Resistor screening method, device and screening equipment

Abstract

The present application relates to a resistor screening method, device and screening equipment. The method comprises: after applying the first sequence of impulse currents to the current batch of resistors in the whole batch of resistors, performing defect detection on the current batch of resistors to obtain the first screening pass rate; after applying the second sequence of impulse currents to the current batch of resistors, performing defect detection on the current batch of resistors to obtain the second screening pass rate; after applying the third sequence of impulse currents to the current batch of resistors, performing defect detection on the current batch of resistors to obtain the third screening pass rate; until it is confirmed that all batches of resistors in the whole batch of resistors are qualified resistors, it is determined that the resistor screening for DC lightning arresters is completed. The present application improves the screening rate of defective resistors in DC lightning arresters by combining square waves and half-sine waves for screening.

Description

Technical Field

[0001] The present application relates to the technical field of electric power equipment, and in particular to a resistor screening method, device and screening equipment. Background Art

[0002] DC lightning arrester is an electrical device that protects DC field electrical equipment from high transient overvoltage hazards. According to the different installation locations, DC lightning arresters are divided into valve lightning arresters, bridge lightning arresters, DC bus lightning arresters, neutral bus lightning arresters, DC transfer switch lightning arresters and other types. When the system generates overvoltage, the lightning arrester presents low resistance due to its nonlinear volt-ampere characteristics. The nonlinear volt-ampere characteristics of the DC lightning arrester are provided by the internal zinc oxide resistor.

[0003] The energy absorption capacity of DC lightning arresters varies significantly according to their installation location and function. Neutral busbar lightning arresters and DC transfer switch lightning arresters can absorb energy up to dozens of times that of other types of lightning arresters, and are also called large-capacity DC lightning arresters. In order to meet the requirements of high energy absorption and reduce the insulation level of the protected equipment, most of these DC lightning arresters are designed as a multi-column structure with resistors connected in parallel inside the column and components connected in parallel outside, which puts higher requirements on uniformity control. Large-capacity DC lightning arresters have a large number of internal resistors and large sizes. The unevenness inside and between resistors directly affects the overall performance. Any unqualified resistor may cause thermal collapse when the DC lightning arrester is in action. Therefore, large-capacity DC lightning arresters have high requirements for the consistency of resistors. After the resistors are finished, defect detection and screening are required.

[0004] However, the current test methods cannot reflect the actual working conditions and cannot completely screen out reliable resistors suitable for large-capacity DC lightning arresters. Summary of the invention

[0005] Based on this, it is necessary to provide a resistor screening method, device and screening equipment that can improve screening reliability in response to the above technical problems.

[0006] In a first aspect, the present application provides a resistor sheet screening method, which is applied to a batch of resistor sheets used to assemble a DC lightning arrester; the method comprises:

[0007] After applying the first sequence of impulse currents to the current batch of resistors in the entire batch of resistors, defect detection is performed on the current batch of resistors to obtain a first screening pass rate; wherein the first sequence of impulse currents uses square wave impulse currents;

[0008] After applying the second sequence of impulse currents to the current batch of resistors, defect detection is performed on the current batch of resistors to obtain a second screening pass rate; wherein the second sequence of impulse currents uses a half-sine wave impulse current, or a square wave impulse current obtained by energy equivalent conversion of the half-sine wave impulse current;

[0009] After the third sequence of impulse currents is applied to the resistors in the current batch, defect detection is performed on the resistors in the current batch to obtain a third screening pass rate; wherein the impulse current type used by the third sequence of impulse currents is the same as that of the second sequence of impulse currents;

[0010] If the first screening pass rate, the second screening pass rate and the third screening pass rate all meet the corresponding thresholds, the current batch of resistors is confirmed to be qualified resistors;

[0011] The next batch of resistors in the entire batch of resistors is used as the current batch of resistors to be screened in the next round to confirm whether the next batch of resistors is qualified; until it is confirmed that all batches of resistors in the entire batch of resistors are qualified, the screening of resistors for DC lightning arresters is completed.

[0012] In one embodiment, the step of applying a first sequence of impulse currents to a current batch of resistors in a whole batch of resistors comprises:

[0013] Apply a square wave impulse current to the current batch of resistors and inject a first energy; wherein the first energy is equal to the design energy of the resistor; the design energy of the resistor is determined based on the number of resistors in the entire batch of resistors and the total energy flowing through the DC lightning arrester when the DC lightning arrester is actuated obtained through simulation of the operating conditions;

[0014] The step of applying a second sequence of impulse currents to the current batch of resistors comprises:

[0015] If a half-sine wave impulse current is applied to the resistors in the current batch, a second energy is injected; the second energy is less than the designed energy of the resistors;

[0016] If a square wave impulse current is applied to the current batch of resistors, a third energy is injected; wherein the third energy is obtained by correcting the second energy based on the fitting relationship between the impulse duration of the impulse current and the energy density of the resistor;

[0017] The step of applying the third sequence impulse current to the current batch of resistors comprises:

[0018] If a half-sine wave impulse current is applied to the resistors in the current batch, a fourth energy is injected; the fourth energy is less than the designed energy of the resistors;

[0019] If a square wave impulse current is applied to the current batch of resistors, a fifth energy is injected; wherein the fifth energy is obtained by correcting the fourth energy based on the fitting relationship between the impulse duration of the impulse current and the energy density of the resistors.

[0020] In one of the embodiments, the DC lightning arrester is a large-capacity DC lightning arrester; the first sequence impulse current uses two continuous square wave impulse currents; the second sequence impulse current uses two continuous sinusoidal half-wave impulse currents, and the second energy is 70% of the resistor design energy; the third sequence impulse current uses one sinusoidal half-wave impulse current, and the fourth energy is 60% of the resistor design energy.

[0021] In one embodiment, the large-capacity DC lightning arrester includes a neutral bus lightning arrester and a DC conversion switch lightning arrester, and the first sequence impulse current uses two consecutive 2ms square wave impulse currents; the second sequence impulse current uses two consecutive 100ms half-sine wave impulse currents.

[0022] In one embodiment, the method further comprises the steps of:

[0023] According to the electromagnetic transient simulation, the operating conditions are simulated to obtain the total energy flowing through the DC arrester when the DC arrester is in action;

[0024] According to the configuration parameters of the DC lightning arrester, the number of resistors in the whole batch of resistors is obtained;

[0025] The quotient of the total energy and the number of resistors is determined as the resistor design energy.

[0026] In one of the embodiments, if the second sequence impulse current adopts a half-sine wave impulse current, the duration of applying the second sequence impulse current to the current batch of resistors is the same as the duration of the current flowing through the DC lightning arrester in the electromagnetic transient simulation operating condition.

[0027] In a second aspect, the present application further provides a resistor sheet screening device, which is applied to a batch of resistor sheets used to assemble a DC lightning arrester; the device comprises:

[0028] A defect screening module, used for performing defect detection on the resistors in the current batch of resistors in the whole batch of resistors after applying a first sequence of impulse currents to the resistors in the current batch of resistors, and obtaining a first screening pass rate; wherein the first sequence of impulse currents adopts a square wave impulse current; and also used for performing defect detection on the resistors in the current batch of resistors after applying a second sequence of impulse currents to the resistors in the current batch, and obtaining a second screening pass rate; wherein the second sequence of impulse currents adopts a half-sine wave impulse current, or a square wave impulse current obtained by energy equivalent conversion of the half-sine wave impulse current; and for performing defect detection on the resistors in the current batch of resistors after applying a third sequence of impulse currents to the resistors in the current batch, and obtaining a third screening pass rate; wherein the impulse current type adopted by the third sequence of impulse currents is the same as that of the second sequence of impulse currents;

[0029] The qualified confirmation module is used to confirm that the current batch of resistors are qualified resistors if the first screening qualified rate, the second screening qualified rate and the third screening qualified rate all meet the corresponding thresholds; and use the next batch of resistors in the entire batch of resistors as the current batch of resistors to be screened in the next round to confirm whether the next batch of resistors are qualified resistors; until it is confirmed that all batches of resistors in the entire batch of resistors are qualified resistors, it is determined that the resistor screening for DC lightning arresters is completed.

[0030] In a third aspect, the present application also provides a resistor screening device, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0031] In a fourth aspect, the present application also provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of the above method when the computer program is executed by a processor.

[0032] In a fifth aspect, the present application also provides a computer program product, including a computer program, which implements the steps of the above method when executed by a processor.

[0033] The above-mentioned resistor screening method, device and screening equipment improve the screening rate of defective resistors in DC lightning arresters through combined screening of square waves and half-sine waves; wherein, for the whole batch of resistors used to assemble DC lightning arresters, defect detection and screening are performed on each batch. The present application sequentially adopts three current impact sequences, namely the first sequence impact current, the second sequence impact current and the third sequence impact current. The test waveform is more in line with the operating conditions, avoiding the actual operation of the lightning arrester due to the failure of the resistor performance not meeting the standard. At the same time, it is proposed to adopt the energy equivalence method of the half-sine wave impact current and the square wave impact current, and then the equivalent screening of the long-duration half-sine wave current impact test can be carried out, which can ensure that the resistors with unqualified energy are not used when assembling the lightning arrester. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of a process flow of a resistor screening method in one embodiment;

[0035] Figure 2 A schematic diagram of a flow chart of a step of confirming a resistor design energy in one embodiment;

[0036] Figure 3 A structural block diagram of a resistor screening device in one embodiment;

[0037] Figure 4 The figure is a diagram showing the internal structure of a resistor screening device in one embodiment. DETAILED DESCRIPTION

[0038] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present application. The terms used herein in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0039] It is understood that the terms "first", "second", etc. used in this application can be used to describe various elements in this article, but these elements are not limited by these terms. These terms are only used to distinguish the first element from another element. Spatial relationship terms such as "under...", "under...", "below...", "under...", "above...", "above", etc. can be used here to describe the relationship between an element or feature shown in the figure and other elements or features. It should be understood that in addition to the orientation shown in the figure, spatial relationship terms also include different orientations of devices in use and operation. For example, if the device in the accompanying drawings is turned over, the element or feature described as "under other elements" or "under it" or "under it" will be oriented to "on" other elements or features. Therefore, the exemplary terms "under..." and "under..." may include upper and lower orientations. In addition, the device may also include other orientations (for example, rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.

[0040] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to another element, or connected to another element through a centering element. In addition, the "connection" in the following embodiments, if there is a transmission of electrical signals or data between the connected objects, should be understood as "electrical connection", "communication connection", etc. When used here, the singular forms of "one", "one" and "said / the" can also include plural forms, unless the context clearly indicates another way. It should also be understood that the terms "include / comprise" or "have" etc. specify the existence of stated features, wholes, steps, operations, components, parts or combinations thereof, but do not exclude the possibility of the existence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0041] In order to ensure that no resistors with unqualified energy are used when assembling lightning arresters, traditional test methods require that all resistors be screened with 2ms to 6ms square wave current impulses to remove unqualified resistors. However, when a large-capacity DC lightning arrester is actuated, the waveform is a long-duration half-sine wave impulse current (generally lasting 50ms to 200ms). There are differences in the screening results of different wavelengths, and there is a lack of a suitable equivalent method between the half-sine wave impulse current and the square wave current. Traditional test methods cannot reflect the actual working conditions and cannot completely screen out reliable resistors suitable for large-capacity DC lightning arresters.

[0042] The present application proposes a method for screening resistors for large-capacity DC lightning arresters. Through a combination screening test of square waves and half-sine waves, the screening rate of defective resistors for large-capacity DC lightning arresters is improved. The test waveform is more in line with the operating conditions, avoiding the actual operation of the arrester due to the failure of the resistor performance not meeting the standards. At the same time, a method for energy equivalence of half-sine wave impulse current and square wave impulse current for large-size resistors (for example, resistors with a diameter greater than 100mm) is proposed, and the difficulty of the test is reduced through an energy equivalence test. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0043] In one embodiment, Figure 1 As shown, a resistor sheet screening method is provided, and the method is applied to a DC lightning arrester as an example for explanation, wherein the method is applied to a whole batch of resistor sheets used to assemble a DC lightning arrester; the method comprises the following steps:

[0044] Step 102, after applying the first sequence of impulse currents to the resistors in the current batch of resistors in the entire batch of resistors, performing defect detection on the resistors in the current batch to obtain a first screening pass rate;

[0045] Wherein, the first sequence impulse current adopts square wave impulse current.

[0046] Specifically, the resistor screening method of the present application targets all resistors of the arrester, and these resistors can be divided into several batches. Furthermore, for a whole batch of resistors used to assemble DC arresters, they can be divided into several batches, and then the screening method for the current batch of resistors can be applied to each batch of resistors, thereby completing the screening of the whole batch of resistors.

[0047] Based on this application, after the resistors are finished, each batch is tested for defects and screened to ensure that resistors with unqualified energy are not used when assembling the arrester. The specific test process can include 3 current impact sequences.

[0048] Furthermore, a first sequence of impulse currents is applied to the current batch of resistors, and the first sequence of impulse currents uses square wave impulse currents. Then, defect detection is performed on the current batch of resistors that have completed the square wave impulse current to obtain the first screening pass rate. The present application can detect internal defects of resistors through square wave impulse currents.

[0049] It should be noted that, in the embodiment of the present application, the criteria for evaluating the test pass of defect detection on the current batch of resistors may include: the current amplitude does not increase during the test, and the resistors should not have any signs of breakdown, flashover, breakage or obvious damage.

[0050] In one embodiment, the step of applying a first sequence of impulse currents to a current batch of resistors in a whole batch of resistors comprises:

[0051] Apply a square wave impulse current to the current batch of resistors and inject a first energy; wherein the first energy is equal to the design energy of the resistor; the design energy of the resistor is determined based on the number of resistors in the entire batch of resistors and the total energy flowing through the DC lightning arrester when the DC lightning arrester is actuated obtained through simulation of the operating conditions;

[0052] Specifically, the first sequence of impulse currents can use continuous square wave impulse currents and inject 100% of the resistor design energy to find internal defects in the resistor. Furthermore, the resistor design energy in the present application can be determined based on the number of resistors in the entire batch of resistors and the total energy flowing through the DC lightning arrester when the DC lightning arrester is in action obtained through simulation of the operating conditions.

[0053] For example, by simulating the operating conditions, the energy (i.e., total energy) flowing through the DC arrester when it is in action is calculated. Then the number of resistors required to assemble the arrester (i.e., the number of resistors in the entire batch of resistors) is determined, that is, the total energy divided by the number of resistors is the resistor design energy.

[0054] In one embodiment, if Figure 2 As shown, the method also includes the steps of:

[0055] Step 202, obtaining the total energy flowing through the DC lightning arrester when the DC lightning arrester is in operation according to the electromagnetic transient simulation operation condition;

[0056] Step 204, obtaining the number of resistors in the entire batch of resistors according to the configuration parameters of the DC lightning arrester;

[0057] Step 206: The quotient of the total energy and the number of resistors is determined as the resistor design energy.

[0058] Specifically, taking a large-capacity DC lightning arrester as an example, this application simulates the operating conditions based on electromagnetic transient simulation, calculates the energy flowing through the lightning arrester when the large-capacity DC lightning arrester is actuated, which is called the total design energy (i.e., total energy), and obtains the duration of the current flowing through the lightning arrester.

[0059] Furthermore, the number of resistors required for assembling the arrester can be determined based on the DC arrester parameter configuration method of each arrester manufacturer, and the total design energy divided by the number of resistors is the resistor design energy.

[0060] In one of the embodiments, the DC lightning arrester is a large-capacity DC lightning arrester; the first sequence impulse current uses two continuous square wave impulse currents.

[0061] Specifically, the embodiment of the present application is applied to the screening of resistors in large-capacity DC lightning arresters, and the first sequence of impulse currents uses two continuous square wave impulse currents and injects 100% of the resistor design energy to find internal defects of the resistor.

[0062] In one embodiment, the large-capacity DC arrester includes a neutral bus arrester and a DC conversion switch arrester, and the first sequence impulse current uses two continuous 2ms square wave impulse currents;

[0063] Specifically, the large-capacity DC lightning arrester used in the embodiment of the present application may include a neutral bus lightning arrester and a DC conversion switch lightning arrester; the first sequence of impulse currents specifically uses two consecutive 2ms square wave impulse currents, injecting 100% of the resistor design energy. The present application discovers internal defects of the resistor through a 2ms square wave.

[0064] Step 104, after the second sequence of impulse currents are applied to the resistors in the current batch, defect detection is performed on the resistors in the current batch to obtain a second screening pass rate;

[0065] The second sequence impulse current adopts a half-sine wave impulse current, or a square wave impulse current obtained by energy equivalent conversion of a half-sine wave impulse current.

[0066] Specifically, after obtaining the first screening pass rate, a second sequence of impulse currents can be applied to the current batch of resistors; based on the present application, after the resistors are finished, each batch needs to be inspected and screened for defects, and the test process may include three current impulse sequences (first sequence impulse current, second sequence impulse current, and third sequence impulse current, respectively); the second current impulse sequence of the three current impulse sequences may refer to applying a second sequence of impulse currents to the current batch of resistors; further, the duration of the second sequence of impulse currents may be consistent with the electromagnetic transient simulation, and the present application uses long waves to screen out internally uneven resistors.

[0067] It should be noted that the criteria for evaluating the test quality of defect detection on the current batch of resistors in the embodiment of the present application may include: the current amplitude does not increase during the test, and the resistor should not have any signs of breakdown, flashover, breakage or obvious damage.

[0068] In some examples, the second sequence impulse current can use a half-sine wave impulse current. Taking the DC arrester as a large-capacity DC arrester as an example, this application uses a combination of square wave and half-sine wave screening test to improve the screening rate of defective resistors in large-capacity DC arresters, and avoids the actual operation of the arrester due to the failure of the resistor performance not meeting the standard. This application uses a combination of square wave and half-sine wave screening test, and the test waveform is more in line with the operating conditions.

[0069] Furthermore, the second sequence impulse current can also adopt a square wave impulse current obtained by energy equivalent conversion of a half-sine wave impulse current, which can be applied to the screening of large-size resistors (for example, resistors with a diameter greater than 100 mm). The present application proposes an energy equivalence method for half-sine wave impulse current and square wave impulse current for large-size resistors, to solve the problem of an equivalent screening method when the test capacity is insufficient and a long-duration half-sine wave current impulse test cannot be carried out. The present application reduces the difficulty of the test through an energy equivalent test.

[0070] For example, when the test conditions are not capable of generating a second sequence impulse current using a half-sine wave (and are not capable of generating a third sequence impulse current using a half-sine wave), the present application can perform an energy equivalence method for a half-sine wave impulse current and a square wave impulse current (in some examples, it can be applicable to large-size resistors with a diameter of about 105 mm). When the test equipment does not have the ability to generate a half-sine wave, the half-sine wave can be converted into a square wave and the injected energy can be corrected.

[0071] In one embodiment, the step of applying a second sequence of impulse currents to the current batch of resistors may include:

[0072] If a half-sine wave impulse current is applied to the resistors in the current batch, a second energy is injected; the second energy is less than the designed energy of the resistors;

[0073] If a square wave impulse current is applied to the current batch of resistors, a third energy is injected; wherein the third energy is obtained by correcting the second energy based on a fitting relationship between the impulse duration of the impulse current and the energy density of the resistors.

[0074] Specifically, after the resistors are finished, each batch needs to be inspected and screened for defects, and the test process includes three current shock sequences; and, in these three current shock sequences, the present application adopts a shock test method with reduced energy, which can avoid potential damage to the resistors caused by the test; for example, when the second sequence of shock currents applied to the current batch of resistors is a half-sine wave shock current, the injected second energy is less than the design energy of the resistors.

[0075] Furthermore, when the second sequence impulse current applied to the current batch of resistors is a square wave impulse current, the injected third energy is obtained by correction; wherein the third energy can be obtained by correcting the second energy based on the fitting relationship between the impulse duration of the impulse current and the energy density of the resistor (for example, increasing the injected energy). In some examples, taking large-size resistors as an example, a curve of the duration and energy density of large-size resistors (the fitting relationship between the impulse duration of the impulse current and the energy density of the resistor) can be fitted, and then the second energy is modified based on the curve to obtain the third energy.

[0076] In one of the embodiments, if the second sequence impulse current adopts a half-sine wave impulse current, the duration of applying the second sequence impulse current to the current batch of resistors is the same as the duration of the current flowing through the DC lightning arrester in the electromagnetic transient simulation operating condition.

[0077] Specifically, the second sequence impulse current in the present application can adopt a half-sine wave, the duration of which should be consistent with the electromagnetic transient simulation, and inject corresponding energy (for example, 70% of the resistor design energy) to screen out internal uneven resistors through long waves.

[0078] In one of the embodiments, the DC lightning arrester is a large-capacity DC lightning arrester; the second sequence impulse current uses two continuous half-sine wave impulse currents, and the second energy is 70% of the design energy of the resistor.

[0079] Specifically, in the process of applying the second sequence impulse current to the current batch of resistors, if the second sequence impulse current uses two consecutive sinusoidal half-waves, 70% of the resistor design energy is injected, and the duration of the sinusoidal half-wave should be consistent with the electromagnetic transient simulation, and then the current batch of resistors is inspected for defects to obtain the second screening pass rate to screen out internally uneven resistors.

[0080] In one embodiment, the large-capacity DC lightning arrester includes a neutral bus lightning arrester and a DC conversion switch lightning arrester, and the second sequence impulse current can be two consecutive 100ms half-sine wave impulse currents.

[0081] Specifically, taking a large-capacity DC lightning arrester as an example, the second sequence impulse current can use two consecutive 100ms half-sine wave impulse currents, and inject 70% of the resistor design energy. The duration of the half-sine wave should be consistent with the electromagnetic transient simulation, and then the internal uneven resistors can be screened out through long waves.

[0082] Furthermore, the second sequence impulse current may also use two consecutive 2ms square waves instead of two consecutive 100ms half-sine waves, and the magnitude of the third energy is determined by correcting the second energy.

[0083] Step 106, after applying the third sequence of impulse currents to the current batch of resistors, perform defect detection on the current batch of resistors to obtain a third screening pass rate; wherein the impulse current type used by the third sequence of impulse currents is the same as that of the second sequence of impulse currents.

[0084] Specifically, after obtaining the first screening pass rate and the second screening pass rate, the present application can apply a third sequence of impulse currents to the current batch of resistors. The type of impulse current used by the third sequence of impulse currents is the same as that of the second sequence of impulse currents; for example, when the second sequence of impulse currents uses a half-sine wave impulse current, the third sequence of impulse currents also uses a half-sine wave impulse current; for another example, when the second sequence of impulse currents uses a square wave impulse current obtained by energy equivalent conversion of a half-sine wave impulse current, the third sequence of impulse currents also uses a square wave impulse current, which is also obtained by energy equivalent conversion of a half-sine wave impulse current.

[0085] After the third sequence of impulse currents are applied to the current batch of resistors, defect detection can be performed on the current batch of resistors to obtain the third screening pass rate. It should be noted that the criteria for the test pass evaluation of defect detection on the current batch of resistors in the embodiment of the present application may include: the current amplitude does not increase during the test, and the resistors should not have any signs of breakdown, flashover, breakage or obvious damage.

[0086] In one embodiment, the step of applying a third sequence of impulse currents to the current batch of resistors includes:

[0087] If a half-sine wave impulse current is applied to the resistors in the current batch, a fourth energy is injected; the fourth energy is less than the designed energy of the resistors;

[0088] If a square wave impulse current is applied to the current batch of resistors, a fifth energy is injected; wherein the fifth energy is obtained by correcting the fourth energy based on the fitting relationship between the impulse duration of the impulse current and the energy density of the resistors.

[0089] Specifically, after the resistors are finished, each batch needs to be inspected and screened for defects, and the test process includes three current shock sequences; and, in these three current shock sequences, the present application adopts a shock test method with reduced energy, which can avoid potential damage to the resistors caused by the test; for example, when the third sequence of shock currents applied to the current batch of resistors is a half-sine wave shock current, the injected fourth energy is less than the design energy of the resistors.

[0090] Further, when the third sequence impulse current applied to the current batch of resistors is a square wave impulse current, the injected fifth energy is obtained by correction; wherein the fifth energy can be obtained by correcting the fourth energy based on the fitting relationship between the impulse duration of the impulse current and the energy density of the resistor (for example, increasing the injected energy). In some examples, taking a large-size resistor as an example, a curve of the duration and energy density of a large-size resistor can be fitted (the fitting relationship between the impulse duration of the impulse current and the energy density of the resistor), and then the fourth energy is modified based on the curve to obtain the fifth energy.

[0091] In one of the embodiments, the DC lightning arrester is a large-capacity DC lightning arrester; the third sequence impulse current adopts a half-sine wave impulse current, and the fourth energy is 60% of the design energy of the resistor.

[0092] Specifically, the third sequence impulse current can use a half-sine wave to inject 60% of the resistor design energy. When the test conditions do not have the ability to generate a third sequence impulse current of a half-sine wave, this application proposes an energy equivalence method for a half-sine wave impulse current and a square wave impulse current, which is applied to large-size resistors (suitable for large-size resistors with a diameter of about 105mm). When the test device does not have the ability to generate a half-sine wave, the half-sine wave can be converted into a square wave and the injected energy can be increased.

[0093] Step 108, if the first screening pass rate, the second screening pass rate and the third screening pass rate all meet the corresponding thresholds, then the resistors in the current batch are confirmed to be qualified resistors;

[0094] Specifically, after obtaining the first screening pass rate, the second screening pass rate and the third screening pass rate, it can be confirmed whether the first screening pass rate, the second screening pass rate and the third screening pass rate respectively meet the corresponding thresholds, and then confirm whether the current batch of resistors are qualified resistors.

[0095] In some examples, the thresholds (evaluation criteria) applicable to the qualified rate in this application may include: the qualified rate of the first screening is ≥ 97%, the qualified rate of the second screening is ≥ 98%, and the qualified rate of the third screening is 100%. When the qualified rate of the test batch screening does not meet the above evaluation criteria, the entire batch of resistors should not be used for large-capacity DC lightning arrester assembly.

[0096] Step 110, the next batch of resistors in the whole batch of resistors is used as the current batch of resistors to be screened in the next round to confirm whether the next batch of resistors is qualified; until it is confirmed that all batches of resistors in the whole batch of resistors are qualified, it is determined that the resistor screening for DC lightning arresters is completed.

[0097] Specifically, after the resistors are finished, each batch needs to be inspected and screened for defects. The test process can include three current impact sequences (the first sequence impact current, the second sequence impact current and the third sequence impact current mentioned above). At the same time, in order to avoid potential damage to the resistors during the test, this application adopts a reduced energy impact test method. When the test batch screening pass rate does not meet the above evaluation criteria, the entire batch of resistors should not be used for large-capacity DC lightning arrester assembly.

[0098] As mentioned above, based on this application, the screening rate of defective resistors in DC arresters is improved through the combined screening test of square waves and half-sine waves. The test waveform is more in line with the operating conditions, avoiding the actual operation of the arrester due to the failure of the resistor performance not meeting the standards. At the same time, a method for the energy equivalence of the half-sine wave impulse current and the square wave impulse current of large-size resistors (resistance diameter greater than 100mm) is proposed, and the difficulty of the test is reduced through the energy equivalence test.

[0099] In order to further explain the solution of this application, a specific example is given below. Taking a large-capacity DC lightning arrester as an example, the purpose of this application is to ensure that no resistors with unqualified energy are used when assembling the lightning arrester. The test sample should be all the resistors of the lightning arrester, and these resistors can be divided into several batches.

[0100] According to the electromagnetic transient simulation operation conditions, the energy flowing through the large-capacity DC arrester when it is in action is calculated, which can be called the total design energy (i.e., total energy), and the duration of the current flowing through the arrester is obtained. According to the DC arrester parameter configuration method of each arrester manufacturer, the number of resistors required to assemble the arrester (i.e., the number of resistors in the entire batch of resistors) is determined, and the total design energy divided by the number of resistors is the resistor design energy.

[0101] After the resistors are finished, each batch needs to be inspected and screened for defects. The test process may include three current impact sequences (first sequence impact current, second sequence impact current and third sequence impact current in sequence); at the same time, the present application adopts a reduced energy impact test method to avoid potential damage to the resistors caused by the test:

[0102] The first sequence of impulse current uses two consecutive 2ms square waves, injecting 100% of the designed energy; the internal defects of the resistor are discovered through the 2ms square wave.

[0103] The second sequence impulse current uses two continuous sinusoidal half waves. The duration of the sinusoidal half waves should be consistent with the electromagnetic transient simulation. 70% of the design energy is injected, and the internal uneven resistor sheets are screened out by long waves.

[0104] The third sequence impulse current adopts 1 half-sine wave and 60% design energy.

[0105] The criteria for the test qualification evaluation are: the current amplitude does not increase during the test, and the resistor should not have any signs of breakdown, flashover, breakage or obvious damage. Furthermore, the first screening qualification rate is ≥97%, the second screening qualification rate is ≥98%, and the third screening qualification rate is 100%.

[0106] When the qualified rate of the test batch screening does not meet the above evaluation criteria, the entire batch of resistors should not be used for large-capacity DC lightning arrester assembly. When the test conditions do not have the ability to generate the second sequence impulse current of the half-sine wave and the third sequence impulse current of the half-sine wave, the energy equivalence method of the half-sine wave impulse current and the square wave impulse current can be used. It is suitable for large-size resistors (for example, large-size resistors with a diameter of about 105mm). When the test device does not have the ability to generate a half-sine wave, the half-sine wave can be converted into a square wave and the injection energy can be increased.

[0107] In some instances, the present application fits a curve of duration and energy density of a large-size resistor. The longer the impact time lasts, the smaller the energy the resistor can withstand. x is the duration, and y is the energy density. When x=2, it represents the energy density under a square wave impact current of 2ms, and when x=50-200, it represents the energy density under a half-sine wave impact current; furthermore, y=1383x^-0.162.

[0108] For example, according to the electromagnetic transient simulation operation conditions, the design energy of a large-capacity lightning arrester is 2.6MJ, and the duration of the lightning arrester current is a 100ms sine half-wave. The lightning arrester parameter configuration determines that the lightning arrester has a total of 224 resistors, so the design energy of the resistor is 2.6MJ / 224=11.6kJ;

[0109] The first sequence of impulse currents uses two consecutive 2ms square waves with an injected energy of 11.6kJ;

[0110] The second sequence impulse current uses two consecutive 100ms half-sine waves with an injected energy of 8.12kJ.

[0111] At this time, when the test device does not have the ability to generate a half-sine wave, the half-sine wave can be converted into a square wave and the injected energy can be corrected. When the resistor size is 105mm in diameter and 22mm in thickness, the volume of the resistor is 190.498cm 3 , the energy density of the resistor is y = 8120 / 190.498 = 42.6 J / cm 3 .

[0112] According to the curve of duration and energy density of large-size resistor, when the impact duration x = 100ms, the energy density of the resistor under the 100ms half-sine wave current impact is y1 = 655.88J / cm 3When the impulse duration x = 2ms, the energy density of the resistor under the 2ms square wave current impulse is y2 = 1236.10J / cm 3 , y2=1.88y1, the energy density of the corrected energy resistor is y'=1.88y=80.09J / cm 3 The corrected injection energy is 80.09*190.498=15260J=15.26kJ. Therefore, the second sequence impulse current can use two consecutive 2ms square waves instead of two consecutive 100ms sine half waves, and the injection energy is =15.26kJ. The energy correction process of the third sequence impulse current is the same.

[0113] This application improves the screening rate of defective resistors in large-capacity DC arresters through a combined screening test of square waves and half-sine waves, avoiding failure problems caused by substandard resistor performance during actual operation of arresters. The energy equivalence method of half-sine wave impulse current and square wave impulse current in this application is suitable for large-size resistors, and solves the equivalent screening method when the test capacity is insufficient and long-duration half-sine wave current impulse tests cannot be carried out. This application adopts an energy-reducing impulse test method to avoid potential damage to the resistors caused by the test.

[0114] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0115] Based on the same inventive concept, the embodiment of the present application also provides a resistor screening device for implementing the resistor screening method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more resistor screening device embodiments provided below can refer to the limitations of the resistor screening method above, and will not be repeated here.

[0116] In one embodiment, Figure 3 As shown, a resistor sheet screening device is provided, which is applied to a batch of resistor sheets used to assemble DC lightning arresters; the device comprises:

[0117] The defect screening module 310 is used to perform defect detection on the resistors in the current batch of the whole batch of resistors after applying the first sequence of impulse currents to the resistors in the current batch of resistors, and obtain the first screening pass rate; wherein the first sequence of impulse currents adopts square wave impulse currents; and is also used to perform defect detection on the resistors in the current batch of resistors after applying the second sequence of impulse currents to the resistors in the current batch, and obtain the second screening pass rate; wherein the second sequence of impulse currents adopts half-sine wave impulse currents, or square wave impulse currents obtained by energy equivalent conversion of half-sine wave impulse currents; and is used to perform defect detection on the resistors in the current batch of resistors after applying the third sequence of impulse currents to the resistors in the current batch, and obtain the third screening pass rate; wherein the impulse current type adopted by the third sequence of impulse currents is the same as that of the second sequence of impulse currents;

[0118] The qualified confirmation module 320 is used to confirm that the current batch of resistors are qualified resistors if the first screening qualified rate, the second screening qualified rate and the third screening qualified rate all meet the corresponding thresholds; and use the next batch of resistors in the entire batch of resistors as the current batch of resistors to be screened in the next round to confirm whether the next batch of resistors are qualified resistors; until it is confirmed that all batches of resistors in the entire batch of resistors are qualified resistors, it is determined that the resistor screening for the DC lightning arrester is completed.

[0119] In one embodiment, the defect screening module 310 includes:

[0120] The first screening module is used to apply a square wave impulse current to the current batch of resistors and inject a first energy; wherein the first energy is equal to the design energy of the resistor; the design energy of the resistor is determined based on the number of resistors in the entire batch of resistors and the total energy flowing through the DC lightning arrester when the DC lightning arrester is actuated obtained by simulating the operating conditions;

[0121] The second screening module is used to inject a second energy if a half-sine wave impulse current is applied to the current batch of resistors; the second energy is less than the design energy of the resistors; and to inject a third energy if a square wave impulse current is applied to the current batch of resistors; wherein the third energy is obtained by correcting the second energy based on a fitting relationship between the impulse duration of the impulse current and the energy density of the resistors;

[0122] The third screening module is used to inject a fourth energy if a half-wave sinusoidal impulse current is applied to the current batch of resistors; the fourth energy is less than the design energy of the resistors; and to inject a fifth energy if a square wave impulse current is applied to the current batch of resistors; wherein the fifth energy is obtained by correcting the fourth energy based on the fitting relationship between the impulse duration of the impulse current and the energy density of the resistors.

[0123] In one of the embodiments, the DC lightning arrester is a large-capacity DC lightning arrester; the first sequence impulse current uses two continuous square wave impulse currents; the second sequence impulse current uses two continuous sinusoidal half-wave impulse currents, and the second energy is 70% of the resistor design energy; the third sequence impulse current uses one sinusoidal half-wave impulse current, and the fourth energy is 60% of the resistor design energy.

[0124] In one embodiment, the large-capacity DC lightning arrester includes a neutral bus lightning arrester and a DC conversion switch lightning arrester, and the first sequence impulse current uses two consecutive 2ms square wave impulse currents; the second sequence impulse current uses two consecutive 100ms half-sine wave impulse currents.

[0125] In one embodiment, the device further comprises:

[0126] A simulation module is used to simulate the operating conditions according to the electromagnetic transient simulation to obtain the total energy flowing through the DC arrester when the DC arrester is in action;

[0127] The energy confirmation module is used to obtain the number of resistors in the whole batch of resistors according to the configuration parameters of the DC lightning arrester; and determine the quotient of the total energy and the number of resistors as the resistor design energy.

[0128] In one of the embodiments, if the second sequence impulse current adopts a half-sine wave impulse current, the duration of applying the second sequence impulse current to the current batch of resistors is the same as the duration of the current flowing through the DC lightning arrester in the electromagnetic transient simulation operating condition.

[0129] Each module in the above resistor screening device can be implemented in whole or in part by software, hardware or a combination thereof. Each module can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute the operations corresponding to each module.

[0130] In one embodiment, a resistor screening device is provided. The device can be implemented by using a corresponding computer device. The computer device can be a terminal. Its internal structure diagram can be as shown in FIG. Figure 4As shown. The computer device includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a resistor screening method is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a button, trackball or touchpad set on the computer device shell, or an external keyboard, touchpad or mouse, etc.

[0131] Those skilled in the art will understand that Figure 4 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0132] In one embodiment, a resistor screening device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps of the above-mentioned resistor screening method when executing the computer program.

[0133] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above-mentioned resistor screening method are implemented.

[0134] In one embodiment, a computer program product is provided, comprising a computer program, which implements the steps of the above-mentioned resistor screening method when executed by a processor.

[0135] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0136] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0137] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A resistor screening method, characterized in that: The method is applied to a batch of resistor sheets used to assemble DC lightning arresters; the method comprises: After applying the first sequence of impulse currents to the current batch of resistors in the entire batch of resistors, defect detection is performed on the current batch of resistors to obtain a first screening pass rate; wherein the first sequence of impulse currents uses square wave impulse currents; After applying the second sequence of impulse currents to the current batch of resistors, defect detection is performed on the current batch of resistors to obtain a second screening pass rate; wherein the second sequence of impulse currents uses a half-sine wave impulse current, or a square wave impulse current obtained by energy equivalent conversion of the half-sine wave impulse current; After the third sequence of impulse currents is applied to the resistors of the current batch, defect detection is performed on the resistors of the current batch to obtain a third screening pass rate; wherein the impulse current type used by the third sequence of impulse currents is the same as that of the second sequence of impulse currents; If the first screening pass rate, the second screening pass rate and the third screening pass rate all meet corresponding thresholds, then the resistors in the current batch are confirmed to be qualified resistors; The next batch of resistors in the entire batch of resistors is used as the current batch of resistors to be screened in the next round to confirm whether the next batch of resistors are qualified resistors; until it is confirmed that each batch of resistors in the entire batch of resistors is qualified, it is determined that the resistor screening for the DC lightning arrester is completed.

2. The method according to claim 1, characterized in that The step of applying a first sequence of impulse currents to a current batch of resistors in the entire batch of resistors comprises: Applying a square wave impulse current to the current batch of resistors, injecting a first energy; wherein the first energy is equal to the resistor design energy; the resistor design energy is determined based on the number of resistors in the entire batch of resistors and the total energy flowing through the DC lightning arrester when the DC lightning arrester is in action obtained through an operating condition simulation; The step of applying a second sequence of impulse currents to the current batch of resistors comprises: If a half-sine wave impulse current is applied to the resistors of the current batch, a second energy is injected; the second energy is less than the designed energy of the resistors; If a square wave impulse current is applied to the resistors of the current batch, a third energy is injected; wherein the third energy is obtained by correcting the second energy based on a fitting relationship between the impulse duration of the impulse current and the energy density of the resistors; The step of applying a third sequence of impulse currents to the current batch of resistors comprises: If a half-sine wave impulse current is applied to the resistors of the current batch, a fourth energy is injected; the fourth energy is less than the designed energy of the resistors; If a square wave impulse current is applied to the current batch of resistors, a fifth energy is injected; wherein the fifth energy is obtained by correcting the fourth energy based on the fitting relationship between the impulse duration of the impulse current and the energy density of the resistors.

3. The method according to claim 2, characterized in that The DC lightning arrester is a large-capacity DC lightning arrester; the first sequence impulse current adopts 2 continuous square wave impulse currents; the second sequence impulse current adopts 2 continuous sinusoidal half-wave impulse currents, and the second energy is 70% of the design energy of the resistor; the third sequence impulse current adopts 1 sinusoidal half-wave impulse current, and the fourth energy is 60% of the design energy of the resistor.

4. The method according to claim 3, characterized in that The large-capacity DC lightning arrester includes a neutral bus lightning arrester and a DC conversion switch lightning arrester. The first sequence impulse current adopts two continuous 2ms square wave impulse currents; the second sequence impulse current adopts two continuous 100ms half-sine wave impulse currents.

5. The method according to claim 2, characterized in that: The method further comprises the steps of: According to the electromagnetic transient simulation operation condition, the total energy flowing through the DC lightning arrester when the DC lightning arrester is in operation is obtained; According to the configuration parameters of the DC lightning arrester, the number of the resistors in the whole batch of resistors is obtained; The quotient of the total energy and the number of resistors is determined as the resistor design energy.

6. The method according to claim 5, characterized in that If the second sequence impulse current adopts a half-sine wave impulse current, the duration of applying the second sequence impulse current to the current batch of resistors is the same as the duration of the current flowing through the DC lightning arrester in the electromagnetic transient simulation operating condition.

7. A resistor screening device, characterized in that: The device is applied to a batch of resistor sheets for assembling DC lightning arresters; the device comprises: A defect screening module, used for performing defect detection on the current batch of resistors in the whole batch of resistors after applying a first sequence of impulse currents to the current batch of resistors, and obtaining a first screening pass rate; wherein the first sequence of impulse currents adopts a square wave impulse current; and also used for performing defect detection on the current batch of resistors after applying a second sequence of impulse currents to the current batch of resistors, and obtaining a second screening pass rate; wherein the second sequence of impulse currents adopts a half-sine wave impulse current, or a square wave impulse current obtained by energy equivalent conversion of the half-sine wave impulse current; and for performing defect detection on the current batch of resistors after applying a third sequence of impulse currents to the current batch of resistors, and obtaining a third screening pass rate; wherein the impulse current type adopted by the third sequence of impulse currents is the same as that of the second sequence of impulse currents; A qualified confirmation module is used to confirm that the current batch of resistors are qualified resistors if the first screening qualified rate, the second screening qualified rate and the third screening qualified rate all meet the corresponding thresholds; and use the next batch of resistors in the entire batch of resistors as the current batch of resistors to be screened in the next round to confirm whether the next batch of resistors are qualified resistors; until it is confirmed that each batch of resistors in the entire batch of resistors are qualified resistors, it is determined that the resistor screening for the DC lightning arrester is completed.

8. A resistor screening device, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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