Device for testing electrical integrity of grounding grid under strong electromagnetic field
By setting the shield of the π-type LC filter circuit on the test lead of the DC resistance tester, the problem that the induced voltage under a strong electromagnetic field affects the accuracy of the test data is solved, and the accuracy of the electrical integrity test data of the grounding grid in a strong electromagnetic field environment is achieved.
Patent Information
- Application Number
- CN202420939753.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-30
- Publication Date
- 2025-05-13
- Estimated Expiration
- 2034-04-30
AI Technical Summary
Under strong electromagnetic fields, when the DC resistance tester detects the electrical integrity of the grounding grid, the induced voltage will cause inaccurate test data, which will misjudgment the health status of the grounding grid.
A shield is provided on the test lead of the DC resistance tester. The shield is a π-type LC filtering circuit, including inductors and capacitors, which are used to filter out the AC voltage and retain the DC voltage signal.
By shielding the induced voltage, we ensure that the voltage signal collected by the test instrument is only DC signal, thereby ensuring the accuracy of the test data and avoiding misjudgment of the health status of the grounding network.
Smart Images
Figure CN222866846U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of electrical testing, in particular to a device for testing the electrical integrity of a grounding grid under a strong electromagnetic field. Background Art
[0002] The electrical integrity of the grounding grid refers to the electrical connectivity between various electrical devices that should be grounded in the grounding device and between various parts of the grounding device. It is an important indicator to measure the health of the grounding grid. During the long-term operation of power equipment, the connection points may be affected by moisture and other factors, resulting in node corrosion or even breakage, which may cause safety hazards in the operation of the equipment. In serious cases, it may cause the equipment to lose ground operation.
[0003] In the past, the impact of electromagnetic fields on test data was not considered during the electrical integrity test of the grounding grid. When using a DC resistance tester to test the electrical integrity of the grounding grid, the strong electromagnetic field in the station will generate an induced voltage on the test wire, causing the voltage signal collected by the test instrument to be too large, affecting the accuracy of the test data, and thus misjudging the health of the grounding grid. Utility Model Content
[0004] Some simplifications or omissions may be made in this section and the abstract of the specification and the title of the utility model of this application to avoid blurring the purpose of this section, the abstract of the specification and the title of the utility model, and such simplifications or omissions shall not be used to limit the scope of the utility model.
[0005] In view of the above problems or problems existing in the prior art, the present utility model is proposed.
[0006] Therefore, the purpose of the utility model is to provide a grounding grid electrical integrity testing device under a strong electromagnetic field, which aims to solve the existing problems.
[0007] In order to solve the above technical problems, the utility model provides the following technical solutions: a grounding grid electrical integrity test device under a strong electromagnetic field, comprising a DC resistance tester, a test lead from a voltage sampling positive electrode of the DC resistance tester is provided with a shielding member, and the DC resistance tester is electrically connected to a tested product;
[0008] The shielding component has a π-type LC filter circuit inside, including an inductor. The inductor is connected to a test wire led out from the voltage sampling positive electrode of a DC resistance tester, and both ends of the inductor are respectively connected to a first capacitor and a second capacitor and then grounded.
[0009] As a preferred solution of the grounding grid electrical integrity testing device under strong electromagnetic field described in the utility model, wherein: the DC resistance tester is provided with an output current positive electrode, an output current negative electrode, a voltage sampling positive electrode and a voltage sampling negative electrode.
[0010] As a preferred solution of the grounding grid electrical integrity testing device under a strong electromagnetic field described in the utility model, when the tested product is selected as a transformer and the high-voltage side of the transformer is directly measured, the output current positive electrode and the voltage sampling positive electrode are both connected to one of the A / B / C windings on the high-voltage side of the transformer, and the output current negative electrode and the voltage sampling negative electrode are both connected to the neutral point O of the transformer.
[0011] As a preferred solution of the grounding grid electrical integrity testing device under a strong electromagnetic field described in the utility model, when the tested product is selected as a transformer and the a / c winding on the low-voltage side of the transformer is measured, the positive electrode of the output current is connected to the A winding on the high-voltage side of the transformer, the positive electrode of the voltage sampling is respectively connected to the B / C winding on the high-voltage side and the a winding on the low-voltage side of the transformer, and the negative electrode of the output current and the negative electrode of the voltage sampling are both connected to the c winding on the low-voltage side of the transformer.
[0012] As a preferred solution of the grounding grid electrical integrity testing device under a strong electromagnetic field described in the utility model, when the tested product is selected as a transformer and the b / a winding on the low-voltage side of the transformer is measured, the positive electrode of the output current is connected to the B winding on the high-voltage side of the transformer, the positive electrode of the voltage sampling is respectively connected to the A / C winding on the high-voltage side and the b winding on the low-voltage side of the transformer, and the negative electrode of the output current and the negative electrode of the voltage sampling are both connected to the a winding on the low-voltage side of the transformer.
[0013] As a preferred solution of the grounding grid electrical integrity testing device under a strong electromagnetic field described in the utility model, when the tested product is selected as a transformer and the c / b winding on the low-voltage side of the transformer is measured, the positive electrode of the output current is connected to the C winding on the high-voltage side of the transformer, the positive electrode of the voltage sampling is respectively connected to the A / B winding on the high-voltage side and the c winding on the low-voltage side of the transformer, and the negative electrode of the output current and the negative electrode of the voltage sampling are both connected to the b winding on the low-voltage side of the transformer.
[0014] The beneficial effects of the utility model are as follows: the device adds a shielding component to the voltage collection circuit of the test instrument to shield the induced voltage generated by the strong magnetic field on the test wire, so that the voltage signal collected by the test instrument is only a DC voltage signal, thereby ensuring the accuracy of the instrument test data. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:
[0016] Figure 1This is the overall structure diagram of the grounding grid electrical integrity test device under strong electromagnetic field described in the utility model;
[0017] Figure 2 It is a schematic diagram of the internal circuit of the shielding component;
[0018] Figure 3 This is the wiring diagram for measuring the high voltage side winding of the transformer;
[0019] Figure 4 This is the wiring diagram for measuring the a / c winding on the low voltage side of the transformer;
[0020] Figure 5 This is the wiring diagram for measuring the b / a winding on the low voltage side of the transformer;
[0021] Figure 6 This is the wiring diagram for measuring the c / b winding on the low-voltage side of the transformer. DETAILED DESCRIPTION
[0022] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.
[0023] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.
[0024] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments.
[0025] Example 1
[0026] Reference Figure 1-Figure 2 , which is the first embodiment of the utility model, and provides a grounding grid electrical integrity test device under a strong electromagnetic field, comprising a DC resistance tester 100, a shielding member 200 is provided on the test wire led out from the voltage sampling positive electrode U+ of the DC resistance tester 100, and the DC resistance tester 100 is electrically connected to a test object 300;
[0027] A shielding member 200 is provided on the test wire led out from the voltage sampling positive electrode U+ of the DC resistance tester 100 , and a π-type LC filter circuit is inside the shielding member 200 .
[0028] The DC resistance tester 100 is provided with an output current positive electrode I+, an output current negative electrode I−, a voltage sampling positive electrode U+ and a voltage sampling negative electrode U−.
[0029] The shielding member 200 has a π-type LC filter circuit inside, including an inductor L. The inductor L is connected to a test lead from the voltage sampling positive electrode U+ of the DC resistance tester 100, and both ends of the inductor L are respectively connected to a first capacitor C1 and a second capacitor C2 and then grounded.
[0030] The detection instrument used in the grounding grid electrical integrity test project is a DC resistance tester 100. The detection principle is to set a constant current source that generates DC current in the instrument. During the test, a constant current I is injected into the test object 300, and the voltage value U generated by the test object 300 is sampled to obtain the resistance value R. When the injected current I is constant, if there is a strong magnetic field in the test wire arrangement path, a certain induced voltage will be generated on the test wire, causing the voltage value U collected by the detection instrument to increase abnormally, resulting in abnormal grounding grid electrical integrity test data. Therefore, the focus of this device is on how to shield the electromagnetic field induced voltage so that it is not collected by the test instrument.
[0031] The AC voltage will pass through the inductor and generate a phase difference on the capacitor. This phase difference causes a difference between the voltage waveform on the capacitor and the voltage waveform on the inductor. Due to this phase difference, the AC signal is filtered by the combined effect of the inductor and capacitor, while the DC signal passes through the capacitor without being affected. Since the inductor has a low impedance to AC and the capacitor has a high impedance to AC, the DC voltage on the capacitor is smoothed and the AC component is filtered out. In this way, the filter circuit can retain the DC voltage while filtering out the fluctuations of the AC voltage.
[0032] The filter inductor has a large inductive reactance to AC and a small inductive reactance to DC, which can improve the filtering effect without reducing the DC output voltage. The unidirectional pulsating DC voltage output by the tested product is first filtered by the first capacitor C1 to remove most of the AC components, and then added to the inductor L and the second capacitor C2 filtering circuit.
[0033] In summary, this device can perform electrical integrity tests on grounding grids in strong electromagnetic field environments, and has the advantages of simple operation, high test accuracy, and strong anti-interference ability.
[0034] Example 2
[0035] Reference Figure 3, which is the second embodiment of the utility model, and is different from the first embodiment in that: when the tested product 300 is selected as a transformer and the high-voltage side of the transformer is directly measured, the output current positive pole I+ and the voltage sampling positive pole U+ are both connected to one of the A / B / C windings on the high-voltage side of the transformer, and the output current negative pole I- and the voltage sampling negative pole U- are both connected to the neutral point O of the transformer.
[0036] Example 3
[0037] Reference Figure 4-Figure 6 , which is the third embodiment of the utility model. It is different from the previous two embodiments in that, when the tested product 300 is selected as a transformer and the a / c winding on the low-voltage side of the transformer is measured, the output current positive electrode I+ is connected to the high-voltage side A winding of the transformer, the voltage sampling positive electrode U+ is respectively connected to the high-voltage side B / C winding and the low-voltage side a winding of the transformer, and the output current negative electrode I- and the voltage sampling negative electrode U- are both connected to the c winding on the low-voltage side of the transformer.
[0038] When the test product 300 is selected as a transformer and the b / a winding on the low-voltage side of the transformer is measured, the positive pole I+ of the output current is connected to the B winding on the high-voltage side of the transformer, the positive pole U+ of the voltage sampling is respectively connected to the A / C winding on the high-voltage side and the b winding on the low-voltage side of the transformer, and the negative pole I- of the output current and the negative pole U- of the voltage sampling are both connected to the a winding on the low-voltage side of the transformer.
[0039] When the test product 300 is selected as a transformer and the c / b winding on the low-voltage side of the transformer is measured, the positive pole I+ of the output current is connected to the C winding on the high-voltage side of the transformer, the positive pole U+ of the voltage sampling is respectively connected to the A / B winding on the high-voltage side and the c winding on the low-voltage side of the transformer, and the negative pole I- of the output current and the negative pole U- of the voltage sampling are both connected to the b winding on the low-voltage side of the transformer.
[0040] When measuring the low-voltage side of a large-capacity transformer, if the maximum current of the DC resistance tester is relatively small, or in order to speed up the measurement, the magnetic assist method can be selected, that is, the wiring method mentioned above can be used.
[0041] The magnetic assist method is generally applicable to the Y(N)-d-11 connection group, where "Y(N)-d-11" is a transformer connection group representation method, commonly used to describe the wiring method of a three-phase transformer. Each part of this representation has a specific meaning:
[0042] Y(N): This indicates how the high voltage side of the transformer is connected. "Y" means a star connection, also known as a "wye" connection, where each phase in the high voltage winding is connected to a common neutral point. "(N)" means that the neutral point is grounded, not ungrounded.
[0043] d: This indicates whether the neutral point of the transformer moves. In this case, "d" means that the neutral point is fixed, i.e. the neutral point does not move with changes in load.
[0044] 11: This indicates how the low voltage side of the transformer is connected. In this case, "11" means that all three phases are connected directly to the load without using a neutral point.
[0045] Putting it all together, "Y(N)-d-11" means a transformer with the high voltage side connected in star fashion (possibly grounded) and a fixed neutral point, and the low voltage side connected directly to the load without using a neutral point.
[0046] Importantly, it should be noted that the construction and arrangement of the present application shown in a plurality of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible (e.g., the size, scale, structure, shape and ratio of various elements, and parameter values (e.g., temperature, pressure, etc.), installation arrangements, use of materials, color, directional changes, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, the element shown as integrally formed can be composed of multiple parts or elements, the position of the element can be inverted or otherwise changed, and the nature or number or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of the present utility model. The order or sequence of any process or method steps can be changed or reordered according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure described herein that performs the function, and is not only structurally equivalent but also an equivalent structure. Without departing from the scope of the present invention, other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments. Therefore, the present invention is not limited to a specific embodiment, but extends to various modifications that still fall within the scope of the appended claims.
[0047] Additionally, in order to provide a concise description of example embodiments, all features of an actual embodiment (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention) may not be described.
[0048] It will be appreciated that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but will be a routine task of design, fabrication, and production for those of ordinary skill having the benefit of this disclosure without undue experimentation.
[0049] It should be noted that the above embodiments are only used to illustrate the technical solution of the utility model and are not intended to limit it. Although the utility model is described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.
Claims
1. A grounding grid electrical integrity test device under strong electromagnetic field, characterized by: include, A direct current resistance tester (100), wherein a shielding member (200) is provided on a test lead extending from a voltage sampling positive electrode (U+) of the direct current resistance tester (100), and the direct current resistance tester (100) is electrically connected to a tested object (300); The shielding member (200) has a π-type LC filter circuit inside, comprising an inductor (L), the inductor (L) being connected to a test lead extending from a voltage sampling positive electrode (U+) of a DC resistance tester (100), and both ends of the inductor (L) being respectively connected to a first capacitor (C1) and a second capacitor (C2) and then grounded.
2. The grounding grid electrical integrity test device under strong electromagnetic field as claimed in claim 1, characterized in that: The DC resistance tester (100) is provided with an output current positive electrode (I+), an output current negative electrode (I-), a voltage sampling positive electrode (U+) and a voltage sampling negative electrode (U-).
3. The grounding grid electrical integrity test device under strong electromagnetic field as claimed in claim 2, characterized in that: When the tested product (300) is selected as a transformer and the high-voltage side of the transformer is directly measured, the output current positive pole (I+) and the voltage sampling positive pole (U+) are both connected to one of the A / B / C windings on the high-voltage side of the transformer, and the output current negative pole (I-) and the voltage sampling negative pole (U-) are both connected to the neutral point O of the transformer.
4. The grounding grid electrical integrity test device under strong electromagnetic field as claimed in claim 3, characterized in that: When the tested product (300) is selected as a transformer and the transformer low-voltage side a / c winding is measured, the output current positive electrode (I+) is connected to the transformer high-voltage side A winding, the voltage sampling positive electrode (U+) is respectively connected to the transformer high-voltage side B / C winding and low-voltage side a winding, and the output current negative electrode (I-) and the voltage sampling negative electrode (U-) are both connected to the transformer low-voltage side c winding.
5. The grounding grid electrical integrity test device under strong electromagnetic field as claimed in claim 4, characterized in that: When the tested product (300) is selected as a transformer and the transformer low-voltage side b / a winding is measured, the output current positive electrode (I+) is connected to the transformer high-voltage side B winding, the voltage sampling positive electrode (U+) is respectively connected to the transformer high-voltage side A / C winding and low-voltage side b winding, and the output current negative electrode (I-) and voltage sampling negative electrode (U-) are both connected to the transformer low-voltage side a winding.
6. The grounding grid electrical integrity test device under a strong electromagnetic field as claimed in any one of claims 2 to 5, characterized in that: When the tested product (300) is selected as a transformer and the transformer low-voltage side c / b winding is measured, the output current positive electrode (I+) is connected to the transformer high-voltage side C winding, the voltage sampling positive electrode (U+) is respectively connected to the transformer high-voltage side A / B winding and low-voltage side c winding, and the output current negative electrode (I-) and the voltage sampling negative electrode (U-) are both connected to the transformer low-voltage side b winding.