Anti-interference high voltage measurement system and method

Abstract

The invention provides an anti-interference high-voltage measuring system and method, and the method comprises the steps: calculating a to-be-measured voltage delta V through measuring the accumulated phase shift delta phi of linearly polarized light with the wavelength of lambda along the length of a transverse polarized optical fiber which is spirally arranged with the electro-optical coefficient of r and the pitch angle of xi in an electric field; the high voltage between two separated points is measured in a strong interference environment. Due to the adoption of a photoelectric conversion structure principle, the device is not easily interfered by a strong current environment, is high in measurement precision, and is suitable for measuring high-voltage alternating current (AC) voltage and direct current (dc) voltage. The device does not need a complex high-voltage insulation device, electrode arrangement or a capacitive voltage divider, and has the advantages of being simple in design, small in size, light in weight and easy to install.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high-voltage measurement, and particularly relates to an anti-interference high-voltage measurement system and method. BACKGROUND

[0002] Traditional electromagnetic voltage transformers or capacitive voltage transformers (capacitive dividers) are heavy and bulky, and are susceptible to interference. Traditional optical voltage transformers based on point sensors require complex high-voltage insulation; optical voltage transformers based on voltage division require complex electrode arrangements or capacitive dividers. Under the existing measurement scheme, the required high-voltage insulation results in a bulky and heavy voltage transformer. SUMMARY

[0003] The technical problem to be solved by the application is to provide an anti-interference high-voltage measurement system and method for measuring high voltage between two spaced points in a strong interference environment.

[0004] The technical scheme adopted by the application to solve the above technical problem is: an anti-interference high-voltage measurement system, comprising an upper connection terminal, a lower connection terminal, a central rod, a transversely polarized optical fiber, an unpolarized optical fiber, a control unit, a 2x2 optical fiber coupler, a 3x3 optical fiber coupler, a first output optical fiber, a second output optical fiber, and a third output optical fiber; the upper connection terminal and the lower connection terminal are respectively arranged at the two ends of the central rod and are used to respectively connect a power line to be measured and the ground to form an electric field; the transversely polarized optical fiber and the unpolarized optical fiber are wound in parallel in the form of a helix with a constant pitch angle outside the central rod; the control unit is arranged at the bottom of the central rod and is used to provide linearly polarized light to the transversely polarized optical fiber and the unpolarized optical fiber through the 2x2 optical fiber coupler; the 3x3 optical fiber coupler is arranged at the top of the central rod and is used to generate interference between the light output by the transversely polarized optical fiber and the unpolarized optical fiber and then output the phase-shifted signals through the first output optical fiber, the second output optical fiber, and the third output optical fiber to the control unit.

[0005] According to the above scheme, the upper connection terminal comprises an upper metal end plate and an upper lug arranged on the upper metal end plate; the lower connection terminal comprises a lower metal end plate and a lower lug arranged on the lower metal end plate; the central rod is a hollow pipe, and the first output optical fiber, the second output optical fiber, and the third output optical fiber pass through the central rod to connect the 3x3 optical fiber coupler at the top of the central rod and the 2x2 optical fiber coupler at the bottom of the central rod; the system further comprises an input optical fiber for connecting the control unit and the 2x2 optical fiber coupler; and an outer layer is arranged outside the central rod on which the optical fiber is wound, and a shed is arranged on the outer layer to provide mechanical protection for the optical fiber.

[0006] Further, the control unit comprises a light source for emitting monochromatic linearly polarized light to the input optical fiber; An isolator is arranged between the light source and the input optical fiber to prevent reflected light from returning to the light source; A polarizer is provided between the input optical fiber and the 2×2 fiber coupler to improve the polarization degree of the light; The control unit also includes a first photodetector, a first amplifier, and a first analog-to-digital converter connected in sequence to the first output optical fiber; a second photodetector, a second amplifier, and a second analog-to-digital converter connected in sequence to the second output optical fiber; and a third photodetector, a third amplifier, and a third analog-to-digital converter connected in sequence to the third output optical fiber, which are used for photoelectric conversion, signal amplification, and analog-to-digital conversion and outputting digital signals, respectively. The control unit also includes an amplitude comparator, a phase lookup table, an accumulator, an arcsine lookup table, an adder, and a switch. The amplitude comparator is used to route the most sensitive digital signal to the arcsine lookup table at any time by controlling the switch, and outputs the fine voltage value corresponding to the current position of the interference fringe through the arcsine lookup table. If the amplitude comparator determines to switch to the most sensitive digital signal, it outputs the phase constant to the accumulator through the phase lookup table. The accumulator is used to output a coarse voltage value to the adder through addition or subtraction operations. The adder is used to add the fine voltage value and the coarse voltage value to output the signal corresponding to the voltage to be measured.

[0007] According to the above scheme, a spiral core polarized fiber is used to replace the transversely polarized fiber; the spiral shape of the core of the spiral core polarized fiber is the same as the spiral shape of the transversely polarized fiber wound with a constant pitch angle; the polarization field that polarizes the core of the spiral core polarized fiber has a component in the direction parallel to the fiber axis; the spiral core polarized fiber, the unpolarized fiber, the first output fiber, the second output fiber and the third output fiber are arranged in a straight line.

[0008] According to the above scheme, polarized optical fibers are used to replace transversely polarized optical fibers; the polarization direction of the optical fiber has a component in the longitudinal direction of the optical fiber; the polarized optical fiber, the unpolarized optical fiber, the first output optical fiber, the second output optical fiber and the third output optical fiber are arranged in a straight line.

[0009] According to the above scheme, polarized optical fibers are used to replace transversely polarized optical fibers; at a certain point along the fiber axis at a distance z, the polarization direction forms a fixed angle of less than 90° with the fiber axis, and as z increases, the polarization direction rotates around the fiber axis; the polarized optical fibers, unpolarized optical fibers, first output optical fibers, second output optical fibers and third output optical fibers are arranged in a straight line.

[0010] According to the above scheme, optical fibers with multiple Bragg gratings formed by alternating closely arranged polarized and unpolarized regions etched in the fiber core are used to replace the transversely polarized fiber, the unpolarized fiber, the first output fiber, the second output fiber, and the third output fiber; 2×2 fiber couplers are used to replace 2×2 fiber couplers and 3×3 fiber couplers; the polarized regions are polarized in the transverse direction; the refractive index of the polarized regions is different from that of the unpolarized regions; the control unit includes a light source for emitting a single broadband light into the input fiber; the light reflected back from the Bragg gratings of the fiber is coupled into the control unit, and the wavelength shift is decoded into a signal corresponding to the voltage to be measured through signal processing.

[0011] Furthermore, the size of the Bragg grating ensures that the zero-field center wavelengths are different and that the reflection bands do not overlap; the optical fiber uses high birefringence fiber to reduce polarization changes caused by mechanical stress and temperature effects on the fiber; the light source uses two polarization states of the guided light and multiple different wavelengths to reduce or eliminate the influence of electric field interference.

[0012] An anti-interference high-voltage measurement method includes the following steps: The electro-optic coefficient of a transversely polarized fiber is r, and the component of the electric field E in the fiber polarization direction is E. p The refractive index of light transmitted through a laterally polarized optical fiber changes by Δn: Δn=rE p ; Let the change in refractive index in the optical fiber be z, then: Δn(z)=rE p (z); The change in refractive index within a fiber unit segment of length ds causes a phase shift dφ: dφ=dφ(z); Let the wavelength of the light used for measurement be λ. The above formula can be written as: dφ=(2πΔn / λ)ds; The pitch angle of the helix of the transversely polarized fiber wound around the central rod is ξ. In an orthogonal coordinate system where the z-axis coincides with the longitudinal axis of the central rod, the radius of a fiber unit segment of length ds in the transversely polarized fiber in the xy plane to the z-axis is R, and the angle between radius R and the x-axis is Θ. Then: ds=(1 / cosξ)dz, ds=(1 / sinξ)RdΘ; electric field component E x E y and E z The combined electric field E in the polarization direction p for: E p =E z sinξ+cosξ(Ex cosΘ+E y sinΘ); Let dφ be expressed as E p The function (z) yields the phase shift dφ generated by the light passing through the transversely polarized fiber and the electric field component E of the fiber unit segment in the polarization direction. p The expression for direct proportion is: dφ(z)=(2π / λ)rE p ds; Combining the above two equations, we get: dφ(z)=(2π / λ)r[E z sinξ+cosξ(E x cosΘ+E y sinΘ)]ds; The cumulative phase shift Δφ of light transmitted through optical fiber is: Δφ=∫dφ; E in a spiral x and E y Treating it as a constant, the cumulative phase shift Δφ of light is: Δφ=(2π / λ) r ∫ E z tanξ dz; The voltage ΔV to be measured along the helix axis is the electric field component E. z The potential V at the upper end of the spiral h Potential V at the lower end of the helix o Line integral: ΔV=∫E z dz; Combining the above two equations, the expression for the cumulative phase shift Δφ along the fiber length being proportional to the measured voltage ΔV is: Δφ=(2π / λ)rtanξΔV; By measuring the cumulative phase shift Δφ of linearly polarized light with wavelength λ along the length of a transversely polarized optical fiber with electro-optic coefficient r and a pitch angle ξ under an electric field, the voltage ΔV to be measured is calculated as follows: ΔV = Δφ / [(2π / λ)rtanξ].

[0013] A computer memory storing a computer program executable by a computer processor, the computer program performing an interference-resistant high-voltage measurement method.

[0014] The beneficial effects of this invention are as follows: 1. The present invention provides an anti-interference high voltage measurement system and method, which calculates the voltage to be measured ΔV by measuring the cumulative phase shift Δφ of linearly polarized light with wavelength λ along the length of a transversely polarized optical fiber with electro-optic coefficient r and pitch angle ξ under an electric field, thereby realizing the measurement of high voltage between two separated points under strong interference environment.

[0015] 2. Because this invention adopts the structural principle of photoelectric conversion, it is not easily affected by strong electric environment, has high measurement accuracy, and is suitable for measuring high voltage AC (ac) voltage and DC (dc) voltage.

[0016] 3. This invention does not require complex high-voltage insulation devices, electrode arrangements, or capacitor dividers, and has the advantages of simple design, small size, light weight, and easy installation.

[0017] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a cross-sectional view of an embodiment of the present invention.

[0020] Figure 2a This is a coordinate system diagram of an optical fiber unit segment with a length of ds according to an embodiment of the present invention.

[0021] Figure 2b This is a coordinate system diagram of an optical fiber unit segment with a length of ds extending inward from radius R towards the rod axis, according to an embodiment of the present invention.

[0022] Figure 3a This is a fiber optic layout diagram according to an embodiment of the present invention.

[0023] Figure 3b This is a partial output diagram of the optical fiber according to an embodiment of the present invention.

[0024] Figure 3c This is a schematic block diagram of the signal processing device according to an embodiment of the present invention.

[0025] Figure 4 This is a schematic diagram of a polarized spiral core optical fiber according to an embodiment of the present invention.

[0026] Figure 5a This is a schematic diagram of writing a Bragg grating in a polarized optical fiber according to an embodiment of the present invention.

[0027] Figure 5b This is a schematic diagram of a spiral arrangement written into a Bragg grating fiber according to an embodiment of the present invention.

[0028] In the diagram: 1. Earth busbar; 2. Upper metal end plate; 3. Lower metal end plate; 4. Upper lug; 5. Lower lug; 6. Central rod; 7. Laterally polarized fiber; 7'. Spiral core polarized fiber; 8. Unpolarized fiber; 9. Input fiber; 10a. 2×2 fiber coupler; 10b. Isolator; 10c. Polarizer; 11. 3×3 fiber coupler; 12a. First output fiber; 12b. Second output fiber; 12c. Third output fiber; 13. Outer layer; 14. Umbrella skirt; 15. Control unit; 16. Light source; 17. Signal processing unit; 20. Cored fiber; 21. Fiber core ; 22. Unpolarized region; 23. Polarized region; 24. Fiber 2×2 coupler; 25. Light source; 26. Return fiber; 27. Unit; 28a. First photodetector; 28b. Second photodetector; 28c. Third photodetector; 29a. First amplifier; 29b. Second amplifier; 29c. Third amplifier; 30a. First analog-to-digital converter; 30b. Second analog-to-digital converter; 30c. Third analog-to-digital converter; 31. Amplitude comparator; 32. Phase lookup table; 33. Accumulator; 34. Arcsine lookup table; 35. Adder; 36. Control switch. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0030] Example 1 See Figure 1 An anti-interference high voltage measurement system is used to measure the voltage between ground busbars 1. It includes an upper metal end plate 2 and a lower metal end plate 3, as well as an upper lug 4 and a lower lug 5 respectively disposed on the upper metal end plate 2 and the lower metal end plate 3, for electrical connection with power lines, busbars or ground.

[0031] It also includes a central rod 6 (or a tube if hollow) made of fiber-reinforced polymer material (such as glass fiber reinforced epoxy resin); a transversely polarized optical fiber 7 is wound around the central rod 6 to form a helix with a constant pitch angle; there is also an unpolarized optical fiber 8 wound parallel to the transversely polarized optical fiber 7 around the central rod 6 to form a helix that intersects with the helix of the transversely polarized optical fiber 7; the transversely polarized optical fiber 7 and the unpolarized optical fiber 8 are wound parallel to each other, so that the two optical fibers are under similar stress and temperature conditions.

[0032] At the lower end of the central rod 6, the transversely polarized fiber 7 and the unpolarized fiber 8 are respectively connected to the first and second pins of the 2×2 fiber coupler 10a; the input fiber 9 is connected to the control unit 15 and the third pin of the 2×2 fiber coupler 10a to provide linearly polarized light to the transversely polarized fiber 7 and the unpolarized fiber 8.

[0033] At the upper end of the central rod 6, the transversely polarized fiber 7 and the unpolarized fiber 8 are respectively connected to the two input pins of the 3×3 fiber coupler 11; the light from these two fibers interferes and is coupled to the three output pins of the 3×3 fiber coupler 11; the three output pins of the 3×3 fiber coupler 11 are respectively connected to the first output fiber 12a, the second output fiber 12b and the third output fiber 12c, which are used to provide three phase-shifted output signals to the control unit 15.

[0034] An outer layer 13 made of polymer material is provided on the outside of the optical fiber, and a skirt 14 is provided on the outer layer 13 to provide the optical fiber with necessary mechanical protection, obtain sufficient leakage path length, and obtain necessary protection against pollution for outdoor use.

[0035] The light emitted by the light source needs to have sufficient coherence, so the light source is usually a laser or a device that is close to the laser emission state, such as a superluminescent diode.

[0036] Figure 3a schematically shown Figure 1 The optical fibers of the measuring device are connected to the control unit 15. This unit has a light source 16 in the form of a laser diode, which emits monochromatic, linearly polarized light into the input fiber 9. The input fiber 9 transmits the light to a 2×2 fiber coupler 10a, and then to the lower ends of the laterally polarized fiber 7 and the unpolarized fiber 8. An isolator 10b is also provided to prevent reflected light from returning to the light source, and a polarizer 10c is provided to increase the polarization degree of the light. At the upper end of the laterally polarized fiber 7, the light undergoes a phase shift, the amount of which corresponds to the voltage between the upper and lower ends of the fiber. The light reaching the upper end of the unpolarized fiber 8 is unaffected by any voltage-related phase shift. The interference light from these two fibers is coupled through a 3×3 coupler 11 to three unpolarized fibers: a first output fiber 12a, a second output fiber 12b, and a third output fiber 12c. These fibers transmit the light downwards to the signal processing unit 17, which converts the total voltage-induced phase shift Δφ into an output signal Sout, which corresponds to the measured voltage ΔV.

[0037] A 3×3 fiber optic coupler 11 is used to prevent signal attenuation and increase dynamic range. For example... Figure 3bAs shown, the output power of the three output arms of the 3×3 fiber coupler 11 is ideally three sine waves with a 120° phase difference between each pair, where Sa, Sb, and Sc are the signal outputs of the three output arms of the 3×3 fiber coupler 11, respectively. Based on this, by processing only the linear portion of the sine waves and constantly monitoring which sine wave is currently in use, the highest sensitivity can be maintained for all output levels.

[0038] Figure 3c An example of a signal processing device is shown, in which the three outputs of the first output fiber 12a, the second output fiber 12b, and the third output fiber 12c, which are connected to the 3×3 fiber coupler 11, are fed into the first photodetector 28a, the second photodetector 28b, and the third photodetector 28c, and then pass through the corresponding first amplifier 29a, the second amplifier 29b, and the third amplifier 29c. The output signal is then converted into digital form in the corresponding first analog-to-digital converter 30a, the second analog-to-digital converter 30b, and the third analog-to-digital converter 30c.

[0039] The first analog-to-digital converter 30a, the second analog-to-digital converter 30b, and the third analog-to-digital converter 30c output digital signals to the amplitude comparator 31 and the control switch 36. The amplitude comparator 31 is used to route the digital signal with the maximum sensitivity to the arcsine lookup table 34 at any time via the control switch 36. This table outputs a fine voltage value corresponding to the current position within the fringe.

[0040] If the amplitude comparator 31 determines that it should switch to a different output signal, it accesses the phase lookup table 32 and outputs a suitable phase constant to the accumulator 33. When the amplitude comparator 31 switches between output signals, the accumulator 33 performs addition or subtraction operations on its contents according to the appropriate value obtained from the phase lookup table 32 and outputs a coarse voltage value; based on the coarse voltage value, it adds it to the fine voltage value obtained from the arcsine lookup table 34 in the adder 35 and outputs a signal S corresponding to the voltage to be measured. out .

[0041] Example 2 This embodiment implements an anti-interference high-voltage measurement method based on the structure of Embodiment 1. The specific steps are as follows: Laterally polarized fiber 7 is a type of quartz fiber that is laterally polarized. The polarization of this fiber is achieved by ultraviolet light excitation polarization in the presence of a strong electric field.

[0042] A polarized optical fiber exposed to an electric field has an electro-optic coefficient r, and the electric field has a component E in the fiber polarization direction. p When the light is transmitted through the optical fiber, the refractive index changes by Δn; the relationship between Δn and Ep is given by formula (1): Δn=rEp (1) exist Figure 1 In the device shown, the transversely polarized fiber 7 is installed in a spiral shape with a known and constant pitch angle ξ. Figure 2a The figure shows a unit segment of transversely polarized fiber 7 with a length of ds. In the orthogonal coordinate system used in this figure, the z-axis coincides with the vertical axis of the central rod 6. R is the radius from the z-axis to the fiber unit segment ds in the xy plane. Θ is the angle between the radius R and the x-axis. z'-z' is a straight line that passes through the fiber unit segment and is parallel to the z-axis. ξ is the pitch angle of the helix, that is, the angle between the fiber unit segment and the straight line z'-z'.

[0043] Assume the upper end of the helix is ​​V h and lower V o Given that the potentials of the electrodes are respectively and , then the voltage ΔV to be measured by the device is: ΔV=V h -V O (2) Voltage measurement is achieved by passing light through a polarized optical fiber. Since the refractive index of the optical fiber depends on the electric field, each unit segment of the fiber causes a phase shift in the transmitted light, and the phase shift is proportional to the electric field component of the unit segment in the polarization direction. The cumulative phase shift dφ along the entire length of the fiber is proportional to the voltage ΔV to be measured.

[0044] The electric field E has different directions and magnitudes in different parts of the optical fiber. Assuming the change in refractive index in the optical fiber is z, then: Δn(z)=rE p (z)(3) The electro-optic coefficient r is independent of z because the polarization is constant along the length of the fiber. A change in refractive index within a unit segment of length ds causes a phase shift dφ, which is also a function of z. dφ=dφ(z)(4) It can also be written as: dφ=(2πΔn / λ)ds(5) Where λ is the wavelength of the light used for measurement.

[0045] Figure 2b This diagram shows a fiber unit segment of length ds, observed from radius R inwards along the axis of the central rod 6. The straight line tt is a unit segment of the rod's curve or arc in the xy-plane, and p is the polarization direction of the fiber. Figure 2b It can be seen that: ds=(1 / cosξ)dz(6) ds=(1 / sinξ)RdΘ(7) electric field component E x E yand E z The combined electric field E in the polarization direction p Given by the formula: E p =E Z sinξ+cosξ(E X cosΘ+E y sinΘ)(8) By combining equations (3) and (5), dφ can be expressed as E p The function of (z): dφ(z)=(2π / λ)rE p ds(9) Combining with equation (8), we get: dφ(z)=(2π / λ)r[Ezsinξ+cosξ(ExcosΘ+EysinΘ)]ds(10) The total cumulative phase shift of light transmitted through the optical fiber is: Δφ=∫dφ(11) If E is in one revolution of the spiral x and E y If it can be considered a constant, then the total cumulative phase shift of light is equal to Δφ=(2π / λ) r ∫ E z tanξ dz(12) If E x and E y If it is not a constant, then the result (12) is only approximately correct. The accuracy of this approximation increases with the increase of the pitch angle of the helix. Therefore, it is preferable to use a long optical fiber to be wound many times with a larger pitch angle; and the accuracy of this approximation also increases when the radius R decreases.

[0046] In each of the above laps, E x and E y Under the assumption that E is a constant, the voltage ΔV to be measured along the helical axis is E. z From V h To V o Line integral: Δv=∫E z dz(13) Combining equations (12) and (13), the total cumulative phase shift along the optical fiber is expressed as follows: Δφ=(2π / λ)rtanξΔv(14) Therefore, the cumulative phase shift is proportional to the voltage ΔV between the two ends of the spiral, that is, proportional to the voltage to be measured.

[0047] This embodiment calculates the voltage ΔV to be measured by measuring the cumulative phase shift Δφ of linearly polarized light with wavelength λ along the length of a transversely polarized optical fiber with electro-optic coefficient r and pitch angle ξ under an electric field. This enables the measurement of high voltage between two separated points in a strong interference environment; it is suitable for measuring high-voltage AC (ac) and DC (dc) voltages.

[0048] Example 3 See Figure 4 The principle and structure of this embodiment are the same as those of Embodiment 1, except that a helical core polarized fiber 7' is used instead of a transversely polarized fiber 7. If the fiber core is polarized and the polarization field has a significant component in the direction parallel to the fiber axis, then the helical shape of the fiber core will produce an effect similar to that of the transversely polarized fiber wound in a helical shape as discussed above. As a result, the electric field component in the z-direction will have a component in the polarization direction of the fiber core. This gives the required field-dependent refractive index, and the phase shift accumulated along the fiber will correspond to the voltage to be measured in the same manner as described above. The helical core polarized fiber 7', the unpolarized fiber 8, the first output fiber 12a, the second output fiber 12b, and the third output fiber 12c can be arranged in a straight line. Figure 4 The device shown is suitable for being equipped with a protective outer layer with a drainage channel (such as...). Figure 1 (Outer layer 13).

[0049] Example 4 The principle and structure of this embodiment are the same as those of Embodiment 1, except that a polarized optical fiber is used, so that its polarization direction has a component in the longitudinal direction of the fiber. If it is pre-assumed that the light in the optical fiber has a significant longitudinal field component, then the optical fiber senses an electric field parallel to the longitudinal direction of the fiber. Therefore, this polarized optical fiber is arranged according to... Figure 4 They are arranged in a straight line in the same way.

[0050] Example 5 The principle and structure of this embodiment are the same as those of Embodiment 1, except that a polarization direction is adopted: at a point along the fiber axis at a distance z, the polarization direction forms a fixed angle of less than 90° with the fiber axis, but as z increases, the polarization direction rotates around this axis. Due to this rotation, the average response of the fiber to the transverse component of the external electric field is almost zero (due to the rotation), thus leaving only the response to the component of the external electric field parallel to the fiber axis. Therefore, the fiber polarized in this way is arranged according to... Figure 4 They are arranged in a straight line in the same way.

[0051] Example 6 Referring to Figure 5, the principle structure of this embodiment is the same as that of embodiment 1, except that: Figure 5aAn element of a cored optical fiber 20 with a core 21 is shown. The cored optical fiber 20 is polarized in the transverse direction; as shown, multiple polarized regions 23 are alternately and closely arranged with unpolarized regions 22. The polarized regions 23 are achieved by applying a strong transverse electric field to the fiber while irradiating the fiber with ultraviolet light using a suitable mask. The refractive index n2 of the polarized region 23 depends on the external electric field and is generally different from the refractive index n1 of the unpolarized region 22. The polarized regions 23 and the unpolarized regions 22 form a Bragg grating, and multiple such gratings are distributed along the length of the fiber. The center wavelength (the maximum reflected wavelength of light reaching each grating through the fiber) is shifted by the external electric field, and the wavelength shift of the reflected light subsequently becomes a measure of the local change in the external electric field.

[0052] Figure 5b This schematically demonstrates how to arrange cored optical fiber 20 in a spiral shape at a potential of V. h Between two points, V0 and V0, to measure the voltage ΔV between these two points. Light source 25 emits light into the optical fiber via fiber optic 2×2 coupler 24. Light reflected from a series of Bragg gratings is coupled into unit 27 via return fiber 26. Unit 27 decodes the wavelength shift into an output signal S corresponding to the voltage ΔV through appropriate signal processing. out .

[0053] The gratings are sized such that their zero-field center wavelengths are all different and their reflection bands do not overlap. Therefore, light source 25 is a single broadband light source used to detect these gratings (and the corresponding local electric fields).

[0054] In this embodiment, a high birefringence fiber (such as a butterfly fiber) is used to reduce polarization changes caused by mechanical stress and temperature effects on the fiber.

[0055] Additional information can be obtained by using two polarization states of the guided light and several different wavelengths; appropriate signal processing of this additional information can be used to reduce or eliminate the effects of unwanted components in the electric field.

[0056] It should be noted that, depending on the implementation needs, the various components described in this application can be divided into more components, or two or more components or parts of the operation of components can be combined into new components to achieve the purpose of this invention.

[0057] This embodiment also includes a processor, a communication interface, a memory, and a communication bus; wherein the processor, the communication interface, and the memory communicate with each other through the communication bus; the memory stores a computer program, and when the program is executed by the processor, the processor performs the steps of an anti-interference high voltage measurement method.

[0058] This embodiment also provides a computer-readable storage medium storing executable instructions that, when executed by a processor, enable the processor to implement an interference-resistant high-voltage measurement method.

[0059] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects.

[0060] Furthermore, this application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0061] This application is described with reference to the flowchart of the method and computer program product according to Embodiment 1 and the block diagram of the device (system) according to Embodiment 3. It should be understood that each step or block in the flowchart or block diagram, as well as combinations of steps or blocks in the flowchart or block diagram, can be implemented by computer program instructions.

[0062] These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing device to produce a machine, such that the instructions, which are executable by the processor of the computer or other programmable data processing device, produce instructions for implementing the process. Figure 1 One or more processes or boxes Figure 1 An anti-interference high-voltage measurement system that specifies the functions in one or more boxes.

[0063] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes or boxes Figure 1 The function specified in one or more boxes.

[0064] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes or boxes Figure 1 The steps of an anti-interference high-voltage measurement method are specified in one or more boxes.

[0065] The above embodiments are only used to illustrate the design concept and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The protection scope of the present invention is not limited to the above embodiments. Therefore, all equivalent changes or modifications made based on the principles and design ideas disclosed in the present invention are within the protection scope of the present invention.

Claims

1. An interference-resistant high-voltage measurement system, characterized by: The system comprises an upper terminal, a lower terminal, a central rod, a transversely polarized optical fiber, an unpolarized optical fiber, a control unit, a 2×2 optical fiber coupler, a 3×3 optical fiber coupler, a first output optical fiber, a second output optical fiber and a third output optical fiber; The upper terminal and the lower terminal are arranged at two ends of the central rod respectively, and are used for connecting the power line to be measured and the ground respectively to form an electric field; The transversely polarized optical fiber and the unpolarized optical fiber are wound in parallel on the outside of the central rod in the form of helixes with constant pitch angles; The control unit is arranged at the bottom of the central rod, and is used for providing linearly polarized light to the transversely polarized optical fiber and the unpolarized optical fiber through the 2×2 optical fiber coupler respectively; The 3×3 optical fiber coupler is arranged at the top of the central rod, and is used for generating interference on the light output by the transversely polarized optical fiber and the unpolarized optical fiber, and then outputting the phase-shifted signals through the first output optical fiber, the second output optical fiber and the third output optical fiber to the control unit respectively.

2. The system according to claim 1, wherein: The upper terminal comprises an upper metal end plate and an upper lug arranged on the upper metal end plate; The lower terminal comprises a lower metal end plate and a lower lug arranged on the lower metal end plate; The central rod is a hollow pipe, and the first output optical fiber, the second output optical fiber and the third output optical fiber pass through the central rod to connect the 3×3 optical fiber coupler at the top of the central rod and the 2×2 optical fiber coupler at the bottom of the central rod; The system further comprises an input optical fiber for connecting the control unit and the 2×2 optical fiber coupler; The system further comprises an outer layer arranged outside the central rod on which the optical fibers are wound, and an umbrella skirt arranged on the outer layer for providing mechanical protection for the optical fibers.

3. The system according to claim 2, wherein: The control unit comprises a light source for emitting monochromatic linearly polarized light to the input optical fiber; An isolator is arranged between the light source and the input optical fiber for preventing reflected light from returning to the light source; A polarizer is arranged between the input optical fiber and the 2×2 optical fiber coupler for improving the polarization degree of the light; The control unit further comprises a first photoelectric detector, a first amplifier and a first analog-to-digital converter connected in sequence with the first output optical fiber, a second photoelectric detector, a second amplifier and a second analog-to-digital converter connected in sequence with the second output optical fiber, and a third photoelectric detector, a third amplifier and a third analog-to-digital converter connected in sequence with the third output optical fiber, for outputting digital signals after photoelectric conversion, signal amplification and analog-to-digital conversion respectively; The control unit further comprises an amplitude comparator, a phase lookup table, an accumulator, an inverse sine lookup table, an adder and a switch; the amplitude comparator is used for routing the digital signal with the highest sensitivity to the inverse sine lookup table at any time through the control switch, and outputting a fine voltage value corresponding to the current interference light fringe position through the inverse sine lookup table; If the amplitude comparator determines to switch the digital signal with the highest sensitivity, a phase constant is outputted to the accumulator through the phase lookup table; the accumulator is used for outputting a coarse voltage value to the adder through addition or subtraction operation; The adder is used for adding the fine voltage value and the coarse voltage value to output a signal corresponding to the voltage to be measured.

4. The system according to claim 1, wherein: A helical core polarized optical fiber is used to replace the transversely polarized optical fiber. The helical shape of the core of the helical-core polarization fiber is the same as that of the helical winding of the transversely polarization fiber with a constant pitch angle; the polarization field for polarizing the core of the helical-core polarization fiber has a component in the direction parallel to the fiber axis; The helical-core polarization fiber, the non-polarization fiber, the first output fiber, the second output fiber and the third output fiber are arranged in a straight line.

5. The anti-interference high voltage measurement system according to claim 1, wherein: The transversely polarization fiber is replaced by a polarization-treated fiber; The polarization direction of the fiber has a component in the longitudinal direction of the fiber; The polarization-treated fiber, the non-polarization fiber, the first output fiber, the second output fiber and the third output fiber are arranged in a straight line.

6. The anti-interference high voltage measurement system according to claim 1, wherein: The transversely polarization fiber is replaced by a polarization-treated fiber; At a point along the fiber axis with a distance of z, the polarization direction forms a fixed included angle with the fiber axis which is less than 90°, and as z increases, the polarization direction rotates around the fiber axis; The polarization-treated fiber, the non-polarization fiber, the first output fiber, the second output fiber and the third output fiber are arranged in a straight line.

7. The anti-interference high voltage measurement system according to claim 1, wherein: The transversely polarization fiber, the non-polarization fiber, the first output fiber, the second output fiber and the third output fiber are replaced by a fiber with a core engraved with a plurality of Bragg gratings of polarization regions and non-polarization regions arranged alternately and closely; and the 2×2 fiber coupler and the 3×3 fiber coupler are replaced by a fiber 2×2 coupler; The polarization regions are polarized in the transverse direction; The refractive index of the polarization regions is different from that of the non-polarization regions; The control unit comprises a light source for emitting single broadband light to the input fiber; The light reflected by the Bragg gratings of the fiber is coupled into the control unit, and the wavelength shift is decoded as a signal corresponding to the voltage to be measured through signal processing.

8. The anti-interference high voltage measurement system according to claim 7, wherein: The sizes of the Bragg gratings are such that the zero-field center wavelengths are different from each other and the reflection bands do not overlap with each other; The fiber is a high-birefringence fiber, so as to reduce the polarization change caused by mechanical stress and temperature effect of the fiber; The light source adopts two polarization states and a plurality of different wavelengths, so as to reduce or eliminate the influence of electric field interference.

9. An anti-interference high-voltage measurement method based on the anti-interference high-voltage measurement system according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: The electro-optic coefficient of the transversely polarized optical fiber is r, and the component of the electric field E in the polarization direction of the optical fiber is E p The refractive index of the light transmitted through the transversely polarized optical fiber changes by Δn: Δn = rE p ; Let the change of the refractive index in the fiber be z, then: Δn(z) = rE p (z) ; The change of the refractive index in the fiber unit segment with a length of ds causes a phase shift dφ: dφ=dφ(z) ; For the wavelength of the light used for measurement, λ, the above formula can be written as: dφ=(2πΔn / λ)ds; The pitch angle of the helical winding of the transversely polarization fiber around the central rod is ξ, in the orthogonal coordinate system in which the z axis coincides with the longitudinal axis of the central rod, the radius of the fiber unit segment with a length of ds of the transversely polarization fiber to the z axis in the x-y plane is R, and the included angle between the radius R and the x axis is Θ, then: ds=(1 / cosξ)dz, ds=(1 / sinξ)RdΘ; The electric field components E x , E y , and E z The resultant electric field E p in the polarization direction is: E p =E z sinξ+cosξ(E x cosΘ+E y sinΘ) ; Expressing dφ as a function of E p (z) gives the expression for the phase shift dφ produced by light passing through a transversely poled fiber in proportion to the electric field component E p in the direction of polarization of the fiber segment. dφ(z) = (2π / λ) rE p ds; Combining the above two formulas, we get: dφ(z) = (2π / λ) r [E z sin ξ + cos ξ (E x cos Θ + E y sin Θ)] ds; The cumulative phase shift Δφ of the light transmitted by the fiber is: Δφ=∫dφ; E x and E y is considered constant, the cumulative phase shift of the light, Δφ, is: Δφ = (2π / λ) r ∫ E z tanξ dz; The voltage to be measured ΔV along the helix axis is the line integral of the electric field component E z from the potential V at the upper end of the helix h to the potential V at the lower end of the helix o of the helix AV = E z dz; Combining the above two equations, the expression of the accumulated phase shift Δφ along the fiber length is proportional to the voltage to be measured ΔV is: Δφ = (2π / λ)rtanξΔV; By measuring the accumulated phase shift Δφ of the linearly polarized light with wavelength λ along the length of the transversely polarized optical fiber with helical pitch angle ξ and electro-optic coefficient r under the electric field, the voltage to be measured ΔV is calculated as: ΔV = Δφ / [(2π / λ)rtanξ].

10. A computer memory, characterized by: The computer program stored therein can be executed by a computer processor, and the computer program performs an anti-interference high-voltage measurement method as claimed in claim 9.

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