A porcelain sleeve type zinc oxide lightning arrester external insulation pollution quantification detection method

Abstract

The application provides a porcelain sleeve type zinc oxide arrester external insulation contamination quantification detection method. The zinc oxide arrester has three sections, from top to bottom, the first section, the second section and the third section, and the bottom of the third section is connected with the first end of the base. The bottom of the first section and the first end of the second section are connected through four galvanized double-end screws with a diameter of 16 mm*150 mm, the connection mode of the bottom of the second section and the first end of the third section and the connection mode of the bottom of the third section and the first end of the base are the same as the connection mode of the bottom of the first section and the first end of the second section. In the technical solution, the microammeter matrix operation is flexible, and the method is various.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of power equipment detection, in particular to a porcelain sleeve type zinc oxide arrester external insulation contamination quantification detection method. BACKGROUND

[0002] According to the Q / GDW 1168-2013 State Maintenance Test Regulation of Power Transmission and Distribution Equipment, the routine test items of the metal oxide arrester include: 1mA DC voltage (U1mA) and 0.75U1mA leakage current measurement, the reference period is 110 (66) kV and above, and the period is 3 years, wherein the requirements are (1) the initial value difference of U1mA is not more than ±5% and is not lower than the value specified in GB11032 (note value); and (2) the initial value difference of 0.75U1mA leakage current is ≤30% or ≤50µA (note value).

[0003] In addition to the requirement that the salt fog on the sea requires a longer creepage distance of the external insulation of the arrester, the contamination on the surface of the arrester can cause the total current and the resistive current of the arrester to increase, and can cause the arrester surface to locally heat, the voltage distribution to be uneven, and in a serious case, can affect the voltage distribution of the internal valve piece, the core rod and the porcelain sleeve of the arrester, accelerate the aging of part of the valve piece or the flashover of the insulation piece, and can also cause the internal discharge of the arrester, causing damage to the arrester.

[0004] According to the DL / T 664 Infrared Test Guide for Power Equipment, the allowable temperature difference of the 220kV arrester is 1.5 degrees or 2 degrees, and the requirement is for the whole arrester, and the local heating is not mentioned. The characteristic of the infrared image is that the part with the temperature rise is generally one or two umbrella skirts (the porcelain sleeve surface is obviously white), and for each group of arrester, the larger the leakage current, the higher the temperature of the heating.

[0005] Contamination level division: 1. The state divides the line equipment contamination level into five levels. 2. The state divides the power plant and substation equipment contamination level into four levels, and proposes the corresponding external insulation creepage distance under each contamination level.

[0006] Figure 1 It is a conventional test method for single-section zinc oxide arrester, and the shielding method is not adopted. The O point is the connection copper bar of the lower flange of the arrester base in contact with the arrester and the leakage current meter or the counter. During the test, the microammeter 2 is directly hung to the O point through the lead, and no copper bar needs to be removed.

[0007] The traditional shielding method, such as Figure 2As shown, the high-voltage line HV is connected to HV1 core wire and HV2 shielding clamp. Bare copper wire is wound 2-3 times around the porcelain bushing and upper flange of the single-section zinc oxide arrester (at a point of non-direct physical contact, approximately 20mm away), marked as shielding ring ①. Similarly, 2-3 times are wound around the porcelain bushing and lower flange of the zinc oxide arrester (at a point of non-direct physical contact, approximately 20mm away), marked as shielding ring ②. The meaning of point O is the same as... Figure 1 As shown.

[0008] During the test, by controlling the output voltage of the DC high voltage generator, read µA1 or µA2. When the reading reaches 1mA, record the voltage displayed on the DC high voltage generator at this time, which is the voltage at point A, i.e., U1mA. Then control the button to reduce the voltage at point A to 75%, i.e., 75%U1mA. At this time, read µA1 or µA2 and record the current at this time. The following conditions must be met: (1) The initial value difference of U1mA does not exceed ±5% and is not lower than the value specified in GB11032 (note value); (2) The initial value difference of 0.75U1mA leakage current is ≤30% or ≤50µA (note value). The corresponding test is completed. At this time, depending on the specific situation, one µA1 or one µA2 is set, or they are set at the same time. If µA2 exists, read the data in this table to indicate accuracy.

[0009] At this time, the leakage current on the porcelain bushing of the zinc oxide surge arrester was not measured, and the pattern was not evaluated. Summary of the Invention

[0010] In view of this, the purpose of this invention is to provide a method for quantitative detection of external insulation pollution in porcelain-insulated zinc oxide surge arresters, which features flexible operation of the microammeter matrix and diverse methods.

[0011] To achieve the above objectives, the present invention adopts the following technical solution: a method for quantitative detection of external insulation pollution in a porcelain-insulated zinc oxide surge arrester. The zinc oxide surge arrester has three sections, from top to bottom: Section 1, Section 2, and Section 3. The bottom of Section 3 is connected to the top end of the base. The bottom of Section 1 and the top end of Section 2 are connected by four galvanized double-ended screws of Φ16mm×150mm. The connection method between the bottom of Section 2 and the top end of Section 3, and the connection method between the bottom of Section 3 and the top end of the base, are the same as the connection method between the bottom of Section 1 and the top end of Section 2.

[0012] Each surge arrester section has the same internal structure. Each surge arrester has flanges at both ends, and the middle part is made of ceramic, including the ceramic body and the flanges at both ends of the ceramic body. The ceramic body is a single piece and is made of high-alumina material. The flanges at both ends of the ceramic body are high-strength cast aluminum alloy or galvanized ductile iron flanges. The ceramic body and the flanges are connected with ≥500# silicate cement adhesive. The total length of the ceramic sleeve is between 1200mm and 1900mm. The ceramic body is cylindrical in shape with a hollow part in the middle and has a structure of large umbrellas and small umbrellas on the outside, which are arranged alternately.

[0013] Both the upper and lower flanges are ring-shaped with a hollow center. The four corners are symmetrically distributed around the circumference, with protruding screw installation positions and screw holes. Each angle is evenly distributed at 90 degrees, which facilitates the connection between different sections using Φ16mm×100cm screws to achieve different voltage levels.

[0014] The hollow part and the outer diameter of the porcelain sleeve are connected by a ring. The outer diameter is the outer diameter of the porcelain sleeve, and the hollow circle is the hollow part. The outer diameter of the porcelain sleeve minus the radius of the hollow circle is the ring width. The ring width is generally between 35mm and 50mm. This part between the upper and lower flanges is a ring, forming a ring with a height of H.

[0015] The surge arrester core is installed inside the hollow part. The core is composed of several zinc oxide valve plates and metal pads stacked together. The zinc oxide valve plates are all the same size, and both the valve plates and the pads are cylinders with the same cross-sectional area but different heights.

[0016] In a preferred embodiment, the flange has a height of h1, and the flange end face protrudes into a square with a thickness of D and a side length of d1. There are four screw holes at the four corners of the flange end face, and the screw holes are d2 from the center of the flange.

[0017] In a preferred embodiment, the porcelain-insulated surge arrester base adopts the same construction process as the porcelain-insulated surge arrester, and a circular body with a height of H is also formed between the upper and lower flanges.

[0018] In a preferred embodiment, the porcelain-insulated surge arrester base is mounted on a steel structure, with the ground of the steel structure in contact with the surge arrester base. The interior of the surge arrester base is entirely hollow, typically a cylindrical cavity with a diameter of Φ250mm. The base is directly mounted on a cylindrical galvanized steel plate base. The aforementioned space creates a seal at the connection between the base and the steel plate. The top of the base is similar to a ring shape. The first end of the base is led down to the leakage current location via a 30mm (width) × 5mm (thickness) conductor supported by an insulator. If a leakage current in-line device exists, a wire is connected to the aforementioned conductor, and after passing through the current terminal of the in-line device, a leakage current input terminal is connected in series. Then, the internal leakage current output terminal is connected to the ground via a grounding wire.

[0019] In a preferred embodiment, a detection circuit is included; the detection circuit includes a first solid-state relay K32, a second solid-state relay K31, a third solid-state relay K2, and a fourth solid-state relay K3; the first solid-state relay K32 and the second solid-state relay K31 are connected in parallel, and their two ends are respectively connected to a first ammeter µA2 and a second ammeter µA3; one end of the third solid-state relay K2 is connected to a third ammeter µA4, one end of the fourth solid-state relay K3 is connected to the third ammeter µA4, and the third ammeter µA4 is grounded;

[0020] Clear meter function: Short-circuit the second ammeter µA3, the first ammeter µA2, and the fourth ammeter µA4. Insert the P1 terminal and the P2 terminal into the leakage current dedicated test lead ① (shielded wire) and the leakage current dedicated test lead ② (shielded wire) respectively. Short-circuit ① and ②. Close the K32, K31, K2, and K3 buttons to complete the clear meter function.

[0021] Standby function: Keep ① and ② floating, and disconnect buttons K32, K31, K2, and K3 to enable standby function;

[0022] Microammeter array access function: (1) Connect the P1 terminal to point O through the leakage current dedicated test line ①, and connect the P2 terminal to the shielding ring ② through the leakage current dedicated test line ②; (2) Connect the high voltage terminal of the DC high voltage generator to the upper flange A of the surge arrester under test through the dedicated high voltage line HV (core line HV1, shield line HV2) through the core line HV1.

[0023] Routine test: (1) Disconnect K3, K32, and K31, and close K2;

[0024] Preliminary estimation of porcelain bushing contamination: (1) The wiring at H1 is done using the traditional method; (2) Disconnect K32 and K31, and connect K2 and K3; read µA2 to raise the voltage at point A to U1mA (at this time, if P2 line is connected or K3 is disconnected, it is considered as the conventional method to test U1mA, and the calibrated voltage is 1). At this time, read µA2=1000µA and µA3=XµA. If µA4 is installed, then µA4=µA2+µA3;

[0025] At this time, the reading of µA3 is the quantitative estimate of the contamination on the porcelain bushing surface under U1mA; this data has a linear relationship with the applied voltage; if the voltage at point A is reduced to 0.75U1mA at this time, then the readings of µA2 and µA3 are the quantitative values ​​of the contamination flowing through the zinc oxide arrester core and surface under 75%U1mA conditions.

[0026] The pollution value of the outer insulation of the porcelain bushing is defined as the current obtained when a voltage U1mA is applied near the upper flange of the porcelain bushing and a measuring circuit is connected near the lower flange of the porcelain bushing; this current is the quantified pollution value of the outer insulation of the porcelain bushing under U1mA.

[0027] In a preferred embodiment, the direct measurement method for porcelain bushing contamination quantification is as follows: (1) Connect the core wire HV1 of the HV line directly to the shielding ring ①; (2) Do not connect the P1 line to the system, connect P2 to the shielding ring ②, disconnect K2, disconnect K31, disconnect K32, and close K3; raise the voltage of the shielding ring ① directly to the calibration voltage 1 of the 5th meter mentioned above, and directly read the data of µA3, which is the contamination value of the porcelain bushing external insulation.

[0028] In a preferred embodiment, the porcelain bushing contamination quantification process estimation method; in Section 5, by changing the closed or open state of K32, K31, K2, and K3, the readings of µA3, µA2, and µA4 meters under different voltage conditions are distinguished, and the circuit diagram is analyzed to clarify the corresponding current and direction, and clearly understand the current flowing through the porcelain bushing surface and the core.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The improved microammeter array and its control methods are protected. All plugs or grounding holes added to this circuit, or control circuits with grounding, are within the scope of this protection.

[0031] The definitions and steps of the above-mentioned preliminary estimation of porcelain sleeve fouling, direct measurement method of porcelain sleeve fouling, and process estimation method of porcelain sleeve fouling are all within the protection scope, and the order of controlling the switches is also within the protection scope.

[0032] Adding other micrometers or constructing other types of matrix diagrams is considered to be inspired by this patent.

[0033] Whether the applied voltage is DC or extended to AC voltage, the wiring and control methods of this test still have protective significance. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of a conventional testing method in the prior art;

[0035] Figure 2 This is a schematic diagram of a conventional shielding method in the prior art;

[0036] Figure 3 This is a schematic diagram of the structure of a porcelain sleeve (single section) of a porcelain sleeve-type surge arrester according to a preferred embodiment of the present invention;

[0037] Figure 4 This is a schematic diagram of the base structure of a porcelain-insulated surge arrester according to a preferred embodiment of the present invention;

[0038] Figure 5 This is a schematic diagram of a flange according to a preferred embodiment of the present invention;

[0039] Figure 6 This is a schematic diagram of an improved microammeter array according to a preferred embodiment of the present invention.

[0040] Among them: 1: Porcelain body; 2: Flange; 3: Large umbrella; 4: Small umbrella; 5: Hollow part.

[0041] H - Length of the porcelain bushing of the surge arrester base; h1 - Height of the flange; D - Thickness of the flange end face protrusion; d1 - Side length of the flange end face protrusion; d2 - Distance from the bolt hole to the center of the flange. Detailed Implementation

[0042] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0043] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, 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 pertains.

[0044] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application; as used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise; furthermore, it should be understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0045] refer to Figures 2-6The zinc oxide surge arrester involved in this invention is shown in the figure. It is a 500kV arrester with three sections, numbered from top to bottom as Section 1, Section 2, and Section 3. The bottom of Section 3 is connected to the top of the base. The bottom of Section 1 and the top of Section 2 are connected by four Φ16mm×150mm galvanized double-ended screws. The bottom of Section 2 and the top of Section 3 are connected in a similar manner. The bottom of Section 3 and the top of the base are connected in a similar way.

[0046] The internal structure of each surge arrester is basically the same. The two ends of each surge arrester are commonly referred to as "flanges". The middle part is made of ceramic material, including the ceramic body and the flanges at both ends of the ceramic body. The ceramic body is a whole piece. The ceramic body is made of high alumina material. The flanges at both ends of the ceramic body are high-strength cast aluminum alloy or galvanized ductile iron flanges. The ceramic body and the flanges are connected with ≥500# silicate cement adhesive. The total length of the ceramic sleeve is between 1200mm and 1900mm. The ceramic body is cylindrical in shape with a hollow part in the middle. It has a structure of large umbrella and small umbrella on the outside, which are arranged alternately.

[0047] Both the upper and lower flanges are circular rings with a hollow center. The four corners are symmetrically distributed around the circumference, with protruding screw mounting positions and screw holes. Each angle is evenly distributed at 90°, which facilitates the connection between different sections using Φ16mm×100cm screws to achieve different voltage levels.

[0048] The hollow part and the outer diameter of the porcelain bushing are connected by a ring. The outer diameter is the outer diameter of the porcelain bushing, and the hollow circle is the hollow part. The outer diameter of the porcelain bushing minus the radius of the hollow circle is the ring width, which is generally between 35mm and 50mm. This part between the upper and lower flanges is a ring, forming a ring with a height of H.

[0049] The surge arrester core is installed inside the hollow part, as shown in the figure. The core is composed of several zinc oxide valve plates and metal pads stacked together. The zinc oxide valve plates are all the same size, and both the valve plates and the pads are cylinders with the same cross-sectional area but different heights.

[0050] The flange has a height of h1, and a square with a thickness of D and a side length of d1 protrudes from the end face of the flange. There are 4 screw holes at the four corners of the end face of the flange, and the distance from the screw holes to the center of the flange is d2.

[0051] The base of the porcelain-insulated surge arrester adopts the same construction process as the porcelain-insulated surge arrester, and a circular body with a height of H is also formed between the upper and lower flanges.

[0052] The porcelain-insulated surge arrester base is installed on a steel structure, with the steel structure in contact with the arrester base. The base is internally hollow, typically a cylindrical cavity with a diameter of Φ250mm. The base is directly mounted on a cylindrical galvanized steel plate base. This space creates a sealed connection between the base and the steel plate. The top of the base is ring-shaped. The first end of the base is led down to the leakage current point via a 30mm (width) × 5mm (thickness) conductor supported by an insulator. If a leakage current in-line device is present, a wire is connected to the aforementioned conductor, passing through the current terminal of the in-line device, and then connected in series to the leakage current input terminal. Finally, the leakage current output terminal is connected to the ground via a grounding wire.

[0053] If the surge arrester system is 110kV, there is only L3 section and base. If the surge arrester system is 220kV, there are L2, L3 and base. The same applies to 750kV, 1000kV and other levels.

[0054] The test range for µA3 and µA2 is 2mA, and for µA4 it is 3mA. K2, K3, K32, and K31 can be self-holding push-button switches or optocoupler-controlled solid-state relays. These switches can be equipped with rubber plugs (4mm²) for easy insertion of other wires, such as grounding wires. P1 and P2 are the jacks for the microammeters µA2 and µA3, respectively.

[0055] When using it, follow the wiring instructions for the microammeter as described above. K2, K3, K32, and K31 are all in the off state by default.

[0056] Functions used

[0057] 1. Clearing the meter function. Short-circuit µA3, µA2, and µA4. Insert the P1 terminal and the P2 terminal into the dedicated leakage current test lead ① (shielded wire) and the dedicated leakage current test lead ② (shielded wire), respectively. Short-circuit ① and ②. Close the K32, K31, K2, and K3 buttons to complete the clearing the meter function.

[0058] 2. Standby function. Connect the wires as shown in the diagram above, keeping ① and ② unconnected, and disconnect buttons K32, K31, K2, and K3 to enable the standby function.

[0059] 3. Microammeter array access function. (1) Connect P1 terminal to point O through leakage current dedicated test line ①, and connect P2 terminal to shielding ring ② through leakage current dedicated test line ②. (2) Connect the high voltage terminal of DC high voltage generator to the upper flange A of the surge arrester under test through dedicated high voltage line HV (core line HV1, shield line HV2) through core line HV1.

[0060] 4. Routine test. (1) Disconnect K3, K32, and K31, close K2, and take the following steps.Figure 1 The traditional method is to read µA2 or µA1.

[0061] 5. Preliminary estimation of porcelain bushing contamination. (1) The wiring at H1 is done using the traditional method. (2) Disconnect K32 and K31, and connect K2 and K3, and then... Figure 1 The traditional method is to read µA2 to raise the voltage at point A to U1mA (at this time, if P2 line is connected or K3 is disconnected, it is considered as the conventional method to test U1mA, and the calibrated voltage is 1). At this time, µA2 = 1000µA and µA3 = XµA. If µA4 is installed, then µA4 = µA2 + µA3.

[0062] At this point, the reading of µA3 represents the quantitative estimate of contamination on the porcelain bushing surface under U1mA. This data has a linear relationship with the applied voltage. If the voltage at point A is reduced to 0.75U1mA, then the readings of µA2 and µA3 represent the quantitative values ​​of contamination flowing through the zinc oxide arrester core and surface under 75%U1mA conditions.

[0063] The pollution value of the porcelain bushing's outer insulation is defined as the current obtained when a voltage U1mA (equivalent to the above) is applied near the upper flange of the porcelain bushing and a measuring circuit is connected near the lower flange. This is the quantified pollution value flowing through the porcelain bushing's outer insulation under U1mA. This value is generally <10µA and typically changes linearly with the voltage.

[0064] 6. Direct Measurement Method for Porcelain Bushing Contamination Quantification. (1) Connect the core wire HV1 of the HV line directly to the shielding ring ①; (2) Do not connect the P1 line to the system, connect P2 to the shielding ring ②, disconnect K2, disconnect K31, disconnect K32, and close K3. Directly raise the voltage of the shielding ring ① to the calibration voltage 1 of the 5th meter mentioned above, and directly read the data of µA3, which is the contamination value of the porcelain bushing external insulation.

[0065] This method is considered a direct measurement method, which involves obtaining the voltage flowing through U1mA and then directly measuring it.

[0066] 7. Estimation method for the quantification process of porcelain bushing contamination. In Section 5, by changing the closed or open states of K32, K31, K2, and K3, and distinguishing the readings of µA3, µA2, and µA4 under different voltage conditions, and analyzing the circuit diagram, the corresponding current and direction can be clarified, and the current flowing through the surface of the porcelain bushing and inside the core can be clearly understood.

Claims

1. A method for quantitatively detecting pollution in the external insulation of a porcelain-insulated zinc oxide surge arrester, characterized in that, The zinc oxide surge arrester has three sections, from top to bottom: Section 1, Section 2, and Section 3. The bottom of Section 3 is connected to the top of the base. The bottom of Section 1 and the top of Section 2 are connected by four galvanized double-ended screws with diameters of 16mm and 150mm. The connection method between the bottom of Section 2 and the top of Section 3, and between the bottom of Section 3 and the top of the base, is the same as that between the bottom of Section 1 and the top of Section 2. Each surge arrester section has the same internal structure. Each surge arrester has flanges at both ends, and the middle part is made of ceramic, including the ceramic body and the flanges at both ends of the ceramic body. The ceramic body is a single piece and is made of high-alumina material. The flanges at both ends of the ceramic body are high-strength cast aluminum alloy or galvanized ductile iron flanges. The ceramic body and the flanges are connected with ≥500# silicate cement adhesive. The total length of the ceramic sleeve is 1200mm~1900mm. The ceramic body is cylindrical in shape with a hollow part in the middle and has a structure of large umbrellas and small umbrellas on the outside, which are arranged alternately. Both the upper and lower flanges are circular rings with a hollow center. They are symmetrically distributed at the four corners, with protruding screw mounting positions and screw holes. Each angle is evenly distributed at 90°, which facilitates the connection of different numbers of sections with Φ16mm×100cm screws to achieve different voltage levels. The hollow part and the outer diameter of the porcelain sleeve are connected by a ring. The outer diameter is the outer diameter of the porcelain sleeve, and the hollow circle is the hollow part. The outer diameter of the porcelain sleeve minus the radius of the hollow circle is the ring width, which is 35mm~50mm. This part between the upper and lower flanges is a ring, forming a ring with a height of H. The surge arrester core is installed inside the hollow part. The core is composed of several zinc oxide valve plates and metal pads stacked together. The zinc oxide valve plates are all the same size, and both the valve plates and the pads are cylinders with the same cross-sectional area but different heights. The system includes a detection circuit; the detection circuit includes a first solid-state relay K32, a second solid-state relay K31, a third solid-state relay K2, and a fourth solid-state relay K3; the first solid-state relay K32 and the second solid-state relay K31 are connected in parallel, the two ends of the first solid-state relay K32 are respectively connected to a first ammeter µA2 and a second ammeter µA3, one end of the second solid-state relay K31 is connected to the first ammeter µA2; one end of the third solid-state relay K2 is connected to a third ammeter µA4, one end of the fourth solid-state relay K3 is connected to the third ammeter µA4, and the third ammeter µA4 is grounded; Clear meter function: Short-circuit the second ammeter µA3, the first ammeter µA2, and the fourth ammeter µA4. Insert the P1 terminal and the P2 terminal into the leakage current special test lead ① and the leakage current special test lead ② respectively. Short-circuit ① and ②. Close the K32, K31, K2, and K3 buttons to complete the clear meter function. Standby function: Keep ① and ② floating, and disconnect buttons K32, K31, K2, and K3 to enable standby function; Microammeter array access function: (1) Connect the P1 terminal to point O through the leakage current dedicated test line ①, and connect the P2 terminal to the shielding ring ② through the leakage current dedicated test line ②; (2) Connect the high voltage terminal of the DC high voltage generator to the upper flange A of the surge arrester under test through the dedicated high voltage line HV and the core wire HV1. Routine test: (1) Disconnect K3, K32, and K31, and close K2; Preliminary estimation of porcelain bushing contamination: (1) Welding method is adopted at the connection of H1; (2) Disconnect K32 and K31, and connect K2 and K3; Read µA2 to raise the voltage of point A to U1mA. At this time, if P2 line is connected or K3 is disconnected, it is considered as the conventional method to test U1mA. The calibrated voltage is 1. At this time, read µA2=1000µA, µA3=XµA. If µA4 is installed, then µA4=µA2+µA3; At this time, the reading of µA3 is the quantitative estimate of the contamination on the porcelain bushing surface under U1mA; this data has a linear relationship with the applied voltage; if the voltage at point A is reduced to 0.75U1mA at this time, then the readings of µA2 and µA3 are the quantitative values ​​of the contamination flowing through the zinc oxide arrester core and surface under 75%U1mA conditions. The contamination value of the outer insulation of the porcelain bushing is defined as the voltage U1mA applied near the upper flange of the porcelain bushing. Connect the measuring circuit near the lower flange of the porcelain bushing and obtain the current; this is the quantification value of the pollution flowing through the outer insulation of the porcelain bushing under U1mA.

2. The method for quantitative detection of external insulation pollution in a porcelain-insulated zinc oxide surge arrester according to claim 1, characterized in that, The flange has a height of h1, and a square with a thickness of D and a side length of d1 protrudes from the end face of the flange. There are four screw holes at the four corners of the end face of the flange, and the distance from the screw holes to the center of the flange is d2.

3. The method for quantitative detection of external insulation pollution in a porcelain-insulated zinc oxide surge arrester according to claim 2, characterized in that, The zinc oxide surge arrester base adopts the same construction process as the zinc oxide surge arrester, and a ring with a height of H is also formed between the upper and lower flanges.

4. The method for quantitative detection of external insulation pollution in a porcelain-insulated zinc oxide surge arrester according to claim 3, characterized in that, The porcelain-insulated surge arrester base is mounted on a steel structure, with the bottom surface of the steel structure in contact with the surge arrester base. The surge arrester base is entirely hollow, consisting of cylindrical openings with a diameter of Φ250mm. The base is directly mounted on a cylindrical galvanized steel plate, and the top of the base is annular. The first end of the base is led down to the leakage current point through a 30mm wide, 5mm thick conductor supported by an insulator. If an online leakage current device is present, the aforementioned conductor is connected by a wire, passing through the current terminal of the online device, and then connected in series to the leakage current input terminal. Finally, the leakage current output terminal is connected to the ground via a grounding wire.

5. The method for quantitative detection of external insulation pollution in a porcelain-insulated zinc oxide surge arrester according to claim 1, characterized in that, Direct measurement method for porcelain bushing contamination: (1) Connect the core wire HV1 of HV line directly to shielding ring ①; (2) Do not connect P1 line to the system, connect P2 to shielding ring ②, disconnect K2, disconnect K31, disconnect K32, and close K3; raise the voltage of shielding ring ① directly to the calibration voltage 1 of the meter, and directly read the data of µA3, which is the contamination value of the porcelain bushing external insulation.

6. The method for quantitative detection of external insulation pollution in a porcelain-insulated zinc oxide surge arrester according to claim 1, characterized in that, Estimation method for quantifying porcelain bushing contamination process: By changing the closed or open states of K32, K31, K2, and K3, and distinguishing the readings of µA3, µA2, and µA4 under different voltage conditions, and analyzing the circuit diagram, the corresponding current and direction can be clarified, and the current flowing through the surface of the porcelain bushing and inside the core can be clearly understood.

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