A high-voltage direct-current GIS insulation gas dark current measuring device and method
By integrating temperature and humidity monitoring and detachable high-voltage electrodes, a high-voltage DC GIS insulating gas dark current measurement device was developed, solving the measurement challenges under weak signals and multiple operating conditions, and enabling high-precision dark current characteristic research and insulation optimization.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XI AN JIAOTONG UNIV
- Filing Date
- 2026-05-18
- Publication Date
- 2026-07-31
AI Technical Summary
Existing high-voltage DC GIS insulating gas dark current measurement devices suffer from weak signals, susceptibility to interference, and difficulty in handling various temperature and humidity conditions and changes in electrode materials, resulting in limited measurement accuracy and repeatability.
A measuring device integrating a high-voltage DC power supply module, a current measurement module, a temperature and humidity monitoring module, and a data acquisition and processing module was designed. It adopts a coaxial measuring core and a protective electrode isolation structure, combined with a detachable high-voltage electrode and a polarity switching module, to achieve synchronous measurement under multiple temperature and humidity conditions and multiple electrode material conditions.
It significantly improves the accuracy and repeatability of pA-level weak current measurements, enabling reliable dark current characteristic data to be obtained under multiple operating conditions, and supporting insulation optimization design.
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Figure CN122487724A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of high voltage DC GIS insulation testing technology, specifically a high voltage DC GIS insulation gas dark current measuring device and method. Background Technology
[0002] High-voltage direct current gas-insulated switchgear (GIS) has significant application value in high-voltage direct current transmission and new energy transmission systems due to its advantages such as compact footprint, strong environmental adaptability, and high operational reliability. Under the long-term influence of a DC electric field, charge accumulation easily occurs on the surface of the insulator, leading to local field strength distortion, gas discharge, and even flashover, affecting the long-term insulation reliability of the equipment. Existing research indicates that one of the important sources of charge on the insulator surface is the conduction current in the insulating gas, i.e., dark current.
[0003] Although dark current is extremely small, typically in the pA range or even lower, its variations can reflect the transport state of charge carriers in the insulating gas and the weak discharge activity near the electrode surface. Furthermore, changes in temperature and humidity affect the generation, migration, and recombination of charge carriers in the gas, and alter the adsorption and desorption states of the electrodes and insulating surfaces, thus further influencing dark current characteristics. Therefore, accurately measuring dark current and analyzing its variation under different temperature and humidity conditions is of great significance for revealing the surface charge accumulation mechanism, judging local micro-discharge behavior, and optimizing the design of DC GIS insulation.
[0004] Currently, research on the testing of dark current in high-voltage direct current GIS insulating gas still has certain shortcomings. First, the dark current signal is extremely weak and easily affected by environmental noise, electromagnetic interference, and leakage current in the test structure, resulting in limited measurement accuracy and repeatability. Second, existing testing devices mostly focus on single factors such as gas type, gas pressure, voltage polarity, electrode material, or surface condition, lacking the ability to simultaneously monitor and adjust temperature and humidity parameters within the test chamber, making it difficult to obtain dark current characteristic data under multiple temperature and humidity conditions. (Invention Content) This invention provides a high-voltage DC GIS insulating gas dark current measurement device and method, which solves the problems of weak signal, susceptibility to interference, difficulty in distinguishing gas dark current from structural leakage current in existing dark current tests, and difficulty in simultaneously testing multiple gases, multiple pressures, multiple humidity levels, multiple temperatures, multiple voltage polarities, multiple electrode materials, and multiple surface states.
[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a high-voltage DC GIS insulating gas dark current measuring device, comprising: a high-voltage DC power supply module, a current measurement module, a temperature and humidity monitoring and adjustment module, and a data acquisition and processing module; a test chamber, wherein a coaxial measuring core, a temperature sensor, a humidity sensor, and a heating resistor are disposed inside the test chamber, the coaxial measuring core including a high-voltage electrode, a measuring electrode, an insulation isolation module, and a protective electrode; and a gas control module connected to the test chamber; wherein the high-voltage DC power supply module is electrically connected to the high-voltage electrode, the current measurement module is electrically connected to the measuring electrode, the protective electrode is grounded and configured in conjunction with the insulation isolation module, the heating resistor heats the test area, and the data acquisition and processing module is connected to the current measurement module, the temperature sensor, and the humidity sensor respectively.
[0006] According to one embodiment of the present invention, the test chamber is a sealed pressure-bearing chamber, and a sleeve, a pressure gauge and a wiring flange are provided on its exterior.
[0007] According to one embodiment of the present invention, the high-voltage electrode is located inside the coaxial structure, the measuring electrode is located outside the coaxial structure, and the protective electrode is disposed in the vicinity of the insulating isolation module.
[0008] According to one embodiment of the present invention, the high-voltage electrode is a detachable and replaceable structure to enable dark current testing under different electrode materials or different electrode surface conditions.
[0009] According to one embodiment of the present invention, it further includes: a polarity switching module, wherein the polarity switching module is disposed between the high voltage output terminal of the high voltage DC power supply module and the high voltage input terminal of the test cavity, the high voltage input terminal is electrically connected to the high voltage electrode through the central guide rod of the sleeve, and the polarity switching module is used to switch the polarity of the DC voltage applied to the high voltage electrode.
[0010] According to one embodiment of the present invention, the temperature sensor and the humidity sensor are disposed inside the test chamber or in communication with the inner cavity of the test chamber; the heating resistor is disposed on the inner wall, outer wall or adjacent area of the coaxial measuring core of the test chamber.
[0011] The present invention also provides a method for measuring the dark current of insulating gas in high-voltage DC GIS, and based on the above embodiments, the present invention also provides a device for measuring the dark current of insulating gas in high-voltage DC GIS, comprising the following steps: Step 1: Clean the test chamber and the coaxial measuring core; Step 2: After evacuating and purging the test chamber, fill it with the insulating gas to be tested with the target humidity to the set pressure. Step 3: Monitor the environmental parameters inside the test chamber using the temperature sensor and the humidity sensor, and adjust the temperature of the test area to the set value using the heating resistor; Step 4: Apply DC voltage to the high-voltage electrode step by step, and simultaneously collect dark current, temperature and humidity signals; Step 5: Filter and reduce noise on the acquired real-time dark current signal, identify the stable range, and extract the dark current feature value; Step 6: Calculate the electric field strength on the surface of the high-voltage electrode based on the applied voltage and the structural parameters of the coaxial measuring core, and establish the correspondence between electric field strength, temperature, humidity and dark current characteristic values to obtain dark current characteristic data under different temperature and humidity conditions.
[0012] According to one embodiment of the present invention, the gas washing process in step 2 includes at least one cycle of filling the gas to be tested and then evacuating; the gas to be tested is a target gas with a preset humidity.
[0013] According to one embodiment of the present invention, in step 5, Wiener filtering is used to process the real-time dark current signal, and multiple sampling points are selected within the identified stable range for averaging to obtain the dark current characteristic value under the corresponding voltage condition.
[0014] According to one embodiment of the present invention, the method further includes: switching the voltage polarity of the high-voltage electrode, replacing the high-voltage electrode with a different electrode material, or replacing the high-voltage electrode with a different surface roughness state, to obtain dark current characteristic data under different electrode conditions.
[0015] Compared with existing technologies, this invention has the following advantages: This invention provides a high-voltage DC GIS insulating gas dark current measurement device. Through the cooperation of a coaxial measuring core and a grounding protection electrode, leakage current through non-gas paths is effectively isolated, ensuring that the signal collected by the measuring electrode mainly originates from the dark current in the insulating gas, significantly improving the measurement accuracy of pA-level weak currents. The test chamber integrates a temperature sensor, a humidity sensor, and a heating resistor, enabling real-time monitoring and active adjustment of temperature and humidity parameters. This achieves synchronous measurement of dark current under different temperature and humidity conditions, overcoming the shortcomings of existing devices in handling multiple environmental factors. The high-voltage electrode adopts a detachable and replaceable structure and is equipped with a polarity switching module, allowing for flexible comparative testing under different electrode materials, surface roughness states, and voltage polarities, greatly expanding the range of test conditions. The data acquisition and processing module is connected to the current, temperature, and humidity sensors, possessing synchronous recording, filtering and noise reduction, and stable range determination functions, further improving the repeatability and reliability of dark current characteristic value extraction. This device provides high-precision, multi-functional experimental support for the study of dark current characteristics of high-voltage DC GIS insulating gas, the analysis of surface charge accumulation mechanisms, and insulation optimization design.
[0016] This invention also provides a method for measuring the dark current of high-voltage DC GIS insulating gas. Through cleaning, vacuum purging, and filling with a target humidity gas, the interference of residual impurities on the dark current is effectively eliminated. Environmental parameters are monitored using temperature and humidity sensors, and the temperature is adjusted by a heating resistor, enabling controllable simulation of multiple temperature and humidity conditions. DC voltage is applied in stages while simultaneously acquiring dark current, temperature, and humidity signals, ensuring the continuity and comparability of data at different voltage levels. Wiener filtering is used to reduce noise in the acquired signals, and stable intervals are identified. Multiple data points are selected and averaged to extract feature values, significantly suppressing local noise and glitches, and improving the signal-to-noise ratio of dark current measurement. The electric field strength is calculated based on the coaxial structure parameters, and a correspondence is established with temperature, humidity, and dark current feature values, allowing for systematic analysis of the influence of various factors. Furthermore, by changing the gas pressure, switching the voltage polarity, and changing the electrode material or surface condition, this method can be extended to obtain dark current characteristic data under various operating conditions, providing reliable experimental basis for revealing the gas carrier transport mechanism, evaluating electrode surface conditions, and optimizing DC GIS insulation structures. Attached Figure Description
[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1 This is a schematic diagram of a high-voltage DC GIS insulating gas dark current measuring device according to the present invention.
[0019] Figure 2 This is a schematic diagram of the measurement core structure in this invention.
[0020] Figure 3 This is a graph showing the dark current test results under different air pressures with positive and negative polarities in this invention.
[0021] Figure 4 The image shows the dark current test results of the large-size measuring core under different air pressures with positive and negative polarities in this invention.
[0022] Figure 5 The figures show the dark current measurement results for different electrode roughnesses under positive and negative polarities in this invention. In the figures, number 01 represents the high-voltage electrode after machining and fine sandblasting; number 02 represents the high-voltage electrode after machining and coarse sandblasting; number 03 represents the high-voltage electrode after machining and polishing; and number 04 represents the high-voltage electrode after machining.
[0023] Figure 6 The figure shows the dark current measurement results for different electrode materials and roughness in this invention.
[0024] Figure 7 The figure shows the dark current test results under different humidity conditions with positive polarity in this invention.
[0025] Figure 8 The figure shows the dark current test results under different temperature conditions with positive polarity in this invention.
[0026] In the diagram, 1-computer, 2-high voltage DC power supply module, 3-electrometer, 4-test chamber, 5-protective electrode, 6-measuring electrode, 7-heating resistor, 8-high voltage electrode, 9-temperature sensor, 10-humidity sensor, 11-insulation isolation module. Detailed Implementation
[0027] 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 embodiments of the present invention, and not all embodiments. 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.
[0028] Therefore, the following detailed description of the embodiments of the 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 invention without inventive effort are within the scope of protection of the invention.
[0029] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0030] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for 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. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In the description of this invention, it should be noted that unless otherwise explicitly specified and limited, the terms "installed," "connected," "linked," and "set up" 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 communication between two components.
[0031] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.
[0032] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. The present invention provides a high-voltage DC GIS insulating gas dark current measurement device and method, which can acquire weak dark current signals at the pA level in real time and simultaneously record temperature and humidity parameters within the test chamber. Through filtering and noise reduction and stable interval determination, effective dark current feature values are extracted, significantly reducing the influence of noise and local glitches, and improving the accuracy, repeatability, and comparability of the test results. Furthermore, the device and method construct a scalable, multifunctional dark current testing platform, which can not only perform basic dark current measurements but also achieve comparative studies of dark current under multiple operating conditions by switching gas types, pressures, humidity, temperatures, voltage polarities, and electrode materials and roughness, thus enhancing the applicability and engineering application value of the testing platform.
[0033] like Figure 1 and Figure 2 As shown, this embodiment provides a high-voltage DC GIS insulating gas dark current measuring device, including: a high-voltage DC power supply module 2, a current measurement module 3, a temperature and humidity monitoring module, a temperature adjustment module, and a data acquisition and processing module 1; a test chamber 4; and a gas control module.
[0034] Test chamber 4 is a sealed pressure-bearing chamber, externally equipped with a sleeve, pressure gauge, and wiring flange. Inside test chamber 4 are a coaxial measuring core, temperature sensor 9, humidity sensor 10, and heating resistor 7. The coaxial measuring core includes a high-voltage electrode 8, a measuring electrode 6, an insulating isolation module 11, and a protective electrode 5. The high-voltage electrode 8 is located inside the coaxial structure, the measuring electrode 6 is located outside the coaxial structure, and the protective electrode 5 is located near the insulating isolation module 11. This coaxial structure, combined with the grounding design of the protective electrode 5, effectively isolates leakage current through non-gas paths, ensuring that the current signal measured by the measuring electrode 6 primarily originates from the dark current in the insulating gas between the high-voltage electrode 8 and the measuring electrode 6, thus guaranteeing the accuracy of the measurement results.
[0035] The gas control module is connected to the test chamber 4 and is used to realize vacuuming, gas washing, filling with target gases of different humidity and pressure adjustment.
[0036] The high-voltage DC power supply module 2 is electrically connected to the high-voltage electrode 8 and is used to apply an adjustable DC voltage to the high-voltage electrode 8. Preferably, the device also includes a polarity switching module, which is disposed between the high-voltage output terminal of the high-voltage DC power supply module 2 and the high-voltage input terminal of the test chamber 4. The high-voltage input terminal is electrically connected to the high-voltage electrode 8 through a central guide rod of a sleeve. The polarity switching module is used to switch the polarity of the DC voltage applied to the high-voltage electrode 8. By switching the polarity, dark current characteristic data under different voltage polarities can be obtained, providing support for analyzing the charge accumulation polarity effect.
[0037] The current measurement module 3 is electrically connected to the measuring electrode 6 and is used to collect the dark current signal in the insulating gas between the high-voltage electrode 8 and the measuring electrode 6. The protective electrode 5 is grounded and is configured in conjunction with the insulation isolation module 11 to isolate leakage current through non-gas paths.
[0038] Temperature sensor 9 and humidity sensor 10 are located inside or in communication with the inner cavity of test chamber 4, respectively, to monitor the temperature and humidity parameters within test chamber 4. Heating resistor 7 is located on the inner wall, outer wall, or adjacent area of the coaxial measuring core of test chamber 4 to heat the test area and create different temperature conditions. By adding temperature and humidity sensors and heating resistor, synchronous monitoring and adjustment of dark current and environmental parameters are achieved, providing an experimental basis for analyzing the dark current variation under multiple temperature and humidity conditions.
[0039] The data acquisition and processing module 1 is electrically connected to the current measurement module 3, the temperature sensor 9, and the humidity sensor 10, respectively, for synchronous recording, filtering, stability range determination, and feature value extraction of dark current, temperature, and humidity signals. The data acquisition and processing module 1 can also calculate the electric field strength on the surface of the high-voltage electrode 8 based on the applied voltage and the structural parameters of the coaxial measuring core (high-voltage electrode radius, measuring electrode inner diameter), and establish the correspondence between electric field strength, temperature, humidity, and dark current feature values, thereby obtaining dark current characteristic curves under different temperature and humidity conditions.
[0040] As a preferred option, the high-voltage electrode 8 is a detachable and replaceable structure to enable dark current testing under different electrode materials (such as aluminum, copper, nickel, etc.) or different electrode surface conditions (such as different surface roughness, which can be formed by machining, polishing, sandblasting, etc.). This replaceable design greatly expands the applicability of the testing device, enabling it to systematically study the influence of electrode factors on dark current.
[0041] Based on the above-described device, this embodiment provides a method for measuring the dark current of insulating gas in high-voltage DC GIS, including the following steps.
[0042] Step 1: Clean the test chamber and coaxial measuring core.
[0043] Before the experiment begins, the inner and outer surfaces of the measuring core and the inner surface of the test chamber 4 are thoroughly cleaned. The high-voltage electrode 8, measuring electrode 6 and protective electrode 5 are wiped with anhydrous ethanol to ensure that the surface of the measuring platform is clean and to reduce the interference of impurities on the dark current.
[0044] Step 2: Vacuum the gas, clean the gas, and fill it with the insulating gas to be tested with the target humidity.
[0045] The test chamber 4 is evacuated, then filled with the gas to be tested and evacuated again; this process is repeated, preferably twice, before filling with the insulating gas to be tested with the target humidity to the set pressure. The gas purging process includes at least one cycle of filling with the gas to be tested and then evacuating again. This step effectively reduces the influence of residual gas and impurities on the dark current measurement results.
[0046] Step 3: Monitor environmental parameters and adjust the temperature to the set value.
[0047] The environmental parameters inside the test chamber 4 are monitored by temperature sensor 9 and humidity sensor 10, and the temperature of the test area is adjusted to the set value by heating resistor 7. After the temperature inside the test chamber 4 reaches the set value and tends to stabilize, the high-voltage DC power supply is turned on. By adjusting the temperature, the dark current characteristics under different operating temperature conditions can be simulated.
[0048] Step 4: Apply DC voltage step by step, and simultaneously collect dark current, temperature and humidity signals.
[0049] A DC voltage is applied to the high-voltage electrode 8 in stages, using a step-by-step voltage increase method. The voltage is maintained at each stage for a preset time before increasing to the next stage. The voltage is ultimately applied to the high-voltage electrode 8 through the central guide rod of the test chamber 4 sleeve and the spherical terminal inside the chamber. The dark current signal is collected by the measuring electrode 6 and transmitted to the data acquisition and processing module 1 via the current measurement module 3. Preferably, the data acquisition and processing module 1 synchronously records dark current, temperature, and humidity data at 1-second time intervals. This step-by-step voltage application and synchronous recording method ensures the stability and repeatability of data under different voltage conditions.
[0050] Step 5: Filter and reduce noise in the real-time dark current signal, identify the stable range, and extract the dark current feature values.
[0051] Because dark current signals are on the order of magnitude (typically in the pA range), they may contain significant local noise and glitches. This method employs a filtering algorithm to process the original dark current signal to obtain more accurate real-time dark current data.
[0052] Data acquisition and processing module 1 employs the Wiener filtering algorithm to filter the measured data. Wiener filtering is an optimal linear filtering algorithm based on the minimum mean square error criterion. It constructs a filter in the frequency domain by estimating the power spectral characteristics of the signal and noise, suppressing noise while preserving as much of the original signal characteristics as possible. In practical applications, the Wiener filtering algorithm can be used in Matlab or equivalent data processing software to process the measured dark current time series, obtaining filtered dark current data.
[0053] After filtering the raw dark current data, the stable interval of the filtered signal is further identified. By analyzing the fluctuation amplitude, rate of change, or variance of the signal within a preset time window, the data interval after the dark current enters a stable state is determined. Then, multiple data points within the stable interval are averaged to obtain the dark current characteristic value under a certain voltage condition.
[0054] Step 6: Calculate the electric field strength and establish the corresponding relationship.
[0055] Based on the applied voltage and the structural parameters of the coaxial measuring core (high-voltage electrode radius, measuring electrode inner diameter), according to the formula... Calculate the electric field intensity on the surface of high-voltage electrode 8, where, E HV It is the electric field strength on the surface of the high-voltage electrode. U It is the voltage applied to the high-voltage electrode. R HV It is the radius of the high-voltage electrode. R mes It is the inner diameter of the measuring electrode.
[0056] A correlation is established between the electric field strength and the corresponding dark current characteristic value, test temperature, and test humidity to obtain the electric field strength-dark current characteristic curve under different temperature and humidity conditions, which can be used to analyze the law of dark current variation with electric field, temperature, and humidity.
[0057] In a preferred embodiment, averaging 200 data points after the dark current has stabilized yields the average dark current value at a given voltage. Based on the radius of the high-voltage electrode, the inner diameter of the measuring electrode, and the applied voltage, the electric field strength on the surface of the high-voltage electrode is calculated. A correlation is established between this electric field strength and the corresponding average dark current value, test temperature, and test humidity, thus obtaining the electric field strength-dark current characteristic curve under different temperature and humidity conditions. This curve is used to analyze the variation of dark current with electric field, temperature, and humidity.
[0058] Comparative dark current tests were conducted under different air pressure conditions. After completing the basic dark current measurement, steps one through four were repeated by adjusting the air pressure of the insulating gas inside the test chamber, while keeping other structural parameters, humidity conditions, and temperature conditions constant, to obtain dark current characteristic data under different air pressure conditions, such as... Figure 3 and Figure 4 As shown in the figure. This method can obtain the variation law of dark current of insulating gas under different gas pressures.
[0059] Comparative tests of dark current under different electrode materials and surface roughness conditions were conducted. After completing tests under basic operating conditions and different gas pressure conditions, extended tests could be carried out by changing the high-voltage electrode material and surface condition. Preferably, the dark current under different electrode material conditions was tested by replacing the high-voltage electrode with a different material, such as aluminum, copper, or nickel; and the dark current under different electrode surface condition conditions was tested by replacing the high-voltage electrode with a different surface roughness condition. Different surface roughness conditions can be achieved through one or more of machining, polishing, and sandblasting. The testing process can be referenced. Figure 5 and Figure 6 The results shown are analyzed.
[0060] Comparative tests of dark current under different humidity and temperature conditions were conducted, and the application effects of the invention were explained based on the measurement results. While maintaining the same structural parameters and testing procedures, dark current characteristic data under different humidity conditions can be obtained by filling the gas with target gases of varying humidity levels. Figure 7 As shown; by adjusting the heating resistor to create different temperature conditions, and with the temperature sensor monitoring the test temperature in real time, dark current characteristic data under different temperature conditions can be obtained, such as... Figure 8 As shown. Combined with Figures 3 to 8As can be seen, this invention can achieve real-time acquisition of weak dark currents in the insulating gas of high-voltage DC GIS, and obtain test results with good repeatability and comparability under various operating conditions such as different gas pressures, temperatures and humidity levels, different electrode materials, and different surface conditions. Because this invention uses a coaxial measuring core and a grounded isolation structure for the protective electrode, it ensures that the measured signal mainly originates from the gas dark current. Simultaneously, by adding a temperature sensor, a humidity sensor, and a heating resistor, it further achieves synchronous measurement of the dark current and environmental parameters, providing an experimental basis for analyzing the variation law of the insulating gas dark current under various temperature and humidity conditions.
[0061] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects.
[0062] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. 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 based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.
Claims
1. A high-voltage DC GIS insulating gas dark current measuring device, characterized in that, include: High voltage DC power supply module (2), current measurement module (3), temperature and humidity monitoring and temperature regulation module and data acquisition and processing module (1); The test chamber (4) is equipped with a coaxial measuring core, a temperature sensor (9), a humidity sensor (10) and a heating resistor (7). The coaxial measuring core includes a high voltage electrode (8), a measuring electrode (6), an insulation isolation module (11) and a protection electrode (5). The gas control module is connected to the test chamber (4); The high voltage DC power supply module (2) is electrically connected to the high voltage electrode (8), the current measurement module (3) is electrically connected to the measurement electrode (6), the protection electrode (5) is grounded and is set in conjunction with the insulation isolation module (11), the heating resistor (7) heats the test area, and the data acquisition and processing module (1) is connected to the current measurement module (3), the temperature sensor (9) and the humidity sensor (10) respectively.
2. The high-voltage DC GIS insulating gas dark current measuring device according to claim 1, characterized in that: The test chamber (4) is a sealed pressure chamber, and its exterior is equipped with a sleeve, a pressure gauge and a wiring flange.
3. The high-voltage DC GIS insulating gas dark current measuring device according to claim 1, characterized in that: The high-voltage electrode (8) is located inside the coaxial structure, the measuring electrode (6) is located outside the coaxial structure, and the protective electrode (5) is located in the vicinity of the insulating isolation module (11).
4. The high-voltage DC GIS insulating gas dark current measuring device according to claim 1, characterized in that: The high-voltage electrode (8) is a detachable and replaceable structure, used for dark current testing under different electrode materials or different electrode surface conditions.
5. The high-voltage DC GIS insulating gas dark current measuring device according to claim 1, characterized in that, Also includes: A polarity switching module is provided between the high voltage output terminal of the high voltage DC power supply module (2) and the high voltage input terminal of the test chamber (4). The high voltage input terminal is electrically connected to the high voltage electrode (8) through the central guide rod of the bushing. The polarity switching module is used to switch the polarity of the DC voltage applied to the high voltage electrode (8).
6. The high-voltage DC GIS insulating gas dark current measuring device according to claim 1, characterized in that: The temperature sensor (9) and the humidity sensor (10) are located inside the test chamber (4) or in a position communicating with the inner cavity of the test chamber (4); the heating resistor (7) is located on the inner wall, outer wall or adjacent area of the coaxial measuring core of the test chamber (4).
7. A method for measuring the dark current of insulating gas in high-voltage direct current GIS, characterized in that, A high-voltage DC GIS insulating gas dark current measuring device according to any one of claims 1 to 6 includes the following steps: Step 1: Clean the test cavity (4) and the coaxial measuring core; Step 2: After evacuating and purging the test chamber (4), fill it with the insulating gas to be tested with the target humidity to the set pressure; Step 3: Monitor the environmental parameters inside the test chamber (4) using the temperature sensor (9) and the humidity sensor (10), and adjust the temperature of the test area to the set value using the heating resistor (7); Step 4: Apply DC voltage to the high-voltage electrode (8) step by step, and simultaneously collect dark current, temperature and humidity signals; Step 5: Filter and reduce noise on the acquired real-time dark current signal, identify the stable range, and extract the dark current feature value; Step 6: Calculate the electric field strength on the surface of the high voltage electrode (8) based on the applied voltage and the structural parameters of the coaxial measuring core, and establish the correspondence between electric field strength, temperature, humidity and dark current characteristic values to obtain dark current characteristic data under different temperature and humidity conditions.
8. The method for measuring the dark current of high-voltage DC GIS insulating gas according to claim 7, characterized in that: The gas washing process in step 2 includes at least one cycle of filling the gas to be tested and then evacuating it; the gas to be tested is a target gas with a preset humidity.
9. The method for measuring the dark current of high-voltage DC GIS insulating gas according to claim 7, characterized in that: In step 5, Wiener filtering is used to process the real-time dark current signal, and multiple sampling points are selected within the identified stable range for averaging to obtain the dark current characteristic value under the corresponding voltage condition.
10. A method for measuring the dark current of insulating gas in high-voltage DC GIS according to claim 7, characterized in that, The method further includes: By switching the voltage polarity of the high-voltage electrode (8), replacing the high-voltage electrode (8) with a different electrode material, or replacing the high-voltage electrode (8) with a different surface roughness state, dark current characteristic data under different electrode conditions can be obtained.