Electrode selection method, recording medium and system for field strength testing

Abstract

The present application belongs to the technical field of electric field test, and particularly relates to an electrode selection method for field strength test, comprising the following steps: by adjusting the outer contour of different vibrating shielding electrode sheets, the shape of strip-shaped hollow grid and the spacing of the grid, and measuring the field strength changes at both ends and the middle of the strip-shaped hollow grid of the shielding electrode sheet, a mathematical model is established, and the type of the shielding electrode sheet which produces the smallest distortion to the measured direct current electric field is selected. The method not only avoids the influence of ion flow disturbance on the measurement signal in the traditional measurement method, but also solves the electric field distortion problem caused by the electrode in the vibrating field strength test, and improves the accuracy of the measurement. The present application also discloses a physical device for implementing the above method, and provides a non-transitory readable recording medium storing the program of the method and a system comprising the medium, and the program can be called by a processing circuit to execute the above method.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electric field testing, and discloses an electrode selection method for field strength testing, a recording medium and a system. BACKGROUND

[0002] The direct current synthetic electric field measurement is basically achieved by the relative movement of the shielding electrode sheet and the sensing electrode sheet, so that the sensing surface is periodically and alternately exposed to the direct current electric field, the received electric field signal is changed by the change of the exposed area, and the relationship between the sinusoidal alternating signal and the field strength is obtained through signal conditioning. Since the alternating signal is obtained by the area exposure, i.e. the gap design, the shape of the gap directly determines the sinusoidal degree of the current signal. The existing field grinding type synthetic field measurement adopts a rotating fan sheet type structure. When measuring, the fan sheet rotates to form a surface wind, which disturbs the ion flow and causes the measurement signal to have a direct current signal, which seriously affects the accuracy of the measurement.

[0003] How to select the type of relative movement of the shielding electrode sheet and the sensing electrode sheet to improve the influence of ion flow disturbance on the measurement signal, and how to design the shape of the shielding electrode sheet to make the field strength distortion caused by the electrode in the field strength detection device smaller has been a technical problem faced by field strength testers. SUMMARY

[0004] In view of the above problems and the fact that the electric field direction formed by high-voltage direct current power transmission is generally vertical, the application provides an electrode selection method for field strength testing. The specific scheme comprises: placing a sensing electrode sheet in a metal shell with a shielding electrode sheet comprising a column of strip-shaped hollow grids, so that the sensing electrode sheet and the shielding electrode sheet are both perpendicular to the electric field line direction. The length of the strip-shaped hollow grid is more than twice the width, and the width is the arrangement direction. The sensing electrode sheet is arranged to vibrate in the plane in which it is located relative to the sensing electrode sheet along the arrangement direction, and the strip-shaped hollow grid is completely closed to completely transparent within one vibration period.

[0005] The selection of the shielding electrode sheet comprises setting different outer shapes of the shielding electrode sheet, shapes of the strip-shaped hollow grids and distances between adjacent strip-shaped hollow grids, adjusting the outer shape, the shape of the strip-shaped hollow grid and the distance between adjacent strip-shaped hollow grids, measuring the field strength changes at both ends and the middle of the strip-shaped hollow grid of the shielding electrode sheet, and selecting the type of the shielding electrode sheet that produces the smallest distortion to the measured direct current electric field.

[0006] The above method can quickly determine how to design the type of the electrode sheet to improve the influence of ion flow disturbance on the measurement signal and make the field strength distortion caused by the electrode in the field strength detection device smaller.

[0007] Preferably, the outer shape is alternatively set as a rectangle or a circle; and the single strip-shaped hollow grid shape is alternatively set as a rectangle, a rectangular end-rounded strip or an ellipse.

[0008] Thus, 2 x 3 = 6 alternative versions are formed by the combination of 2 outer shapes and 3 single strip-shaped hollow grid shapes. From experience, the regular shape is more likely to match the motion of the induction electrode to form an alternating induction current than other shapes, thereby avoiding the test of other shape arrangements, saving test time and computing resources.

[0009] Preferably, the outer shape of the strip-shaped hollow grid is alternatively set as a rectangle or a circle.

[0010] Further, the outer shape of the strip-shaped hollow grid is alternatively set as only a rectangle.

[0011] Further, when the outer shape of the strip-shaped hollow grid is alternatively set as a circle, the single strip-shaped hollow grid shape is alternatively set as only a rectangular end-rounded strip.

[0012] After further screening, when the outer shape of the strip-shaped hollow grid is alternatively set as a rectangle, there are the above-mentioned 6 alternative versions;

[0013] When the outer shape of the strip-shaped hollow grid is alternatively set as a circle, there are 1 x 2 = 2 alternative versions because the single strip-shaped hollow grid shape is alternatively set as only a rectangular end-rounded strip, combined with the outer shape alternatively set as a rectangle or a circle.

[0014] Further, each strip-shaped hollow grid is set to have the same width as the spacing between adjacent strip-shaped hollow grids.

[0015] Preferably, the spacing between adjacent strip-shaped hollow grids is set to any one of 3 mm, 5 mm, 10 mm, and 15 mm.

[0016] After the preliminary screening of the scheme, the amount of meaningless data redundancy can be greatly reduced, and the structure type of the shielding electrode sheet that we need and is easy to process can be quickly searched.

[0017] Another scheme of the present application is to provide a non-transitory readable recording medium for storing one or more programs containing a plurality of instructions, which when executed, will cause the processing circuit to perform the above-mentioned electrode selection method for field strength testing.

[0018] Still another aspect of the present application provides an electrode selection system for field strength testing, comprising a processing circuit and a memory electrically coupled to the processing circuit, the memory configured to store at least one program, the program comprising a plurality of instructions, and the processing circuit is configured to execute the program to perform the electrode selection method for field strength testing. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 There are 6 alternative types of shielding electrode sheet structure schematic diagrams when the outer contour shape of a column of strip-shaped hollow grids in the embodiment of the present application is alternatively set as a rectangle.

[0020] Figure 2 There are 2 alternative types of shielding electrode sheet structure schematic diagrams when the outer contour shape of a column of strip-shaped hollow grids in the embodiment of the present application is alternatively set as a circle.

[0021] Figure 3 A simulation model diagram of a metal sheet as an electrode placed in an electric field in the embodiment of the present application.

[0022] Figure 4 A surface field strength cloud chart of a metal sheet as an electrode placed in an electric field in the embodiment of the present application.

[0023] Figure 5 A selection schematic diagram of the coordinate system of the field strength simulation analysis curve in the embodiment of the present application.

[0024] Figure 6 A field strength distribution diagram in the length direction of the grid when different grid spacings are selected in the embodiment of the present application.

[0025] Figure 7 A curve of the area through which the electric field lines pass the induction electrode sheet in one period in the embodiment of the present application.

[0026] Figure 8 A time domain and frequency domain diagram of the induced current generated when a single strip-shaped hollow grid shape in the embodiment of the present application is set as an ellipse.

[0027] Figure 9 A time domain and frequency domain diagram of the induced current generated by the original field grinding type measuring device in the embodiment of the present application. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described below with reference to the drawings of the embodiments of the present application. The described embodiments are part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making innovative labor fall within the scope of protection of the present application.

[0029] When there is a metal body in the electric field, the spatial field strength will be affected and distorted. When designing the structure of the measuring device probe (i.e. including the shielding electrode sheet, the sensing electrode sheet and the attached moving mechanism mentioned below), the influence of the probe itself on the field strength should be minimized. When the influence of the probe on the field strength of the electric field in which it is located is within an acceptable range, the place can be regarded as a uniform field strength, and the measured data can be calibrated to obtain the accurate field strength; but if the probe causes local distortion of the original field strength at the location, the field strength is no longer uniform, and the dispersion of the data measured by the probe from the actual field strength will increase. In order to reduce this influence, the shielding electrode sheet is simulated and analyzed, and a suitable structure is selected to minimize the degree of field strength distortion near the shielding electrode.

[0030] An electrostatic field model is used in simulation. In the area where the electrode sheet is located, the field is passive, and the potential function satisfies the Laplace equation:

[0031] The field strength in which the metal sheet is located is determined by the boundary conditions, which satisfy the following equation:

[0032]

[0033] wherein represents the electric potential, Γ represents the boundary surface, and the meaning of the equation is that the upper boundary electric potential in the model is U, and the lower boundary electric potential is 0.

[0034] Among the 8 structure types of Figure 1 , Figure 2 , the structure of taking the outer contour of the shielding electrode sheet as a square with a side length of 200 mm, taking the outer contour of a row of strip-shaped hollow grids as a rectangle, taking each single strip-shaped hollow grid as a rectangular frame with a length of 60 mm and a width of 5 mm, and taking the distance between each adjacent strip-shaped hollow grid as 5 mm is taken as an embodiment for simulation experiment. The way of applying a constant field strength is to build parallel plates with a vertical distance of 2 m, the upper plate is at a potential of 10 kV, and the lower plate is grounded, so that the field strength in which the shielding electrode sheet is located is 5 kV / m, and the upper and lower plates are both squares of 3 m x 3 m, which is much larger than the side length of the metal sheet, so the space in which the metal sheet is located can be regarded as infinite and uniform field strength. One of the shielding electrode sheet models is built as shown in Figure 3 . In the figure, the large cube is the simulation area, the upper surface and the lower surface are pressurized for control, the shielding electrode sheet is 20 mm away from the ground (the lower surface with a potential of 0), and the surface field strength cloud distribution of the shielding electrode sheet area is shown in Figure 4 .

[0035] Each of the strip-shaped hollow grids is set to have the same width and the same distance as each adjacent strip-shaped hollow grid, and different width values are simulated (i.e. simulated test) by the control variable method.​​

[0036] Referring to Figure 5 、 Figure 6 Since the degree of field distortion is affected by many factors, it is necessary to control the rest of the factors unchanged to explore the influence of air gap width and spacing on distortion. In combination with the actual situation, the air gap of the metal plate (i.e. the width of the above-mentioned strip-shaped hollow grid) is the same as the gap spacing. Taking a rectangular air gap as an example, under the condition that the outer contour of the shielding electrode sheet is rectangular and circular, the air gap spacing is 3mm, 5mm, 10mm, 15mm, respectively, and the field strength variation curves of the two ends of the air gap and the middle part of the air gap (including the x-axis and y-axis directions) are analyzed. It can be seen that the wider the strip-shaped hollow grid, the greater the field strength distortion at both ends, but if the strip-shaped hollow grid is too narrow, the field strength distortion of the middle part is large, and in general, the width of the strip-shaped hollow grid is set to 5mm. On this basis, the selection of the above-mentioned Figures 1-2 8 different shielding electrode sheets is simulated, and the simulation results are shown in Table 1:

[0037] Under different air gap shapes, the influence of the metal shell on the distortion degree is shown in Table 1, where the distortion coefficient k is used for analysis. k is given by the following formula:

[0038]

[0039] In the formula, E smax represents the maximum field strength at the edge of the strip-shaped hollow grid, and E imin represents the minimum field strength inside the strip-shaped hollow grid.

[0040] The selection of the combination in the table represents that when the outer contour shape of a column of strip-shaped hollow grids is circular, the shape of a single strip-shaped hollow grid is a rectangular end rounded strip, and the rest of the selection is that the outer contour shape of a column of strip-shaped hollow grids is rectangular.

[0041] Through the table, it is concluded that when the outer contour shape of the shielding electrode sheet is rectangular, the outer contour shape of a column of strip-shaped hollow grids is rectangular, and the shape of a single strip-shaped hollow grid is an ellipse, the selection has the smallest influence on field strength distortion. At this time, the short axis of the ellipse and the spacing between adjacent ellipses are both 5mm, and the long axis of the ellipse can be set to any value within the interval of greater than 10mm to 190mm. For the convenience of subsequent analysis, we set the length of the long axis of the ellipse to a fixed value of 60mm.

[0042] Table 1 Field strength distortion coefficient table under different structures

[0043]

[0044] The results obtained in the above selection test are analyzed as follows:

[0045] The two-dimensional coordinate system is established on the plane of the shielding electrode sheet with the centroid of any strip-shaped hollow grid as the coordinate origin, the x direction is the vibration direction, i.e. the width direction of the strip-shaped hollow grid. The motor vibration frequency is f, the motor drives the sensor to vibrate horizontally at a constant speed, so the period of one vibration of the sensor is 1 / f, the area of the sensing electrode exposed to the electric field at the initial time is 0, then when the time satisfies x = 10ft-2.5(mm); and the elliptic equation is:

[0046] Therefore,

[0047]

[0048] In the half cycle, the area of the sensing electrode exposed to the electric field is expressed as:

[0049]

[0050] If the measured direct current field strength is E and the dielectric constant is ε0, the induced charge on the sensing electrode is:

[0051] Q(t) = ε0ES(t)

[0052] The current generated by the induced charge is:

[0053]

[0054] When the vibration frequency is 50 Hz, the area curve in one cycle is shown in Figure 7 . Fourier analysis is performed by using mathematical software, the sampling frequency is 1 kHz, and the data points are 1024. The time domain and frequency domain graphs of the current in one cycle are obtained Figure 8 , and compared with the time domain and frequency domain graphs of the square wave signal obtained by the conventional field mode detection device Figure 9 , it can be seen that the current waveform obtained by the current selection has less fundamental wave content and is less disturbed by periodic motion, and the optimization effect is better.

[0055] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can adopt a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented on one or more computers containing computer usable program code, a computer usable storage medium (including but not limited to disk storage, CD-ROM, optical storage, etc.).

[0056] The present application is described in reference to the flowchart and / or block diagram of the method, device (system), and computer program product according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of flows and / or blocks in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate a device that implements the flow Figure 1 one or more flows and / or blocks Figure 1 one or more blocks or a combination of one or more flows and / or blocks.

[0057] These computer program instructions can also be stored in a computer readable storage medium that can direct the computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable storage medium produce a manufactured product including instruction devices that implement the flow Figure 1 one or more flows and / or blocks Figure 1 one or more blocks or a combination of one or more flows and / or blocks.

[0058] These computer program instructions can also be loaded into a computer or other programmable data processing device, so that a series of operation steps are performed on the computer or other programmable device to produce a computer implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the flow Figure 1 one or more flows and / or blocks Figure 1 one or more blocks or a combination of one or more flows and / or blocks.

[0059] The above method steps are assembled into a program and stored in a hard disk or other non-transient storage medium to constitute the "non-transient readable recording medium" technical solution of the present application; and the storage medium is electrically connected with a computer processor, and through data processing, the electrode selection for field strength test can be completed, which constitutes the "electrode selection system for field strength test" technical solution of the present application.

[0060] Finally, it should be pointed out that: the above only describes the preferred embodiments of the present application and is not used to limit the present application, although the present application has been described in detail with reference to the foregoing embodiments, and for those skilled in the art, the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for electrode selection for field strength testing, comprising placing an induction electrode patch within a metal shell having a shield electrode patch with a column of strip-shaped, lattice-shaped, hollowed grids, such that both the induction electrode patch and the shield electrode patch are perpendicular to the direction of the electric field lines, characterized in that Further comprising the following steps: The length of the strip-shaped hollow grid is more than twice the width, and the width is the arrangement direction. The sensing electrode sheet is arranged to vibrate in the plane relative to the sensing electrode sheet along the arrangement direction. The strip-shaped hollow grid is completely closed to completely transparent within one vibration period. The selection of the shielding electrode sheet includes setting different shielding electrode sheet outer shapes, a column of strip-shaped hollow grid outer shapes, single strip-shaped hollow grid shapes, and distances between adjacent strip-shaped hollow grids. The parameters of various selections are adjusted, and the field strength changes of the strip-shaped hollow grid ends and middle of the shielding electrode sheet are measured. The type of the shielding electrode sheet that produces the smallest distortion to the DC electric field to be measured is selected.

2. The electrode selection method for field strength testing of claim 1, wherein, The alternative setting of the outer shape is a rectangle or a circle; the alternative setting of the shape of a single strip-shaped hollow grid is a rectangle, a rectangular end rounded strip, or an ellipse.

3. The electrode selection method for field strength testing of claim 2, wherein, The outer contour shape of a column of strip-shaped hollow grids is alternatively set to a rectangle or a circle.

4. The electrode selection method for field strength testing of claim 3, wherein, The outer contour shape of a column of strip-shaped hollow grids is alternatively set to only a rectangle.

5. The electrode selection method for field strength testing of claim 3, wherein, When the outer contour shape of a column of strip-shaped hollow grids is alternatively set to a circle, the alternative setting of the shape of a single strip-shaped hollow grid is only a rectangular end rounded strip.

6. The electrode selection method for field strength testing according to any one of claims 4-5, wherein, Each strip-shaped hollow grid is set to be equal in width, and the width is the same as the distance between adjacent strip-shaped hollow grids.

7. The electrode selection method for field strength testing of claim 6, wherein, The distance between adjacent strip-shaped hollow grids is set to any of 3mm, 5mm, 10mm, and 15mm.

8. A non-transitory, readable recording medium storing one or more programs including a plurality of instructions, wherein the plurality of instructions, when executed by a processor, cause the processor to perform the method of any one of claims 1 to 7. When the instructions are executed, the processing circuit will perform the electrode selection method for field strength testing as claimed in claim 7.

9. An electrode selection system for field strength testing, comprising a processing circuit and a memory electrically coupled thereto, wherein, The memory is configured to store at least one program, and the program includes a plurality of instructions. The processing circuit runs the program and can perform the electrode selection method for field strength testing as claimed in claim 7. The memory is configured to store at least one program, and the program includes a plurality of instructions. The processing circuit runs the program and can perform the electrode selection method for field strength testing as claimed in claim 7.

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