A non-contact voltage measurement method suitable for single-core insulated wires

Abstract

The present invention discloses a non-contact voltage measurement method applicable to single-core insulated conductors. The method involves wrapping a multilayer film around the insulated conductor to reconstruct the conductor's columnar electric field. The multilayer film comprises a detection metal film and an auxiliary insulating film. Based on the constructed columnar electric field, a voltage measurement equation is established using three sensors, and the voltage of the insulated conductor is obtained by solving the equation. This method can measure voltage amplitude without breaking the circuit or damaging the conductor's insulation, offering the advantages of safety, convenience, and improved voltage measurement efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of voltage measurement, and in particular to a non-contact AC voltage amplitude measurement method suitable for a single-core insulated conductor. Background Art

[0002] Voltage is a critical parameter in power systems, and voltage measurement is of great significance. Traditional voltage measurement methods involve directly connecting the conductor to be measured. However, while ensuring personal safety, the insulation layer of the conductor limits the convenience of measurement. This requires disconnecting the circuit or destroying the insulation layer of the conductor for wiring measurement, which is not very applicable and affects measurement efficiency. Summary of the Invention

[0003] The purpose of the present invention is to provide a non-contact AC voltage amplitude measurement method suitable for single-core insulated wires. The method can realize voltage amplitude measurement without disconnecting the circuit and damaging the insulation layer of the wire. It has the advantages of safety and convenience and improves the voltage measurement efficiency.

[0004] The purpose of the present invention is achieved through the following technical solutions:

[0005] A non-contact voltage measurement method applicable to a single-core insulated conductor, the method comprising:

[0006] Step 1: Wrapping the insulated wire to be tested with a multilayer film to reconstruct the columnar electric field of the insulated wire to be tested; wherein the multilayer film includes a detection metal film and an auxiliary insulating film;

[0007] Step 2: Based on the cylindrical electric field constructed in step 1, three sensors are used to establish a voltage measurement equation, and the voltage of the insulated wire to be measured is obtained by solving the voltage measurement equation.

[0008] It can be seen from the technical solution provided by the above invention that the above method can realize voltage amplitude measurement without disconnecting the circuit and damaging the insulation layer of the wire, has the advantages of safety and convenience, and improves the voltage measurement efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0010] Figure 1 A schematic flow chart of a non-contact voltage measurement method for a single-core insulated conductor provided in an embodiment of the present invention;

[0011] Figure 2A schematic diagram of the process of deriving the voltage to be measured provided by an embodiment of the present invention.

[0012] Figure 3 This is a schematic cross-sectional view of sensor No. 1 according to an embodiment of the present invention after it surrounds the insulated wire to be measured;

[0013] Figure 4 This is a schematic cross-sectional view of the No. 2 sensor according to an embodiment of the present invention after it surrounds the insulated wire to be measured;

[0014] Figure 5 This is a schematic cross-sectional view of the No. 3 sensor according to an embodiment of the present invention after it surrounds the insulated wire to be measured;

[0015] Figure 6 This is the image of the function F(R1) provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0016] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments, and do not constitute a limitation of the present invention. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0017] Figure 1 A schematic flow chart of a non-contact voltage measurement method for a single-core insulated conductor provided in an embodiment of the present invention includes:

[0018] Step 1: Wrapping the insulated wire to be tested with a multilayer film to reconstruct the columnar electric field of the insulated wire to be tested; wherein the multilayer film includes a detection metal film and an auxiliary insulating film;

[0019] In this step, if Figure 3 The figure shows a cross-sectional view of the insulated wire to be tested after being wrapped with a film according to an embodiment of the present invention. The electric field in the space around the insulated wire to be tested is expressed as Formula 1:

[0020]

[0021] Where E is the electric field intensity, and the direction is radial; k is the charge per unit length of the cylinder; ε is the dielectric constant of the insulating layer, and r is the radius;

[0022] Since voltage is the integral of the electric field along the radial direction, we have formulas (2) and (3):

[0023]

[0024]

[0025] Among them, U i is the voltage to be measured; U o1 is the voltage between the detection metal film and the grounded metal film in sensor No. 1; R0 is the inner metal radius of the insulated wire; R1 is the outer radius of the insulated wire; R2 is the outer radius of the detection metal film; R3 is the outer radius of the auxiliary insulating film;

[0026] Combining equations (2) and (3) we can get U o1 with U i The relationship between them is as follows:

[0027]

[0028] Step 2: Based on the cylindrical electric field constructed in step 1, three sensors are used to establish a voltage measurement equation, and the voltage of the insulated wire to be measured is obtained by solving the voltage measurement equation.

[0029] In this step, if Figure 2 FIG2 is a schematic diagram of a process for deriving a voltage to be measured provided by an embodiment of the present invention, wherein the diagram includes three sensors, namely, sensors No. 1, No. 2, and No. 3. Figure 3 This is a schematic cross-sectional view of sensor No. 1 according to an embodiment of the present invention after it surrounds the insulated wire to be measured; Figure 4 This is a schematic diagram of the cross section of the No. 2 sensor wrapped around the insulated wire to be measured. Specifically:

[0030] The voltage measurement equation established using sensors 1 and 2 is:

[0031]

[0032] Among them, the thickness of the detection metal film is D1; the thickness of the auxiliary insulation film is D2; U o1 U is the voltage between the detection metal film and the grounded metal film in sensor No. 1; o2 The voltage between the detection metal film and the grounded metal film in sensor No. 2;

[0033] Further obtain the measured voltage U that needs to be solved i The function f(R1) of the outer radius R1 of the insulated wire is shown in formula (6):

[0034]

[0035] When the outer radius R1 of the insulated wire can be measured, the measured R1 is substituted into formula (6) to obtain the voltage to be measured U i .

[0036] In the specific implementation, when the outer radius R1 of the insulated wire cannot be accurately measured, the number of measurement equations is increased by using sensor No. 3, such as Figure 5 FIG. 1 is a schematic cross-sectional view of sensor No. 3 according to an embodiment of the present invention. The voltage measurement equation established using sensors No. 1 and No. 3 is:

[0037]

[0038] Among them, U o1 U is the voltage between the detection metal film and the grounded metal film in sensor No. 1; o3 The voltage between the detection metal film and the grounded metal film in sensor No. 3;

[0039] Get a new voltage to be measured U i The function g(R1) of the outer radius R1 of the insulated wire is shown in formula (8):

[0040]

[0041] Since the input voltage is the same, the function F(R1) with R1 as the independent variable can be obtained from equations (6) and (8), as shown in equation (9):

[0042] F(R1)=f(R1)-g(R1) (9)

[0043] It can be observed that its zero point cannot be directly calculated. The function F(R1) is monotonic and continuous in the domain of R1, such as Figure 6 The figure shows the function F(R1) corresponding to the parameters in the embodiment of the present invention. The outer radius R1 of the insulated wire is obtained by stepwise approximation using the bisection method. Then R1 is substituted into formula (6) or (8) to obtain the voltage to be measured U i .

[0044] It should be noted that the contents not described in detail in the embodiments of the present invention belong to the prior art known to those skilled in the art.

[0045] In order to more clearly demonstrate the technical solution and the technical effects provided by the present invention, a simulation test of the above measurement method is performed using 220V AC voltage as an example. The specific parameters are shown in Table 1:

[0046] Table 1 Simulation parameters

[0047]

[0048]

[0049] At this time, formula (6) is specifically:

[0050]

[0051] If R1 is known to be 0.0030000m, the voltage to be measured, U, can be obtained by substituting it intoi =220.00V.

[0052] If R1 is unknown, it needs to be solved using F(R1). In this case, the formula F(R1) is:

[0053]

[0054] Its function graph is as follows Figure 6 As shown, the function is monotonically continuous. Using the bisection method, we can get R1 = 0.0029999m. Substituting R1 into formula (6) we can get the voltage to be measured U i =220.00V.

[0055] In summary, the method described in the embodiment of the present invention can achieve voltage measurement without disconnecting the circuit and damaging the insulation layer of the wire, has the advantages of safety and convenience, and improves the voltage measurement efficiency.

[0056] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims. The information disclosed in the background technology section of this article is only intended to deepen the understanding of the overall background technology of the present invention, and should not be regarded as an admission or any form of implication that the information constitutes prior art already known to those skilled in the art.

Claims

1. A non-contact voltage measurement method suitable for single-core insulated wires, characterized in that: The method comprises: Step 1: Wrapping the insulated wire to be tested with a multilayer film to reconstruct the columnar electric field of the insulated wire to be tested; wherein the multilayer film includes a detection metal film and an auxiliary insulating film; In step 1, the electric field in the space surrounding the insulated conductor to be measured is expressed as Formula 1: Where E is the electric field intensity, and the direction is radial; k is the charge per unit length of the cylinder; ε is the dielectric constant of the insulating layer, and r is the radius; Since voltage is the integral of the electric field along the radial direction, we have formulas (2) and (3): Among them, U i is the voltage to be measured; U o1 is the voltage between the detection metal film and the grounded metal film in sensor No. 1; R0 is the inner metal radius of the insulated wire; R1 is the outer radius of the insulated wire; R2 is the outer radius of the detection metal film; R3 is the outer radius of the auxiliary insulating film; Combining equations (2) and (3) we can get U o1 with U i The relationship between them is as follows: Step 2: Based on the cylindrical electric field constructed in step 1, three sensors are used to establish a voltage measurement equation, and the voltage of the insulated wire to be measured is obtained by solving the voltage measurement equation; In step 2, the voltage measurement equation established using sensors 1 and 2 is: Among them, the thickness of the detection metal film is D1; the thickness of the auxiliary insulation film is D2; U o1 U is the voltage between the detection metal film and the grounded metal film in sensor No. 1; o2 The voltage between the detection metal film and the grounded metal film in sensor No. 2; Further obtain the measured voltage U that needs to be solved i The function f(R1) of the outer radius R1 of the insulated wire is shown in formula (6): When the outer radius R1 of the insulated wire can be measured, the voltage to be measured can be obtained by substituting the measured R1 into formula (6); When the outer radius R1 of the insulated wire cannot be accurately measured, a measurement equation is added using sensor No.

3. At this time, the voltage measurement equation established using sensors No. 1 and No. 3 is: Among them, the thickness of the detection metal film is D1; the thickness of the auxiliary insulation film is D2; U o1 U is the voltage between the detection metal film and the grounded metal film in sensor No. 1; o3 The voltage between the detection metal film and the grounded metal film in sensor No. 3; Get a new voltage to be measured U i The function g(R1) of the outer radius R1 of the insulated wire is shown in formula (8): Since the input voltage is the same, the function F(R1) with R1 as the independent variable can be obtained from equations (6) and (8), as shown in equation (9): F(R1)=f(R1)-g(R1) (9) The function F(R1) is monotonic and continuous in the domain of R1. The outer radius R1 of the insulated wire is gradually approximated by the bisection method, and then R1 is substituted into formula (6) or (8) to obtain the voltage to be measured.

Images