An on-line monitoring system for discharge of internal insulation of high voltage circuit breaker and method thereof

Abstract

This invention discloses an online monitoring system and method for internal insulation discharge in high-voltage circuit breakers. It utilizes the system overvoltage during frequent opening and closing operations of the high-voltage circuit breaker as a natural excitation source for internal insulation discharge. Simultaneously, under this operating condition, the physical process of the arc affecting the insulating cylinder during circuit breaker operation naturally exists. Based on this "hot" operating condition, the system performs online monitoring of potential internal insulation discharge in the high-voltage circuit breaker. A high-speed data acquisition card and host computer software jointly complete data acquisition, transmission, and further analysis and processing to obtain the characteristic patterns of the internal insulation discharge signals and predict potential insulation faults in the high-voltage circuit breaker. It can stably acquire a large number of characteristic signals, thereby further improving the accuracy and timeliness of fault prediction.

Description

Technical Field

[0001] This invention belongs to the field of online monitoring technology, specifically relating to an online monitoring system and method for internal insulation discharge of high-voltage circuit breakers. Background Technology

[0002] Circuit breakers are critical switching devices in power systems, and high-performance circuit breakers ensure the safe and stable operation of the power system. Compared to low-voltage circuit breakers, circuit breakers in ultra-high voltage / extra-high voltage substations (converter stations) have higher insulation requirements. During the commissioning of the Shaanxi ultra-high voltage converter station, multiple SF6 tank-type circuit breakers experienced surface creepage issues inside the insulation cylinders. AC filter bank (ACF) circuit breakers in DC converter stations, as important equipment for connecting and disconnecting AC filters on the AC side of the converter station in ultra-high voltage DC substations, can reduce harmonics generated during AC-DC conversion and ensure power quality meets standards. Statistics show that the frequency of insulation faults in ACF circuit breakers is significantly higher than that in conventional AC filter banks, posing a significant impact on the safe operation of the power grid. The main differences between ACF circuit breakers and ordinary circuit breakers are as follows:

[0003] ①ACF circuit breakers need to disconnect capacitive loads, and the transient recovery voltage (TRV) has higher technical requirements;

[0004] ②The ACF circuit breaker is frequently switched on and off, resulting in harsh operating conditions;

[0005] ③ The ACF circuit breaker must withstand mixed AC and DC voltages;

[0006] ④ The ACF circuit breaker must adopt a closing phase selection device, and the requirements for the dispersion of the circuit breaker's time characteristics are very strict, with the deviation generally required to be within 1 to 3 ms.

[0007] Statistical analysis of faults in ACF circuit breakers operating in 550–800kV converter stations shows that the main faults are external insulation flashover faults, internal flashover and re-breakdown faults within the arc-extinguishing chamber, and radial breakdown faults within the arc-extinguishing chamber. These faults severely affect the electrical reliability of ACF circuit breakers, with internal flashovers accounting for the highest proportion. Internal flashovers are also the most difficult to monitor online and predict in advance, and there is currently a lack of monitoring for switching overvoltages. Therefore, an effective protection and control scheme for capacitor current-limiting power supply devices is urgently needed to solve these problems.

[0008] Currently, the main online monitoring method is partial discharge testing under power frequency operating voltage, but practice has shown that its detection effectiveness is very low. Regarding online monitoring based on overvoltage excitation conditions, on the one hand, research under laboratory conditions shows that using switching impulse voltage is more effective for detecting insulation defects caused by metal particle accumulation in SF6 circuit breakers, and potential insulation defects can be diagnosed by extracting the characteristics of partial discharge signals. However, experimental studies, due to the artificial setting of the metal particle discharge model, make the metal particles and their specific locations different from actual operating conditions, and the applied excitation form cannot completely simulate actual operating conditions; in fact, the field strength of the micro-discharge is much higher than the industry standard for circuit breaker operating conditions. On the other hand, partial discharge testing is performed simultaneously during lightning impulse or switching overvoltage experiments in the field. While theoretically this method can improve the accuracy of insulation defect diagnosis, the energy of the external detection equipment is far less than the energy of the system power supply, and it cannot simulate the effects of arc and overvoltage during the actual circuit breaker opening and closing operations. Furthermore, for high-voltage circuit breakers in operation in the field, the conditions for frequent shutdowns for testing are not feasible. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide an online monitoring system and method for internal insulation discharge of high-voltage circuit breakers, which addresses the shortcomings of the prior art and solves the technical problem of insulation faults caused by internal insulation discharge in high-voltage circuit breakers.

[0010] The present invention adopts the following technical solution:

[0011] An online monitoring system for internal insulation discharge of a high-voltage circuit breaker, comprising:

[0012] The high-voltage circuit breaker interruption and recovery overvoltage monitoring unit extracts the voltage and current signals of the busbar through the busbar surge arrester to monitor the high-voltage circuit breaker interruption and recovery overvoltage.

[0013] The online monitoring window time signal extraction unit extracts the voltage and current signals of the bus as the window time criterion for starting to monitor the internal insulation discharge signal;

[0014] The circuit breaker enclosure ground wave signal extraction unit measures the high-voltage circuit breaker enclosure ground wave signal in real time and obtains the circuit breaker enclosure ground wave signal after signal conditioning;

[0015] The circuit breaker internal insulation discharge signal unit measures the internal insulation discharge signal of the high-voltage circuit breaker in real time, and obtains the internal insulation discharge signal of the circuit breaker after signal conditioning.

[0016] The data acquisition unit receives the circuit breaker casing grounding signal and the circuit breaker internal insulation discharge signal;

[0017] The online monitoring data processing unit analyzes, processes, displays, and records the grounding signal of the circuit breaker casing and the insulation discharge signal inside the circuit breaker, thereby realizing online monitoring of the internal insulation discharge of the high-voltage circuit breaker.

[0018] Specifically, the high-voltage circuit breaker interruption and recovery overvoltage monitoring unit includes a voltage divider and a coil, which are respectively installed on the bus arrester to extract the bus voltage signal and current signal.

[0019] Specifically, the online monitoring window time signal extraction unit includes a voltage divider valve plate, which is connected in series with the bus arrester to form an arrester voltage divider. The voltage and current signals of the arrester voltage divider are monitored using a high-voltage probe and a Rogowski coil, thereby realizing the recording of voltage and current signals when the circuit breaker is in different operating states.

[0020] Specifically, the circuit breaker housing ground wave signal extraction unit includes a high-frequency current sensor. The high-frequency current sensor is located at the connection between the circuit breaker housing cavity and the base and is connected to the data acquisition unit through the signal conditioning unit. It is used to acquire the high-frequency current signal that propagates to the outer layer when creepage occurs on the inner surface of the circuit breaker insulation cylinder.

[0021] Furthermore, the signal conditioning unit is used to amplify, isolate, and filter high-frequency current signals.

[0022] Furthermore, the high-frequency current sensor comprises multiple components.

[0023] Specifically, the internal insulation discharge signal unit of the circuit breaker includes an ultra-high frequency antenna sensor, which is installed at the maintenance manhole, oil drain valve, medium window or bushing.

[0024] Specifically, the data acquisition unit includes a high-speed acquisition card, which is connected to the online monitoring data processing unit via an FPGA integrated circuit board.

[0025] Specifically, the online monitoring data processing unit operates based on a cloud-edge collaborative architecture.

[0026] Another technical solution of the present invention is an online monitoring method for internal insulation discharge of a high-voltage circuit breaker. The method involves extracting bus voltage and current signals from a bus arrester to monitor the overvoltage during the interruption and recovery of the high-voltage circuit breaker; using the recovery overvoltage to induce internal insulation discharge; effectively extracting the internal insulation discharge signal in time according to a window criterion; and when the circuit breaker operates, using the high-frequency discharge signal captured after the arc crosses zero as the internal insulation discharge induced by the system's own overvoltage excitation.

[0027] Compared with the prior art, the present invention has at least the following beneficial effects:

[0028] An online monitoring system for internal insulation discharge of a high-voltage circuit breaker is disclosed. This system monitors the overvoltage during circuit breaker interruption and recovery using bus voltage and current. Simultaneously, the system's own excitation source, the recovery overvoltage, effectively triggers internal insulation discharge. Based on window criteria, the system effectively extracts the internal insulation discharge signal in time, thus avoiding interference from the arc during circuit breaker operation. Utilizing the lower frequency of the current signal on the circuit breaker's outer casing ground wire compared to the internal insulation discharge signal, the system filters out the influence of ground wave signals on the discharge waveform. When the circuit breaker operates, the high-frequency discharge signal captured after the arc crosses zero is the internal insulation discharge triggered by the system's own overvoltage excitation. Because the circuit breaker operates frequently during normal operation, the entire online monitoring system for internal insulation discharge can stably acquire a large number of characteristic signals, thereby further improving the accuracy and timeliness of fault prediction.

[0029] Furthermore, the voltage divider for extracting the bus voltage signal utilizes the bus surge arrester as the high-voltage arm, greatly enhancing the flexibility of the voltage divider assembly and facilitating the widespread application of this online monitoring system in actual working conditions; the coil (openable and closable) for extracting the bus current signal is connected in series with the low-voltage end of the bus surge arrester nearby, which helps to reduce the impact of coupled high-frequency signals on the extraction of the current signal.

[0030] Furthermore, the applicability of high-voltage probes to measure AC, DC, and pulse voltage signals is tested, and the voltage signal on the voltage divider valve plate is tested to monitor the voltage signal of the surge arrester voltage divider; the wide bandwidth characteristics of the Rogowski coil are used to monitor the current signal of the surge arrester voltage divider; at the same time, high-voltage probes and Rogowski coils can be customized according to existing operating conditions to further improve monitoring accuracy.

[0031] Furthermore, based on the propagation characteristics of high-frequency current signals, the sensor needs to be installed nearby. Using an openable high-frequency current sensor at the connection between the circuit breaker housing and the base satisfies both the selection of the signal monitoring location and the flexibility of sensor installation.

[0032] Furthermore, since the current operating conditions are in a complex electromagnetic environment, the high-frequency current signal must be amplified, isolated, and filtered by the conditioning unit before being connected to the data acquisition unit for data transmission, thereby improving the sensor's resistance to electromagnetic interference.

[0033] Furthermore, a circuit breaker typically has four connection points between the circuit breaker housing and the base, where at least four high-frequency current signal sensors can be installed to compare and analyze the signals extracted, thereby further improving the accuracy of the monitoring system.

[0034] Furthermore, based on the propagation characteristics of UHF signals and the available installation locations of existing operational equipment, UHF antenna sensors can be installed in multiple locations such as maintenance manholes, drain valves, medium windows, or sleeves. This can also increase the sample size of test signals for the data processing unit to perform machine learning.

[0035] Furthermore, the cloud-edge collaborative architecture requires the edge device to have a certain data processing capability. The high-speed acquisition card needs to be connected to the edge FPGA integrated circuit board and have local computing capabilities through the edge program algorithm, thereby improving the effectiveness of the signal uploaded to the data processing unit.

[0036] Furthermore, the cloud-edge collaborative architecture can provide deeper data mining, more efficient data training, and more comprehensive data sharing through the cloud platform—the main server of the substation; then push the upgraded algorithm model after machine learning to the edge to complete the closed loop of autonomous learning, while also having functions such as visualization.

[0037] A method for online monitoring of internal insulation discharge in high-voltage circuit breakers utilizes the system overvoltage during frequent opening and closing operations of the high-voltage circuit breaker as a natural excitation source for internal insulation discharge. Simultaneously, under this operating condition, the physical process of the arc affecting the insulating cylinder during circuit breaker operation naturally exists. Based on this "hot" operating condition, the method performs online monitoring of potential internal insulation discharge in the high-voltage circuit breaker. A high-speed data acquisition card and host computer software jointly complete data acquisition, transmission, and further analysis and processing to obtain the characteristic patterns of the internal insulation discharge signal and predict potential insulation faults in the high-voltage circuit breaker.

[0038] In summary, this invention utilizes the frequent opening and closing operations of high-voltage circuit breakers during operation to conduct online monitoring of internal insulation discharge in high-voltage circuit breakers under the combined action of system overvoltage and discharge arc in a "hot state." Based on measured data, it extracts the characteristic patterns of internal insulation discharge and continuously trains the system through machine learning to improve the efficiency of insulation fault prediction.

[0039] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0040] Figure 1 This is a block diagram illustrating an implementation scheme for the online monitoring method for internal insulation discharge of the present invention.

[0041] Figure 2 This is a hardware platform architecture diagram of the implementation scheme of the online monitoring method for internal insulation discharge of the present invention;

[0042] Figure 3 This is a ground wave detection diagram;

[0043] Figure 4A diagram showing the selection of monitoring window intervals based on the duration of creepage influencing factors on circuit breakers under "hot" conditions;

[0044] Figure 5 This is a schematic diagram of the ZYNQ architecture. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "one side," "one end," and "one side," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0047] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0048] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0049] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0050] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0051] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0052] This invention provides an online monitoring system and method for internal insulation discharge of high-voltage circuit breakers. It monitors the overvoltage of high-voltage circuit breaker interruption recovery by extracting voltage and current signals from the bus arrester. Simultaneously, it uses the recovery overvoltage as an excitation source and the monitoring window time unit as a criterion to monitor the internal insulation discharge signal and the circuit breaker ground wave online. The data acquisition, transmission and analysis are completed by a high-speed data acquisition card and host computer software.

[0053] Please see Figure 1 The present invention discloses an online monitoring system for internal insulation discharge of a high-voltage circuit breaker, comprising:

[0054] High-voltage circuit breaker interruption and recovery overvoltage monitoring unit: It extracts the voltage and current signals of the busbar through the bus arrester to monitor the overvoltage during the high-voltage circuit breaker interruption and recovery.

[0055] Specifically, by adding valve plates or monitors to the bus arrester to form a voltage divider to extract the bus voltage signal and adding coils to extract the current signal, the overvoltage during the interruption and recovery of the high-voltage circuit breaker is monitored.

[0056] Online monitoring window time signal extraction unit: Extracts the voltage and current signals of the bus as the window time criterion for starting to monitor the internal insulation discharge signal.

[0057] Specifically, by acquiring bus voltage and current signals and analyzing their changes during the opening and closing operations of the high-voltage circuit breaker, this is used as a window time criterion for starting to monitor internal insulation discharge signals.

[0058] Circuit breaker enclosure ground wave signal extraction unit: Equipped with a high-frequency current sensor to measure the high-voltage circuit breaker enclosure ground wave signal in real time, and then the signal conditioning unit performs preliminary processing before sending it to the data acquisition unit.

[0059] By equipping the circuit breaker housing with multiple high-frequency current sensors, the ground wave signal of the circuit breaker can be measured in real time.

[0060] Circuit breaker internal insulation discharge signal unit: Equipped with an ultra-high frequency antenna sensor to measure the internal insulation discharge signal of the high-voltage circuit breaker in real time, and then the signal is preliminarily processed by the signal conditioning unit and sent to the data acquisition unit.

[0061] An ultra-high frequency antenna sensor is installed outside the circuit breaker cavity to measure the internal insulation discharge signal in real time.

[0062] Data acquisition unit: Equipped with an 8-channel high-speed acquisition card, it acquires and preprocesses the above signals and transmits them to the online monitoring data processing unit via Ethernet communication.

[0063] Online monitoring data processing unit: Analyzes, processes, displays and records the signals transmitted by the data acquisition unit, thereby realizing the online monitoring function of internal insulation discharge of high-voltage circuit breaker, predicting potential fault hazards and outputting relevant reports.

[0064] This invention discloses an online monitoring method for internal insulation discharge in high-voltage circuit breakers. It monitors the overvoltage during circuit breaker interruption recovery by extracting bus voltage and current signals from bus arresters. The method effectively induces internal insulation discharge using the system's own excitation source—the recovery overvoltage. It extracts the internal insulation discharge signal in time according to window criteria, thus avoiding interference from the arc during circuit breaker operation. When the circuit breaker operates, the high-frequency discharge signal captured after the arc crosses zero is the internal insulation discharge induced by the system's own overvoltage excitation. Since circuit breakers operate frequently during normal operation, the entire online monitoring system for internal insulation discharge can stably acquire a large number of characteristic signals, thereby further improving the accuracy and timeliness of fault prediction.

[0065] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0066] 1. Ground wave signal monitoring

[0067] Please see Figure 3 The ground wave signal contains two main frequency components: high frequency (several hundred MHz) and low frequency (several to tens of MHz); the high frequency is the high frequency current generated by the electromagnetic waves emitted by the partial discharge power source exciting the metal outer surface of the device; the low frequency is caused by the current flowing through the ground wire when partial discharge occurs.

[0068] When partial discharge occurs inside electrical equipment, depending on the size of the metal enclosure, it emits electromagnetic waves with a wide frequency range. These electromagnetic waves leak from dielectric discontinuities (joints, bushings, etc.) within the metal enclosure and are transmitted to the outer surface of the enclosure wall. Then, a surface current induced according to Maxwell's electromagnetic field principle propagates on the outer surface of the metal enclosure wall. This signal can be detected by a ground wave sensor (red line in the figure). Simultaneously, the discharge current generated by the partial discharge flows to the ground through an external circuit and propagates to the metal enclosure wall through the ground wire. This partial discharge current has a low-frequency component (blue line in the figure).

[0069] In summary, ground waves can be obtained by installing Rogowski coils near the metal box and grounding point of power equipment, and low-frequency components in the current can be extracted using a high-speed acquisition card for discharge analysis.

[0070] Because the selected frequency band is low-frequency, it is susceptible to electromagnetic interference sources, thus requiring further research and analysis. According to the survey results, the amplitudes of broadcast signals and shortwave signals that may appear in this frequency band are all on the order of μV, while the transient overvoltages generated by the circuit breaker's opening operation can reach the order of kV. Therefore, the interference from electromagnetic interference sources can be ignored. For internal insulation discharge, a high-frequency Rogowski coil can be installed at the connection between the cavity and the base to obtain the high-frequency current signal propagating to the outer layer during creepage on the inner surface of the circuit breaker's insulation cylinder.

[0071] 2. Internal insulation discharge signal monitoring

[0072] Ultra-high frequency (UHF) antenna sensors are crucial for internal insulation discharge detection systems. They directly determine the system's sensitivity. Antennas are generally made of metal wires, metal surfaces, or other dielectric materials, and have a specific shape. They are devices used to transmit or receive radio waves. During transmission, they convert high-frequency current into electromagnetic waves; during reception, they convert electromagnetic waves into high-frequency current. The antenna used for UHF internal insulation discharge detection is a receiving antenna.

[0073] UHF antennas can be divided into two types based on their installation location: internal antennas and external antennas. Typical internal antennas include sleeve monopole antennas, Hilbert fractal antennas, and Goubau antennas, usually installed at maintenance manholes and drain valves. Internal antennas offer advantages such as high detection sensitivity and low electromagnetic interference, but modifications are generally not permitted for transformers already in operation. Commonly used external antennas include Archimedes spiral antennas, planar equiangular spiral antennas, and dielectric window sensors, which can be installed at locations such as dielectric windows and bushings.

[0074] 3. Window time signal extraction

[0075] A voltage divider valve is connected in series with the busbar surge arrester to form a surge arrester voltage divider. Voltage and current signals are monitored using a high-voltage probe and a Rogowski coil to record voltage and current signals under different operating states of the circuit breaker. Based on the characteristics of the voltage and current signals during the circuit breaker's opening and closing processes, the extracted voltage and current signals are used as the window time criterion for initiating monitoring of internal insulation discharge signals. Simultaneously, the voltage signal can be used for online monitoring of operational overvoltage and recovery overvoltage.

[0076] Please see Figure 4 Since the creepage phenomenon of the circuit breaker insulation cylinder most likely occurs during the circuit breaker's opening and closing process, when the power frequency current crosses zero and the circuit breaker is subjected to transient recovery overvoltage, such as... Figure 4 The signal duration is short within the monitoring window, which is very different from the monitoring time window of traditional monitoring methods. Therefore, the detection technology and online monitoring system for creepage phenomena need to meet the requirements of high-speed acquisition, identification and processing of complex signals within a very short time after the opening and closing action, and also need to ensure that the detection equipment is not affected by electromagnetic interference from recovery overvoltage.

[0077] 4. Signal conditioning unit

[0078] A signal conditioning unit is a circuit board that converts analog signals into digital signals for data acquisition, control processes, calculations, or other purposes. Signal conditioning devices primarily have the following functions:

[0079] Signal amplification

[0080] To improve the accuracy of analog-to-digital signal conversion, the maximum value of the input analog signal needs to be exactly equal to the input range of the A / D converter. Most sensors have an input range in the mV range, while A / D converters have an input range in the V range; therefore, signal conditioning devices are needed to amplify the sensor signal.

[0081] isolation

[0082] When measuring high-voltage signals, isolation circuits can protect downstream equipment from damage caused by accidental high-voltage inputs. Common types include optical isolation and magnetic isolation.

[0083] Signal filtering

[0084] Analog signals must be low-pass filtered before digitization to eliminate noise and prevent aliasing.

[0085] 5. AD9226 high-speed data acquisition card

[0086] One of the most critical components in a data acquisition system is the ADC (Analog-to-Digital Converter), which converts the sensor output into a digital data stream that a computing device can process. Due to the pulse characteristics of internal insulating discharge, its UHF component can have a transient time of less than 1 ns. To accurately capture the pulse, several parameters of the ADC need to be considered, such as analog input bandwidth, resolution, sampling rate, and number of channels.

[0087] Analog-to-digital converters (ADCs) designed and manufactured by Analog Devices (ADI) are widely used, and the AD9226 is one such example. Its circuit schematic is shown above. The AD9226 is a monolithic, single-supply, 12-bit ADC with a sampling rate of up to 65Msps. It integrates a high-performance reference voltage source and a sample-and-hold amplifier. Furthermore, the AD9226 features a low power consumption of 475mW and a high signal-to-noise ratio of 69dB.

[0088] 6. FPGA integrated circuit board

[0089] Another key component of the acquisition system is the front-end processing unit that interfaces with the ADC. FPGAs have abundant dedicated DSP and block RAM resources, which can be used to implement parallel and pipelined algorithms. FPGAs can perfectly interface with the ADC to perform the first-level real-time processing (such as digital filtering, nonlinear noise suppression, digital baseline stabilization, etc.), and then select useful data to transmit to the next-level computing device for the second-level data processing based on a complex triggering mechanism.

[0090] Please see Figure 5The ZYNQ series is Xilinx's first scalable processing platform, designed to provide the processing and computing performance required for high-end embedded applications such as video surveillance, automotive driver assistance, and factory automation. The ZYNQ architecture, shown in the diagram, is an FPGA with an embedded processor core, i.e., a SoC FPGA, offering advantages such as high hardware integration, small size, higher communication speed between ARM and FPGA, and flexible configuration of peripheral interfaces.

[0091] 7. Cloud-edge collaborative architecture

[0092] Originating in the media industry, edge computing refers to an open platform that integrates network, computing, storage, and application capabilities closer to the data source, providing services at the nearest edge. Applications are initiated at the edge, resulting in faster network service responses and meeting the industry's fundamental needs in real-time business, artificial intelligence, security, and privacy protection. Edge computing is transforming how millions of devices worldwide process, handle, and transmit data. The explosive growth of connected devices (IoT) and new applications requiring real-time computing capabilities continue to drive the development of edge computing systems.

[0093] Online monitoring of internal insulation discharge in circuit breakers is characterized by large data volume, high data transmission bandwidth, increased storage costs, and high real-time computing requirements. Therefore, it is necessary to adopt edge computing, that is, to perform real-time processing at the data source, quickly identify internal insulation discharge anomalies, and respond promptly to prevent further insulation degradation.

[0094] In the cloud-edge collaborative architecture, the cloud platform refers to the substation's central server, which can provide deeper data mining, more efficient data training, and more comprehensive data sharing. It can push upgraded algorithm models to the edge to complete the closed loop of autonomous learning, while also having visualization and display functions.

[0095] Example

[0096] Please see Figure 1 The online monitoring system of this invention was installed on the high-voltage circuit breaker of the AC filter field of a 750kV DC converter station.

[0097] By installing voltage divider valves and current coils on the 750kV surge arrester on the bus, the bus voltage and bus current signals are obtained.

[0098] High-frequency current sensors are installed at the four support posts of the high-voltage circuit breaker to measure the grounding waves of the circuit breaker casing in real time.

[0099] A high-frequency antenna sensor is placed outside the high-voltage circuit breaker cavity to measure the climbing discharge signal of the circuit breaker in real time.

[0100] The aforementioned signals are sent to the high-speed data acquisition card via the signal conditioning unit;

[0101] The host computer-based online monitoring data processing software extracts patterns from the online monitoring data, uses machine learning, and trains to improve the efficiency of insulation fault prediction.

[0102] The embodiment enables online monitoring of internal insulation discharge in high-voltage circuit breakers. It utilizes the overvoltage during the opening and closing operations of the high-voltage circuit breaker as a self-excitation source to effectively induce internal insulation discharge. Based on window criteria, the internal insulation discharge signal is effectively extracted in time, thus avoiding interference from the arc caused by the circuit breaker's operation. Because the circuit breaker operates frequently during normal operation, the entire online monitoring system for internal insulation discharge can stably acquire a large number of characteristic signals, thereby further improving the accuracy and timeliness of fault prediction.

[0103] The above embodiments can be installed at the working site of high-voltage circuit breakers in substations and converter stations of various voltage levels, and can be used for online monitoring of internal insulation discharge of various high-voltage circuit breakers for insulation faults. The operation is efficient, reliable and stable.

[0104] In summary, the present invention provides an online monitoring system and method for internal insulation discharge of high-voltage circuit breakers. Under the actual operating condition of "hot state" when an overvoltage occurs during the opening operation of a high-voltage circuit breaker, the system monitors the internal insulation discharge online and tracks the accumulation of the number of high-voltage circuit breaker operations to detect internal insulation discharge phenomena early. This provides a scientific basis for power outage maintenance and has the value of being promoted and applied in actual operating conditions in substations, converter stations, and other similar locations.

[0105] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. An online monitoring system for internal insulation discharge of a high-voltage circuit breaker, characterized in that, include: The high-voltage circuit breaker interruption and recovery overvoltage monitoring unit extracts the voltage and current signals of the busbar through the busbar surge arrester to monitor the high-voltage circuit breaker interruption and recovery overvoltage. The online monitoring window time signal extraction unit extracts the voltage and current signals of the bus as the window time criterion for starting to monitor the internal insulation discharge signal; The circuit breaker enclosure ground wave signal extraction unit measures the high-voltage circuit breaker enclosure ground wave signal in real time and obtains the circuit breaker enclosure ground wave signal after signal conditioning; The circuit breaker internal insulation discharge signal unit measures the internal insulation discharge signal of the high-voltage circuit breaker in real time, and obtains the internal insulation discharge signal of the circuit breaker after signal conditioning. The data acquisition unit receives the circuit breaker casing grounding signal and the circuit breaker internal insulation discharge signal; The online monitoring data processing unit analyzes, processes, displays, and records the ground wave signal of the circuit breaker casing and the insulation discharge signal inside the circuit breaker, thereby realizing online monitoring of the insulation discharge inside the high-voltage circuit breaker. The bus voltage and current signals are extracted by the bus arrester to monitor the overvoltage recovery of the high-voltage circuit breaker; the recovery overvoltage is used to induce internal insulation discharge; the internal insulation discharge signal is effectively extracted in time according to the window criterion; when the circuit breaker operates, the high-frequency discharge signal captured after the arc crosses zero is used as the internal insulation discharge caused by the system's own overvoltage excitation.

2. The online monitoring system and method for internal insulation discharge of high-voltage circuit breakers according to claim 1, characterized in that, The high-voltage circuit breaker interruption and recovery overvoltage monitoring unit includes a voltage divider and a coil, which are respectively installed on the bus arrester to extract the bus voltage signal and current signal.

3. The online monitoring system and method for internal insulation discharge of high-voltage circuit breakers according to claim 1, characterized in that, The online monitoring window time signal extraction unit includes a voltage divider valve plate, which is connected in series with the bus arrester to form an arrester voltage divider. The voltage and current signals of the arrester voltage divider are monitored using a high-voltage probe and a Rogowski coil, so as to record the voltage and current signals of the circuit breaker under different operating conditions.

4. The online monitoring system for internal insulation discharge of a high-voltage circuit breaker according to claim 1, characterized in that, The circuit breaker housing ground wave signal extraction unit includes a high-frequency current sensor. The high-frequency current sensor is located at the connection between the circuit breaker housing cavity and the base and is connected to the data acquisition unit through the signal conditioning unit. It is used to acquire the high-frequency current signal that propagates to the outer layer when creepage occurs on the inner surface of the circuit breaker insulation cylinder.

5. The online monitoring system and method for internal insulation discharge of high-voltage circuit breakers according to claim 4, characterized in that, The signal conditioning unit is used to amplify, isolate, and filter high-frequency current signals.

6. The online monitoring system and method for internal insulation discharge of a high-voltage circuit breaker according to claim 4, characterized in that, The high-frequency current sensor comprises multiple components.

7. The online monitoring system and method for internal insulation discharge of high-voltage circuit breakers according to claim 1, characterized in that, The internal insulation discharge signal unit of the circuit breaker includes an ultra-high frequency antenna sensor, which is installed at the maintenance manhole, drain valve, medium window or bushing.

8. The online monitoring system and method for internal insulation discharge of high-voltage circuit breakers according to claim 1, characterized in that, The data acquisition unit includes a high-speed acquisition card, which is connected to the online monitoring data processing unit via an FPGA integrated circuit board.

9. The online monitoring system and method for internal insulation discharge of a high-voltage circuit breaker according to claim 1, characterized in that, The online monitoring data processing unit operates based on a cloud-edge collaborative architecture.

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