CN112505431A - Method and device for determining mutual inductance coupling component between grounding impedance test lines - Google Patents
Method and device for determining mutual inductance coupling component between grounding impedance test lines Download PDFInfo
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Abstract
The embodiment of the invention discloses a method and a device for determining mutual inductance coupling components among grounding impedance test lines, wherein the method for determining the mutual inductance coupling components among the grounding impedance test lines comprises the following steps: segmenting the current pole lead and the voltage pole lead according to the position information and the angle information based on a segmented differential method, and determining a direct mutual inductance value between each segment of the current pole lead and the corresponding voltage pole lead and a mirror image mutual inductance value between each segment of the voltage pole lead and a mirror image of the corresponding current pole lead; determining a total value of direct mutual inductance between the current pole lead and the voltage pole lead according to the direct mutual inductance value based on a Newman integral method, and determining a total value of mirror image mutual inductance between the voltage pole lead and a mirror image of the corresponding current pole lead according to the mirror image mutual inductance value; and determining the mutual inductance resistance value between the current pole lead and the voltage pole lead according to the direct mutual inductance total value and the mirror image mutual inductance total value. The technical scheme provided by the embodiment of the invention can improve the accuracy of determining the mutual inductance coupling component between the grounding impedance test lines.
Description
Technical Field
The embodiment of the invention relates to a medium-high voltage technology, in particular to a method and a device for determining mutual inductance coupling components between grounding impedance test lines.
Background
In the electric power system, the transformer substation grounding grid can drain fault current into the ground rapidly when the electric power system breaks down, the maximum potential of the grounding grid is controlled to rise, and the safety of a human body and equipment is guaranteed. Therefore, the qualified grounding grid plays an important role in the safe operation of the power system, whether the grounding grid is qualified or not is related to the accuracy of the detection of the grounding impedance in the grounding grid, and the accuracy of the determination of the mutual inductance coupling component between the grounding impedance test lines directly influences the accuracy of the detection of the grounding impedance.
At present, the existing method for determining mutual inductance coupling components between ground impedance test lines usually performs simple mathematical formula compensation on the measurement situation during parallel wiring, but angular ground impedance test lines with longer distance and smaller distance still exist in the field environment, and if the mutual inductance coupling components are determined only for the parallel situation at this time, the accuracy of the result is affected.
Disclosure of Invention
The embodiment of the invention provides a method and a device for determining mutual inductance coupling components among grounding impedance test lines, which are used for improving the accuracy of determining the mutual inductance coupling components among the grounding impedance test lines.
In a first aspect, an embodiment of the present invention provides a method for determining a mutual inductance coupling component between ground impedance test lines, including:
acquiring position information among a current pole lead, a voltage pole lead and a mirror image of the current pole lead, and acquiring angle information of the current pole lead relative to the voltage pole lead;
segmenting the current pole lead and the voltage pole lead according to the position information and the angle information based on a segmented differential method, determining a direct mutual inductance value between each segment of the current pole lead and the corresponding voltage pole lead, and determining a mirror image mutual inductance value between each segment of the voltage pole lead and a mirror image of the corresponding current pole lead;
determining a total value of direct mutual inductance between the current pole lead and the voltage pole lead according to the direct mutual inductance value based on a Newman integral method, and determining a total value of mirror image mutual inductance between the voltage pole lead and a mirror image of the corresponding current pole lead according to the mirror image mutual inductance value;
and determining the mutual inductance resistance value between the current pole lead and the voltage pole lead according to the direct mutual inductance total value and the mirror image mutual inductance total value.
Optionally, determining a direct mutual inductance value between each segment of the current pole wire and the corresponding voltage pole wire includes:
taking the distance from the midpoint of each voltage pole lead to the current pole lead as the distance between the voltage pole lead and the current pole lead of the corresponding section;
and determining the direct mutual inductance value between each section of current pole lead and the corresponding voltage pole lead according to the distance between each section of voltage pole lead and each section of current pole lead.
Optionally, determining a mutual image inductance value between images of each voltage pole wire and the corresponding current pole wire includes:
taking the distance from the midpoint of each section of voltage pole wire to the mirror image of the current pole wire as the distance between the voltage pole wire and the mirror image of the current pole wire of the corresponding section;
and determining the mutual inductance value of the mirror images between the voltage pole lead and the mirror images of the corresponding current pole lead according to the distance between the voltage pole lead and the mirror images of the current pole lead.
Optionally, determining a total value of direct mutual inductance between the current pole lead and the voltage pole lead according to the direct mutual inductance value based on a newmann integration method, including:
summing the direct mutual inductance values between each section of current pole lead and the corresponding voltage pole lead to obtain a direct mutual inductance total value Md。
Optionally, direct mutual inductance total value MdExpressed as:
wherein n is the total number of segments of the current pole wire and the total number of segments of the voltage pole wire, LIIs the length of the current pole wire,
LVis the length of the voltage pole wire, theta is the angle between the voltage pole wire and the current pole wire, GA＝GI+GV，GVThe distance of the voltage pole conductor from the actual ground, GIThe distance of the current pole wire from the actual ground.
Optionally, determining a total mirror image mutual inductance value between the voltage pole wire and the mirror image of the corresponding current pole wire according to the mirror image mutual inductance value includes:
summing the mutual inductance values of the images between the voltage pole leads and the corresponding current pole leads to obtain a total mutual inductance value M of the imagesi。
Optionally, the total value M of image mutual inductanceiExpressed as:
wherein n is the total number of segments of the current pole wire and the total number of segments of the voltage pole wire, LIIs the length of the current pole wire,
LVas a voltage pole wireTheta is the angle between the voltage pole wire and the current pole wire, GB＝GI+GV，GVThe distance of the voltage pole conductor from the actual ground, GIThe distance of the current pole wire from the actual ground,
j is an imaginary unit, mu0＝4π/107σ is 1/ρ, ρ is the soil resistivity, and f is the mutual inductance frequency.
Optionally, the mutual inductance value is ZMP，ZMPExpressed as:
wherein j is an imaginary unit, mu0＝4π/107，MdFor total value of direct mutual inductance, MiIs the total value of mirror image mutual inductance, n is the total segment number of the current pole lead and the total segment number of the voltage pole lead, LIIs the length of the current pole wire, LVIs the length of the voltage pole wire,
theta is the angle between the voltage and current pole wires,
optionally, the current pole wire and the voltage pole wire are both parallel to the ground, an angle of the current pole wire relative to the voltage pole wire is an included angle between a vertical projection of the current pole wire on the ground and a vertical projection of the voltage pole wire on the ground, and a mirror image of the current pole wire is a mirror image of a complex plane in which the current pole wire has a preset distance from the ground below the ground.
In a second aspect, an embodiment of the present invention further provides a device for determining a mutual inductance coupling component between ground impedance test lines, including:
the data acquisition module is used for acquiring position information among the current pole lead, the voltage pole lead and the mirror image of the current pole lead and acquiring angle information of the current pole lead relative to the voltage pole lead;
the lead segmenting module is used for segmenting the current pole lead and the voltage pole lead according to the position information and the angle information based on a segmented differential method, and determining a direct mutual inductance value between each segment of the current pole lead and the corresponding voltage pole lead and a mirror image mutual inductance value between each segment of the voltage pole lead and the mirror image of the corresponding current pole lead;
the mutual inductance total value determining module is used for determining a direct mutual inductance total value between the current pole lead and the voltage pole lead according to a direct mutual inductance value based on a Newman integral method, and determining a mirror image mutual inductance total value between the voltage pole lead and a mirror image of the corresponding current pole lead according to a mirror image mutual inductance value;
and the wire mutual inductance determining module is used for determining a mutual inductance reactance value between the current pole wire and the voltage pole wire according to the direct mutual inductance total value and the mirror image mutual inductance total value.
The method and the device for determining the mutual inductance coupling component between the grounding impedance test lines are based on a sectional differentiation method, a current pole lead and a voltage pole lead are sectioned according to the obtained position information and angle information, a direct mutual inductance value between each section of the current pole lead and the corresponding voltage pole lead is determined, and a mirror image mutual inductance value between each section of the voltage pole lead and a mirror image of the corresponding current pole lead is determined; determining a total value of direct mutual inductance between the current pole lead and the voltage pole lead according to the direct mutual inductance value based on a Newman integral method, and determining a total value of mirror image mutual inductance between the voltage pole lead and a mirror image of the corresponding current pole lead according to the mirror image mutual inductance value; therefore, the mutual inductance value between the current pole lead and the voltage pole lead is determined according to the direct mutual inductance total value and the mirror image mutual inductance total value. The method and the device for determining the mutual inductance coupling component between the grounding impedance test lines provided by the embodiment of the invention are based on a segmented differential method and a Newman integral method, and determine the mutual inductance value between the current pole lead and the voltage pole lead according to the direct mutual inductance value between each section of current pole lead and the corresponding voltage pole lead and the mirror image mutual inductance value between each section of voltage pole lead and the mirror image of the corresponding current pole lead, so that the mutual inductance determination between non-parallel leads is realized, the problem that the mutual inductance is determined only aiming at the parallel leads to influence the result accuracy in the prior art is solved, and the accuracy of determining the mutual inductance coupling component between the grounding impedance test lines is improved.
Drawings
FIG. 1 is a schematic diagram of a prior art parallel wire;
FIG. 2 is a flowchart of a method for determining mutual inductance coupling component between ground impedance test lines according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a current pole wire and a mirror image of the current pole wire according to an embodiment of the present invention;
FIG. 4 is a schematic diagram illustrating analysis of mutual inductance between current and voltage pole leads according to an embodiment of the present invention;
FIG. 5 is a flowchart illustrating a method for determining mutual inductance coupling component between ground impedance test lines according to a second embodiment of the present invention;
FIG. 6 is a schematic diagram of a voltage pole wire segment according to a second embodiment of the present invention;
fig. 7 is a schematic structural diagram of a device for determining a mutual inductance coupling component between ground impedance test lines according to a third embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
FIG. 1 is a schematic diagram of a prior art parallel wire, in which a current pole lead L, a voltage pole lead α L and an equivalent mirror image L' of the current pole lead L are parallel to each other, as shown in FIG. 1, a current I in the current pole lead flows back through the ground, dx and dx0Respectively, the micro-elements on the current pole lead and the voltage pole lead with the distance r, and the likeThe effective mirror image distance is r', the depth of the equivalent mirror image of the current pole lead in the soil is 2 lambda,
ρ is the resistivity of the soil, μ0For the permeability of the soil layer, w is the angular frequency, the mutual inductive reactance between the voltage pole leads and between the current pole leads is:
m is the mutual inductance between the voltage pole lead and the current pole lead, and M' is the mutual inductance between the mirror images of the voltage pole lead and the current pole lead.
Generally, the measurement result of the ground impedance between the parallel wires by the parallel straight line method includes the following components: the real grounding impedance of the grounding grid, the mutual inductance and resistance of the current and voltage pole leads, the mutual inductance resistance, the self-inductance and interference errors and the like are measured. Although the pilot frequency power supply measures the grounding impedance, the inductive interference of the power frequency signal in a measuring loop can be effectively filtered, the mutual inductance and mutual resistance existing between the current pole lead and the voltage pole lead cannot be avoided, the mutual inductance is the primary factor causing the error of the measuring result of the grounding impedance, and the mutual resistance between the current pole lead and the voltage pole lead is very small and can be ignored. The self-inductance of the measuring loop during the measurement of the grounding impedance of the grounding grid comprises two parts, namely the inductance of the grounding grid and the self-inductance of the voltage pole lead. In a large-scale grounding grid, the self-inductance of the voltage pole lead is very small compared with that of the grounding grid, the current passing through the voltage pole lead is very small during measurement, and the voltage drop generated on the self-inductance of the voltage pole lead is very small. The self-inductance of the measuring loop therefore only takes into account the inductance of the earth grid itself. The concept of the grounding resistance is only suitable for small grounding nets, and along with the increase of the scale of the grounding nets and the decrease of the short-circuit impedance of the system, the inductance of the grounding nets cannot be ignored. Particularly in ac systems, the proportion of the inductive component of the earth impedance of the earth network increases with decreasing soil resistivity, increasing area of the earth network and increasing frequency of the earth current.
Based on the parallel wires, mutual inductance coupling components among the wires are determined, the condition that the wires are parallel is ideal, angled grounding impedance test wires with longer distance and smaller distance still exist in a field environment, and the accuracy of results can be influenced if the mutual inductance coupling components are determined only aiming at the parallel condition.
Example one
Fig. 2 is a flowchart of a method for determining mutual inductance coupling components between ground impedance test lines according to an embodiment of the present invention, where the present embodiment is applicable to ground impedance tests and the like, and may be applied to large-scale ground nets and the like, where the method may be executed by a device for determining mutual inductance coupling components between ground impedance test lines, where the device may be implemented by software and/or hardware, and may be integrated in an electronic device, such as a computer, having a function of determining mutual inductance coupling components between ground impedance test lines, and the method specifically includes the following steps:
and step 110, acquiring position information among the current pole lead, the voltage pole lead and the mirror image of the current pole lead, and acquiring angle information of the current pole lead relative to the voltage pole lead.
The current pole wire and the voltage pole wire are used as grounding impedance test wires, the current pole wire and the voltage pole wire are both parallel to the ground, the angle of the current pole wire relative to the voltage pole wire is the included angle between the vertical projection of the current pole wire on the ground and the vertical projection of the voltage pole wire on the ground, and the mirror image of the current pole wire is the mirror image of a complex plane with a preset distance between the current pole wire and the ground below the ground.
Specifically, fig. 3 is a schematic diagram of a current pole wire and a mirror image of the current pole wire, in which the earth surface is an XY coordinate plane in an XYZ coordinate system, the current pole wire is at a certain distance from the earth surface, a complex plane ground loop as an ideal conductive plane can replace the earth surface and is represented by a complex plane distance H under the earth surface, the distance of the current pole wire from the real earth surface is GIThe distance between the mirror image of the current pole wire and the ground is GI+2H，LIThe length of the current pole wire is H, the distance of the real ground from the mirror plane, i.e. the conductor mirror plane. Determination device for mutual inductance coupling component between grounding impedance test linesThe position information among the current pole wire, the voltage pole wire and the mirror image of the current pole wire which are input from the outside and the angle information of the current pole wire relative to the voltage pole wire can be obtained and stored, so that the mutual inductance coupling component of the grounding impedance test wire, namely the current pole wire relative to the voltage pole wire, can be determined according to the obtained position information and angle information.
And 120, segmenting the current pole lead and the voltage pole lead according to the position information and the angle information based on a segmented differential method, and determining a direct mutual inductance value between each segment of the current pole lead and the corresponding voltage pole lead and a mirror image mutual inductance value between each segment of the voltage pole lead and the mirror image of the corresponding current pole lead.
Specifically, fig. 4 is a schematic diagram of analysis of mutual inductance between a current pole wire and a voltage pole wire according to an embodiment of the present invention, as shown in fig. 4, the current pole wire and the voltage pole wire are segmented according to position information and angle information based on a segmented differentiation method, where the length of each segment of the current pole wire is dx, and the length of each segment of the voltage pole wire is dx0，GVThe induced voltage in the voltage pole wire P depends on the current pole wire L for the distance of the voltage pole wire P from the real groundICurrent of (1) l, riThe distance between the ith differential section of the voltage pole lead and the mirrored differential section of the corresponding current pole lead; r isdThe distance between the ith differential section of the voltage pole lead and the corresponding micro-section of the current pole lead; kp is the perpendicular distance of the current pole wire from the voltage pole wire. Because the current pole lead and the voltage pole lead are segmented based on a segmented differential method, the direct mutual inductance value between each segment of current pole lead and the corresponding voltage pole lead can be regarded as the mutual inductance value between the parallel lead segments, and similarly, the mirror image mutual inductance value between each segment of voltage pole lead and the mirror image of the corresponding current pole lead can also be regarded as the mutual inductance value between the parallel lead segments, so that the mutual inductance value between each segment of lead is determined according to the mutual inductance value calculation method of the parallel leads.
And step 130, determining a total value of direct mutual inductance between the current pole lead and the voltage pole lead according to the direct mutual inductance value based on a Newman integration method, and determining a total value of mirror image mutual inductance between the voltage pole lead and a mirror image of the corresponding current pole lead according to the mirror image mutual inductance value.
Specifically, referring to fig. 4, the mutual inductance value of each micro-segment between the wires in fig. 4 can be integrated based on the niemann integration method, specifically by calculating the micro-increment length dx of each segment of the voltage pole wire0The sum of the mutual inductance value between the current pole lead and the micro increment length dx of the corresponding section of current pole lead obtains the total direct mutual inductance value between the current pole lead and the voltage pole lead, and the micro increment length dx of each section of voltage pole lead is calculated0And the sum of the mutual inductance values between the current pole lead and the micro increment length dx of the mirror image of the corresponding section of the current pole lead obtains the total mirror image mutual inductance value between the mirror image of the current pole lead and the voltage pole lead.
And 140, determining a mutual inductance value between the current pole lead and the voltage pole lead according to the direct mutual inductance total value and the mirror image mutual inductance total value.
The mutual inductance between the current pole lead and the voltage pole lead can be determined according to the direct mutual inductance total value and the mirror image mutual inductance total value, namely mutual inductance between non-parallel leads is determined, the problem that the accuracy of results is affected due to the fact that mutual inductance is determined for the parallel leads is solved, the accuracy of determining mutual inductance coupling components between the grounding impedance test lines is improved, therefore, the mutual inductance coupling components are eliminated from the detected grounding impedance, and the accuracy of detecting the grounding impedance is improved.
The method for determining mutual inductance coupling components between grounding impedance test lines provided by this embodiment is based on a piecewise differentiation method and a niemann integration method, and determines mutual inductance values between current pole wires and voltage pole wires according to direct mutual inductance values between each current pole wire and a corresponding voltage pole wire and mirror image mutual inductance values between each voltage pole wire and a corresponding mirror image of the current pole wire, so as to determine mutual inductance between non-parallel wires, and solve the problem that in the prior art, mutual inductance is determined only for parallel wires, so that result accuracy is affected, thereby improving accuracy of determining mutual inductance coupling components between grounding impedance test lines.
Example two
Fig. 5 is a flowchart of a method for determining mutual inductance coupling components between ground impedance test lines according to a second embodiment of the present invention, where the second embodiment of the present invention is applicable to ground impedance tests and the like, and is applicable to large-scale ground nets and the like, the method may be executed by determining mutual inductance coupling components between ground impedance test lines, the apparatus may be implemented by software and/or hardware, the apparatus may be integrated in an electronic device, such as a computer, having a function of determining mutual inductance coupling components between ground impedance test lines, and the method specifically includes the following steps:
The current pole wire and the voltage pole wire are used as grounding impedance test wires, the current pole wire and the voltage pole wire are both parallel to the ground, the angle of the current pole wire relative to the voltage pole wire is the included angle between the vertical projection of the current pole wire on the ground and the vertical projection of the voltage pole wire on the ground, and the mirror image of the current pole wire is the mirror image of a complex plane with a preset distance between the current pole wire and the ground below the ground.
Specifically, referring to fig. 3, the distance H between the real ground and the mirror plane, i.e. the conductor mirror plane, and the distance G between the current pole wire and the real groundIThe distance between the mirror image of the current pole wire and the ground is GI+ 2H. The device for determining the mutual inductance coupling component between the grounding impedance test lines can acquire and store position information among externally input current pole leads, voltage pole leads and mirrors of the current pole leads and angle information of the current pole leads relative to the voltage pole leads, so as to determine the mutual inductance coupling component of the grounding impedance test lines, namely the current pole leads relative to the voltage pole leads according to the acquired position information and angle information.
And step 220, segmenting the current pole lead and the voltage pole lead according to the position information and the angle information based on a segmented differential method.
Specifically, referring to fig. 4, the current pole wire and the voltage pole wire are segmented according to the position information and the angle information based on the segmentation differentiation method, and each segment of the current poleThe length of the micro increment of the lead is dx, and the length of the micro increment of each section of the voltage pole lead is dx0。
And step 230, taking the distance from the midpoint of each segment of the voltage pole wire to the current pole wire as the distance between the voltage pole wire and the current pole wire of the corresponding segment.
Specifically, fig. 6 is a schematic diagram of a voltage pole conducting wire segment according to the second embodiment of the present invention, where an angle between the voltage pole conducting wire and the current pole conducting wire is θ, and a length of the voltage pole conducting wire is LVThe length of the current pole wire is LIThe voltage pole wire can be divided into n sections, and the distances from two end points of the k section to the origin are LV respectively1kAnd LV2kThe distance between the kth section voltage pole lead and the current pole lead is KkThe distance from the midpoint of the kth segment voltage pole wire to the current pole wire is also the distance from the line parallel to the midpoint of the current pole wire to the current pole wire.
And 240, determining a direct mutual inductance value between each section of the current pole lead and the corresponding voltage pole lead according to the distance between each section of the voltage pole lead and the current pole lead.
The direct mutual inductance value is related to the distance between the voltage pole wire and the current pole wire of the corresponding segment, and the specific relationship is illustrated in step 270, which can be referred to the description of step 270.
And step 250, taking the distance from the midpoint of each segment of the voltage pole wire to the mirror image of the current pole wire as the distance between the voltage pole wire and the mirror image of the current pole wire of the corresponding segment.
Specifically, referring to fig. 6, the current pole wire in fig. 6 may be regarded as a mirror image of the current pole wire, and the process of determining the distance between each voltage pole wire and the mirror image of the current pole wire is the same as the process of determining the distance between each voltage pole wire and the current pole wire in fig. 6, which is not described herein again.
And step 260, determining the mutual inductance value of the mirror images between the voltage pole lead and the corresponding mirror image of the current pole lead according to the distance between the voltage pole lead and the mirror image of the current pole lead.
The mutual inductance of the images is related to the distance between the images of the voltage pole wire and the current pole wire of the corresponding segment, and the specific relationship is illustrated in step 280, which can be referred to the description of step 280.
Wherein, the total value M of direct mutual inductancedCan be expressed as:
wherein n is the total number of segments of the current pole wire and the total number of segments of the voltage pole wire, LIIs the length of the current pole wire,
LVis the length of the voltage pole wire, theta is the angle between the voltage pole wire and the current pole wire, GA 2＝(GI+GV)2，GVThe distance of the voltage pole conductor from the actual ground, GIThe distance of the current pole wire from the actual ground.
Specifically, the total value M of the direct mutual inductance is obtained from the above-mentioneddThe expression of (2) shows that the total value M of the direct mutual inductancedThe total value M of the direct mutual inductance is related to the corresponding distance between the leads and the length of the leadsdThe expression in the brackets is the direct mutual inductance value between the kth section of voltage pole lead and the corresponding current pole lead, k is a positive integer from 1 to n, and thus the direct mutual inductance total value M is obtained by the direct mutual inductance value sum between each section of current pole lead and the corresponding voltage pole leadd。
The specific values of the length of the current pole wire, the length of the voltage pole wire, the distance between each wire and the ground, and other distances are set according to actual conditions, and are not limited herein.
Wherein, the total value M of the mirror image mutual inductanceiCan be expressed as:
wherein n is the total number of segments of the current pole wire and the total number of segments of the voltage pole wire, LIIs the length of the current pole wire,
LVis the length of the voltage pole wire, theta is the angle between the voltage pole wire and the current pole wire, GB＝GI+GV，GVThe distance of the voltage pole conductor from the actual ground, GIThe distance of the current pole wire from the actual ground,
j is an imaginary unit, mu0＝4π/107σ is 1/ρ, ρ is the soil resistivity, and f is the mutual inductance frequency.
Specifically, the total value M of the mutual inductance from the mirror imageiThe expression of (3) shows that the total value M of the mirror image mutual inductanceiThe total value M of the mutual inductance of the mirror images is related to the corresponding distance between the leads and the length of the leadsiThe expression in brackets in the expression is the mutual image inductance value between the images of the kth section of voltage pole lead and the corresponding current pole lead, k is a positive integer from 1 to n, and therefore the total mutual image inductance value M is obtained by summing the mutual image inductance values between the images of each section of voltage pole lead and the corresponding current pole leadi。
And 290, determining a mutual inductance value between the current pole lead and the voltage pole lead according to the direct mutual inductance total value and the mirror image mutual inductance total value.
Wherein the mutual inductance value is ZMP，ZMPCan be expressed as:
wherein j is an imaginary unit, mu0＝4π/107，MdFor total value of direct mutual inductance, MiIs the total value of mirror image mutual inductance, n is the total segment number of the current pole lead and the total segment number of the voltage pole lead, LIIs the length of the current pole wire, LVIs the length of the voltage pole wire,
theta is the angle between the voltage and current pole wires,
in particular, the mutual inductance ZMPThe expression (c) is an expression of the difference between the total value of the direct mutual inductance and the total value of the mirror mutual inductance, and the total value of the direct mutual inductance M in step 270 may be expressed asdExpression of (d) and total value of mirror image mutual inductance M in step 280iSubstitution of expression (c)
Finally obtaining the mutual inductance value ZMPThe mutual inductance value between the impedance test lines, namely the non-parallel wires, is determined according to the expression related to the wire distance and the wire-to-wire distance, the problem that the accuracy of the result is influenced by the fact that the mutual inductance is determined aiming at the parallel wires is solved, the accuracy of determining the mutual inductance coupling component between the grounding impedance test lines is improved, the mutual inductance coupling component is removed from the detected grounding impedance, and the accuracy of detecting the grounding impedance is improved.
The method for determining mutual inductance coupling components between grounding impedance test lines provided by this embodiment is based on a piecewise differentiation method and a niemann integration method, and determines mutual inductance values between current pole wires and voltage pole wires according to direct mutual inductance values between each current pole wire and a corresponding voltage pole wire and mirror image mutual inductance values between each voltage pole wire and a corresponding mirror image of the current pole wire, so as to determine mutual inductance between non-parallel wires, and solve the problem that in the prior art, mutual inductance is determined only for parallel wires, so that result accuracy is affected, thereby improving accuracy of determining mutual inductance coupling components between grounding impedance test lines.
EXAMPLE III
Fig. 7 is a block diagram illustrating a device for determining a mutual inductance coupling component between ground impedance test lines according to a third embodiment of the present invention, where the device includes a data acquisition module 310, a line segmentation module 320, a mutual inductance total value determination module 330, and a line mutual inductance determination module 340; the data obtaining module 310 is configured to obtain position information among the current pole wire, the voltage pole wire, and the mirror image of the current pole wire, and obtain angle information of the current pole wire with respect to the voltage pole wire; the lead segmenting module 320 is configured to segment the current pole lead and the voltage pole lead according to the position information and the angle information based on a segmented differential method, determine a direct mutual inductance value between each segment of the current pole lead and the corresponding voltage pole lead, and determine a mirror mutual inductance value between each segment of the voltage pole lead and a mirror image of the corresponding current pole lead; the mutual inductance total value determining module 330 is used for determining a direct mutual inductance total value between the current pole lead and the voltage pole lead according to a direct mutual inductance value based on a Newman integral method, and determining a mirror image mutual inductance total value between the voltage pole lead and a mirror image of the corresponding current pole lead according to a mirror image mutual inductance value; the lead mutual inductance determining module 340 is configured to determine a mutual inductance reactance value between the current pole lead and the voltage pole lead according to the direct mutual inductance total value and the mirror mutual inductance total value.
On the basis of the above embodiment, the wire segmenting module 320 includes a first distance determining unit and a direct mutual inductance value determining unit; the first distance determining unit is used for taking the distance from the midpoint of each section of voltage pole lead to the current pole lead as the distance between the voltage pole lead and the current pole lead of the corresponding section; the direct mutual inductance value determining unit is used for determining the direct mutual inductance value between each section of current pole lead and the corresponding voltage pole lead according to the distance between each section of voltage pole lead and each section of current pole lead.
Preferably, the wire segmenting module 320 includes a second distance determining unit and a mirror mutual inductance value determining unit; the second distance determining unit is used for taking the distance from the midpoint of each section of voltage pole wire to the mirror image of the current pole wire as the distance between the voltage pole wire and the mirror image of the current pole wire of the corresponding section; the mirror image mutual inductance value determining unit is used for determining mirror image mutual inductance values between the mirror images of the voltage pole lead wires and the corresponding current pole lead wires according to the distance between the mirror images of the voltage pole lead wires and the current pole lead wires.
In an embodiment, the mutual inductance total value determining module 330 includes a direct mutual inductance total value determining unit, and the direct mutual inductance total value determining unit is configured to sum direct mutual inductance values between each segment of current pole wire and corresponding voltage pole wire to obtain a direct mutual inductance total value Md. Wherein, the total value M of direct mutual inductancedExpressed as:
wherein n is the total number of segments of the current pole wire and the total number of segments of the voltage pole wire, LIIs the length of the current pole wire,
LVis the length of the voltage pole wire, theta is the angle between the voltage pole wire and the current pole wire, GA＝GI+GV，GVThe distance of the voltage pole conductor from the actual ground, GIThe distance of the current pole wire from the actual ground.
Preferably, the mutual inductance total value determining module 330 includes a mirror mutual inductance total value determining unit, and the mirror mutual inductance total value determining unit is configured to sum mirror mutual inductance values between mirror images of each voltage pole wire and the corresponding current pole wire to obtain a mirror mutual inductance total value Mi. Wherein, the total value M of the mirror image mutual inductanceiExpressed as:
wherein n isThe total number of segments of the current pole conductor and the total number of segments of the voltage pole conductor, LIIs the length of the current pole wire,
LVis the length of the voltage pole wire, theta is the angle between the voltage pole wire and the current pole wire, GB＝GI+GV，GVThe distance of the voltage pole conductor from the actual ground, GIThe distance of the current pole wire from the actual ground,
j is an imaginary unit, mu0＝4π/107σ is 1/ρ, ρ is the soil resistivity, and f is the mutual inductance frequency.
Wherein the mutual inductance value is ZMP，ZMPExpressed as:
wherein j is an imaginary unit, mu0＝4π/107，MdFor total value of direct mutual inductance, MiIs the total value of mirror image mutual inductance, n is the total segment number of the current pole lead and the total segment number of the voltage pole lead, LIIs the length of the current pole wire, LVIs the length of the voltage pole wire,
theta is the angle between the voltage and current pole wires,
preferably, the current pole wire and the voltage pole wire are both parallel to the ground, the angle of the current pole wire relative to the voltage pole wire is the included angle between the vertical projection of the current pole wire on the ground and the vertical projection of the voltage pole wire on the ground, and the mirror image of the current pole wire is the mirror image of a complex plane with a preset distance between the current pole wire and the ground below the ground.
The device for determining the mutual inductance coupling component between the grounding impedance test lines provided by the embodiment of the invention and the method for determining the mutual inductance coupling component between the grounding impedance test lines provided by any embodiment of the invention belong to the same inventive concept, and have corresponding beneficial effects, and detailed technical details which are not provided in the embodiment of the invention are not referred to in the method for determining the mutual inductance coupling component between the grounding impedance test lines provided by any embodiment of the invention.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious modifications, rearrangements, combinations and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (10)
1. A method for determining mutual inductance coupling components between grounding impedance test lines is characterized by comprising the following steps:
acquiring position information among a current pole lead, a voltage pole lead and a mirror image of the current pole lead, and acquiring angle information of the current pole lead relative to the voltage pole lead;
segmenting the current pole lead and the voltage pole lead according to the position information and the angle information based on a segmented differential method, determining a direct mutual inductance value between each segment of the current pole lead and the corresponding voltage pole lead, and determining a mirror mutual inductance value between each segment of the voltage pole lead and a mirror image of the corresponding current pole lead;
determining a total value of direct mutual inductance between the current pole lead and the voltage pole lead according to the direct mutual inductance value based on a Newman integral method, and determining a total value of mirror image mutual inductance between the voltage pole lead and a mirror image of the corresponding current pole lead according to the mirror image mutual inductance value;
and determining the mutual inductance value between the current pole lead and the voltage pole lead according to the direct mutual inductance total value and the mirror image mutual inductance total value.
2. The method for determining the mutual inductance coupling component between the grounding impedance test lines according to claim 1, wherein the step of determining the direct mutual inductance value between each segment of the current pole wire and the corresponding voltage pole wire comprises:
taking the distance from the midpoint of each voltage pole lead to the current pole lead as the distance between the voltage pole lead and the current pole lead of the corresponding section;
and determining the direct mutual inductance value between each section of current pole lead and the corresponding voltage pole lead according to the distance between each section of voltage pole lead and each section of current pole lead.
3. The method of claim 1, wherein said determining a mutual mirror inductance between each segment of the voltage pole conductor and the corresponding mirror image of the current pole conductor comprises:
taking the distance from the midpoint of each section of voltage pole wire to the mirror image of the current pole wire as the distance between the voltage pole wire and the mirror image of the current pole wire of the corresponding section;
and determining the mutual inductance value of the mirror images between the voltage pole lead and the mirror images of the corresponding current pole lead according to the distance between the voltage pole lead and the mirror images of the current pole lead.
4. The method for determining the mutual inductance coupling component between the grounding impedance test lines according to claim 1, wherein the step of determining the total value of the direct mutual inductance between the current pole wire and the voltage pole wire according to the direct mutual inductance value based on the Newman integration method comprises the following steps:
summing the direct mutual inductance values between each section of current pole lead and the corresponding voltage pole lead to obtain a direct mutual inductance total value Md。
5. The method for determining mutual inductance coupling component between lines according to claim 4, wherein said total value of direct mutual inductance MdExpressed as:
wherein n is the total number of segments of the current pole wire and the total number of segments of the voltage pole wire, LIIs the length of the current pole wire,
LVis the length of the voltage pole wire, theta is the angle between the voltage pole wire and the current pole wire, GA＝GI+GV，GVThe distance of the voltage pole conductor from the actual ground, GIThe distance of the current pole wire from the actual ground.
6. The method of claim 1, wherein determining a total value of image mutual inductance between the images of the voltage pole wire and the corresponding current pole wire from the image mutual inductance value comprises:
summing the mutual inductance values of the images between the voltage pole leads and the corresponding current pole leads to obtain a total mutual inductance value M of the imagesi。
7. The method for determining mutual inductance coupling component between ground impedance test lines according to claim 6, wherein the total value M of mirror mutual inductanceiExpressed as:
wherein n is the total segment number of the current pole wire and the voltage pole wireTotal number of segments of line, LIIs the length of the current pole wire,
LVis the length of the voltage pole wire, theta is the angle between the voltage pole wire and the current pole wire, GB＝GI+GV，GVThe distance of the voltage pole conductor from the actual ground, GIThe distance of the current pole wire from the actual ground,
is an imaginary unit, mu0＝4π/107σ is 1/ρ, ρ is the soil resistivity, and f is the mutual inductance frequency.
8. The method for determining the mutual inductance coupling component between the grounding impedance test lines as claimed in claim 1, wherein the mutual inductance value is ZMP，ZMPExpressed as:
wherein j is an imaginary unit, mu0＝4π/107，MdFor said total value of direct mutual inductance, MiN is the total segment number of the current pole lead and the total segment number of the voltage pole lead, LIIs the length of the current pole wire, LVIs the length of the voltage pole wire,
theta is the angle between the voltage and current pole wires,
9. the method for determining the mutual inductance coupling component between the grounding impedance test lines according to claim 1, wherein the current pole wire and the voltage pole wire are both parallel to the ground, the angle of the current pole wire relative to the voltage pole wire is the angle between the vertical projection of the current pole wire on the ground and the vertical projection of the voltage pole wire on the ground, and the mirror image of the current pole wire is the mirror image of the complex plane of the current pole wire below the ground and at a predetermined distance from the ground.
10. An apparatus for determining a mutual inductance coupling component between ground impedance test lines, comprising:
the data acquisition module is used for acquiring position information among the current pole lead, the voltage pole lead and the mirror image of the current pole lead and acquiring angle information of the current pole lead relative to the voltage pole lead;
a wire segmenting module, configured to segment the current pole wire and the voltage pole wire according to the position information and the angle information based on a segmented differential method, and determine a direct mutual inductance value between each segment of the current pole wire and the corresponding voltage pole wire, and a mirror mutual inductance value between each segment of the voltage pole wire and a mirror image of the corresponding current pole wire;
the mutual inductance total value determining module is used for determining a direct mutual inductance total value between the current pole lead and the voltage pole lead according to the direct mutual inductance value based on a Newman integral method, and determining a mirror image mutual inductance total value between the voltage pole lead and a mirror image of the corresponding current pole lead according to the mirror image mutual inductance value;
and the wire mutual inductance determining module is used for determining a mutual inductance value between the current pole wire and the voltage pole wire according to the direct mutual inductance total value and the mirror image mutual inductance total value.
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