High-precision voltage measuring device

Abstract

The utility model belongs to the field of high voltage measurement, and particularly relates to a high-precision voltage measuring device. The device comprises m high-voltage arm resistor-capacitor strings, n low-voltage arm resistors and 1 low-voltage arm capacitor, the m high-voltage arm resistor-capacitor strings are sequentially connected in series to form a high-voltage arm circuit; the head end of the first high-voltage arm resistor-capacitor string is used for connecting to-be-measured voltage U, and the tail end of the mth high-voltage arm resistor-capacitor string is used for connecting to-be-measured voltage U2 for measurement; the n low-voltage arm resistors are sequentially connected in series to form a low-voltage arm resistor string; the low-voltage arm resistor string and the low-voltage arm capacitors are arranged in parallel to form a low-voltage arm circuit; one end of the low-voltage arm circuit is connected with the tail end of the mth high-voltage arm resistor-capacitor string, and the other end of the low-voltage arm circuit is grounded. The voltage measuring device is wide in measuring range and high in accuracy, and the accuracy is less than or equal to + / -0.2%; and the operation is simple, the cost is low and the yield is high.

Description

Technical Field

[0001] This utility model relates to a measuring device, specifically a high-precision voltage measuring device. Background Technology

[0002] Voltage measuring devices are widely used in various industries such as power systems, electrical / electronic equipment, high-voltage switch discharge, sensor measurement, pulse networks, and signal processing. They are used to accurately measure high voltages in AC / DC circuits to ensure stable system operation, control protection, and equipment safety and performance.

[0003] For high-voltage, high-precision voltage measuring devices, multiple resistive and capacitive elements are required, connected in series and parallel to form a high-voltage arm resistor-capacitor string and a low-voltage arm resistor-capacitor string. The impedance value of the high-voltage arm resistor-capacitor string is divided by the impedance value of the low-voltage arm resistor-capacitor string to form the voltage division ratio k. Depending on the actual application of the circuit system, the manufacturing accuracy (precision) requirement for the voltage division ratio k is usually extremely high, requiring an accuracy value of ±0.2%, or even higher, ±0.1%. This necessitates that the manufacturing accuracy of the selected resistive and capacitive elements cannot exceed ±0.2% or ±0.1%. However, due to limitations in technology and manufacturing processes, it is difficult to achieve the above-mentioned high precision requirements for capacitors in actual production. Similarly, achieving high precision for resistors in actual production often results in a low yield rate and high manufacturing cost due to material properties and manufacturing processes. For these two reasons, high-precision voltage measuring devices struggle to meet the market demand for large-volume, high-reliability systems.

[0004] Therefore, there is an urgent need to develop a new type of high-precision voltage measurement device to overcome the limitations of current technology, material properties, and manufacturing processes, meet the high accuracy requirements of voltage division ratio, and supply the market with high reliability in batches. Utility Model Content

[0005] The purpose of this invention is to solve the technical problems that existing voltage measuring devices are limited by the inability of capacitors to achieve the desired high precision requirements, and the low yield and high production cost of high precision resistors in manufacturing, which makes it difficult for high precision voltage measuring devices to meet the market demand for large-volume and high-reliability applications. Therefore, this invention provides a high-precision voltage measuring device.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0007] A high-precision voltage measuring device, characterized by:

[0008] It includes m high-voltage arm resistor-capacitor strings, n low-voltage arm resistors, and l low-voltage arm capacitors; m≥2, n≥2, l≥2;

[0009] The m high-voltage arm resistor-capacitor strings are connected in series to form a high-voltage arm circuit, and the m high-voltage arm resistor-capacitor strings are sequentially denoted as the 1st high-voltage arm resistor-capacitor string, the 2nd high-voltage arm resistor-capacitor string, ..., the mth high-voltage arm resistor-capacitor string;

[0010] The first end of the first high-voltage arm resistor-capacitor string is used to connect the voltage to be measured U, and the end of the m-th high-voltage arm resistor-capacitor string is used to connect the measurement voltage U2 for measurement.

[0011] n low-voltage arm resistors are connected in series to form a low-voltage arm resistor string;

[0012] The low-voltage arm resistor series and one low-voltage arm capacitor are connected in parallel to form a low-voltage arm circuit.

[0013] One end of the low-voltage arm circuit is connected to the end of the m-th high-voltage arm resistor-capacitor string, and the other end is grounded.

[0014] The voltage division ratio k of the high-voltage arm circuit and the low-voltage arm circuit satisfies the following condition:

[0015]

[0016] RM×CM=RN×CL

[0017] In the formula: RM is the total resistance of all resistors in the m high-voltage arm resistor-capacitor strings;

[0018] CM is the total capacitance of all capacitors in the m high-voltage arm resistor-capacitor strings;

[0019] RN is the total resistance of the n low-voltage arm resistors;

[0020] CL is the total capacitance of the l low-voltage arm capacitors.

[0021] Furthermore, each of the m high-voltage arm resistor-capacitor strings includes a high-voltage arm resistor and a high-voltage arm capacitor connected in parallel.

[0022] In the first high-voltage arm resistor-capacitor string, one end of the high-voltage arm resistor R1 and the high-voltage arm capacitor C1 is used to connect the voltage to be measured U.

[0023] The other end of the high-voltage arm resistor R2 and high-voltage arm capacitor C2 in the second high-voltage arm resistor-capacitor string is connected to one end of the high-voltage arm resistor R3 and high-voltage arm capacitor C3 in the third high-voltage arm resistor-capacitor string.

[0024] Similarly, the other end of the high-voltage arm resistor Rm-1 and high-voltage arm capacitor Cm-1 in the (m-1)th high-voltage arm resistor-capacitor string is connected to one end of the high-voltage arm resistor Rm and high-voltage arm capacitor Cm in the mth high-voltage arm resistor-capacitor string; the other end of the high-voltage arm resistor Rm and high-voltage arm capacitor Cm in the mth high-voltage arm resistor-capacitor string is connected to one end of the low-voltage arm circuit, and the measured voltage U2 is connected out.

[0025] Furthermore, it also includes a package body and a package base disposed at the bottom of the package body;

[0026] The m high-voltage arm resistor-capacitor strings are all disposed within the cavity of the package body, and the n low-voltage arm resistors and l low-voltage arm capacitors are all disposed within the cavity of the package base.

[0027] Furthermore, it also includes m insulating rods;

[0028] The m high-voltage arm resistor-capacitor strings are respectively arranged in the internal cavities of the m insulating rods.

[0029] Furthermore, a voltage equalization ring is provided on the top of the package, and the first end of the first high-voltage arm resistor-capacitor string passes through the voltage equalization ring and is connected to the voltage to be measured U.

[0030] Furthermore, the end of the m-th high-voltage arm resistor-capacitor string is connected to the measurement voltage U2 via a coaxial shielded wire.

[0031] The beneficial effects of this utility model are:

[0032] The voltage measuring device of this invention determines the voltage division ratio k based on the voltage to be measured and the measured voltage, and then adjusts the resistance and capacitance values ​​of the resistive and capacitive elements in the high-voltage arm circuit and the low-voltage arm circuit based on the voltage division ratio k to meet the high precision requirement of the voltage division ratio k. It has a wide measurement range and high accuracy, with an accuracy of ≤±0.2%. In addition, it is simple to operate, low in cost, and has a high yield. Attached Figure Description

[0033] Figure 1 This is a structural schematic diagram of an embodiment of the present utility model;

[0034] In the diagram: 01-package body, 02-equalizing ring, 03-package base, 04-high voltage arm resistor and capacitor string, 05-insulating rod, 06-low voltage arm resistor, 07-low voltage arm capacitor, 08-coaxial shielded wire. Detailed Implementation

[0035] To make the objectives, advantages, and features of this utility model clearer, the high-precision voltage measuring device proposed by this utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this utility model will become clearer according to the following specific embodiments.

[0036] See Figure 1 The structural features of the high-precision voltage measuring device in this embodiment are as follows:

[0037] It includes a package body 01, an equalizing ring 02 located at the top of the package body 01, a package base 03 located at the bottom of the package body 01, m high-voltage arm resistor-capacitor strings 04 and m insulating rods 05 located inside the package body 01, n low-voltage arm resistors 06 and l low-voltage arm capacitors 07 located inside the package base 03, and a coaxial shielded wire 08 led out from the end of the m-th high-voltage arm resistor-capacitor.

[0038] Its electrical characteristics are:

[0039] The m high-voltage arm resistor-capacitor strings 04 within the package 01 are electrically connected in series. Specifically, each of the m high-voltage arm resistor-capacitor strings 04 includes a high-voltage arm resistor and a high-voltage arm capacitor connected in parallel. One end of the high-voltage arm resistor R1 and high-voltage arm capacitor C1 in the first high-voltage arm resistor-capacitor string is used to connect to the voltage to be measured, U. The other end of the high-voltage arm resistor R2 and high-voltage arm capacitor C2 in the second high-voltage arm resistor-capacitor string is connected to one end of the high-voltage arm resistor R3 and high-voltage arm capacitor C3 in the third high-voltage arm resistor-capacitor string; and so on. The other end of the high-voltage arm resistor Rm-1 and high-voltage arm capacitor Cm-1 in the (m-1)th high-voltage arm resistor-capacitor string is connected to one end of the high-voltage arm resistor Rm and high-voltage arm capacitor Cm in the mth high-voltage arm resistor-capacitor string; the other end of the high-voltage arm resistor Rm and high-voltage arm capacitor Cm in the mth high-voltage arm resistor-capacitor string is connected to one end of the low-voltage arm circuit and connected to the measurement voltage U2 for measurement.

[0040] The manufacturing error of the resistance values ​​of the m high-voltage arm resistors is ±1%, and the manufacturing error of the capacitance values ​​of the m high-voltage arm capacitors is ±5%. The total resistance RM and total capacitance CM of the high-voltage arms are obtained by instrument measurement.

[0041] The n low-voltage arm resistors 06 are sequentially labeled R1, R2, ..., Rn. The n low-voltage arm resistors 06 inside the package base 03 are electrically connected in series. The l low-voltage arm capacitors 07 are sequentially labeled C1, C2, ..., C1. The l low-voltage arm capacitors 07 inside the package base 03 are electrically connected in parallel. The n low-voltage arm resistors 06 are connected in series and then electrically connected in parallel with the l low-voltage arm capacitors 07, and then connected in parallel again to form a low-voltage arm circuit. One end of the low-voltage arm circuit is connected to the other end of the high-voltage arm resistor Rm and the high-voltage arm capacitor Cm in the m-th high-voltage arm resistor-capacitor series, and the other end is grounded.

[0042] The total resistance of the n low-voltage arm resistors 06 is RN = 0.95RM / k + 0.05RM / k = R1 + R2 + ... + Rn. The manufacturing tolerance of each low-voltage arm resistor 06 is ±1%.

[0043] 0.95RM / k=R1+···+Rn-20 (R1=R2=···=R n-20 )

[0044] 0.05RM / k=R n-19 +R n-18 +···+R n (R n-19 =R n-18 =···=R n )

[0045] To ensure the accuracy of the voltage divider ratio k is ≤ ±0.2%, the number of resistors 06 in the last 20 low-voltage arms is matched by increasing or decreasing the number of resistors 06.

[0046] The total capacitance of the l low-voltage arm capacitors is 0.7.

[0047] CN=0.9CM / k+0.06CM / k+0.03CM / k+0.01CM / k=C1+C2+···+Cl, the manufacturing error of the capacitance value of each low-voltage arm capacitor 07 is ±5%, where:

[0048] 0.9CM / k=C1+C2+···+C l-40 (C1=C2=···=C l-40 )

[0049] 0.06CM / k=C l-39 +C l-38 +···+C l-30 (C l-39 =C l-38 =···=C l-30 )

[0050] 0.03CM / k=C l-29 +C l-28 +···+C l-20 (C l-29 =C l-28 =···=C l-20 )

[0051] 0.01CM / k=C l-19 +C l-18 +···+C l (C l-19 =C l-18 =···=C l )

[0052] To ensure the accuracy of the voltage divider ratio k is ≤ ±0.2%, the number of capacitors 07 in the last 40 low-voltage arms is matched by increasing or decreasing the number of capacitors 07.

[0053] The partial pressure ratio k satisfies:

[0054]

[0055] Where: Zm is the impedance value of the high-voltage arm circuit:

[0056]

[0057] Zn is the impedance value of the low-voltage arm circuit:

[0058]

[0059] j is the imaginary unit, and w is the angular frequency;

[0060] Substituting into the above formula, we get:

[0061]

[0062] If both U and U2 are real numbers with an imaginary part of 0, then U2 changes with U according to the value of k, and the waveform is not distorted, satisfying RM×CM=RN×CL. This enables indirect measurement after converting high voltage to low voltage, with a wide measurement range and high accuracy, satisfying ≤±0.2%.

Claims

1. A high-precision voltage measuring device, characterized in that: It includes m high-voltage arm resistor-capacitor strings (04), n low-voltage arm resistors (06) and l low-voltage arm capacitors (07); m≥2, n≥2, l≥2; The m high-voltage arm resistor-capacitor strings (04) are connected in series to form a high-voltage arm circuit, and the m high-voltage arm resistor-capacitor strings (04) are sequentially denoted as the first high-voltage arm resistor-capacitor string, the second high-voltage arm resistor-capacitor string, ..., the mth high-voltage arm resistor-capacitor string; The first end of the first high-voltage arm resistor-capacitor string is used to connect the voltage to be measured U, and the end of the m-th high-voltage arm resistor-capacitor string is used to connect the measurement voltage U2 for measurement. n low-voltage arm resistors (06) are connected in series to form a low-voltage arm resistor string; The low-voltage arm resistor series and one low-voltage arm capacitor (07) are connected in parallel to form a low-voltage arm circuit; One end of the low-voltage arm circuit is connected to the end of the m-th high-voltage arm resistor-capacitor string, and the other end is grounded. The voltage division ratio k of the high-voltage arm circuit and the low-voltage arm circuit satisfies the following condition: In the formula: RM is the total resistance of all high-voltage arm resistors in the m high-voltage arm resistor-capacitor string (04); CM is the total capacitance of all high-voltage arm capacitors in the m high-voltage arm resistor-capacitor string (04); RN is the total resistance of the n low-voltage arm resistors (06); CL is the total capacitance of the l low-voltage arm capacitors (07).

2. The high-precision voltage measuring device according to claim 1, characterized in that: Each of the m high-voltage arm resistor-capacitor strings (04) includes a high-voltage arm resistor and a high-voltage arm capacitor connected in parallel; In the first high-voltage arm resistor-capacitor string, one end of the high-voltage arm resistor R1 and the high-voltage arm capacitor C1 is used to connect the voltage to be measured U. The other end of the high-voltage arm resistor R2 and high-voltage arm capacitor C2 in the second high-voltage arm resistor-capacitor string is connected to one end of the high-voltage arm resistor R3 and high-voltage arm capacitor C3 in the third high-voltage arm resistor-capacitor string. Similarly, the other end of the high-voltage arm resistor Rm-1 and high-voltage arm capacitor Cm-1 in the (m-1)th high-voltage arm resistor-capacitor string is connected to one end of the high-voltage arm resistor Rm and high-voltage arm capacitor Cm in the mth high-voltage arm resistor-capacitor string; the other end of the high-voltage arm resistor Rm and high-voltage arm capacitor Cm in the mth high-voltage arm resistor-capacitor string is connected to one end of the low-voltage arm circuit, and the measured voltage U2 is connected out.

3. A high-precision voltage measuring device according to claim 1 or 2, characterized in that: It also includes a package (01) and a package base (03) disposed at the bottom of the package (01); The m high-voltage arm resistor-capacitor strings (04) are all disposed in the cavity of the package body (01), and the n low-voltage arm resistors (06) and the l low-voltage arm capacitors (07) are all disposed in the cavity of the package base (03).

4. A high-precision voltage measuring device according to claim 3, characterized in that: It also includes m insulating rods (05); The m high-voltage arm resistor-capacitor strings (04) are respectively disposed in the internal cavities of the m insulating rods (05).

5. A high-precision voltage measuring device according to claim 4, characterized in that: The top of the package (01) is provided with a voltage equalization ring (02), and the first end of the first high voltage arm resistor-capacitor string passes through the voltage equalization ring (02) and is connected to the voltage to be measured U.

6. A high-precision voltage measuring device according to claim 5, characterized in that: The end of the m-th high-voltage arm resistor-capacitor string is connected to the measurement voltage U2 via a coaxial shielded wire (08).

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