An electric field measurement system and method for the interior of an ultra-high voltage GIS

Abstract

The application provides an electric field measurement system and method for the interior of an ultra-high voltage GIS, and belongs to the technical field of electric field measurement; the system comprises a laser, an electro-optic sensing probe, a photoelectric detector and a test assembly; the laser is connected with the output end of the electro-optic sensing probe through a polarization maintaining optical fiber penetrating a cover plate of the GIS shell; the electro-optic sensing probe is fixed to the inner wall of the GIS shell through an epoxy resin adhesive, and is axially parallel to the electric field direction in the GIS; the output end of the electro-optic sensing probe is connected with the photoelectric detector through a single-mode optical fiber penetrating the cover plate of the GIS shell; the test assembly is used for response calibration of the electro-optic sensing probe; the electro-optic sensing probe adopts a serial double-wave plate design, and is used for non-contact electric field measurement in the GIS after the response calibration is completed; and the application can realize accurate non-contact electric field measurement in the compact GIS.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electric field measurement, and particularly relates to an electric field measurement system and a measurement method for the interior of an ultra-high voltage GIS. BACKGROUND

[0002] The statements in this section merely provide background information related to the present application and do not necessarily constitute prior art.

[0003] The ultra-high voltage GIS is a key device in the power system and is crucial to the safe and stable operation of the power system. The electric field distribution inside the GIS is complex, and its strength directly affects the insulation performance and operational reliability of the device. Therefore, accurate measurement of the electric field parameters inside the GIS is of great significance for assessing the insulation state of the device, achieving state monitoring, and fault warning.

[0004] However, existing electric field measurement techniques have significant limitations in the ultra-high voltage GIS environment, for example:

[0005] (1) Existing electric field measurement methods mostly use capacitive sensors. Such sensors have a large volume, and the interior space of the GIS is usually extremely compact, resulting in great difficulty in installation, and even the inability to adapt to the internal structure of the device. Moreover, such sensors have poor insulation performance, and once installed inside the GIS, they may interfere with the internal electric field distribution of the device, thereby affecting the accuracy of the measurement results, and even possibly causing damage to the original insulation structure of the GIS, leading to safety hazards.

[0006] (2) Existing measurement techniques have limitations in response speed, measurement bandwidth, and applicable electric field types (such as alternating current, direct current, and impulse electric field), making it difficult to cover the electric field measurement needs of the ultra-high voltage GIS under complex working conditions.

[0007] (3) Existing sensor designs mostly use 1 / 4 wave plates for electro-optical sensor probes. In actual scenarios, the phase shift produced by the 1 / 4 wave plate is easily deviated from the ideal value due to manufacturing process errors, environmental factors, or optical path assembly errors, resulting in inaccurate polarization state conversion. In addition, the phase shift produced by the electro-optical crystal under the action of the electric field may also have additional deviations due to differences in the uniformity of the crystal itself, external interference, etc. These phase shift deviations will directly accumulate in the subsequent optical signal conversion process, causing distortion in the mapping relationship between light intensity changes and electric field strength, ultimately affecting the precision and stability of the electric field measurement. SUMMARY

[0008] To overcome the shortcomings of the prior art, the present application provides an electric field measurement system and a measurement method for the interior of an ultra-high voltage GIS, which can achieve accurate non-contact electric field measurement in a compact GIS interior.

[0009] To achieve the above object, one or more embodiments of the present application provide the following technical solutions:

[0010] The present application provides a kind of electric field measurement system for the interior of super-high voltage GIS.

[0011] An electric field measurement system for the interior of super-high voltage GIS, comprising: a laser, an electro-optic sensing probe, a photodetector, and a test assembly;

[0012] The laser is connected to the output end of the electro-optic sensing probe based on the Pockels effect through a polarization-maintaining optical fiber penetrating a first via of the GIS cover plate;

[0013] The electro-optic sensing probe is fixed to the inner wall of the GIS housing through a modified adhesive, and the axial direction is parallel to the electric field direction inside the GIS; the output end of the electro-optic sensing probe is connected to the photodetector through a single-mode optical fiber penetrating a second via of the GIS cover plate;

[0014] The test assembly is used to calibrate the response of the electro-optic sensing probe; the electro-optic sensing probe adopts a serial double-waveplate design for non-contact electric field measurement inside the GIS after the response calibration is completed.

[0015] Further, the electro-optic sensing probe includes, in order, a first optical fiber collimator, a polarizer, a 1 / 4 waveplate, an electro-optic crystal, a 1 / 2 waveplate, an analyzer, and a second optical fiber collimator; wherein the input end of the first optical fiber collimator is connected to the polarization-maintaining optical fiber, and the output end of the second optical fiber collimator is connected to the single-mode optical fiber.

[0016] Further, the electro-optic sensing probe adopts a serial double-waveplate design, specifically: the output end of the 1 / 4 waveplate in the electro-optic sensing probe is connected to the input end of the electro-optic crystal, for causing a phase shift between the two polarization components of linearly polarized light passing through the polarizer; the output end of the electro-optic crystal is connected to the input end of the 1 / 2 waveplate, and the 1 / 2 waveplate is used to compensate for the phase shift deviation.

[0017] Further, the modified adhesive is an epoxy adhesive.

[0018] Further, the epoxy adhesive is provided with a buffer layer on the side in contact with the inner wall of the GIS for buffering the vibration of the electro-optic sensing module.

[0019] Further, the first via and the second via are filled with epoxy resin glue and covered with a silicone layer, forming a double-sealing structure.

[0020] Further, the test assembly includes a power supply, an electrode unit, and a measurement unit; wherein the power supply includes a high-voltage AC generator, a DC source, and an impulse source, respectively used to test the response characteristics of the electro-optic sensing probe under alternating current, direct current, and impulse electric field.​

[0021] Further, the test assembly further comprises a fast pulse voltage generating device for testing the time-domain response characteristics of the electro-optic sensing probe under a pulse electric field.

[0022] The second aspect of the present application provides a method for measuring electric field inside an ultra-high voltage GIS.

[0023] A method for measuring electric field inside an ultra-high voltage GIS, comprising:

[0024] Based on the test assembly, the response of the electro-optic sensing probe is calibrated;

[0025] Based on the calibrated electro-optic sensing probe, non-contact electric field measurement is performed inside the GIS.

[0026] Further, the response calibration of the electro-optic sensing probe comprises: based on the test assembly, the linearity characteristics of the electro-optic sensing probe under different electric field strengths and the time-domain response characteristics under a pulse electric field are tested in sequence to obtain the applicable electric field range and the measurement bandwidth of the electro-optic sensing probe, respectively.

[0027] The above one or more technical solutions have the following beneficial effects:

[0028] (1) The electro-optic sensing probe based on Pockels effect is adopted in the present application, and the epoxy resin adhesive is combined to realize full insulation design. Among them, the electro-optic sensing probe has compact structure, and can be flexibly installed on the inner wall of the GIS shell in cooperation with the epoxy resin adhesive, solving the problem of poor installation adaptability of the capacitive sensor. At the same time, the full insulation design avoids the interference of the sensing component on the original electric field distribution inside the GIS, and also does not damage the insulation structure of the equipment itself, fundamentally eliminating the safety hidden danger caused by the characteristics of the sensor itself, and ensuring the stability and safety of the measurement environment.

[0029] (2) Based on the test assembly, the response of the electro-optic sensing probe is calibrated comprehensively, that is, the response characteristics of the electro-optic sensing probe under alternating current, direct current and impulse electric field are tested by using a high-voltage alternating current generator, a direct current source and an impulse source respectively, and the time-domain response characteristics under a pulse electric field are tested by using a fast pulse voltage generating device, so that the electro-optic sensing probe has the characteristics of wide frequency band and high response speed, and can cover various electric field measurement requirements of the ultra-high voltage GIS under complex working conditions, effectively breaking through the limitations of the prior art in measurement range and dynamic response.

[0030] (3) The electro-optic sensing probe of the present application adopts a serial double-wave plate design, that is, the output end of the 1 / 4 wave plate in the electro-optic sensing probe is connected to the input end of the electro-optic crystal, which is used to generate a phase difference between the two polarization components of the linearly polarized light passing through the polarizer The output end of the electro-optic crystal is connected to the input end of the 1 / 2 wave plate, and the 1 / 2 wave plate compensates for the phase shift deviation, so as to avoid inaccurate polarization state conversion or distortion of the mapping relationship between light intensity change and electric field intensity, and further ensure the accuracy and stability of electric field measurement.

[0031] Advantages of the additional aspects of the application will be partially given in the following description, partially will become obvious from the following description, or will be understood by the practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0032] The drawings accompanying the specification of this application form a part thereof, serve to provide further understanding of the application, and together with the description of the exemplary embodiments of the application given below, explain the application, and do not limit the application unduly.

[0033] Figure 1 It is a structure diagram of an electric field measurement system for inside of an ultra-high voltage GIS in the embodiment one of the application.

[0034] Figure 2 It is a structure diagram of a cover plate on a GIS shell in the embodiment one of the application; wherein, Figure 2 (a) in the above is a sectional view of the cover plate under partial enlargement, Figure 2 (b) in the above is a plan view of the cover plate under partial enlargement.

[0035] Figure 3 It is a structure diagram of an electro-optic sensing probe in the embodiment one of the application.

[0036] Figure 4 It is a GIS Laplace field curve diagram without partial discharge in the embodiment two of the application.

[0037] Figure 5 It is a linearity test curve diagram of an electro-optic sensing probe in the embodiment two of the application.

[0038] In the figure: 1, laser; 2, electro-optic sensing probe; 3, photoelectric detector; 4, GIS shell; 5, cover plate; 6, via hole; 61, first via hole; 62, second via hole; 7, polarization maintaining optical fiber; 8, single-mode optical fiber; 9, modified adhesive. DETAILED DESCRIPTION

[0039] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0040] It should be noted that the terms used herein are only for the purpose of describing specific embodiments, and are not intended to limit the exemplary embodiments according to the application.

[0041] In the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0042] Embodiment one

[0043] The embodiment discloses an electric field measurement system for inside of super-high voltage GIS.

[0044] An electric field measurement system for inside of super-high voltage GIS, comprising: a laser 1, an electro-optic sensing probe 2, a photoelectric detector 3 and a test assembly.

[0045] The laser 1 is connected with the output end of the electro-optic sensing probe 2 based on Pockels effect through a polarization maintaining optical fiber 7 penetrating a first through hole 61 of an upper cover plate 5 of a GIS shell 4.

[0046] The electro-optic sensing probe 2 is fixed to the inner wall of the GIS shell 4 through a modified adhesive 9, and is axially parallel to the direction of the electric field inside the GIS; the output end of the electro-optic sensing probe 2 is connected with the photoelectric detector 3 through a single-mode optical fiber 8 penetrating a second through hole 62 of the upper cover plate 5 of the GIS shell 4.

[0047] The test assembly is used for response calibration of the electro-optic sensing probe 2; the electro-optic sensing probe adopts a serial double-wave plate design, and is used for non-contact electric field measurement inside the GIS after the response calibration is completed.

[0048] Based on the above systematic design, the present application can realize accurate non-contact electric field measurement inside the GIS with compact space. In order to facilitate the understanding of the technical scheme of the present application, the specific implementation method in the technical scheme of the present application is further explained and described below.

[0049] An electric field measurement system for inside of super-high voltage GIS, comprising: a laser 1, an electro-optic sensing probe 2, a photoelectric detector 3 and a test assembly.

[0050] As shown in Figure 3 The electro-optic sensing probe comprises, in sequence, a first optical fiber collimator, a polarizer, a 1 / 4 wave plate, an electro-optic crystal, a 1 / 2 wave plate, a polarimeter and a second optical fiber collimator.

[0051] The input end of the first optical fiber collimator is connected with the polarization maintaining optical fiber, the polarization maintaining optical fiber is used for transmitting the optical signal emitted by the laser to the first optical fiber collimator of the sensing probe, and the polarization state of the light is kept stable to avoid the influence of polarization state distortion on the measurement accuracy; the output end of the first optical fiber collimator is aligned with the input end of the polarizer; the output end of the polarizer is aligned with the input end of the 1 / 4 wave plate; the output end of the 1 / 4 wave plate is aligned with the input end of the electro-optic crystal; the output end of the electro-optic crystal is aligned with the input end of the 1 / 2 wave plate; the output end of the 1 / 2 wave plate is aligned with the input end of the analyzer; the output end of the analyzer is aligned with the input end of the second optical fiber collimator; and the output end of the second optical fiber collimator is connected with the single-mode optical fiber.

[0052] In the embodiment, the model of the laser is Thorlabs TLX1 C-Band, the center wavelength is set to 1550nm, the line width is 10 kHz, and the optical power is 0.02-20mW; the polarization maintaining optical fiber adopts PM1550 panda type optical fiber jumper; the models of the first optical fiber collimator and the second optical fiber collimator are both F280APC-1550; the single-mode optical fiber adopts SM1550 single-mode optical fiber jumper; and the model of the photodetector is PDB470C.

[0053] Further, the electro-optic sensing probe adopts a serial double-wave plate design, that is, the output end of the 1 / 4 wave plate in the electro-optic sensing probe is connected with the input end of the electro-optic crystal, which is used for generating a phase shift of between the two polarization components of the linearly polarized light passing through the polarizer; the output end of the electro-optic crystal is connected with the input end of the 1 / 2 wave plate, and the 1 / 2 wave plate is used for compensating the phase shift deviation to avoid inaccurate polarization state conversion or distortion of the mapping relationship between the light intensity change and the electric field intensity, thereby ensuring the accuracy and stability of the electric field measurement.

[0054] As shown in Figure 1 , the electro-optic sensing probe 2 is fixed to the inner wall of the GIS shell 4 through the epoxy resin adhesive in the modified adhesive, and is axially parallel to the internal electric field direction of the GIS. Moreover, the epoxy resin adhesive is provided with a buffer layer for buffering the vibration of the electro-optic sensing probe on the side in contact with the inner wall of the GIS.

[0055] Therefore, the electro-optic sensing probe based on the Pockels effect is adopted, and the epoxy resin adhesive is combined to realize the full insulation design. The electro-optic sensing probe has a compact structure, and can be flexibly installed on the inner wall of the GIS shell in cooperation with the epoxy resin adhesive, thereby solving the poor installation adaptability of the capacitive sensor; meanwhile, the full insulation design avoids the interference of the sensing components on the original electric field distribution in the GIS, and also does not damage the insulation structure of the equipment itself, thereby fundamentally eliminating the safety hazards caused by the characteristics of the sensor itself, and ensuring the stability and safety of the measurement environment.

[0056] As​Figure 1 As shown, the laser is connected with the output end of the Pockels effect-based electro-optic sensor probe through the polarization maintaining optical fiber penetrating the first via of the GIS shell cover plate; the output end of the electro-optic sensor probe is connected with the photoelectric detector through the single-mode optical fiber penetrating the second via of the GIS shell cover plate.

[0057] Based on the above electro-optic sensor probe adopting the serial double-wave plate design, the non-contact electric field measurement is carried out inside the GIS. Specifically, the Pockels effect is an electro-optic effect. When an electric field acts on certain crystal materials, the refractive index will change, thereby affecting the phase of the light wave passing through the crystal.

[0058] The Pockels effect-based optical electric field sensor probe (electro-optic sensor probe) is placed inside the GIS and fixed by using a high-strength insulating material epoxy resin adhesive. The optical fiber is led out of the GIS through the sealed interface type via 6 (i.e. the first via 61 and the second via 62 on the cover plate 5), ensuring that the air tightness of the GIS is not affected, thereby realizing the measurement of the electric field inside the GIS. As shown in Figure 2 The first via and the second via are filled with epoxy resin glue and covered with a silicone layer to form a double-sealing structure. Among them, Figure 2 (a) is a sectional view of the cover plate under partial enlargement, Figure 2 (b) is a plan view of the cover plate under partial enlargement.

[0059] In actual work process, the light beam is adjusted to linearly polarized light by the polarizer, and the size and phase of the polarization components of the light beam in z direction and y direction are the same. After passing through the 1 / 4 wave plate, the phase shift between the two polarization components of the light beam is , which is circularly polarized light. When there is an electric field, the crystal is anisotropic, the refractive index experienced by the two polarization components is different and has a linear relationship with the amplitude of the electric field, resulting in a linear relationship between the phase shift between the polarization components of the light beam in z direction and y direction and the size of the electric field. At this time, the light beam shows elliptical polarization, that is:

[0060] ;

[0061] Among them, represents the intrinsic refractive index of the electro-optic crystal, represents the electro-optic coefficient of the electro-optic crystal, represents the length of the light transmission direction of the electro-optic crystal, represents the electric field intensity, represents the wavelength of the light beam, represents the elliptical polarization.

[0062] When the light beam passes through the 1 / 2 wave plate, the phase difference increases to supplement, that is:

[0063] ;

[0064] The light beam is adjusted to linear polarization after passing through the polarizer, and the change of the phase shift between the two polarization components of the light beam is converted into the change of the light intensity, and the phase shift is measured by detecting the light intensity of the light beam, that is:

[0065] ;

[0066] Wherein, represents the output light power, represents the input light power; represents the elliptical polarization after 1 / 2 wave plate processing. Thus, by detecting the output light power The information of the change of the electric field can be obtained.

[0067] When the condition is met, the following expression can be obtained, that is:

[0068] ;

[0069] ;

[0070] Wherein, represents the average field strength inside the crystal. Based on this, the modulation relationship of the external electric field to the light power can be obtained, and after the light signal is received by the backend photodetector, the light power can be converted into the corresponding electric signal.

[0071] In order to ensure the measurement accuracy of the electro-optic sensing probe, the present application also constructs a test assembly to calibrate the response of the electro-optic sensing probe. The test assembly includes a power supply, an electrode unit, a measurement unit and a fast pulse voltage generating device. Among them, the power supply includes a high-voltage alternating current generator, a direct current source and an impact source, which are respectively used to test the response characteristics of the electro-optic sensing probe under alternating current, direct current and impact electric field; the fast pulse voltage generating device is used to test the time domain response characteristics of the electro-optic sensing probe under pulse electric field. In the actual application process, based on the test assembly, the linearity characteristics of the electro-optic sensing probe under different electric field strengths and the time domain response characteristics under pulse electric field are tested in turn, so as to obtain the applicable electric field range and measurement bandwidth of the electro-optic sensing probe. Thus, by testing the time domain response characteristics under pulse electric field through the fast pulse voltage generating device, the electro-optic sensing probe has the characteristics of wide frequency band and high response speed, which can cover various electric field measurement requirements of super-high voltage GIS under complex working conditions, and effectively breaks through the limitations of the prior art in measurement range and dynamic response.

[0072] In order to further prove the significant advantages of the present application, the following experimental verification is made in this embodiment:

[0073] As Figure 4The GIS Laplace field curve measured by the embodiment in the laboratory true model 1100kV GIS experimental platform without partial discharge is shown, which is used to represent the Laplace field. Figure 4 It can be seen from the above that the electric field measurement system provided by the embodiment can stably measure the 50Hz power frequency electric field, and thus can measure the electric field inside the GIS. Figure 5 The test result schematic diagram of the linearity test of the electro-optic sensing probe by the laboratory linearity test platform is shown, and the linearity test platform is composed of a voltage regulator, a power frequency test transformer, a protection resistor and parallel plate electrodes. Figure 5 It can be seen from the above that the fitting straight line passes through the data points, that is, the applied electric field and the sensor response are in a linear relationship, so the linearity of the electro-optic sensing probe is good, and the performance is excellent.

[0074] Embodiment two

[0075] The embodiment discloses an electric field measurement method for inside a super-high voltage GIS.

[0076] An electric field measurement method for inside a super-high voltage GIS, comprising:

[0077] Based on the test assembly, the response of the electro-optic sensing probe is calibrated.

[0078] Based on the calibrated electro-optic sensing probe, non-contact electric field measurement is carried out inside the GIS.

[0079] Further, the response calibration of the electro-optic sensing probe comprises: based on the test assembly, the linearity characteristics of the electro-optic sensing probe under different electric field intensities and the time domain response characteristics under the pulse electric field are tested in sequence, so as to obtain the applicable electric field range and the measurement bandwidth of the electro-optic sensing probe.

[0080] Although the specific embodiments of the present application are described above with reference to the drawings, it is not a limitation on the protection scope of the present application, and those skilled in the art should understand that various modifications or changes made on the basis of the technical solutions of the present application without creative labor are still within the protection scope of the present application.

Claims

1. An electric field measurement system for use in an ultra extra high voltage GIS, characterized in that, The application relates to a GIS (Gas Insulated Switchgear) electric field sensor and a test assembly thereof. The laser is connected with the output end of the Pockels effect-based electro-optic sensor probe through a polarization maintaining optical fiber penetrating a first through hole of a GIS cover plate. The electro-optic sensor probe is fixed to the inner wall of the GIS through a modified adhesive, and is axially parallel to the internal electric field direction of the GIS; the output end of the electro-optic sensor probe is connected with a photoelectric detector through a single-mode optical fiber penetrating a second through hole of the GIS cover plate. The test assembly is used for response calibration of the electro-optic sensor probe. The electro-optic sensor probe adopts a serial double-wave plate design and is used for non-contact electric field measurement in the GIS after the response calibration is completed. The electro-optic sensor probe comprises a first optical fiber collimator, a polarizer, a 1 / 4 wave plate, an electro-optic crystal, a 1 / 2 wave plate, a polarimeter and a second optical fiber collimator which are sequentially aligned. The output end of the electro-optic crystal is connected with the input end of the 1 / 2 wave plate, and the 1 / 2 wave plate is used for compensating phase shift deviation. The electro-optic sensing probe adopts a serial double-wave plate design, specifically: the output end of the 1 / 4 wave plate in the electro-optic sensing probe is connected to the input end of the electro-optic crystal, for generating a phase shift between the two polarization components of the linearly polarized light passing through the polarizer ; The test assembly comprises a power supply, an electrode unit and a measurement unit; wherein the power supply comprises an AC high-voltage generator, a DC source and an impulse source which are respectively used for testing the response characteristics of the electro-optic sensor probe under AC, DC and impulse electric fields. The test assembly further comprises a fast pulse voltage generating device which is used for testing the time-domain response characteristics of the electro-optic sensor probe under a pulse electric field. The input end of the first optical fiber collimator is connected with the polarization maintaining optical fiber, and the output end of the second optical fiber collimator is connected with the single-mode optical fiber.

2. A system for electric field measurement inside an ultra-extra high voltage GIS according to claim 1, characterized in that, The modified adhesive is an epoxy resin adhesive. The epoxy resin adhesive is provided with a buffer layer for buffering the vibration of the electro-optic sensor module on the side in contact with the inner wall of the GIS.

3. A system for electric field measurement inside an ultra-extra high voltage GIS according to claim 1, characterized in that, The first through hole and the second through hole are filled with epoxy resin adhesive and covered with a silica gel layer, forming a double-sealing structure.

4. A system for electric field measurement inside an ultra-extra high voltage GIS according to claim 3, characterized in that, The application relates to a GIS (Gas Insulated Switchgear) electric field sensor and a test assembly thereof.

5. The electric field measurement system for use in the interior of an ultra- extra high voltage GIS according to claim 1, characterized in that, The application relates to a GIS (Gas Insulated Switchgear) electric field sensor and a test assembly thereof.

6. A method for measuring electric field inside EHT GIS using the electric field measuring system for measuring electric field inside EHT GIS according to claim 1, characterized in that, The application relates to a GIS (Gas Insulated Switchgear) electric field sensor and a test assembly thereof. ​ ​ 7. A method for electric field measurement inside an ultra-extra high voltage GIS as claimed in claim 6, characterized in that, ​

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