when the monitored values ​​reach the alarm thresholds, push notifications are sent to relevant monitoring terminals, including mobile apps and SMS messages.

[0143] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A real-time online monitoring system for ground potential spikes in transient grounding grids, characterized in that: It can monitor the insulation status and operating conditions of various devices in the central switch cabinet in real time, changing from passive handling to proactive defense, and providing strong technical support for predicting power grid faults, ensuring power supply reliability, and curbing sudden and uncontrollable faults; Specifically, it includes a capture terminal selection and determination module, a capture terminal deployment and installation module, a host parameter configuration module, a field potential spike detection module, and a network alarm module; The deployment and installation module of the capture terminal specifically includes a background noise confirmation unit, an effective test point confirmation unit, and a key information consistency acquisition unit; The field potential spike detection module includes a ground power spike detection unit and an ultrasonic detection unit; The background noise confirmation unit is necessary because the operation of substations is complex and the equipment inside substations is diverse, which will cause various kinds of background noise. Therefore, background noise must be initialized and confirmed before commissioning and included in the judgment criteria. Background noise is specifically divided into air background and metal background. The effective test point confirmation unit is because test points have a significant impact on test results. Therefore, the selection of test points should be based on the structure of the device under test, with multiple points installed, and a comprehensive evaluation should be made to confirm the effective test points. Valid test points include front middle, front lower, rear upper, rear middle, rear lower, side upper, side middle, and side lower. Assume the effect of background noise is a constant. The validity of the test points is weighted by their distance and angle relative to the noise source, and the following formula is proposed: ； in: This is valid noise data; n is the number of test points; is the position factor of the i-th test point, and is the acoustic characteristic of the test point; α is the distance from the i-th test point to the noise source, and α is the attenuation coefficient; This is the weight of the i-th test point, assigned a value based on the importance of that test point; It is the background noise factor, representing the combined effect of air background noise and metallic background noise; in ； This reflects the influence of the geometric position and angle of the test point; It is a frequency-dependent sound absorption coefficient, which can take into account the sound absorption characteristics of the material at different frequencies; It is the device noise radiation pattern predicted by machine learning; Weight of each test point This represents the importance of the test point in the entire noise test. The weight is allocated according to the location of the test point, its distance from the noise source, and the noise intensity that the test point can receive. Test points closer to the noise source will receive stronger noise, so their weight is greater. The closer the test point is to the noise source, the greater the weight value should be. The weight of the test point is proportional to the inverse of the distance. Let the distance to test point i be... Then calculate using the following formula. : ； It is the distance between the i-th test point and the noise source; γ is the attenuation coefficient of the weight, consistent with the noise attenuation model, and takes a value of 2 or 3, indicating that the noise attenuates as the distance increases; in: ； For background noise, it represents the overall background noise intensity at frequency f. This value comes directly from actual measurements or some preset background noise standards. ； The frequency response function is used to describe the variation of background noise at different frequencies; It is the characteristic frequency, representing the dominant frequency of the noise source; σ is the width of the frequency response, which determines the sensitivity to noise changes; ； An environmental correction factor, taking into account the effects of temperature T and humidity H, is used to dynamically adjust background noise. and It is the influence coefficient of temperature and humidity on background noise, obtained through experimental data or experience; The key information consistency acquisition unit determines the information of the uploaded data. The data information specifically includes: temperature, humidity, load, and background noise of air and metal. The installation position of the same detection terminal should be consistent in different central cabinets so that stable recorded values ​​can be read during detection. Abnormal values ​​in ground wave detection results include the following: A test value <10dB indicates no fault. If 10dB < test value < 20dB, it indicates that attention is needed and the testing cycle should be shortened. If the test value is greater than 20dB, it indicates that combined acoustic and electrical detection is required to determine the signal source. Abnormal values ​​in ultrasound test results include the following: The test value is greater than 6dB and there is a clear discharge sound, indicating that the obvious sound signal is being monitored through headphones.

2. The real-time online monitoring system for transient grounding grid ground potential spikes according to claim 1, characterized in that: When selecting a transient grounding grid ground potential spike capture terminal, the capture terminal selection and determination module uses a composite TEV sensor. The contact part between the sensor and the switch cabinet body is made of polytetrafluoroethylene material with good dielectric constant. It has a built-in receiving electrode and forms a capacitor with the switch cabinet wall to couple the discharge signal inside the cabinet to the sensor for signal processing, ensuring that the partial discharge signal inside the switch cabinet is detected. Composite TEV sensors detect partial discharge in electrical equipment. TEV stands for Transient Ground Voltage. When partial discharge occurs in electrical equipment, electromagnetic waves are generated. These electromagnetic waves induce a transient ground voltage signal on the metal casing of the equipment. By detecting this signal using composite TEV sensors, the partial discharge status of the electrical equipment can be monitored. The measurement signals include ultrasonic signals and electrical signals. The ultrasonic measurement frequency band ranges from 20kHz to 120kHz, with a center frequency of 40kHz. The TEV measurement frequency band ranges from 10MHz to 100MHz.

3. The real-time online monitoring system for ground potential spikes in transient grounding grids according to claim 2, characterized in that: When the terminal selection and determination module determines that the terminal has detected a partial discharge signal inside the switch cabinet, it needs to obtain the type of partial discharge and make a corresponding selection based on the type of partial discharge. The partial discharge specifically includes corona discharge, surface discharge, internal discharge and floating discharge. The corona discharge is a discharge phenomenon generated between a high-voltage conductor and the surrounding gas. Corona discharge exhibits the characteristics of a non-uniform electric field, which can produce a continuous discharge phenomenon. The surface discharge is a phenomenon that occurs on the surface of an insulating medium; this phenomenon is a gas discharge phenomenon. The internal discharge exists inside the insulating medium. During the production and processing of the insulating medium, design and manufacturing defects in materials and processes are inevitable, resulting in quality defects inside the insulating medium. The floating discharge occurs because one of the conductor components in the high-voltage equipment has a design defect or poor contact at a certain part, causing the component to be located between the high-voltage electrode and the low-voltage electrode and receive a voltage division according to the impedance ratio of its position, resulting in a floating potential on the conductor component relative to ground.

4. The real-time online monitoring system for ground potential spikes in transient grounding grids according to claim 1, characterized in that: In the specific installation process of the capture terminal, the transient grounding grid ground potential spike capture terminal is installed in a self-adhesive manner and connected to the host. The system adopts multiple connection methods, and the terminal sensor and the host can switch between three methods: BNC, SMA interface, and optical fiber for easy use. The number of multiple distribution points is determined according to the background noise of the site and the specific situation of the central cabinet structure.

5. The real-time online monitoring system for ground potential spikes in transient grounding grids according to claim 1, characterized in that: The host parameter configuration module, when configuring the host technical parameters, specifically includes configuring the measurement channel, measurement range, capacitance range of testable items, voltage surge resistance, charging power supply, and built-in rechargeable battery; The measurement channel selection includes 4 / 8 independent measurement channels, each channel supports optical and electrical dual input modes, supports Ethernet networking, sampling accuracy up to 12 bits, sampling rate of 60MHz per channel, and detection sensitivity of 1pC. The measurement range is 1pC to 100nC, the nonlinear error of this range is ≤±5%, the capacitance range of the testable samples is 6pF to 250µF, and the voltage surge resistance is 2500V. The charging power supply is AC220V±10%, frequency is 50Hz, and power is <50W; Built-in rechargeable battery: 4 hours of continuous operation; When the built-in rechargeable battery loses AC power and the battery level drops to 70%, it will automatically send an alarm to the main station.

6. The real-time online monitoring system for ground potential spikes in transient grounding grids according to claim 1, characterized in that: The grounding spike detection unit is a transient grounding grid potential spike detection unit. When the partial discharge part of the switch cabinet is in the insulation layer of the switch cabinet, electromagnetic waves will appear. Some of these electromagnetic waves will be shielded by the metal shell, and the remaining electromagnetic waves will propagate out from the gas-insulated switch or the gap of the switch cabinet. At the same time, a grounding wave will be generated and will travel from the equipment shell to the main grounding grid. At this time, there is an instantaneous ground potential in the grounding grid. The grounding grid potential spike exists for a very short time, only on the nanosecond level. When the switch cabinet is working, the instantaneous ground potential spike is captured using a special capacitive sensing probe.

7. The real-time online monitoring system for ground potential spikes in transient grounding grids according to claim 1, characterized in that: The ultrasonic detection unit actually uses the principle of mechanical vibration to analyze energy discharge from the perspective of energy theory. The phenomenon of partial discharge energy burst and breakdown in the air gap is the whole discharge process. Electrical energy is converted into thermal energy, causing the gas at the discharge center to expand. The expanding gas propagates in the form of sound waves, heating the surrounding gas during propagation to form a temperature zone. When the gas cools and contracts, it eventually produces a frequency band containing a certain frequency component, which is between 10 Hz and 10 MHz.

8. The real-time online monitoring system for ground potential spikes in transient grounding grids according to claim 1, characterized in that: The network alarm module connects the intelligent gateway at the station control layer with the built-in host in the central cabinet, transmits the alarm data to the main station via a 5G network, and stores it in a cloud platform, which includes Alibaba Cloud and Baidu Cloud. Alarm thresholds are set within the main station, and when the monitored values ​​reach the alarm thresholds, push notifications are sent to relevant monitoring terminals, including mobile apps and SMS messages.

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