Online monitoring device and monitoring method for vacuum degree of vacuum circuit breaker

Abstract

The invention relates to the technical field of vacuum monitoring, and discloses a vacuum circuit breaker vacuum degree on-line monitoring device and method, and the method comprises the steps: obtaining an attenuation value measured by a vacuum arc extinguish chamber sample at a preset vacuum degree grade, and building a corresponding relation between the attenuation value and the vacuum degree; interpolation processing is carried out on the attenuation values obtained through measurement, and a calibration database of the corresponding relation between the vacuum degree and the attenuation values is constructed; periodically emitting terahertz waves to the vacuum arc-extinguishing chamber to be tested, and calculating an average attenuation value in each period; according to the average attenuation value, the real-time vacuum degree is obtained through calibration database query; and judging the real-time vacuum degree and a preset vacuum degree threshold value, and triggering an early warning strategy according to a judgment result. Real-time feedback of the vacuum degree is achieved, and equipment faults caused by abnormal vacuum degree are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of vacuum monitoring, and particularly relates to an on-line monitoring device and method for the vacuum degree of a vacuum circuit breaker. Background Art

[0002] The vacuum circuit breaker uses vacuum as the arc extinguishing medium. Accurately measuring its vacuum degree is of great significance for evaluating the operating state of the vacuum circuit breaker. When the vacuum circuit breaker operates for a long time, it is continuously eroded by the natural environment, and at the same time, it is also continuously impacted by the operating mechanism, as well as continuously eroded by the arc during the long-term repeated opening process, resulting in a certain degree of decline in the vacuum degree of the vacuum interrupter. If the vacuum degree in the vacuum interrupter drops significantly, its arc extinguishing ability will also be greatly affected, thereby causing opening failure.

[0003] Traditional vacuum degree measurement methods rely on applying a high voltage across the two ends of the vacuum interrupter, making real-time on-line monitoring difficult. Existing research has also proposed a new method of applying terahertz waves to vacuum degree monitoring. For example, patent CN202311821333.6 proposes a terahertz wave calibration method and a corresponding device, but this disclosed patent cannot directly carry out real-time measurement on an actual vacuum interrupter. Summary of the Invention

[0004] Aiming at the problem in the prior art that it is impossible to directly measure an actual vacuum interrupter, the present invention provides an on-line monitoring device and method for the vacuum degree of a vacuum circuit breaker, which can realize real-time measurement of the vacuum degree. The specific technical solutions are as follows:

[0005] An on-line monitoring method for the vacuum degree of a vacuum circuit breaker includes:

[0006] Obtaining the attenuation value measured from a vacuum interrupter sample at a preset vacuum degree level, and establishing a corresponding relationship between the attenuation value and the vacuum degree;

[0007] Performing interpolation processing on the measured attenuation value to construct a calibration database for the corresponding relationship between the vacuum degree and the attenuation value;

[0008] Periodically emitting terahertz waves to the vacuum interrupter to be measured, and calculating the average attenuation value within each period;

[0009] Querying the real-time vacuum degree through the calibration database according to the average attenuation value;

[0010] Judging the magnitude relationship between the real-time vacuum degree and a preset vacuum degree threshold, and triggering an early warning strategy according to the judgment result.

[0011] Preferably, the obtaining the attenuation value measured from a vacuum interrupter sample at a preset vacuum degree level, and establishing a corresponding relationship between the attenuation value and the vacuum degree includes:

[0012] Set the vacuum degrees of multiple vacuum interrupter samples to different vacuum gradients respectively;

[0013] Fix the vacuum duct at a preset distance position of the vacuum interrupter sample;

[0014] After a terahertz wave generator emits terahertz waves through the vacuum duct, and forms reflections inside the vacuum interrupter sample and then passes through the vacuum duct again to return to the terahertz wave receiver, record the attenuation values after reflection by each vacuum interrupter sample;

[0015] Establish the corresponding relationship between the vacuum degree and the attenuation value according to the attenuation values after reflection of the vacuum interrupter samples under different vacuum gradients.

[0016] Preferably, the calibration database for constructing the corresponding relationship between the vacuum degree and the attenuation value by interpolating the measured attenuation values includes:

[0017] Perform equidistant interpolation for a preset number of times on two adjacent measured attenuation values to generate a complete data set containing interpolated attenuation values

[0018] Use numerical analysis software to establish a calibration database for the corresponding relationship between the interpolated attenuation value and the vacuum degree.

[0019] Preferably, the method for periodically emitting terahertz waves to the vacuum interrupter to be measured and calculating the average attenuation value in each period includes:

[0020] Emit terahertz waves to the vacuum interrupter to be measured a preset number of times within a preset period, and calculate the average attenuation value at the preset number of times within the preset period.

[0021] Preferably, the method for judging the magnitude of the real-time vacuum degree and the preset vacuum degree threshold and triggering an early warning strategy according to the judgment result includes:

[0022] If the real-time vacuum degree is lower than the first threshold, it is determined that the vacuum degree is normal;

[0023] If the real-time vacuum degree is higher than the second threshold, directly trigger an early warning;

[0024] If the real-time vacuum degree is between the first and second thresholds, further judge whether it exceeds the preset critical value, and if it exceeds, trigger an early warning.

[0025] Preferably, an on-line monitoring method for the vacuum degree of a vacuum circuit breaker further includes:

[0026] Establish a vacuum degree attenuation trend curve based on time series according to the real-time vacuum degree obtained in each period;

[0027] Evaluate the deterioration rate of the vacuum degree according to the vacuum degree attenuation trend curve.

[0028] An on-line monitoring device for the vacuum degree of a vacuum circuit breaker, which is applied to the on-line monitoring method for the vacuum degree of the aforementioned vacuum circuit breaker, includes:

[0029] A vacuum interrupter, inside which a metal shielding cover is provided;

[0030] A vacuum duct, which is composed of a side wall and sealing materials at both ends. The side wall is made of a metal material, and the sealing materials at both ends are terahertz wave highly permeable materials;

[0031] A flange, which is installed on the vacuum duct. A vacuum gauge is provided on the flange, and the flange is connected to a vacuum pump through an air extraction duct;

[0032] A terahertz wave generator and a terahertz wave receiver, both of which are arranged at one end of the vacuum duct and are used for emitting and receiving the terahertz wave reflected by the vacuum interrupter;

[0033] A control terminal, which is respectively connected to the terahertz wave generator, the terahertz wave receiver and the vacuum gauge of the flange, and is used for controlling the terahertz wave emission, receiving attenuation signals, and performing data acquisition and data analysis and processing.

[0034] Preferably, the sealing materials at both ends of the vacuum duct are poly-4-methylpentene-1, low-density polyethylene or polytetrafluoroethylene.

[0035] Preferably, the flange includes:

[0036] A valve, which is used to control the on-off of the vacuum duct and the air extraction duct;

[0037] A conductive column, which is used to connect the vacuum gauge to monitor the vacuum degree inside the vacuum duct.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] An on-line monitoring method for the vacuum degree of a vacuum circuit breaker according to the present invention is based on a calibration database. By using the average attenuation value, it can be quickly converted into the real-time vacuum degree. At the same time, combined with a preset vacuum degree threshold, it can immediately judge whether the current vacuum degree is within the safe range and trigger corresponding warning strategies. It realizes the real-time feedback of the vacuum degree and avoids equipment failures caused by abnormal vacuum degrees. By periodically emitting terahertz waves and calculating the average attenuation value within each period, the current state information of the vacuum interrupter can be continuously obtained. The periodic monitoring method ensures the timely capture of the change of the vacuum degree and avoids missing key changes due to too long monitoring intervals. Description of the Drawings

[0040] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0041] Figure 1 This is a flowchart of a method for an on-line monitoring device of the vacuum degree of a vacuum circuit breaker according to the present invention.

[0042] Figure 2 This is a schematic composition diagram of an on-line monitoring device for the vacuum degree of a vacuum circuit breaker according to the present invention. Specific embodiments

[0043] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0044] It should be understood that when used in this specification and the appended claims, the terms "comprises" and "comprising" indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0045] It should also be understood that the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms.

[0046] It should be further understood that the term " / and / " used in the specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the related listed items, and includes these combinations.

[0047] The following embodiments refer to Figure 1 and Figure 2 .

[0048] The embodiments of the present application provide an on-line monitoring device for the vacuum degree of a vacuum circuit breaker, which is characterized by comprising:

[0049] A vacuum interrupter 1, which is internally provided with a metal shielding cover;

[0050] The vacuum duct 2 is composed of a side wall and sealing materials at both ends. The side wall is made of a metal material, and the sealing materials at both ends are terahertz wave highly permeable materials;

[0051] The flange 201 is installed on the vacuum duct 2. A vacuum gauge is provided on the flange 201, and the flange 201 is connected to a vacuum pump 203 through an air extraction duct 202;

[0052] The terahertz wave generator 301 and the terahertz wave receiver 302 are both arranged at one side end of the vacuum duct 2 and are used for emitting and receiving the terahertz waves reflected by the vacuum interrupter 1;

[0053] The control terminal 4 is respectively connected to the terahertz wave generator 301, the terahertz wave receiver 302 and the vacuum gauge of the flange 201, and is used for controlling the terahertz wave emission, receiving attenuation signals, and performing data acquisition and data analysis and processing.

[0054] In this embodiment, a metal shielding cover is arranged inside the vacuum interrupter 1, which can effectively shield external electromagnetic interference, ensure the stable propagation of terahertz waves and the accuracy of reflected signals. The side wall of the vacuum duct 2 is made of a metal material, which has good mechanical strength and electromagnetic shielding performance and can protect the internal terahertz wave signals from external interference.

[0055] Specifically, the sealing materials at both ends of the vacuum duct 2 are poly-4-methylpentene-1, low-density polyethylene or polytetrafluoroethylene. The two ends of the vacuum duct 2 adopt highly permeable materials such as poly-4-methylpentene-1, low-density polyethylene or polytetrafluoroethylene. These materials have a high transmittance to terahertz waves, can reduce signal attenuation, and improve the monitoring accuracy.

[0056] Specifically, the flange 201 includes:

[0057] A valve for controlling the on-off of the vacuum duct 2 and the air extraction duct 202;

[0058] A conductive column for connecting the vacuum gauge to monitor the vacuum degree inside the vacuum duct 2.

[0059] In this embodiment, a valve is provided on the flange 201, which can be opened and closed. There is a conductive column on the flange 201, and the vacuum gauge can be connected to the conductive column to monitor the vacuum degree inside the vacuum duct in real time. The usage method of the flange 201 is as follows: Connect the flange 201, the air extraction duct 202 and the vacuum pump 203, then turn on the vacuum pump 203 to extract air until the air pressure drops to the set value. After the air extraction is completed, close the valve of the flange 201 to keep the vacuum duct 2 in a high vacuum state. Subsequently, remove the air extraction duct 202 and the vacuum pump 203 and wait for further measurement work to be carried out.

[0060] The valve provided on the flange 201 can control the on-off of the vacuum conduit 2 and the air extraction conduit 202. Cooperating with the vacuum pump 203, it can flexibly reduce the air pressure in the vacuum conduit 2 to the set value and close the valve after air extraction is completed to maintain a high vacuum state. This enables the device to adjust the vacuum environment according to actual measurement requirements and maintain stable vacuum conditions before measurement, providing a stable environment for the propagation and reflection of terahertz waves and improving the accuracy of measurement.

[0061] In this embodiment, the control terminal of the on-line monitoring device for the vacuum degree of the vacuum circuit breaker can adopt a terminal computer or other devices with data processing, analysis and acquisition functions. The working principle of the on-line monitoring device for the vacuum degree of the vacuum circuit breaker is as follows:

[0062] The control terminal 4 sends an action signal command to the terahertz wave generator 301. The terahertz wave generator 301 emits terahertz waves, which then pass through the terahertz wave highly permeable materials at both ends of the vacuum conduit 2, then pass through the ceramic shell of the vacuum interrupter 1 and enter the interior of the vacuum interrupter 1. Subsequently, they are reflected by the metal shielding cover inside the vacuum interrupter 1, pass through the ceramic shell of the vacuum interrupter 1 again, return to the vacuum conduit 2, pass through the terahertz wave highly permeable materials at both ends thereof, and then return to the terahertz wave receiver 302. The control terminal 4 performs data acquisition, recording, and data analysis and processing. The control terminal 4 has a data analysis and processing function, and can compare the collected attenuation value with the preset calibration database, quickly obtain the vacuum degree of the vacuum interrupter, and judge whether it is necessary to trigger an alarm.

[0063] The working process of the on-line monitoring device for the vacuum degree of the vacuum circuit breaker of the present application is automatically controlled by the control terminal. From sending the action signal command to data acquisition, analysis and processing, and alarm judgment, no excessive manual intervention is required. This improves the monitoring efficiency, reduces the errors and workload of manual operations, enables the operation and maintenance personnel to manage and maintain the vacuum circuit breaker more efficiently, promptly discover and handle potential problems, and reduces the operation and maintenance costs.

[0064] In addition, the on-line monitoring device for the vacuum degree of the vacuum circuit breaker of the present application applies terahertz waves to vacuum degree monitoring and sets up a unique signal transmission mechanism for the terahertz wave reflection path (vacuum conduit → interrupter → reflection by the metal shielding cover → vacuum conduit); combined with the design of a special vacuum conduit, it provides a non-invasive and highly sensitive on-line monitoring device for vacuum degree.

[0065] The embodiment of the present application also provides a method for on-line monitoring the vacuum degree of a vacuum circuit breaker. This monitoring method can be utilized according to the working principle of the monitoring device and includes:

[0066] Step S1, obtain the attenuation value measured from the vacuum interrupter sample at the preset vacuum degree level, and establish the corresponding relationship between the attenuation value and the vacuum degree;

[0067] Traditional vacuum degree detection mostly relies on off-line sampling inspection or indirect inference based on electrical parameters, and non-destructive on-line monitoring cannot be achieved. In this step, through the unique signal transmission mechanism of the terahertz wave reflection path (vacuum duct → arc extinguishing chamber → reflection of the metal shielding cover → vacuum duct), the interference problem of signal transmission caused by the ceramic shell and metal shielding cover of the vacuum arc extinguishing chamber is solved, and the direct on-line measurement of the internal vacuum degree of the fully enclosed arc extinguishing chamber is realized.

[0068] According to the implementation principle of the on-line vacuum degree monitoring device and to make the measurement data more accurate, the design of the terahertz wave reflection path also includes that the symmetry error of the terahertz wave incident angle and reflection angle is <0.5°, and the surface roughness Ra of the metal shielding cover is ≤0.8μm, ensuring that the fluctuation of the reflected signal intensity is <5%. Based on the parameters designed for the terahertz wave reflection path, step S1 specifically includes:

[0069] The vacuum degrees of multiple vacuum arc extinguishing chamber samples are respectively set to different vacuum gradients. For example, 7 vacuum arc extinguishing chamber samples are selected, and their vacuum degrees are 10 -4 Pa, 5*10 -3 Pa, 1*10 -3 Pa, 5*10 -2 Pa, 1*10 -2 Pa, 5*10 -1 Pa, 1*10 - 1 Pa. Selecting 7 samples covers the typical vacuum degree range from 10 -4 Pa to 1*10 -1 Pa, covering the full life cycle states from normal use, critical deterioration to complete failure.

[0070] Fix the vacuum duct at a preset distance position of the vacuum arc extinguishing chamber sample, and set the distance to 10 cm;

[0071] After a terahertz wave generator emits a terahertz wave through the vacuum duct and forms a reflection inside the vacuum arc extinguishing chamber sample and then passes through the vacuum duct again to return to the terahertz wave receiver, record the attenuation value after reflection by each vacuum arc extinguishing chamber sample. Under the measurement conditions of 7 vacuum arc extinguishing chamber samples, the attenuation values of the terahertz wave are denoted as Q1, Q2, Q3, Q4, Q5, Q6, Q7.

[0072] Establish the corresponding relationship between the vacuum degree and the attenuation value according to the attenuation values after reflection of the vacuum arc extinguishing chamber samples under different vacuum gradients.

[0073] In this step, by measuring the attenuation values on samples with different preset vacuum levels, the vacuum level range in which the vacuum interrupter may operate is covered to ensure the applicability of the monitoring system. At the same time, the quantitative relationship between the attenuation value and the vacuum level is clarified, enabling the system to accurately judge the vacuum level based on the actually measured attenuation value.

[0074] Step S2: Interpolate the measured attenuation values to construct a calibration database for the corresponding relationship between the vacuum level and the attenuation value; specifically including:

[0075] Perform equidistant interpolation a preset number of times on two adjacent measured attenuation values to generate a complete data set containing interpolated attenuation values;

[0076] By interpolating the measured Q1, Q2, Q3, Q4, Q5, Q6, Q7 respectively, with an average of four values inserted between each two values. For example, between Q1 and Q2, the inserted values are Q12A, Q12B, Q12C, Q12D. The specific calculation method of interpolation is:

[0077]

[0078] Use numerical analysis software to establish a calibration database for the corresponding relationship between the interpolated attenuation value and the vacuum level.

[0079] By corresponding each attenuation value Q obtained by interpolation to the vacuum level one by one, based on MATLAB software, construct a calibration database for the corresponding relationship between the vacuum level - attenuation value Q.

[0080] In this step, interpolation processing can fill the gaps between sample measurement data, making the relationship between the vacuum level and the attenuation value more continuous and complete. Even if the actually measured attenuation value is not at the sample data points, the corresponding vacuum level can be accurately estimated through interpolation. By constructing a prepared calibration database, the precise corresponding relationship between the vacuum level and the attenuation value is stored. Through database query, the system can quickly and accurately convert the measured attenuation value into the vacuum level, improving the monitoring efficiency. In addition, using interpolation processing enables the system to adapt to a wider vacuum level range. Even in the vacuum level interval not covered by the samples, reliable monitoring results can be provided through interpolation.

[0081] Step S3: Periodically emit terahertz waves to the vacuum interrupter to be measured, and calculate the average attenuation value within each period;

[0082] By emitting terahertz waves a preset number of times (such as 3 times, 4 times or 5 times) to the vacuum interrupter to be measured within a preset period (such as setting an interval of 1 day, 7 days, or 10 days), and calculate the average attenuation value under the preset number of times within the preset period.

[0083] By controlling the computer (4) to make the terahertz wave generator (301) emit terahertz waves three times every 10 days. After the terahertz waves pass through the vacuum interrupter test sample, the terahertz wave receiver (302) receives the reflected terahertz waves and records the attenuation values QX1, QX2, and QX3.

[0084] Calculate the average attenuation value: QXA = (QX1 + QX2 + QX3) / 3

[0085] The terahertz wave emission adopts the time window staggering technology to emit pulses near the zero crossing point of the power grid power frequency cycle (20 ms) to avoid strong electromagnetic interference periods. If the change rate of QXA in a certain cycle exceeds 10% compared with the previous time, the monitoring cycle is automatically shortened to 3 days to continuously track the deterioration trend of the vacuum degree and implement adaptive cycle adjustment.

[0086] Through the continuous monitoring of the vacuum degree of the vacuum interrupter by periodically emitting terahertz waves, the change of the vacuum degree can be captured in time to avoid missing key information due to too long monitoring intervals. At the same time, by calculating the average attenuation value in each cycle, the random error of single measurement can be effectively reduced and the reliability of the measurement result can be improved.

[0087] Step S4: Query the real-time vacuum degree through the calibration database according to the average attenuation value;

[0088] The calibration database provides an accurate corresponding relationship between the attenuation value and the vacuum degree, enabling the system to quickly query the real-time vacuum degree according to the average attenuation value, improving the real-time performance and efficiency of monitoring. And the calibration database constructed based on a large number of sample data and interpolation processing makes the query result have high reliability and reduces the possibility of misjudgment.

[0089] Step S5: Judge the size relationship between the real-time vacuum degree and the preset vacuum degree threshold, and trigger the early warning strategy according to the judgment result. The early warning strategy specifically includes:

[0090] If the real-time vacuum degree is lower than the first threshold, it is determined that the vacuum degree is normal;

[0091] For example, compare QXA with Q1, Q2, Q3, Q4, Q5, Q6, Q7. If QXA is less than Q1, it is judged that the vacuum degree is high;

[0092] If the real-time vacuum degree is higher than the second threshold, directly trigger the early warning;

[0093] If QXA is greater than Q7, it is judged that the vacuum degree is low and an early warning is issued;

[0094] If the real-time vacuum degree is between the first and second thresholds, further judge whether it exceeds the preset critical value. If it exceeds, trigger the early warning.

[0095] If QXA is greater than Q1 but less than Q7, query the established calibration database, compare QXA with the Q values in the calibration database, and obtain that QXA is between the vacuum degrees PX1 and PX2. If PX2 is greater than the set critical value of 6.6×10-2, issue a warning to remind to replace the arc extinguishing chamber.

[0096] In this step, the warning strategy breaks through the traditional single-threshold judgment and proposes a multi-level warning mechanism:

[0097] First-level warning (QXA is greater than Q7): The vacuum degree has been lower than 1×10 -1 Pa. Set to trigger an audible and visual alarm and upload an emergency work order.

[0098] Second-level warning (PX2>6.6×10-2Pa): The vacuum degree enters the accelerated deterioration stage, push a warning message and recommend maintenance within 30 days.

[0099] An online monitoring method for the vacuum degree of a vacuum circuit breaker according to the present invention can accurately reflect the actual vacuum degree of the vacuum arc extinguishing chamber by measuring on samples with preset vacuum degree levels and establishing the corresponding relationship between the attenuation value and the vacuum degree, and further optimizes this corresponding relationship through interpolation processing, so that accurate calibration relationships can also be obtained for measurements at non-standard vacuum degrees. Based on the calibration database of the calibration relationship, the average attenuation value can be quickly converted into the real-time vacuum degree, and combined with the preset vacuum degree threshold, it can immediately judge whether the current vacuum degree is within the safe range and trigger the corresponding warning strategy. Realize the real-time feedback of the vacuum degree and avoid equipment failures caused by abnormal vacuum degrees. By periodically emitting terahertz waves and calculating the average attenuation value within each period, the current state information of the vacuum arc extinguishing chamber can be continuously obtained. The periodic monitoring method ensures the timely capture of changes in the vacuum degree and avoids missing key changes due to too long monitoring intervals. Through the automated warning mechanism, equipment failures caused by abnormal vacuum degrees can be effectively prevented, reducing maintenance costs and power outage time. The real-time monitoring and warning functions enable the operation and maintenance personnel to discover problems at the initial stage of the vacuum degree drop and intervene in advance to avoid serious failures such as breakdown of the arc extinguishing chamber caused by too low vacuum degree, thereby extending the service life of the equipment.

[0100] In some other embodiments, step S1 can also design a more accurate terahertz wave reflection path according to the implementation principle of the vacuum degree online monitoring device. The design of the terahertz wave reflection path also includes:

[0101] The symmetry error between the terahertz wave incident angle and the reflection angle <0.5°;

[0102] The surface roughness Ra of the metal shielding cover ≤0.8μm;

[0103] Set the fluctuation of the reflected signal intensity <5%.

[0104] In some other embodiments, for the interpolation calculation in step S2, a sine correction term can be introduced. At this time, taking Q12A interpolation as an example, its calculation expression is:

[0105]

[0106] where k is the interpolation point serial number, N is the total number of interpolation points, and α is the correction coefficient related to the vacuum degree gradient. The introduction of the sine term compensates for the non-linear attenuation characteristic.

[0107] In some other embodiments, in step S4, during the vacuum degree query phase, the traditional method uses the linear look-up table method, resulting in a vacuum degree jump error near the critical value (such as 6.6×10-2Pa). This step can introduce the dichotomy approximation + curve fitting correction method for query, specifically as follows:

[0108] Use the dichotomy to quickly locate the interval [Q, Q] where QXA is located in the calibration database.

[0109] Perform quadratic polynomial fitting on the interpolation points within this interval to calculate the accurate vacuum degree. The vacuum degree calculation formula is as follows:

[0110] PX = aQ2 + bQ + c

[0111] In the formula, PX represents the vacuum degree; the coefficients a, b, and c can be obtained by MATLAB fitting, so that the vacuum degree resolution is improved to the order of 10-3Pa.

[0112] Specifically, in a preferred embodiment of the present application, an on-line monitoring method for the vacuum degree of a vacuum circuit breaker further includes:

[0113] Establish a vacuum degree decay trend curve based on time series according to the real-time vacuum degree obtained in each cycle;

[0114] Evaluate the deterioration rate of the vacuum degree according to the vacuum degree decay trend curve.

[0115] In this embodiment, the trend warning can be used as the third-level warning. Based on the vacuum degree-time curve, in this embodiment, the vacuum degree change rate can be set to exceed 5% for three consecutive cycles, and then the potential fault can be warned in advance. According to the real-time vacuum degree obtained in each cycle, a vacuum degree decay trend curve based on the time series is established, which can show the change of the vacuum degree of the vacuum circuit breaker over time in an intuitive graphical way. By observing the trend of the curve, the operation and maintenance personnel can clearly see how the vacuum degree gradually decreases, whether it decays steadily or fluctuates, and the degree of decay in different time periods. Based on the established vacuum degree decay trend curve to evaluate the vacuum degree degradation rate, the speed of change of the vacuum degree can be accurately quantified. By analyzing the characteristics such as the slope of the curve, the rate value of the vacuum degree decrease in different time periods can be obtained. This helps the operation and maintenance personnel understand the speed of vacuum degree degradation and judge whether it is within an acceptable range. For example, if the degradation rate is too fast, it may mean that there is a potential fault or abnormality in the vacuum circuit breaker, and timely measures need to be taken for inspection and maintenance; if the degradation rate is relatively slow and stable, the maintenance plan can be reasonably arranged to avoid excessive maintenance or untimely maintenance. By evaluating the rate of vacuum degradation, possible faults of vacuum circuit breakers can be discovered in advance. When the degradation rate exceeds the normal range, it means that the vacuum degree is decreasing faster, which may indicate problems such as reduced sealing performance of the vacuum bubble and damage to the internal structure. Timely discovery of these potential faults and taking corresponding measures, such as replacing the vacuum bubble, can avoid further development of the fault and prevent the vacuum circuit breaker from failing to work properly due to a serious decrease in vacuum, thereby ensuring the safe and stable operation of the power system.

[0116] In addition, a large amount of vacuum data has been accumulated in the process of establishing the vacuum attenuation trend curve and evaluating the degradation rate. These data can be used for further analysis and research, such as analyzing the impact of different environmental conditions and operating conditions on vacuum degradation, and providing data support for the design improvement and operation management of vacuum circuit breakers. Through in-depth mining and analysis of these data, the performance and reliability of vacuum circuit breakers can be continuously improved, promoting the development of power equipment technology.

[0117] Those of ordinary skill in the art will appreciate that the units of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition of each example has been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0118] In the embodiments provided by the present invention, it should be understood that the division of units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units can be combined into one unit, one unit can be split into multiple units, or some features can be ignored, etc.

[0119] In addition, each functional unit in various embodiments of the present invention can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

[0120] If the above-mentioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that makes a contribution to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes: various media such as USB flash drives, read-only memories (ROMs), random access memories (RAMs), mobile hard disks, magnetic disks, or optical discs that can store program codes.

[0121] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of various embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention.

Claims

1. An on-line monitoring method for the vacuum degree of a vacuum circuit breaker, characterized in that, Including: Obtain the attenuation values measured for vacuum interrupter samples at a preset vacuum level, and establish the corresponding relationship between the attenuation values and the vacuum level; Perform interpolation processing on the measured attenuation values to construct a calibration database for the corresponding relationship between the vacuum level and the attenuation values; Periodically emit terahertz waves to the vacuum interrupter to be measured, and calculate the average attenuation value within each period; According to the average attenuation value, query the real-time vacuum level through the calibration database; Judge the magnitude relationship between the real-time vacuum level and the preset vacuum level threshold, and trigger an early warning strategy according to the judgment result.

2. The on-line monitoring method for the vacuum degree of the vacuum circuit breaker according to claim 1, characterized in that, The obtaining the attenuation values measured for vacuum interrupter samples at a preset vacuum level and establishing the corresponding relationship between the attenuation values and the vacuum level includes: setting the vacuum levels of multiple vacuum interrupter samples to different vacuum gradients respectively; Fix the vacuum conduit at a preset distance position of the vacuum interrupter sample; Emit terahertz waves through a terahertz wave generator, after passing through the vacuum conduit, and form reflections inside the vacuum interrupter sample and then pass through the vacuum conduit again to return to the terahertz wave receiver, and record the attenuation values after being reflected by each vacuum interrupter sample; According to the attenuation values after reflection of the vacuum interrupter samples under different vacuum gradients, establish the corresponding relationship between the vacuum level and the attenuation values.

3. The online monitoring method for the vacuum degree of the vacuum circuit breaker according to claim 1, wherein, The performing interpolation processing on the measured attenuation values to construct a calibration database for the corresponding relationship between the vacuum level and the attenuation values includes: Perform a preset number of equally spaced interpolation processes on two adjacent measured attenuation values to generate a complete data set containing interpolated attenuation values Use numerical analysis software to establish a calibration database for the corresponding relationship between the interpolated attenuation values and the vacuum level.

4. The on-line monitoring method for the vacuum degree of the vacuum circuit breaker according to claim 1, characterized in that, The periodically emitting terahertz waves to the vacuum interrupter to be measured and calculating the average attenuation value within each period includes: Emit terahertz waves to the vacuum interrupter to be measured a preset number of times within a preset period, and calculate the average attenuation value at the preset number of times within the preset period.

5. The on-line monitoring method for the vacuum degree of the vacuum circuit breaker according to claim 1, characterized in that, The judging the magnitude relationship between the real-time vacuum level and the preset vacuum level threshold and triggering an early warning strategy according to the judgment result includes: If the real-time vacuum level is lower than the first threshold, it is determined that the vacuum level is normal; If the real-time vacuum level is higher than the second threshold, directly trigger an early warning; If the real-time vacuum level is between the first and second thresholds, further judge whether it exceeds the preset critical value, and if it exceeds, trigger an early warning.

6. The on-line monitoring method for the vacuum degree of a vacuum circuit breaker according to any one of claims 1, characterized in that, It also includes: According to the real-time vacuum level obtained in each period, establish a vacuum level attenuation trend curve based on the time series; Evaluate the deterioration rate of the vacuum level according to the vacuum level attenuation trend curve.

7. An on-line monitoring device for the vacuum degree of a vacuum circuit breaker, which is applied to the on-line monitoring method for the vacuum degree of the vacuum circuit breaker according to any one of claims 1-6, characterized in that, Including: A vacuum interrupter, inside which there is a metal shielding cover; A vacuum conduit, which is composed of a side wall and end sealing materials, the side wall is made of a metal material, and the end sealing materials are terahertz wave highly permeable materials; A flange, which is installed on the vacuum conduit, a vacuum gauge is arranged on the flange, and the flange is connected to a vacuum pump through an air extraction conduit; a terahertz wave generator and a terahertz wave receiver are both arranged at one end of the vacuum conduit, and are used for emitting and receiving terahertz waves reflected by the vacuum interrupter; A control terminal, which is respectively connected to the terahertz wave generator, the terahertz wave receiver and the vacuum gauge of the flange, and is used for controlling terahertz wave emission, receiving attenuation signals, and performing data acquisition and data analysis and processing.

8. The on-line monitoring device for the vacuum degree of a vacuum circuit breaker according to claim 7, characterized in that, The sealing materials at both ends of the vacuum conduit are poly-4-methylpentene-1, low-density polyethylene or polytetrafluoroethylene.

9. The on-line monitoring device for the vacuum degree of a vacuum circuit breaker according to claim 7, characterized in that, The flange includes: a valve for controlling the connection and disconnection between the vacuum conduit and the air extraction conduit; a conductive column for connecting a vacuum gauge to monitor the vacuum degree inside the vacuum conduit.

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