Verification method for GIS partial discharge medium window type ultrahigh frequency sensor

Abstract

The invention discloses a verification method for a GIS partial discharge medium window type ultrahigh frequency sensor, and relates to the field of partial discharge ultrahigh frequency sensor verification. According to the method, a standard ultrahigh-frequency sensor and an ultrahigh-frequency sensor to be verified are arranged on a GIS defect simulation device, a network analyzer is utilized to inject a discharge signal, and the ultrahigh-frequency sensor to be verified is verified by measuring the signal amplitude and background noise of the sensor to be verified at a dielectric window flange opening. And the maximum installation height hmax of the ultrahigh frequency sensor is calculated by combining the waveguide cut-off theory and the medium transmission characteristics according to the diameter of the metal disc antenna of the ultrahigh frequency sensor to be verified and the diameter of the medium window. According to the invention, the GIS ultrahigh frequency sensor can be verified on site without power failure, the problem of overlarge signal attenuation caused by improper installation depth of the sensor in the prior art is effectively solved, and the accuracy and reliability of the verification result are ensured.

Description

Technical Field

[0001] This invention relates to the field of partial discharge ultra-high frequency sensor calibration technology, and more specifically, to a calibration method for a GIS partial discharge dielectric window type ultra-high frequency sensor. Background Technology

[0002] Gas-insulated switchgear (GIS) is a core switching device in power systems, and its insulation condition directly affects the safe operation of the power grid. Partial discharge is a major cause of insulation degradation in high-voltage equipment and a precursor to insulation faults. Ultra-high frequency (UHF) detection technology, due to its high sensitivity and strong anti-interference capabilities, has been widely applied to online partial discharge monitoring of GIS.

[0003] However, during long-term operation, the performance of UHF sensors can degrade due to aging, corrosion, physical damage, and other factors, leading to a decrease in sensitivity. The installation method and location of the UHF sensor can also affect signal reception. This can result in the inability to promptly detect and warn of partial discharges within the GIS system, potentially causing serious consequences. Therefore, regular sensor calibration is necessary.

[0004] In actual operation, UHF sensors are mostly installed inside the media window of GIS (Gas Insulation System). The installation depth of the UHF sensor will affect the calibration results. If the installation depth is too shallow, the UHF signal attenuation will be too large, leading to missed detections and affecting the calibration of the UHF sensor. If the installation depth is too large, it will affect the insulation. Summary of the Invention

[0005] The present invention will be described in detail through the following specific embodiments to fully illustrate the technical solution and expected effects of the present invention.

[0006] This invention provides a method for calibrating a GIS partial discharge dielectric window-type ultra-high frequency sensor, the method comprising the following steps:

[0007] Step 1: Design a gas-insulated switchgear (GIS) defect simulation device, which includes a GIS housing, a standard UHF sensor, a UHF sensor to be calibrated, a network analyzer, and a coaxial cable.

[0008] Step 2: Connect the first port of the network analyzer to the standard UHF sensor via a coaxial cable, and connect the second port of the network analyzer to the UHF sensor to be calibrated via a coaxial cable.

[0009] Step 3: Use a network analyzer to inject a discharge signal into the standard UHF sensor, and use the UHF sensor to be calibrated to receive the signal. Based on the diameter of the metal disk antenna and the diameter of the dielectric window manhole of the UHF sensor to be calibrated, establish a model of the maximum installation height of the UHF sensor to be calibrated.

[0010] Furthermore, both the standard UHF sensor and the UHF sensor to be calibrated in step 1 are disc-type sensors, installed inside the medium window.

[0011] Furthermore, the maximum installation height of the UHF sensor to be verified is:

[0012] ;

[0013] In the formula, D s D is the diameter of the sensor's metal disk antenna. h h is the diameter of the medium window handhole. w U is the dielectric window thickness, U0 is the voltage amplitude measured at the UHF sensor to be calibrated when h=0, and U min The noise floor voltage amplitude is measured at the ultra-high frequency sensor under test when there is no partial discharge signal h=0. The relative permittivity of the window medium, The relative permittivity of the transformer oil;

[0014] This is the interface transmittance correction factor. ;

[0015] The installation depth h of the UHF sensor to be verified must meet h <H max .

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] This invention enables on-site calibration of GIS UHF sensors without power interruption, effectively solving the problem of excessive signal attenuation caused by improper sensor installation height in existing technologies, and ensuring the accuracy and reliability of calibration results. Attached Figure Description

[0018] Figure 1 This is a flowchart of the calibration method for a GIS partial discharge dielectric window-type ultra-high frequency sensor provided in this invention;

[0019] Figure 2 This is a schematic diagram of the GIS media window structure provided in this invention;

[0020] Figure 3 This is a schematic diagram illustrating the verification of the UHF partial discharge sensor for GIS provided in this invention.

[0021] Numbering on the map:

[0022] 1-GIS housing; 2-Flange; 3-UHF sensor to be calibrated; 4-Dielectric sealing plate; 5-Metal disc antenna; 6-Standard UHF sensor; 7-UHF sensor to be calibrated; 8-Network analyzer; 9-Coaxial cable. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1

[0025] Figure 1 This is a flowchart of the calibration method for a GIS partial discharge dielectric window-type ultra-high frequency sensor provided in this invention, as shown below. Figure 1 As shown, this verification method can be applied in actual field situations. The method includes the following steps:

[0026] Step 1: Design a gas-insulated switchgear (GIS) defect simulation device. The device includes a GIS housing 1, a standard UHF sensor 6, a UHF sensor to be calibrated 7, a network analyzer 8, a coaxial cable 9, and a GIS media window.

[0027] An opening is made at a designated location on the GIS housing 1, and the opening is sealed with a media sealing plate 4 to ensure the airtightness of the GIS. The UHF sensor 7 to be calibrated is then installed at the media window to detect the UHF signal. This installation location is the most common in field applications, ensuring consistency between the calibration process and the actual application environment. A standard UHF sensor 6 is installed at the same horizontal position on the GIS housing 1, and a coaxial cable 9 connects the network analyzer 8 to the standard UHF sensor 6.

[0028] Step 2: Connect the first port of the network analyzer 8 to the standard UHF sensor 6 via coaxial cable 9, and connect the second port of the network analyzer 8 to the UHF sensor 7 to be calibrated via coaxial cable 9.

[0029] In this embodiment of the invention, a network analyzer 8 is used to inject a discharge signal into a standard UHF sensor 6.

[0030] Step 3: Use network analyzer 8 to inject discharge signal into standard UHF sensor 6, use UHF sensor 7 to receive signal, and establish maximum installation height model of UHF sensor 7 based on disk diameter and medium window manhole diameter.

[0031] In this embodiment of the invention, a network analyzer 8 is connected to a UHF sensor 7 to be calibrated via a coaxial cable 9. The UHF sensor 7 to be calibrated is used to receive signals and collect signal parameters of the UHF sensor 7 to be calibrated.

[0032] The UHF sensor 7 to be calibrated is installed inside the media window of the GIS housing 1. The maximum installation height of the UHF sensor 7 to be calibrated is:

[0033] ;

[0034] In the formula, D s The diameter of the sensor's metal disk antenna is D. h h is the diameter of the medium window handhole. w The dielectric window thickness is set to 20 mm, and U0 is the voltage amplitude measured at the UHF sensor to be calibrated when h=0. min The noise floor voltage amplitude is measured at the ultra-high frequency sensor under test when there is no partial discharge signal h=0. The relative permittivity of the window medium is taken as 4.0. The relative permittivity of the transformer oil is taken as 2.3;

[0035] This is the interface transmittance correction factor. ;

[0036] The installation depth h of the UHF sensor 7 to be calibrated must meet h. <H max .

[0037] This invention involves arranging a standard UHF sensor 6 and a UHF sensor 7 to be calibrated on a GIS defect simulation device. A network analyzer 8 injects a discharge signal, and by measuring the signal amplitude and background noise of the sensor 7 at the dielectric window flange (h=0), as well as the diameter of the metal disk antenna 5 and the dielectric window diameter of the UHF sensor 7, and combining waveguide cutoff theory and dielectric transmission characteristics, the maximum installation height h of the UHF sensor 7 to be calibrated is calculated. max This invention enables on-site calibration of GIS UHF sensors without power interruption, effectively solving the problem of excessive signal attenuation caused by improper sensor installation depth in existing technologies, and ensuring the accuracy and reliability of calibration results.

[0038] The above description is merely an illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific structure described, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, and all such modifications or additions should fall within the protection scope of the present invention.

Claims

1. A method for verifying a GIS partial discharge dielectric window-type ultra-high frequency sensor, characterized in that, The method includes the following steps: Step 1: Design a gas-insulated switchgear (GIS) defect simulation device, which includes a GIS housing (1), a standard UHF sensor (6), a UHF sensor to be calibrated (7), a network analyzer (8), and a coaxial cable (9). Step 2: Connect the first port of the network analyzer (8) to the standard UHF sensor (6) via a coaxial cable (9), and connect the second port of the network analyzer (8) to the UHF sensor to be verified (7) via a coaxial cable (9). Step 3: Use a network analyzer (8) to inject a discharge signal into the standard UHF sensor (6), and use the UHF sensor to be verified (7) to receive the signal. Based on the diameter of the metal disk antenna (5) and the diameter of the dielectric window hand hole of the UHF sensor to be verified (7), establish the maximum installation height model of the UHF sensor to be verified (7).

2. The calibration method for a GIS partial discharge dielectric window-type ultra-high frequency sensor according to claim 1, characterized in that, The standard UHF sensor (6) and the UHF sensor to be calibrated (7) in step 1 are both disc-type sensors, installed inside the medium window.

3. The calibration method for a GIS partial discharge dielectric window-type ultra-high frequency sensor according to claim 1, characterized in that, The maximum installation height of the UHF sensor to be calibrated is: ； In the formula, D s D is the diameter of the metal disk antenna (5) of the sensor. h h is the diameter of the medium window handhole. w U is the dielectric window thickness, U0 is the voltage amplitude measured at the UHF sensor to be calibrated when h=0, and U min The noise floor voltage amplitude is measured at the ultra-high frequency sensor under test when there is no partial discharge signal h=0. The relative permittivity of the window medium, The relative permittivity of the transformer oil; This is the interface transmittance correction factor. ; The installation depth h of the ultra-high frequency sensor (7) to be verified must meet h <H max .

Images