A voltage decoupling method for non-contact voltage measurement

Abstract

The present invention belongs to the technical field of voltage detection, and particularly relates to a voltage decoupling method for non-contact voltage measurement, including the steps of: S1, obtaining the position information between the three-phase line to be measured and other three-phase lines in the current substation; S2, analyzing according to the position information whether there are other three-phase lines that will interfere with the three-phase line to be measured; S3, if there are other three-phase lines that will interfere with the three-phase line to be measured, determining the current coupling matrix of the three-phase line to be measured according to the coupling matrix of the three-phase lines that will interfere with the three-phase line to be measured and the coupling matrix when the three-phase line to be measured is free of interference. The voltage decoupling method for non-contact voltage measurement provided by the present invention fully considers the interference of other three-phase lines in the substation on the three-phase line to be measured, and determines the current coupling matrix of the three-phase line to be measured according to the interference relationship, and can more accurately obtain the current coupling matrix of the three-phase line to be measured.

Description

Technical Field

[0001] The present invention belongs to the technical field of voltage detection, and particularly relates to a voltage decoupling method for non-contact voltage measurement. Background Art

[0002] In a power system, the distances between three-phase conductors in the same circuit are relatively close, and a non-contact voltage sensor will inevitably be affected by the electric fields generated by each phase conductor in the three-phase conductors at the same time. The charge of the non-contact voltage sensor is generated by the coupled electric field, and the voltage at the measured point cannot be directly obtained. Therefore, a solution is needed to more accurately determine the coupling matrix of the measured three-phase line. Summary of the Invention

[0003] To solve the above problems, the present invention provides a voltage decoupling method for non-contact voltage measurement to more accurately determine the coupling matrix of the measured three-phase line. The specific technical solution is as follows:

[0004] A voltage decoupling method for non-contact voltage measurement includes the following steps:

[0005] S1. Obtain the position information between the measured three-phase line and other three-phase lines in the current substation;

[0006] S2. Analyze according to the position information whether there are other three-phase lines that will interfere with the measured three-phase line;

[0007] S3. If there are other three-phase lines that will interfere with the measured three-phase line, determine the current coupling matrix of the measured three-phase line according to the coupling matrix of the three-phase lines that will interfere with the measured three-phase line and the coupling matrix of the measured three-phase line when there is no interference.

[0008] Preferably, the position information in step S1 is obtained from the historical installation information in the substation data management server.

[0009] Preferably, step S2 is specifically: analyze according to the position information between each other three-phase line and the measured three-phase line in the current substation whether the distance between any one phase line in each other three-phase line and any one phase line in the measured three-phase line is less than a preset value;

[0010] If the distance between any one phase line in each other three-phase line and any one phase line in the measured three-phase line is less than the preset value, then this three-phase line will interfere with the measured three-phase line.

[0011] Preferably, in step S3, specifically: if a three-phase line in the current substation interferes with the measured three-phase line, then an addition operation is performed based on the coupling matrix of this three-phase line and the coupling matrix of the measured three-phase line when there is no interference, to obtain the current coupling matrix of the measured three-phase line.

[0012] Preferably, step S3 further includes: analyzing whether there is a three-phase line in other three-phase lines that interfere with the measured three-phase line and is symmetric with respect to the measured three-phase line as the axis;

[0013] If there is a three-phase line in other three-phase lines that interfere with the measured three-phase line and is symmetric with respect to the measured three-phase line as the axis, then the transpose matrix of the coupling matrix of one of the three-phase lines in the other three-phase lines that interfere with the measured three-phase line and the three-phase line symmetric to it is used to replace the coupling matrix of the other three-phase line.

[0014] Preferably, it further includes: if the distance from a certain phase line in other three-phase lines that interfere with the measured three-phase line to a certain phase line in the measured three-phase line is greater than a preset value, then the parameter at the corresponding position in the coupling matrix of this three-phase line is 0.

[0015] Preferably, step S3 further includes: analyzing whether there is a same-tower line of the measured three-phase line in other three-phase lines that interfere with the measured three-phase line;

[0016] If there is a same-tower line of the measured three-phase line in other three-phase lines that interfere with the measured three-phase line, then when determining the coupling matrix of the measured three-phase line when a lightning-induced transient overvoltage occurs, the coupling matrix of this same-tower line is multiplied by the voltage matrix of the measured three-phase line when a lightning-induced transient overvoltage occurs and then added to the coupling matrix of the measured three-phase line when there is no interference, to obtain the coupling matrix of the measured three-phase line when a lightning-induced transient overvoltage occurs.

[0017] Preferably, step S3 further includes: if there is no same-tower line of the measured three-phase line in other three-phase lines that interfere with the measured three-phase line, then the coupling matrix of the measured three-phase line when there is no interference is multiplied by the voltage matrix of the measured three-phase line when a lightning-induced transient overvoltage occurs, and then added to the product of the coupling matrix of other three-phase lines that interfere with the measured three-phase line and the steady-state voltage matrix of the measured three-phase line, to obtain the coupling matrix of the measured three-phase line when a lightning-induced transient overvoltage occurs.

[0018] The beneficial effects of the present invention are as follows: The voltage decoupling method for non-contact voltage measurement provided by the present invention fully considers the interference of other three-phase lines in the substation on the measured three-phase lines, and determines the current coupling matrix of the measured three-phase lines according to the interference relationship, and can obtain the current coupling matrix of the measured three-phase lines more accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0020] Figure 1 It is a schematic overall flow chart of a voltage decoupling method for non-contact voltage measurement provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0022] It should be understood that when used in this specification and the appended claims, the terms "comprises" and "comprising" indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0023] It should also be understood that the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms.

[0024] It should be further understood that the term " / and / " used in the specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the related listed items, and includes these combinations.

[0025] As Figure 1 shown, the specific embodiment of the present invention provides a voltage decoupling method for non-contact voltage measurement, including the following steps:

[0026] S1. Obtain the position information between the three-phase line to be measured and other three-phase lines in the current substation; the position information is obtained from the historical installation information in the substation data management server.

[0027] S2. Analyze whether there are other three-phase lines that will interfere with the three-phase line to be measured according to the position information; specifically: analyze whether there is any phase line in other three-phase lines in the current substation whose distance from any phase line in the three-phase line to be measured is less than a preset value according to the position information between other three-phase lines and the three-phase line to be measured;

[0028] If there is any phase line in other three-phase lines whose distance from any phase line in the three-phase line to be measured is less than the preset value, then this three-phase line will interfere with the three-phase line to be measured.

[0029] Exemplarily, if the distance between each phase in the three-phase line to be measured is 2 cm, and there is a distance between a certain phase in other three-phase lines and a certain phase in the three-phase line to be measured that is less than the maximum distance between this phase and the other two phases in the three-phase line to be measured, then this three-phase line will interfere with the three-phase line to be measured. If the distance between any phase in other three-phase lines and any phase in the three-phase line to be measured is much greater than the maximum distance between two phases in the three-phase line to be measured, then this three-phase line will not interfere with the three-phase line to be measured.

[0030] S3. If there are other three-phase lines that will interfere with the three-phase line to be measured, then determine the current coupling matrix of the three-phase line to be measured according to the coupling matrix of the three-phase line that will interfere with the three-phase line to be measured and the coupling matrix when the three-phase line to be measured has no interference. Specifically: if a certain three-phase line in the current substation will interfere with the three-phase line to be measured, then perform an addition operation according to the coupling matrix of this three-phase line and the coupling matrix when the three-phase line to be measured has no interference to obtain the current coupling matrix of the three-phase line to be measured.

[0031] Let U a 、U b 、U c be the three-phase power frequency voltages in the ideal state, corresponds to the phase angle of the A-phase voltage at power frequency, V A 、V B 、V C are the three-phase power frequency voltages actually measured, is the initial phase angle corresponding to V A , is the initial phase angle corresponding to V B , is the initial phase angle corresponding to V C . The coupling equation can be listed as:

[0032]

[0033] Among them, h1 to h9 are coupling coefficients, and k1, k2, and k3 are scale factors of the ABC three-phase sensors;

[0034] h1: Influence coefficient of the A-phase wire on the electric field at the measurement point of the A-phase wire;

[0035] h2: Influence coefficient of the B-phase wire on the electric field at the measurement point of the A-phase wire;

[0036] h3: Influence coefficient of the C-phase wire on the electric field at the measurement point of the A-phase wire;

[0037] h4: Influence coefficient of the A-phase wire on the electric field at the measurement point of the B-phase wire;

[0038] h5: Influence coefficient of the B-phase wire on the electric field at the measurement point of the B-phase wire;

[0039] h6: Influence coefficient of the C-phase wire on the electric field at the measurement point of the B-phase wire;

[0040] h7: Influence coefficient of the A-phase wire on the electric field at the measurement point of the C-phase wire;

[0041] h8: Influence coefficient of the B-phase wire on the electric field at the measurement point of the C-phase wire;

[0042] h9: Influence coefficient of the C-phase wire on the electric field at the measurement point of the C-phase wire.

[0043] Exemplarily, if the coupling matrix when the measured three-phase line has no interference is:

[0044]

[0045] h 10 ~h 90 are the coupling coefficients without interference, and the definitions of h 10 ~h 90 are the same as those of h1 to h9. Due to the mutual influence relationship of the ABC three-phase electric fields, at this time, the phase of the AB phase shifts to the B phase, while the actual phase of the B phase does not change. Therefore, from the above equations.

[0046] The three-phase line having no interference means that the line is not affected by other lines outside the ABC three phases of this line at this time.

[0047] Meanwhile, if there is another three-phase line that will cause interference to the measured three-phase line, the current coupling matrix of the measured three-phase line is:

[0048]

[0049] Among them, The coupling matrix of the three-phase line that will interfere with the three-phase line under test. Since any vector can be obtained by adding three non-parallel vectors, the influence of adjacent wires on the electric field at the measurement point can be calculated by reducing it to the electric fields of the three phases A, B, and C. Among them:

[0050] h 11 : The coefficient after reducing the influence of adjacent wires on the electric field at the measurement point of phase A wire to phase A voltage;

[0051] h 21 : The coefficient after reducing the influence of adjacent wires on the electric field at the measurement point of phase A wire to phase B voltage;

[0052] h 31 : The coefficient after reducing the influence of adjacent wires on the electric field at the measurement point of phase A wire to phase C voltage;

[0053] h 41 : The coefficient after reducing the influence of adjacent wires on the electric field at the measurement point of phase B wire to phase A voltage;

[0054] h 51 : The coefficient after reducing the influence of adjacent wires on the electric field at the measurement point of phase B wire to phase B voltage;

[0055] h 61 : The coefficient after reducing the influence of adjacent wires on the electric field at the measurement point of phase B wire to phase C voltage;

[0056] h 71 : The coefficient after reducing the influence of adjacent wires on the electric field at the measurement point of phase C wire to phase A voltage;

[0057] h 81 : The coefficient after reducing the influence of adjacent wires on the electric field at the measurement point of phase C wire to phase B voltage;

[0058] h 91 : The coefficient after reducing the influence of adjacent wires on the electric field at the measurement point of phase C wire to phase C voltage.

[0059] If there are two other three-phase lines that will interfere with the three-phase line under test, the current coupling matrix of the three-phase line under test is:

[0060]

[0061] Among them, is the coupling matrix of another three-phase line that will interfere with the three-phase line under test, and its definition When the adjacent line is symmetric about the measurement point, there is h 22 = h 62 ; h 42 = h 82 ; h 12 = h52 = h 92 。

[0062] Step S3 further includes: analyzing whether there are three-phase lines that are symmetric with respect to the axis of the measured three-phase line among other three-phase lines that can interfere with the measured three-phase line;

[0063] If there are three-phase lines that are symmetric with respect to the axis of the measured three-phase line among other three-phase lines that can interfere with the measured three-phase line, then replace the coupling matrix of one three-phase line with the transposed matrix of the coupling matrix of the other three-phase line among the other three-phase lines that can interfere with the measured three-phase line and the three-phase line that is axisymmetric with it.

[0064] Exemplarily, if there are two three-phase lines that are symmetric with respect to the axis of the measured three-phase line among other three-phase lines that can interfere with the measured three-phase line, then:

[0065] h 11 = h 51 = h 91 = h 12 = h 52 = h 92 ;

[0066] h 41 = h 81 = h 22 = h 62 ;

[0067] h 21 = h 61 = h 42 = h 82 ;

[0068] h 31 = h 72 ;

[0069] h 71 = h 32 ;

[0070]

[0071] Step S3 further includes: if the distance from a certain phase line in other three-phase lines that can interfere with the measured three-phase line to a certain phase line in the measured three-phase line is greater than a preset value, then the parameter at the corresponding position in the coupling matrix of this three-phase line is 0.

[0072] Exemplarily, taking two three-phase lines that are symmetric with respect to the axis as an example, the above coupling matrix can be further expressed as:

[0073]

[0074] Step S3 further includes: analyzing whether there is a same-tower line of the measured three-phase line among other three-phase lines that can interfere with the measured three-phase line;

[0075] If there is a same-tower line of the measured three-phase line among other three-phase lines that can interfere with the measured three-phase line, when determining the coupling matrix when the measured three-phase line generates a lightning transient overvoltage, multiply the coupling matrix of this same-tower line by the voltage matrix when the measured three-phase line generates a lightning transient overvoltage, and then add the coupling matrix when the measured three-phase line has no interference to obtain the coupling matrix when the measured three-phase line generates a lightning transient overvoltage.

[0076] Step S3 further includes: if there is no same-tower line of the measured three-phase line among other three-phase lines that can interfere with the measured three-phase line, multiply the coupling matrix when the measured three-phase line has no interference by the voltage matrix when the measured three-phase line generates a lightning transient overvoltage, and then add the product of the coupling matrix of other three-phase lines that can interfere with the measured three-phase line and the steady-state voltage matrix of the measured three-phase line to obtain the coupling matrix when the measured three-phase line generates a lightning transient overvoltage.

[0077] Specifically, taking the example that there are two other three-phase lines that interfere with the measured three-phase line, if there is a same-tower line of the measured three-phase line among other three-phase lines that can interfere with the measured three-phase line, the coupling relationship when the measured three-phase line generates a lightning transient overvoltage is:

[0078]

[0079] U a稳态 ~U c稳态 represent the steady-state voltage values of the three phases A, B, and C of the line, and U a暂态 ~U c暂态 represent the transient voltage values of the three phases A, B, and C of the line.

[0080] If there is no same-tower line of the measured three-phase line among other three-phase lines that can interfere with the measured three-phase line, the coupling relationship when the measured three-phase line generates a lightning transient overvoltage is:

[0081]

[0082] In summary, through the above method, the present invention can more accurately obtain the current coupling matrix of the measured three-phase line.

[0083] Those of ordinary skill in the art can realize that the units of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the composition of each example has been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0084] In the embodiments provided in the present application, it should be understood that the division of units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units can be combined into one unit, one unit can be split into multiple units, or some features can be ignored, etc.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered by the scope of the claims and the specification of the present invention.

Claims

1. A voltage decoupling method for non-contact voltage measurement, characterized in that It includes the following steps: S1. Obtain the position information between the three-phase line under test and other three-phase lines in the current substation; S2. Analyze whether there are other three-phase lines that will interfere with the three-phase line under test according to the position information; specifically: analyze whether there is any phase line in each of the other three-phase lines in the current substation whose distance from any phase line in the three-phase line under test is less than a preset value according to the position information between each of the other three-phase lines and the three-phase line under test; If there is any phase line in each of the other three-phase lines whose distance from any phase line in the three-phase line under test is less than the preset value, then this three-phase line will interfere with the three-phase line under test; S3. If there are other three-phase lines that will interfere with the three-phase line under test, then determine the current coupling matrix of the three-phase line under test according to the coupling matrix of the three-phase line that will interfere with the three-phase line under test and the coupling matrix of the three-phase line under test when there is no interference; specifically: if a certain three-phase line in the current substation will interfere with the three-phase line under test, then perform an addition operation according to the coupling matrix of this three-phase line and the coupling matrix of the three-phase line under test when there is no interference to obtain the current coupling matrix of the three-phase line under test.

2. The voltage decoupling method for non-contact voltage measurement according to claim 1, wherein The position information in step S1 is obtained from the historical installation information in the substation data management server.

3. The voltage decoupling method for non-contact voltage measurement according to claim 1, characterized in that, Step S3 further includes: analyzing whether there are three-phase lines that are symmetric with respect to the three-phase line under test among the other three-phase lines that will interfere with the three-phase line under test; If there are three-phase lines that are symmetric with respect to the three-phase line under test among the other three-phase lines that will interfere with the three-phase line under test, then replace the coupling matrix of one of the three-phase lines with the transposed matrix of the coupling matrix of a certain three-phase line among the other three-phase lines that will interfere with the three-phase line under test and the three-phase line that is axisymmetric with it.

4. A voltage decoupling method for non-contact voltage measurement according to claim 3, wherein It also includes: If the distance from a certain phase line in the other three-phase lines that will interfere with the three-phase line under test to a certain phase line in the three-phase line under test is greater than the preset value, then the parameter at the corresponding position in the coupling matrix of this three-phase line is 0.

5. A voltage decoupling method for non-contact voltage measurement according to claim 1, characterized in that, Step S3 further includes: analyzing whether there are same-tower lines of the three-phase line under test among the other three-phase lines that will interfere with the three-phase line under test; If there are same-tower lines of the three-phase line under test among the other three-phase lines that will interfere with the three-phase line under test, then when determining the coupling matrix of the three-phase line under test when a lightning strike transient overvoltage occurs, multiply the coupling matrix of this same-tower line by the voltage matrix of the three-phase line under test when a lightning strike transient overvoltage occurs and then add the coupling matrix of the three-phase line under test when there is no interference to obtain the coupling matrix of the three-phase line under test when a lightning strike transient overvoltage occurs.

6. The voltage decoupling method for non-contact voltage measurement according to claim 5, characterized in that The step S3 further includes: if there is no same-tower line of the measured three-phase line among other three-phase lines that will interfere with the measured three-phase line, then multiplying the coupling matrix of the measured three-phase line when there is no interference by the voltage matrix of the measured three-phase line when a lightning transient overvoltage occurs, and then adding the product of the coupling matrix of other three-phase lines that will interfere with the measured three-phase line and the steady-state voltage matrix of the measured three-phase line to obtain the coupling matrix of the measured three-phase line when a lightning transient overvoltage occurs.

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