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CN-122017312-A - Rogowski coil zero-region current sensor and design method thereof

CN122017312ACN 122017312 ACN122017312 ACN 122017312ACN-122017312-A

Abstract

The invention discloses a Rogowski coil zero-zone current sensor and a design method thereof, and relates to the technical field of current sensors, wherein the current sensor comprises a central conductor, an insulating sleeve, a coil framework and a coil winding; the insulating sleeve is coaxially sleeved in the middle of the central conductor, two ends of the central conductor are electric connection ends for being connected in series into an arc extinguishing chamber test loop, the coil framework is coaxially sleeved on the periphery of the insulating sleeve, the coil winding is wound on the coil framework and is used for detecting current, the central conductor is made of copper alloy, silver is plated on the surface, the diameter of the central conductor is 20-30 mm, the ratio of the length of the coil winding to the outer diameter of the coil winding is 2-3, the mutual inductance coefficient of the current sensor is 10-50 mu H, and the dynamic range of a signal output end of the coil winding is-10V. The invention has the characteristics of wide dynamic range, high sensitivity and wide frequency band, and has the characteristics of stable structure and good safety.

Inventors

  • LI MIAOXIN
  • LI JUNFENG
  • SUN MENGQI
  • SONG YUNLEI
  • ZHANG HUIZHEN
  • Dou Wenping
  • CAO CONG
  • WANG DONGHUI

Assignees

  • 河南平高电气股份有限公司

Dates

Publication Date
20260512
Application Date
20251231

Claims (8)

  1. 1. The Rogowski coil zero-zone current sensor is characterized by comprising a central conductor (1), an insulating sleeve (2), a coil framework (3) and a coil winding (4); The coil framework (3) is coaxially sleeved on the periphery of the insulating sleeve (2), and the coil winding (4) is wound on the coil framework (3) and used for detecting current; The central conductor (1) is made of copper alloy, and the surface of the central conductor is plated with silver, and the diameter of the central conductor is 20-30 mm; the ratio of the length to the outer diameter of the coil winding (4) is 2-3; The mutual inductance of the current sensor is 10-50 mu H, and the dynamic range of the signal output by the signal output end of the coil winding (4) is-10V.
  2. 2. The rogowski coil zero region current sensor according to claim 1, characterized in that the coil winding (4) is a rogowski coil and is cylindrical, the number of turns of the rogowski coil is 1000-2000, and the wire diameter of the coil winding (4) is 0.1-0.2 mm.
  3. 3. The Rogowski coil zero-zone current sensor according to claim 2, wherein the central conductor (1) is a rod body, the thickness of a silver coating on the surface of the central conductor is 5-30 mu m, the conductivity of the central conductor (1) is more than or equal to 58mS/m, and the deflection of the central conductor under the action of 63kA power frequency short-circuit current is less than or equal to 0.1mm.
  4. 4. A rogowski coil zero current sensor according to claim 3, characterized in that the dielectric strength of the insulating sleeve (2) is not less than 20kV/mm, and the coil former (3) is cylindrical and has a breakdown voltage not less than 30kV.
  5. 5. A rogowski coil zero current sensor according to claim 4, characterized by further comprising a housing (5) and a shielding layer (6); The shell (5) is provided with a central through hole, the insulating sleeve (2) is coaxially arranged in the central through hole in a penetrating mode, the shielding layers (6) are arranged at two ends of the coil winding (4), the coil framework (3), the coil winding (4) and the shielding layers (6) are all located in the shell (5), and the shielding layers (6) are connected with the shell (5) and grounded.
  6. 6. The rogowski coil zero current sensor according to claim 5, characterized in that the housing (5) is made of aluminum alloy and is surface anodized, and the shielding effectiveness of the housing (5) is not less than 40dB.
  7. 7. The Rogowski coil zero region current sensor according to claim 6, wherein the frequency band range of the current sensor is 50 Hz-2 MHz, the current sensitivity is more than or equal to 1mV/A, the linearity of the phase frequency characteristic is less than or equal to +/-1 DEG, and the signal to noise ratio is more than or equal to 60dB.
  8. 8. A method of designing a rogowski coil zero current sensor according to any one of claims 1-7, comprising the steps of: calculating electrodynamic force and checking by combining mechanical strength based on a short-circuit current value to be detected and the conductivity of a central conductor (1), and determining the material, diameter and surface treatment mode of the central conductor; Step two, according to the insulation grade requirement between the central conductor (1) and the coil winding (4), the radial minimum insulation distance between the central conductor (1) and the coil winding (4) is determined by combining the insulation performance of the insulation sleeve (2), and then the inner diameter of the coil winding (4) is determined; Thirdly, deducing and calibrating the mutual inductance coefficient of the current sensor according to the dynamic range of the zero-region current in the breaking test of the arc extinguishing chamber and the + -10V output signal requirement of the coil winding (4) by an electromagnetic induction principle; step four, designing the turns, the wire diameter, the length and the outer diameter ratio of a coil winding (4) and a winding process according to the amplitude frequency and phase frequency characteristic requirements; and fifthly, assembling a current sensor and performing performance test and calibration.

Description

Rogowski coil zero-region current sensor and design method thereof Technical Field The invention relates to the technical field of current sensors, in particular to a Rogowski coil zero-zone current sensor and a design method thereof. Background In the research and development and detection process of high-voltage switch equipment, the switching-on and switching-off performance of an arc-extinguishing chamber is a core index for determining the safety reliability of the equipment, and accurate measurement of zero-zone current is a key means for analyzing the switching-on and switching-off performance of the arc-extinguishing chamber. The zero-zone current covers the power frequency fault current (which can reach tens of kiloamperes, such as 63 kA) before the arc extinguishing chamber is opened and the high-frequency small current (the amplitude is only hundreds of amperes to several amperes, and the frequency is as high as 1-2 MHz) after the arc extinguishing chamber is opened, and the measurement needs to meet the severe requirements of a wide dynamic range, high sensitivity and a wide frequency band. Currently, the main current measurement method of the high-voltage switch test current is a rogowski coil direct measurement method. However, the conventional rogowski coil has inherent defects that sensitivity is always sacrificed to ensure a measurement frequency band, and the frequency band is narrowed if high sensitivity is required, so that a contradiction between the sensitivity and the measurement frequency band is formed. The contradiction is particularly prominent in zero-region current measurement, so that the conventional Rogowski coil cannot achieve the required measurement sensitivity when facing high-frequency small current after arc, and is difficult to accurately capture the fine change of a current signal, and the problem of signal saturation or distortion easily occurs when measuring large current of power frequency, thereby seriously affecting the accuracy of the switching-on and switching-off performance analysis of an arc extinguishing chamber and restricting the research and development efficiency and the test reliability of high-voltage switch equipment. In the prior art, partial improvement schemes attempt to alleviate the contradiction by optimizing a coil winding process or selecting special materials, but the problem of adaptability of a dynamic range is not fundamentally solved, or full-range measurement from power frequency heavy current to high frequency light current cannot be covered, or measurement accuracy and stability are insufficient, and severe standards of a high-voltage switch test are difficult to meet. In addition, the existing current sensor has poor mechanical strength, cannot bear the electrodynamic force effect generated by 63kA power frequency short-circuit current, has obvious deformation and displacement, cannot guarantee the stability of a measurement structure, has poor insulation safety, cannot avoid the risk of insulation breakdown or electric leakage in a high-voltage scene, and cannot reliably guarantee the electrical safety in the test process. Therefore, how to provide a rogowski coil zero-region current sensor and a design method thereof, which can give consideration to the characteristics of wide dynamic range, high sensitivity and wide frequency band, and has the characteristics of stable structure and good safety is a problem to be solved by those skilled in the art. Disclosure of Invention In view of the above, the present invention provides a rogowski coil zero current sensor and a design method thereof, which aim to solve at least one of the above technical problems. In order to achieve the above purpose, the present invention adopts the following technical scheme: the invention provides a Rogowski coil zero-zone current sensor, which comprises a central conductor, an insulating sleeve, a coil framework and a coil winding, wherein the central conductor is connected with the insulating sleeve; The coil framework is coaxially sleeved on the periphery of the insulating sleeve, and the coil winding is wound on the coil framework and is used for detecting current; the central conductor is made of copper alloy, silver is plated on the surface of the central conductor, and the diameter of the central conductor is 20-30 mm; The ratio of the length of the coil winding to the outer diameter is 2-3; The mutual inductance of the current sensor is 10-50 mu H, and the dynamic range of the signal output by the signal output end of the coil winding is-10V. When the Rogowski coil zero-zone current sensor is used, two ends of the central conductor are connected into the arc-extinguishing chamber test loop in series, full-range measurement of high current of power frequency 63kA to 1-2 MHz and high frequency low current of hundreds of milliamperes can be realized, the dynamic range is wide in coverage, the measurement performance is comprehensively improved, and th