Voltage divider based on active impedance broadband matching

Abstract

The invention provides a voltage divider based on active impedance broadband matching. The voltage divider comprises a high-voltage arm resistor, a low-voltage arm resistor and a signal processing circuit unit, the high-voltage arm resistor and the low-voltage arm resistor are connected in series; an input end cover of the high-voltage arm resistor is provided with a first shielding electrode, and a grounding end cover of the low-voltage arm resistor is provided with a second shielding electrode; the first shielding electrode and the second shielding electrode are both curved-surface electrodes of which one ends are opened; a signal output end of the divider resistor part is formed at the joint of the high-voltage arm resistor and the low-voltage arm resistor; and the signal processing circuit unit is connected with the signal output end. Shielding electrodes are added to the high-voltage input end and the low-voltage grounding end of the voltage divider to serve as a compensation measure, so that power lines around the divider resistor part are parallel to the divider resistor part, and equivalent stray capacitance value solidification is achieved; furthermore, the outer surface of the shielding electrode is arranged to be of a curved-surface sphere-like structure, and the electric field distortion of the voltage divider is effectively reduced through a space electric field equipotential surface and shielding structure coincidence technology.

Description

Technical Field

[0001] The present invention relates to the technical field of voltage measurement, and in particular to a voltage divider based on active impedance broadband matching. Background Art

[0002] my country's power industry is currently entering a critical period of improving quality, efficiency, and scientific development. With diverse user load types and the rapid development of renewable energy generation, demands for power supply reliability and power quality are increasing. Sensors are a fundamental supporting technology for the control, protection, and metering of DC distribution networks, and are crucial for ensuring the safe, stable, economical, and efficient operation of DC distribution systems. However, DC distribution networks differ from HVDC transmission in that they require consideration of power metering reliability, voltage levels, and application economics.

[0003] Currently, DC voltages below 10kV are measured using a Josephson junction array voltage reference. DC voltages above 10kV require a voltage divider to convert the DC voltage to a certain ratio before measurement. The DC resistor divider is the mainstream DC voltage measurement device, converting a high DC voltage to a low DC voltage at a certain ratio. While its structure is simple and easy to install, it lacks shielding technology, presents a risk of leakage, and lacks stability and reliability.

[0004] Based on the above situation, it is urgent to improve the design of resistor dividers, study efficient impedance matching technology, study capacitor solidification and electrode shielding technology, improve the voltage division accuracy of the voltage divider, ensure insulation safety and primary and secondary shielding effects under high voltage environments, and ensure the reliability of power metering in DC distribution networks. Summary of the Invention

[0005] In view of this, the present invention proposes a voltage divider based on active impedance broadband matching, aiming to solve the problems of low safety and measurement accuracy of DC distribution network electric energy metering equipment in the prior art. The present invention proposes a voltage divider based on active impedance broadband matching, comprising: a high-voltage arm resistor, a low-voltage arm resistor and a signal processing circuit unit; wherein, The high-voltage arm resistor and the low-voltage arm resistor are connected in series to form a voltage divider resistor portion, which is used to proportionally convert the high-voltage signal to be measured into a low-voltage signal output; and the input end cover of the high-voltage arm resistor is provided with a first shielding electrode, and the ground end cover of the low-voltage arm resistor is provided with a second shielding electrode; the first shielding electrode and the second shielding electrode are both curved electrodes with one end open; The connection point between the high-voltage arm resistor and the low-voltage arm resistor forms the signal output end of the voltage-dividing resistor part; The signal processing circuit unit is connected to the signal output end and is used to perform amplitude adjustment and impedance isolation on the output signal of the signal output end of the voltage divider resistor part.

[0006] Furthermore, in the above-mentioned voltage divider based on active impedance broadband matching, the high-voltage arm resistor and the low-voltage arm resistor are S-shaped non-inductive resistor sheets.

[0007] Furthermore, in the above-mentioned voltage divider based on active impedance broadband matching, the preparation method of the S-shaped non-inductive resistor comprises: A nickel-chromium alloy sheet made of Ni20Cr80 is bent into an S-shaped resistor sheet. The entire sheet is solution treated at a first preset temperature. After being kept warm for a period of time, it is water-cooled to dissolve the carbides in the nickel-chromium alloy and obtain single-phase austenite. The S-shaped non-inductive resistor sheet is then obtained after aging treatment at a second preset temperature lower than the first preset temperature for a preset period of time.

[0008] Furthermore, in the above-mentioned voltage divider based on active impedance broadband matching, the first preset temperature is 980° C. to 1150° C.

[0009] Furthermore, in the above-mentioned voltage divider based on active impedance broadband matching, the second preset temperature is 900° C. to 950° C.

[0010] Furthermore, in the above-mentioned voltage divider based on active impedance broadband matching, the openings of the first shielding electrode and the second shielding electrode are arranged opposite to each other.

[0011] Furthermore, in the above-mentioned voltage divider based on active impedance broadband matching, both the first shielding electrode and the second shielding electrode are hemispherical electrodes.

[0012] Furthermore, in the above-mentioned voltage divider based on active impedance broadband matching, the first shielding electrode and the second shielding electrode are spherical structures with multiple curved surfaces.

[0013] Furthermore, in the above-mentioned voltage divider based on active impedance broadband matching, the signal processing circuit unit includes: an input resistor, an impedance matching resistor, a feedback resistor, an operational amplifier and a buffer; wherein, The input resistor is connected between the signal output terminal of the voltage divider resistor part and the non-inverting input terminal of the operational amplifier; The buffer is connected to the output terminal of the operational amplifier to receive the output signal of the operational amplifier and provide a current signal with the same voltage but a stronger current to a subsequent circuit or load; The impedance matching resistor is connected between the inverting input terminal of the operational amplifier and the ground, so as to make the input impedance of the operational amplifier equal to the load impedance, thereby achieving impedance matching over a wide frequency; The feedback resistor is connected between the output terminal of the operational amplifier and the non-inverting input terminal of the buffer for controlling the gain.

[0014] Furthermore, the voltage divider based on active impedance broadband matching further includes: a housing; wherein, The high-voltage arm resistor and the low-voltage arm resistor are respectively encapsulated in a ceramic tube body to form a gas discharge tube respectively; The interior of the shell is filled with epoxy resin, and the epoxy resin is sealed on the outside of each gas discharge tube.

[0015] The voltage divider based on active impedance broadband matching provided by the present invention adds shielding electrodes as compensation measures at the high-voltage input end and the low-voltage grounding end of the voltage divider, so that the power lines around the voltage divider resistor part are parallel to itself, thereby achieving the solidification of the equivalent stray capacitance value, significantly reducing the installation environment dependency of the voltage divider, and improving the product adaptability and economic value; further, the outer surface of the shielding electrode is set to a curved spherical structure, and the electric field distortion of the voltage divider is effectively reduced through the technology of overlapping the spatial electric field equipotential surface with the shielding structure, further reducing the operating field strength of the voltage divider, and improving the operating insulation safety; and a signal processing circuit unit 3 is set at the low-voltage signal output end of the voltage divider for impedance isolation, thereby finally achieving broadband impedance matching of the voltage divider. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. The same reference symbols are used throughout the drawings to represent the same components. In the drawings: Figure 1 A schematic structural diagram of a voltage divider provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0017] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, unless there is a conflict, the embodiments of the present disclosure and the features described in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0018] See Figure 1The voltage divider based on active impedance broadband matching of an embodiment of the present invention includes: a high-voltage arm resistor 1, a low-voltage arm resistor 2 and a signal processing circuit unit 3; wherein the high-voltage arm resistor 1 and the low-voltage arm resistor 2 are connected in series to form a voltage divider resistor part a, which is used to proportionally convert the high voltage signal to be measured into a low voltage signal output; and the input end cover of the high-voltage arm resistor is provided with a first shielding electrode 11, and the grounding end cover of the low-voltage arm resistor 2 is provided with a second shielding electrode 21; the first shielding electrode 11 and the second shielding electrode 21 are both curved electrodes with one end open; the connection point between the high-voltage arm resistor 1 and the low-voltage arm resistor 2 forms a signal output end of the voltage divider resistor part, forming the signal output end of the voltage divider resistor part a; the signal processing circuit unit 3 is connected to the signal output end, and is used to perform amplitude adjustment and impedance isolation on the output signal of the signal output end of the voltage divider resistor part a.

[0019] Specifically, one end of the high-voltage arm resistor 1 is connected to the power supply voltage, and the other end is connected to one end of the low-voltage arm resistor 2; the other end of the low-voltage arm resistor 2 is grounded.

[0020] The high-voltage arm resistor 1 and the low-voltage arm resistor 2 are S-shaped, non-inductive resistor sheets. By bending the nickel-chromium alloy sheet into an "S" shape, the inductive component in the resistor element can be effectively reduced, thereby reducing the impact of the inductive damping effect on the product's frequency response characteristics. This makes the resulting high-voltage resistor divider non-inductive, improving its performance under high-frequency conditions.

[0021] In a specific implementation, the preparation method of the S-shaped non-inductive resistor is as follows: A nickel-chromium alloy sheet made of Ni20Cr80 is bent into an S-shaped resistor sheet. The entire sheet is solution treated at a first preset temperature. After being kept warm for a period of time, it is water-cooled to dissolve the carbides in the nickel-chromium alloy and obtain single-phase austenite. The S-shaped non-inductive resistor sheet is then obtained after aging treatment at a second preset temperature lower than the first preset temperature for a preset period of time.

[0022] The first preset temperature is 980°C to 1150°C; the second preset temperature is 900°C to 950°C.

[0023] Using nickel-chromium alloy sheets made of Ni20Cr80 to make high-voltage arm resistor 1 and low-voltage arm resistor 2 has the following advantages: After solution treatment at 980°C to 1150°C and subsequent aging treatment (900°C to 950°C), the carbides in the nickel-chromium alloy are largely dissolved, forming a single-phase austenite structure. This structure improves the material's temperature stability, ensuring stable resistance values across various operating temperatures and reducing errors caused by ambient temperature fluctuations. Aging not only improves the material's temperature stability, but also helps the resistor divider maintain its physical shape and electrical properties, making it less susceptible to deformation or damage.

[0024] From the above, it can be concluded that subjecting the resistor to solid solution, water cooling, and aging treatment steps provides better conditions for the subsequent pouring of epoxy resin, reducing the adverse effects that may be caused by temperature and stress changes. The selection of quick-drying epoxy resin encapsulation not only protects the internal structure, but also further enhances the mechanical strength and corrosion resistance of the gas discharge tube.

[0025] In this embodiment, both the first shielding electrode 11 and the second shielding electrode 21 are hemispherical electrodes.

[0026] In a specific implementation, the openings of the first shielding electrode 11 and the second shielding electrode 21 are arranged opposite to each other, so as to shield the high-voltage arm resistor 1 and the low-voltage arm resistor 2 respectively.

[0027] Shielding electrodes are respectively provided at the ends of the first shielding electrode 11 and the second shielding electrode 21 to introduce the stray capacitance current originally flowing from the high-voltage end to the signal end into the ground potential. At the same time, due to the presence of the first shielding electrode 11 and the second shielding electrode 21, the power lines around the high-voltage arm resistor 1 and the low-voltage arm resistor 2 are basically parallel to the resistor body, thereby achieving a basic solidification of the equivalent stray capacitance value, significantly reducing the correlation with the installation environment of the voltage divider, and improving the environmental adaptability of the product. With such a shielding structure, the distributed parameter of the voltage divider is adjusted from 3.1pF to 5.8pF, so that the influence of external interference on the measurement accuracy of the resistor body is minimized, which can effectively ensure the measurement accuracy of the product.

[0028] Preferably, the first shielding electrode 11 and the second shielding electrode 21 are spherical structures with multiple curved surfaces. Arranging the first shielding electrode 11 and the second shielding electrode 21 into a multi-curved spherical structure can achieve substantial overlap between the spatial electric field equipotential surfaces and the shielding structure surfaces, further reducing the electric field strength at various locations within the product, effectively alleviating electric field distortion, and improving the insulation safety of the product during operation.

[0029] From the above, it can be concluded that: the voltage divider provided by the present invention adds a shielding electrode as a compensation measure by adding a shielding electrode to the high-voltage input end and the low-voltage grounding end of the voltage divider, so that the power lines around the voltage divider resistor part a are parallel to itself, thereby achieving the solidification of the equivalent stray capacitance value, significantly reducing the installation environment correlation of the voltage divider, and improving the product adaptability and economic value; further, the outer surface of the shielding electrode is set to a curved spherical structure, and through the technology of overlapping the spatial electric field equipotential surface and the shielding structure, the electric field distortion of the voltage divider is effectively reduced, the operating field strength of the voltage divider is further reduced, and the operating insulation safety is improved, and a signal processing circuit unit 3 is set at the low-voltage signal output end of the voltage divider for impedance isolation, and finally the wide-frequency impedance matching of the voltage divider is achieved.

[0030] Continue reading Figure 1 The signal processing circuit unit 3 includes: an input resistor R2, an impedance matching resistor R1, a feedback resistor R3, an operational amplifier L1 and a buffer L2; wherein the input resistor R2 is connected between the signal output end of the voltage divider resistor part a and the non-inverting input end of the operational amplifier L1; the buffer L2 is connected to the output end of the operational amplifier L1 to receive the output signal of the operational amplifier L1 and provide a current signal of the same voltage but stronger to the subsequent circuit or load; the impedance matching resistor R1 is connected between the inverting input end of the operational amplifier L1 and ground to make the input impedance of the operational amplifier L1 equal to the load impedance, thereby achieving wide-frequency impedance matching; the feedback resistor R3 is connected between the output end of the operational amplifier L1 and the non-inverting input end of the buffer L2 to control the gain.

[0031] The above embodiment further includes: a housing 4; wherein the high-voltage arm resistor 1 and the low-voltage arm resistor 2 are respectively encapsulated in a ceramic tube body to form a gas discharge tube respectively; the interior of the housing is filled with epoxy resin, and the epoxy resin is encapsulated on the outside of each gas discharge tube.

[0032] Specifically, the housing can be a cylindrical structure with an shed structure 41 disposed in the center. The gas discharge tube formed by the high-voltage arm resistor 1 and the gas discharge tube formed by the low-voltage arm resistor 2 are both housed within the housing 4. In practice, a quick-drying epoxy resin can be used to fill the interior of the housing and wrap around the exterior of the ceramic tube.

[0033] In summary, the voltage divider provided by the present invention uses nickel-chromium alloy to undergo solid solution treatment, water cooling treatment and aging treatment to make a stable and reliable resistor sheet, and then uses quick-drying epoxy resin to encapsulate the ceramic tube body to form a non-inductive high-voltage resistor divider, improve the frequency response characteristics, and use an operational amplifier module for impedance isolation at the low-voltage signal output position of the voltage divider, and finally achieve wide-frequency impedance matching of the voltage divider; by adding a shielding electrode as a compensation measure at the high-voltage input end and the low-voltage grounding end of the voltage divider, the power lines around the voltage divider resistor part are parallel to themselves, and the equivalent stray capacitance value is solidified, which significantly reduces the installation environment correlation of the voltage divider and improves the product adaptability and economic value; the outer surface of the shielding electrode is further set to a curved spherical structure, and the electric field distortion of the voltage divider is effectively reduced through the overlap technology of the spatial electric field equipotential surface and the shielding structure, further reducing the operating field strength of the voltage divider and improving the operating insulation safety.

[0034] The voltage divider of the present invention has the following advantages: (1) Improve the insulation safety of distribution network power metering equipment: The maximum field strength before improvement was 3.17×10 4 V / cm. After the improvement, the maximum field strength is reduced to 2.10×104V / m, which improves the insulation safety.

[0035] (2) Improving the shielding effect of the primary and secondary sides: Before the improvement, the power lines at the high and low voltage ends of the resistor divider were relatively concentrated. After the improvement, the concentration of the power lines at the high and low voltage ends of the resistor divider was significantly reduced, and the shielding effect was obvious.

[0036] (3) Effectively guarantee the measurement accuracy of the measuring equipment: before and after the improvement, the distribution parameter was adjusted from 3.1pF to 5.8pF. After the improvement, the electric lines in the outer area of the resistor were evenly distributed and parallel to the resistor body, and the phenomenon of concentrated injection and injection was significantly reduced. This shows that due to the existence of the shielding structure, the influence of external interference on the measurement accuracy of the resistor body is reduced to a minimum, which can effectively guarantee the measurement accuracy of the product.

[0037] (4) Improved the frequency response characteristics of the voltage divider: Through the use of specially treated stable non-inductive resistors and the use of operational amplifier modules for impedance isolation at the low-voltage signal output position of the voltage divider, wide-frequency impedance matching of the voltage divider is achieved, thereby improving the frequency response characteristics.

[0038] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A voltage divider based on active impedance broadband matching, characterized in that: include: High voltage arm resistor, low voltage arm resistor and signal processing circuit unit; wherein, The high-voltage arm resistor and the low-voltage arm resistor are connected in series to form a voltage divider resistor portion, which is used to proportionally convert the high-voltage signal to be measured into a low-voltage signal output; and the input end cover of the high-voltage arm resistor is provided with a first shielding electrode, and the ground end cover of the low-voltage arm resistor is provided with a second shielding electrode; the first shielding electrode and the second shielding electrode are both curved electrodes with one end open; The connection point between the high-voltage arm resistor and the low-voltage arm resistor forms a signal output end of the voltage divider resistor part; The signal processing circuit unit is connected to the signal output end and is used to perform amplitude adjustment and impedance isolation on the output signal of the signal output end of the voltage divider resistor part.

2. The voltage divider based on active impedance broadband matching according to claim 1, characterized in that: The high-voltage arm resistor and the low-voltage arm resistor are S-shaped non-inductive resistor sheets.

3. The voltage divider based on active impedance broadband matching according to claim 2, characterized in that: The preparation method of the S-shaped non-inductive resistor comprises: The material is Ni 20 Cr 80 The nickel-chromium alloy sheet is bent into an S-shaped resistor sheet, and the whole is subjected to a solid solution treatment at a first preset temperature. After being kept warm for a period of time, it is water-cooled to dissolve the carbides in the nickel-chromium alloy and obtain single-phase austenite; then, it is aged for a preset period of time at a second preset temperature lower than the first preset temperature to obtain an S-shaped non-inductive resistor sheet.

4. The voltage divider based on active impedance broadband matching according to claim 3, characterized in that: The first preset temperature is 980°C~1150°C.

5. The voltage divider based on active impedance broadband matching according to claim 3, characterized in that: The second preset temperature is 900°C to 950°C.

6. The voltage divider based on active impedance broadband matching according to claim 1, characterized in that: The openings of the first shielding electrode and the second shielding electrode are arranged opposite to each other.

7. The voltage divider based on active impedance broadband matching according to claim 1, characterized in that: The first shielding electrode and the second shielding electrode are both hemispherical electrodes.

8. The voltage divider based on active impedance broadband matching according to claim 1, characterized in that: The first shielding electrode and the second shielding electrode are spherical structures with multiple curved surfaces.

9. The voltage divider based on active impedance broadband matching according to claim 1, characterized in that: The signal processing circuit unit includes: an input resistor, an impedance matching resistor, a feedback resistor, an operational amplifier and a buffer; wherein, The input resistor is connected between the signal output terminal of the voltage divider resistor part and the non-inverting input terminal of the operational amplifier; The buffer is connected to the output terminal of the operational amplifier to receive the output signal of the operational amplifier and provide a current signal with the same voltage but a stronger current to a subsequent circuit or load; The impedance matching resistor is connected between the inverting input terminal of the operational amplifier and the ground, so as to make the input impedance of the operational amplifier equal to the load impedance, thereby achieving impedance matching over a wide frequency; The feedback resistor is connected between the output terminal of the operational amplifier and the non-inverting input terminal of the buffer for controlling the gain.

10. The voltage divider based on active impedance broadband matching according to claim 1, characterized in that: Also includes: housing; wherein The high-voltage arm resistor and the low-voltage arm resistor are respectively encapsulated in a ceramic tube body to form a gas discharge tube respectively; The interior of the shell is filled with epoxy resin, and the epoxy resin is sealed on the outside of each gas discharge tube.

Images