Transformer bushing arcing test safety area optimization method

Abstract

The invention relates to a transformer bushing arcing test safety area optimization method, which comprises the following specific steps: S1, test pretreatment: arranging an arc striking buried wire in a transformer bushing; s2, building a test monitoring device, wherein the test monitoring device comprises a voltage transformer, a current transformer and a high-speed camera; s3, a test is carried out, rated voltage is applied to the high-voltage end of the sleeve until insulation breakdown and arcing tests are finished, field splashing fragments are photographed and recorded, and the mass mi (i = 1, 2, 3,..., n), the fragment windward area Si (i = 1, 2, 3,..., n), the fragment volume Vi (i = 1, 2, 3,..., n) and the fragment surface area Ai (i = 1, 2, 3,..., n) of n field splashing fragments are measured; and S4, determining a splashing fragment influence range, and optimizing a test safety protection area. The test site area can be reduced, the test comprehensive cost is remarkably reduced, and meanwhile the scientificity and economical efficiency of safety protection are improved.

Description

Technical Field

[0001] This invention relates to the field of high-voltage equipment testing technology, and in particular to an arcing test method for transformer bushings and riser bases, and dynamically optimizes the safety protection zone based on test data. Background Technology

[0002] Transformer bushings are core insulating components of power systems, and their internal insulation condition directly determines the operational safety of equipment and even the power grid. However, existing arcing tests generally use external arc ignition methods, which cannot realistically reproduce the internal discharge evolution process of the bushing under actual operating conditions. Meanwhile, the industry lacks quantitative assessment methods for the impact range of explosive debris, and the determination of safe distances has long relied on empirical formulas, which are both overly conservative and lack sufficient evidence, resulting in large test sites, prolonged test cycles, and high overall costs. Therefore, there is an urgent need for a new method that can determine the maximum lethal radius of flying debris in arcing tests and scientifically optimize the safety protection zone accordingly. Summary of the Invention

[0003] This invention aims to provide a method for optimizing the safety zone of a transformer bushing arc test. By collecting the physical property parameters of the flying debris at the test site and calculating the maximum kill radius of the flying debris generated by the explosion based on the Gurney model and the air resistance model, the test safety protection zone can be optimized scientifically and economically.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] A method for optimizing the safe zone of a transformer bushing arc test includes:

[0006] S1: Test pretreatment, arc-starting buried wire is installed inside the transformer bushing;

[0007] S2: Set up the test monitoring device, including: voltage transformer, current transformer, and high-speed camera;

[0008] S3: Conduct the test by applying the rated voltage to the high-voltage end of the bushing until insulation breakdown occurs. After the arc test is completed and it is determined that there is no danger at the site, enter the test area, photograph and record the splashed debris, and measure the mass m of n splashed debris at the site. i (i=1,2,3,…,n), the windward area S of the fragment i (i=1,2,3,…,n), fragment volume V i (i=1,2,3,…,n) and the surface area A of the fragments i (i=1,2,3,…,n);

[0009] S4: Determine the impact range of splash debris and optimize the test safety protection area.

[0010] Furthermore, in step S1, the test pretreatment method is as follows: copper round wire is used to penetrate the main insulation of the bushing to achieve a direct connection between the zero screen of the main insulation of the bushing and the ground potential, thereby constructing a penetrating discharge channel inside the bushing.

[0011] Furthermore, in step S2, the voltage transformer is used to measure the arc voltage U. arc Current transformers are used to measure arc current I. arc A high-speed camera records the arc burning time t, from which the arc energy E can be obtained. arc :

[0012]

[0013] Furthermore, in step S3, a test is conducted by applying the rated voltage to the high-voltage end of the bushing until insulation breakdown occurs. After confirming that there is no danger at the test site, entry is made, and the mass m of n flying fragments at the site is measured and recorded. i (i=1,2,3,…,n), use a 3D scanner to record the windward area S of n splash fragments. i (i=1,2,3,…,n), fragment volume V i (i=1,2,3,…,n) and the surface area A of the fragments i (i=1,2,3,…,n), the initial velocity v of the i-th fragment splash can be obtained. 0i :

[0014]

[0015] The aforementioned Gurney constant for arc energy equivalent explosive;

[0016] The β i The arc energy of the i-th fragment is converted into the equivalent explosive mass M. i With fragment mass m i The ratio:

[0017]

[0018] The specific kinetic energy e of the i-th fragment can be obtained. i :

[0019]

[0020] Furthermore, in step S4, the i-th fragment has a lethal range:

[0021]

[0022] In the formula m i C represents the mass of the fragment, expressed in kilograms. Dρ is the drag coefficient; ρ is the air density, in kilograms per cubic meter; S i The windward area is expressed in square meters; e si The specific kinetic energy of the fragments, expressed in joules per square meter; e s,crit The critical specific kinetic energy for debris safety is expressed in joules per square meter.

[0023] Choose the fragment with the maximum lethal range from among n fragments:

[0024]

[0025] The radius of the test safety protection zone is D≥R max .

[0026] The beneficial effects of this invention are: through this method, the algorithm of the safety protection zone for transformer bushing arc test can be optimized, and the test safety distance can be upgraded from empirical estimation to scientific algorithm, which can significantly reduce the scale of the test site, reduce the overall test cost, and at the same time improve the scientific and economic aspects of safety protection to a new level. Attached Figure Description

[0027] Figure 1 This is a flowchart of the present invention;

[0028] Figure 2 This is a schematic diagram of the test method of the present invention. Detailed Implementation

[0029] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] like Figure 1 As shown, the method for optimizing the safe zone of a transformer bushing arc test according to the present invention includes the following steps:

[0031] S1: Test pretreatment, arc-starting buried wire is installed inside the transformer bushing;

[0032] S2: Set up the test monitoring device, including: voltage transformer 201, current transformer 202, and high-speed camera 203;

[0033] S3: Conduct the test by applying the rated voltage to the high-voltage end of the bushing until insulation breakdown occurs. After the arc test is completed and it is determined that there is no danger at the site, enter the test area and use a 3D scanner 301 to photograph and record the splashed debris at the site and measure the mass m of n splashed debris at the site. i (i=1,2,3,…,n), the windward area S of the fragment i (i=1,2,3,…,n), fragment volume V i (i=1,2,3,…,n) and the surface area A of the fragmentsi (i=1,2,3,…,n);

[0034] S4: Determine the impact range of splash debris and optimize the test safety protection area.

[0035] In step S1, the test pretreatment method is as follows: the current path is conductor 101-copper wire 102-grounding busbar 103, and copper round wire 102 is used to penetrate the main insulation of the bushing to realize the direct connection between the main insulation zero screen of the bushing and the ground potential, thereby constructing a penetrating discharge channel inside the bushing.

[0036] In step S2, the voltage transformer 201 is used to measure the arc voltage U. arc Current transformer 202 is used to measure arc current I. arc The high-speed camera 203 records the arc burning time t, from which the arc energy E can be obtained. arc :

[0037]

[0038] In step S3, the test is conducted by applying the rated voltage to the high-voltage end of the bushing until insulation breakdown occurs. After confirming that there is no danger at the test site, the mass m of n flying fragments at the site is measured and recorded. i (i=1,2,3,…,n), use a 3D scanner 301 to record the windward area S of n splash fragments. i (i=1,2,3,…,n), fragment volume V i (i=1,2,3,…,n) and the surface area A of the fragments i (i=1,2,3,…,n), the initial velocity v of the i-th fragment splash can be obtained. 0i :

[0039]

[0040] in The Gurney constant of an arc energy equivalent explosive, using TNT as the arc energy equivalent explosive, and the Gurney constant of TNT. The detonation velocity v of TNT is 6900 m / s, and the Gurney constant is... Approximately 2320 m / s;

[0041] Where β i The arc energy of the i-th fragment is converted into the equivalent explosive mass M. i With fragment mass m i The ratio:

[0042]

[0043] M iThe energy of the electric arc is equivalent to the energy of TNT explosive:

[0044]

[0045] In the formula E arc The electric arc energy is expressed in joules; Q represents the thermal explosion of TNT, which is 4.52 × 10⁻⁶. 6 J / kg, the unit is joules per kilogram;

[0046] The specific kinetic energy e of the i-th fragment can be obtained. i :

[0047]

[0048] In step S4, the i-th fragment has a lethal range:

[0049]

[0050] In the formula m i C represents the mass of the fragment, expressed in kilograms. D ρ is the drag coefficient; ρ is the air density, in kilograms per cubic meter; S i The windward area is expressed in square meters; e si The specific kinetic energy of the fragments, expressed in joules per square meter; e s,crit The critical specific kinetic energy for debris safety is expressed in joules per square meter.

[0051] Where the drag coefficient C D The morphology-equivalent sphere method involves the following steps:

[0052] Measure fragment volume V using a 3D scanner i Fragment surface area A i ;

[0053] Calculate the sphericity ψ of the fragment:

[0054]

[0055] Calculate the drag coefficient C D :

[0056]

[0057] Fragment safety critical specific kinetic energy e s,crit Value 10 5 J / m 2 Generally, it is considered that the specific kinetic energy e s ≤10 5 J / m 2 This ensures the safety of personnel;

[0058] Choose the fragment with the maximum lethal range from among n fragments:

[0059]

[0060] R is obtained after each experiment maxi For subsequent similar experiments, refer to the R values ​​obtained from previous experiments. maxi The maximum value determines the radius of the test safety protection zone. .

[0061] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for optimizing the safe zone of a transformer bushing arc test, characterized in that, The method comprises the following specific steps: S1: test pretreatment, arc striking and buried wire are arranged inside the transformer bushing; S2: build test monitoring device, including: voltage transformer, current transformer, high-speed camera; S3: Develop a test, apply rated voltage at the high pressure end of the casing until the insulation breaks down, after the arc test, take pictures and record the mass of the n splashes on site i (i=1, 2, 3, …, n), the area of the splashes S i (i=1, 2, 3, …, n), the volume of the splashes V i (i=1, 2, 3, …, n) and the surface area of the splashes A i (i=1, 2, 3, …, n); S4: determine the influence range of splashing fragments, optimize the test safety protection area.

2. The method of claim 1, wherein, In the step S1, copper round wire is used to penetrate the main insulation of the bushing, to realize the direct connection between the zero screen of the main insulation of the bushing and the ground potential, and to construct a penetrating discharge channel inside the bushing.

3. The method of claim 1, wherein, In the step S2, the voltage transformer measures the arc voltage U arc , the current transformer measures the arc current I arc , the high-speed camera records the burning time t of the arc, and the arc energy E arc is obtained. 。 4. The method of claim 3, wherein, In step S3, the rated voltage is applied to the high-voltage end of the bushing until insulation breakdown, the end of the arc test, and the judgment that the site is no longer dangerous, then enter the test area, measure and record the mass m of n splashes of fragments i (i=1, 2, 3, …, n), and the windward area S of n splashes of fragments is recorded by a three-dimensional scanner i (i=1, 2, 3, …, n), the volume V of the fragments i (i=1, 2, 3, …, n), and the surface area A of the fragments i (i=1, 2, 3, …, n).

5. The method of claim 4, wherein, Arc energy and mass of n fragments m i (i = 1, 2, 3,..., n), the initial velocity of the i-th fragment v 0i : ， Gurney constant for arc energy equivalent explosive; β i The arc energy of the i-th fragment is converted into the equivalent explosive mass M i The ratio of the arc energy of the i-th fragment to the mass m i of the fragment: 。 6. The method of claim 5, wherein, The mass of the ith fragment m i (i = 1, 2, 3,..., n), the windward area S of the fragment i (i = 1, 2, 3,..., n) and the initial speed v of the spatter 0i (i = 1, 2, 3,..., n), the specific kinetic energy e of the ith fragment can be obtained i : ， The i-th fragment has a killing range: ， where m i is the mass of the debris in kilograms; C D is the drag coefficient; p is the air density in kilograms per cubic meter; S i is the frontal area in square meters; e si is the specific kinetic energy of the debris in joules per square meter; e s,crit is the safe critical specific kinetic energy of the debris in joules per square meter; The maximum killing distance of the n fragments is: ， Test safety protection zone radius D ≥ R max .

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