Verification device of ultrahigh frequency partial discharge detection device based on GTEM cell

Abstract

The utility model discloses a verification device of an ultrahigh frequency partial discharge detection device based on a GTEM cell, comprising a calibration signal source, a GTEM cell, a test tool and a radio frequency coaxial cable, the calibration signal source is connected to a feed interface of the GTEM cell through the radio frequency coaxial cable, the top of the GTEM cell is provided with a sensor coupling window, and the coupling window is provided with the test tool; the tested ultrahigh frequency sensor is placed close to the coupling window and is connected to the ultrahigh frequency partial discharge detection device through a radio frequency coaxial cable; the tested ultrahigh frequency sensor couples an electric field signal in the GTEM cell through a test tool arranged at the coupling window and converts the electric field signal into voltage, and the voltage is transmitted to the tested ultrahigh frequency partial discharge detection device through the radio frequency coaxial cable. The calibration signal source simulates different pulse signals, the pulse signals are transmitted to the GTEM cell through the radio frequency coaxial cable, and electric field signals are formed in the GTEM cell, so that the tested sensor can perform discharge detection at a coupling window, and the test accuracy and repeatability are improved.

Description

Technical Field

[0001] The utility model relates to a device for verifying a discharge detection device, in particular to a verification device for a UHF local discharge detection device based on a GTEM cell. Background Art

[0002] UHF partial discharge detection is the main monitoring method for defects in power transmission and transformation equipment, especially GIS (gas insulated switchgear) and GIL (gas insulated transmission line) equipment. It can timely detect partial discharge phenomena inside the equipment, predict the life and status of the equipment, and ensure the reliable operation of the equipment. It has been widely used in the power industry. However, the existing UHF partial discharge live detection devices have the following problems: low sensitivity, the amplitude of the UHF partial discharge signal is usually small, especially in high-voltage equipment, the signal is masked by noise, resulting in reduced detection sensitivity; large interference, the UHF partial discharge signal is often confused by other interference sources, such as power supply noise, radio interference, etc., which will reduce the accuracy of detection; high equipment cost, in order to improve the sensitivity and accuracy of detection, high-quality and high-precision hardware equipment is required, which undoubtedly increases the cost of the equipment; data analysis is difficult, the frequency range of the UHF partial discharge signal is usually very high, which makes signal processing and analysis more difficult.

[0003] Therefore, in order to ensure that the detection device can detect partial discharge faults in a timely and accurate manner during the operation of electrical equipment, it is necessary to effectively verify the parameters such as the effective height, sensitivity, dynamic range, etc. of the detection device. Utility Model Content

[0004] In order to solve the deficiencies in the prior art, the purpose of the utility model is to provide a calibration device for a UHF partial discharge detection device based on a GTEM cell.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] A calibration device for a UHF partial discharge detection device based on a GTEM chamber comprises a calibration signal source, a GTEM chamber, a test fixture, and a radio frequency coaxial cable, and is used to calibrate the UHF partial discharge detection device; the calibration signal source is connected to a feed interface at the front end of the GTEM chamber through the radio frequency coaxial cable, a sensor coupling window is arranged on the GTEM chamber, and a test fixture is arranged at the coupling window; a UHF sensor to be tested is placed close to the coupling window and connected to the UHF partial discharge detection device through the radio frequency coaxial cable; the UHF sensor to be tested is coupled to an electric field signal in the GTEM chamber through the test fixture arranged at the coupling window and converted into a voltage, and transmitted to the UHF partial discharge detection device to be tested through the radio frequency coaxial cable;

[0007] Furthermore, the lower surface of the coupling sensor is parallel to the upper surface of the GTEM cell and is higher than the inclined surface.

[0008] Furthermore, the test fixture is connected to the coupling window in a snap-fit ​​manner.

[0009] Furthermore, the outer shell of the GTEM cell is a shielding shell, which is composed of two side plates, upper and lower cover plates, and a rear cover to form a closed shell.

[0010] Furthermore, a bracket is arranged below the shielding shell, a coupling window is arranged on the upper cover plate, and a shielding door is arranged on one side plate.

[0011] Furthermore, a core board is arranged inside the shielding shell at a position corresponding to the upper cover plate. The core board serves as an inner conductor and forms a conical coaxial transmission cavity with the shielding shell. The front end of the core board is connected to the feeding interface, and the rear end of the core board is connected to the rear cover of the shell through an impedance board.

[0012] Furthermore, a wave-absorbing material is arranged on the inner side of the rear cover.

[0013] Furthermore, the test tooling includes insulating basin tooling and casting hole tooling for GIS equipment of different manufacturers, different models and different voltage levels, and the tooling can be replaced according to different tested products.

[0014] Furthermore, the pulse amplitude of the calibration signal source is designed to have a step value of 5mV in the 0-5V range, the pulse repetition frequency is adjustable from 50Hz to 200Hz, and the output impedance of the signal source is 50Ω.

[0015] Furthermore, the shielding shell is made of aluminum plate and has a rectangular cross-section trumpet-shaped structure. The two side plates and the upper and lower cover plates are all triangular, and the rear cover is rectangular.

[0016] Furthermore, the core plate is a triangular structure of aluminum material with a 30° opening angle, and the rear end of the core plate is connected to the rear cover of the shell through an impedance plate.

[0017] Furthermore, a φ200mm coupling window is provided at a distance of 1 / 4 from the rear end of the upper cover plate.

[0018] Compared with the prior art, the beneficial effects of the utility model are as follows: by simulating different pulse signals through the calibration signal source, pulse signals of different types and intensities can be generated, so that the performance under different conditions can be tested, and then the pulse signal is transmitted to the GTEM chamber through the radio frequency coaxial cable, which can ensure the stability and transmission efficiency of the signal, avoid the attenuation and interference of the signal during the transmission process, and form an electric field signal in the GTEM chamber, which can provide a stable and controllable electric field environment, so that the sensor under test can perform discharge detection in the coupling window, thereby improving the accuracy and repeatability of the test; it is easy to install and easy to operate, and different test fixtures can be replaced according to different types of ultra-high frequency sensors, which is suitable for the calibration of different discharge detection devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0020] Figure 1 It is a schematic diagram of the overall structure of the verification device of the ultra-high frequency partial discharge detection device based on the GTEM cell of the present invention;

[0021] Figure 2 It is a schematic diagram of the structure of the GTEM cell of the present invention;

[0022] Figure 3 is a schematic diagram of a control panel for a calibration signal source of the present invention;

[0023] In the figure: 1-1, two side plates, 1-2, upper and lower cover plates, 1-3, back cover, 2, shielding door, 3, bracket, 4, coupling window, 5, feeding interface, 6, core plate, 7, impedance plate, 8, absorbing material. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Example 1

[0026] like Figure 1As shown, it is a schematic diagram of the overall structure of the calibration device of the ultra-high frequency partial discharge detection device based on the GTEM chamber of the present invention, which is composed of a calibration signal source, a GTEM chamber, a test fixture and matching RF coaxial cables and other components, and is used to calibrate the ultra-high frequency partial discharge detection device (including the sensor); wherein the test fixture is the triangular part on both sides of the sensor (circular ring shape from a perspective perpendicular to the inclined plane), and is connected to the GTEM chamber by a snap-fit ​​method.

[0027] Example 2

[0028] The minimum transient electric field intensity peak value that can be detected by the UHF partial discharge detection device (including sensor) is its sensitivity, unit: V / m.

[0029] Test process: A calibration signal source is connected to the feed interface 5 of the GTEM chamber through an RF coaxial cable, and a signal is injected into the GTEM chamber to establish an electric field signal covering a frequency band of 300MHz to 1.5GHz in the GTEM chamber. The UHF sensor under test collects the electric field signal in the GTEM chamber through a test fixture placed at the coupling window and converts it into a voltage, which is transmitted to the UHF partial discharge detection device under test through an RF coaxial cable. The signal processing device controls the output amplitude of the calibration signal source through the serial port and adjusts the output voltage of the calibration signal source until the detection device can reliably reflect the verification signal with a signal-to-noise ratio of not less than 2. The incident field strength at this time is calculated, and the field strength is the sensitivity of the detection device.

[0030] Example 3

[0031] The ratio of the maximum transient electric field intensity peak value that can be detected by the ultra-high frequency partial discharge live detection device (including sensor) to the sensitivity is called the system dynamic range, unit: dB.

[0032] Test process: After the sensitivity test is completed, continue to adjust the output voltage of the calibration signal source. When the output of the calibration signal source increases to a certain value, the signal measured by the detection device reaches saturation. Exceeding this value will cause the detection device to record and display overflow. Calculate the incident field strength at this time. This field strength is the maximum measurable transient field strength peak of the detection device. Calculate the multiple relationship between the maximum measurable transient electric field strength peak and the device sensitivity to obtain the dynamic range of the device.

[0033] Example 4

[0034] like Figure 2 As shown, Figure 2 It is a schematic diagram of the GTEM cell structure of the present invention.

[0035] The GTEM chamber is an electromagnetic wave test chamber in which the longitudinal components of the electric field and the magnetic field along the propagation direction are both zero and only the modal components are present. It is composed of a shielding shell, a shielding door 2, a bracket 3 and other components, and is provided with a coupling window 4 and a feeding interface 5. A core board 6, an impedance board 7 and an absorbing material 8 are also provided inside.

[0036] Example 5

[0037] The shielding shell includes two side plates 1-1, upper and lower cover plates 1-2, and a back cover 1-3. The two side plates 1-1 and the upper and lower cover plates 1-2 are all triangular, and the back cover 1-3 is rectangular, forming a closed shell with a rectangular cross-section horn-shaped structure.

[0038] Example 6

[0039] The shielding shell is made of aluminum plate and has a rectangular cross-section horn-shaped structure, which can effectively shield external electromagnetic interference signals.

[0040] Example 7

[0041] A bracket 3 is provided below the shielding shell for stably placing the shielding shell on the ground.

[0042] Example 8

[0043] A coupling window 4 is provided on the upper cover plate, and a shielding door 2 is provided on one side plate to facilitate installation and operation by personnel.

[0044] Example 9

[0045] A core board 6 is arranged inside the shielding shell at a position corresponding to the upper cover plate. The core board 6 is a triangular structure made of aluminum with a 30° opening angle, which can effectively conduct electromagnetic wave signals. The core board 6 serves as an inner conductor and forms a conical coaxial transmission cavity with the shielding shell. The front end of the core board 6 is connected to the feeding interface 5, and the rear end of the core board 6 is connected to the rear cover of the shell through a 50Ω impedance board 7, and an absorbing material 8 is installed on the inner side of the rear cover of the shell to effectively prevent signal reflection from affecting the test results.

[0046] Example 10

[0047] A φ200mm coupling window is set at 1 / 4 of the rear end of the upper cover plate. Test fixtures for different types of UHF sensors are set at the coupling window, including insulating basin fixtures and casting hole fixtures that simulate GIS equipment of different manufacturers, models and voltage levels. The fixtures can be replaced according to different tested products.

[0048] Embodiment 11

[0049] like Figure 3As shown, turn on the calibration signal source control panel switch to generate a picosecond double-exponential pulse signal with adjustable pulse repetition frequency and voltage amplitude, which can form a stable, uniform calibration pulse electromagnetic field with a spectrum coverage of up to GHz inside the GTEM cell, which is used to calibrate the effective height, sensitivity and dynamic range of partial discharge ultra-high frequency sensors and detection devices. The key indicators of the calibration signal source include pulse amplitude, pulse rising edge, half-wave time, repetition frequency, output impedance, etc.

[0050] Example 12

[0051] The pulse amplitude of the calibration signal source is designed to have a step value of 5mV in the 0-5V gear, so that the sensitivity value of the detection device can be measured more accurately. The step value is designed to be 1V in the 5-200V gear to meet the test of the dynamic range of the detection system. The rising edge time of the pulse signal is inversely proportional to the signal spectrum coverage range. The rising edge time determines the spectrum coverage range of the signal. In order to ensure accurate measurement of the effective height value of the sensor within 300MHz-1.5GHz, the rising edge time (20%-80%) of the calibration signal source should not be greater than 250ps, and the half-wave time should be in the range of 4ns-100ns, which can cover various typical partial discharge signal spectrum characteristics. The pulse repetition frequency is adjustable from 50Hz to 200Hz and is an integer multiple of the power frequency period. In order to ensure the output of the maximum power of the signal and avoid the influence of signal reflection on the output power, the output impedance of the signal source is 50Ω.

[0052] Example 13

[0053] The pulse amplitude of the calibration signal source is designed to have a step value of 5mV in the 0-5V range, so that the sensitivity value of the detection device can be measured more accurately. The step value is designed to be 1V in the 5-200V range to meet the test of the dynamic range of the detection system. The rising edge time of the pulse signal is inversely proportional to the signal spectrum coverage range. The rising edge time determines the spectrum coverage range of the signal. In order to ensure accurate measurement of the effective height value of the sensor within 300MHz~1.5GHz, the rising edge time (20%~80%) of the calibration signal source should be 50ps, and the half-wave time should be 4ns. The pulse repetition frequency is 50Hz, and it is an integer multiple of the power frequency period. In order to ensure the output of the maximum power of the signal and avoid the influence of signal reflection on the output power, the output impedance of the signal source is 50Ω.

[0054] Embodiment 14

[0055] The pulse amplitude of the calibration signal source is designed to have a step value of 5mV in the 0-5V range, so that the sensitivity value of the detection device can be measured more accurately. The step value is designed to be 1V in the 5-200V range to meet the test of the dynamic range of the detection system. The rising edge time of the pulse signal is inversely proportional to the signal spectrum coverage range. The rising edge time determines the spectrum coverage range of the signal. In order to ensure accurate measurement of the effective height value of the sensor within 300MHz~1.5GHz, the rising edge time (20%~80%) of the calibration signal source should be 200ps, and the half-wave time should be 100ns. The pulse repetition frequency is 200Hz, and it is an integer multiple of the power frequency period. In order to ensure the output of the maximum power of the signal and avoid the influence of signal reflection on the output power, the output impedance of the signal source is 50Ω.

[0056] Embodiment 15

[0057] The pulse amplitude of the calibration signal source is designed to have a step value of 5mV in the 0-5V range, so that the sensitivity value of the detection device can be measured more accurately. The step value is designed to be 1V in the 5-200V range to meet the test of the dynamic range of the detection system. The rising edge time of the pulse signal is inversely proportional to the signal spectrum coverage range. The rising edge time determines the spectrum coverage range of the signal. In order to ensure accurate measurement of the effective height value of the sensor within 300MHz~1.5GHz, the rising edge time (20%~80%) of the calibration signal source should not be greater than 100ps, and the half-wave time should be 52ns. The pulse repetition frequency is 125Hz, and it is an integer multiple of the power frequency period. In order to ensure the output of the maximum power of the signal and avoid the influence of signal reflection on the output power, the output impedance of the signal source is 50Ω.

[0058] Example 16

[0059] The pulse amplitude of the calibration signal source is designed to have a step value of 5mV in the 0-5V range, so that the sensitivity value of the detection device can be measured more accurately. The step value is designed to be 1V in the 5-200V range to meet the test of the dynamic range of the detection system. The rising edge time of the pulse signal is inversely proportional to the signal spectrum coverage range. The rising edge time determines the spectrum coverage range of the signal. In order to ensure accurate measurement of the effective height value of the sensor within 300MHz~1.5GHz, the rising edge time (20%~80%) of the calibration signal source should be 150ps, and the half-wave time should be within 28ns. The pulse repetition frequency is 90Hz, and it is an integer multiple of the power frequency period. In order to ensure the output of the maximum power of the signal and avoid the influence of signal reflection on the output power, the output impedance of the signal source is 50Ω.

[0060] Embodiment 17

[0061] The pulse amplitude of the calibration signal source is designed to have a step value of 5mV in the 0-5V range, so that the sensitivity value of the detection device can be measured more accurately. The step value is designed to be 1V in the 5-200V range to meet the test of the dynamic range of the detection system. The rising edge time of the pulse signal is inversely proportional to the signal spectrum coverage range. The rising edge time determines the spectrum coverage range of the signal. In order to ensure accurate measurement of the effective height value of the sensor within 300MHz~1.5GHz, the rising edge time (20%~80%) of the calibration signal source should be 75ps, and the half-wave time should be within 80ns. The pulse repetition frequency is 100Hz, and it is an integer multiple of the power frequency period. In order to ensure the output of the maximum power of the signal and avoid the influence of signal reflection on the output power, the output impedance of the signal source is 50Ω.

[0062] Embodiment 18

[0063] The pulse amplitude of the calibration signal source is designed to have a step value of 5mV in the 0-5V range, so that the sensitivity value of the detection device can be measured more accurately. The step value is designed to be 1V in the 5-200V range to meet the test of the dynamic range of the detection system. The rising edge time of the pulse signal is inversely proportional to the signal spectrum coverage range. The rising edge time determines the spectrum coverage range of the signal. In order to ensure accurate measurement of the effective height value of the sensor within 300MHz~1.5GHz, the rising edge time (20%~80%) of the calibration signal source should be 125ps, and the half-wave time should be within 90ns. The pulse repetition frequency is 180Hz, and it is an integer multiple of the power frequency period. In order to ensure the output of the maximum power of the signal and avoid the influence of signal reflection on the output power, the output impedance of the signal source is 50Ω.

[0064] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0065] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation" and the like should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; "connection" can be a mechanical connection or an electrical connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0066] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0067] The implementation examples of the utility model are illustrated and described in detail in conjunction with the drawings in the specification. However, those skilled in the art should understand that the above implementation examples are only preferred implementation schemes of the utility model, and the detailed description is only to help readers better understand the spirit of the utility model, but not to limit the protection scope of the utility model. On the contrary, any improvements or modifications based on the inventive spirit of the utility model should fall within the protection scope of the utility model.

Claims

1. A calibration device for a UHF partial discharge detection device based on a GTEM cell, characterized in that: The device comprises a calibration signal source, a GTEM chamber, a test fixture, and a radio frequency coaxial cable. The calibration signal source is connected to a feed interface (5) at the front end of the GTEM chamber via the radio frequency coaxial cable. A sensor coupling window (4) is provided on the GTEM chamber, and a test fixture is provided at the coupling window (4). A tested ultra-high frequency sensor is provided above the coupling window (4) and connected to an ultra-high frequency partial discharge detection device via the radio frequency coaxial cable. The tested ultra-high frequency sensor couples an electric field signal in the GTEM chamber via the test fixture provided at the coupling window (4) and converts the electric field signal into a voltage, which is then transmitted to the tested ultra-high frequency partial discharge detection device via the radio frequency coaxial cable.

2. The verification device of the ultra-high frequency partial discharge detection device based on the GTEM cell according to claim 1, characterized in that: The GTEM cell shell is a shielding shell, which is composed of two side plates (1-1), upper and lower cover plates (1-2), and a rear cover (1-3), forming a closed shell.

3. The verification device of the ultra-high frequency partial discharge detection device based on the GTEM cell according to claim 2, characterized in that: A bracket (3) is arranged below the shielding shell, a coupling window (4) is arranged on the upper cover plate, and a shielding door (2) is arranged on one side plate.

4. The verification device of the ultra-high frequency partial discharge detection device based on the GTEM cell according to claim 2, characterized in that: A core plate (6) is arranged at a position inside the shielding shell corresponding to the upper cover plate, and the core plate serves as an inner conductor and forms a conical coaxial transmission cavity with the shielding shell; the front end of the core plate (6) is connected to the feeding interface (5), and the rear end of the core plate (6) is connected to the rear cover of the shell via an impedance plate (7).

5. The verification device of the ultra-high frequency partial discharge detection device based on the GTEM cell according to claim 2, characterized in that: A wave absorbing material (8) is arranged on the inner side of the back cover (1-3).

6. The verification device of the ultra-high frequency partial discharge detection device based on the GTEM cell according to claim 1, characterized in that: The test tooling is an insulating basin tooling and a pouring hole tooling of the GIS equipment.

7. The verification device of the ultra-high frequency partial discharge detection device based on the GTEM cell according to claim 1, characterized in that: The pulse amplitude of the calibration signal source is designed to have a step value of 5mV in the 0-5V range, a pulse repetition frequency of 50Hz-200Hz, and a signal source output impedance of 50Ω.

8. The verification device of the ultra-high frequency partial discharge detection device based on the GTEM cell according to claim 2, characterized in that: The shielding shell is made of aluminum plate and is a horn-shaped structure with a rectangular cross-section. The two side plates (1-1) and the upper and lower cover plates (1-2) are all triangular, and the rear cover (1-3) is rectangular.

9. The verification device of the ultra-high frequency partial discharge detection device based on the GTEM cell according to claim 4, characterized in that: The core plate (6) is a triangular structure made of aluminum with an opening angle of 30°, and the rear end of the core plate (6) is connected to the rear cover (1-3) via an impedance plate (7).

10. The verification device of the ultra-high frequency partial discharge detection device based on the GTEM cell according to claim 1, characterized in that: A φ200mm coupling window (4) is arranged at a distance of 1 / 4 from the rear end of the upper cover plate.

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