Lightning current monitoring device

Abstract

The invention provides a lightning current monitoring device, the core of the lightning current monitoring device is a Rogowski coil based on a printed circuit board technology, the lightning current monitoring device is realized by uniformly arranging printed conductors on a PCB, and the lightning current monitoring device comprises an integrating circuit, a sampling channel and a microprocessor. And the integrating circuit is used for integrating the differential signal output by the Rogowski coil to restore the original signal. The sampling channel is divided into a small-range part and a large-range part, each part comprises an amplifying circuit and a sampling circuit, and the amplifying circuit and the sampling circuit are used for amplifying and sampling current signals in the ranges of 0-1.5 kA and 1.5-100 kA respectively. And the microprocessor is used for processing the sampling signal, automatically judging whether the signal of the small-range sampling channel exceeds the range or not, and correspondingly outputting the sampling signal of the small-range or large-range channel. The device can realize wide-range and high-precision lightning current monitoring, and is suitable for lightning protection of a power system.

Description

Technical Field

[0001] The invention relates to the technical field of lightning current monitoring, and in particular to a lightning current monitoring device. Background Art

[0002] In recent years, research on actual lightning intrusion waves in substations has attracted attention. Regarding the measurement methods and measurement technologies of lightning intrusion wave overvoltage in substations, the measurement technologies are roughly divided into two categories at home and abroad: direct measurement and inversion. The direct measurement mainly includes: external voltage divider method, bushing end screen capacitor voltage divider method, distributed capacitor voltage divider method, lightning arrester valve plate voltage divider method, etc.; the inversion mainly includes: electric field inversion measurement method based on all-optical sensors, secondary side measurement waveform function inversion method, ground wire current inversion voltage method, etc.

[0003] The most commonly used device in lightning current monitoring is the Rogowski coil. The Rogowski coil is a measuring device that winds a wire evenly on a frame of non-magnetic material with uniform cross-section, allowing a wire with a large current to pass vertically through the center of the coil. Through the change in the magnetic flux generated by the measured current-carrying conductor, a voltage signal that can reflect the magnitude of the measured current is induced. The theoretical basis for measuring current with the Rogowski coil is the law of electromagnetic induction and Ampere's loop law. However, it is difficult for ordinary Rogowski coils to achieve uniform winding of the coil and equal cross-section of each turn of the coil. In addition, it has the disadvantages of easy wire breakage and increased error of interlayer capacitance. In industrial production, parameter consistency is difficult to ensure, which affects the characteristics of the Rogowski coil when measuring current. Summary of the invention

[0004] The purpose of the present invention is to provide a lightning current monitoring device, design a Rogowski coil made of a printed circuit board, realize lightning current monitoring based on the Rogowski coil, and improve the accuracy of lightning current monitoring.

[0005] To achieve the above object, the present invention provides a lightning current monitoring device, comprising:

[0006] A Rogowski coil, wherein the Rogowski coil is formed by evenly arranging printed conductors on a printed circuit board;

[0007] An integration circuit, used for integrating the differential signal output by the Rogowski coil to restore the original signal;

[0008] A sampling channel, used for sampling the integrated signal of the integration circuit;

[0009] The microprocessor is used to process the sampling signal of the sampling channel and output a lightning current signal.

[0010] Preferably, the sampling channel comprises:

[0011] A small-range sampling channel is used to sample the current integral signal within a preset small-range measurement range;

[0012] The large-range sampling channel is used to sample the current integration signal within a preset large-range measurement range.

[0013] Preferably, the small-range sampling channel includes:

[0014] A first amplifier circuit, used to amplify the integrated signal output by the integration circuit with a small magnification factor;

[0015] The first sampling circuit is used to sample the amplified signal output by the first amplifying circuit.

[0016] Preferably, the large-range sampling channel includes:

[0017] A second amplifier circuit is used to amplify the integrated signal output by the integration circuit with a large magnification factor;

[0018] The second sampling circuit is used to sample the amplified signal output by the second amplifying circuit.

[0019] Preferably, the preset small-range measurement range is 0-1.5 kA.

[0020] Preferably, the preset large-range measurement range is 1.5-100 kA.

[0021] Preferably, the microprocessor is used to determine whether the current amplitude of the sampling signal of the small-range sampling channel exceeds the preset small-range measurement range. If so, it outputs the sampling signal of the large-range channel; if not, it outputs the sampling signal of the small-range channel.

[0022] The present invention has the following beneficial effects:

[0023] By evenly arranging printed conductors on a printed circuit board to make a Rogowski coil, the winding uniformity of the coil and the cross-sectional area of ​​each coil turn can be more accurately controlled, thereby reducing the measurement error caused by coil non-uniformity and interlayer capacitance and improving the accuracy of lightning current monitoring. The traditional Rogowski coil is easy to break, but the Rogowski coil of the present invention has a more solid structure and is not easy to break due to the use of printing technology, thereby improving the stability and reliability of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 The figure is a frame structure diagram of a lightning current monitoring device in an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The detailed description of the accompanying drawings is intended as an illustration of the current embodiments of the present invention and is not intended to represent the only form in which the present invention can be implemented. It should be understood that the same or equivalent functions can be accomplished by different embodiments that are intended to be included in the spirit and scope of the present invention.

[0027] See also Figure 1 , an embodiment of the present invention provides a lightning current monitoring device, comprising:

[0028] A Rogowski coil, wherein the Rogowski coil is formed by evenly arranging printed conductors on a printed circuit board;

[0029] An integration circuit, used for integrating the differential signal output by the Rogowski coil to restore the original signal;

[0030] A sampling channel, used for sampling the integrated signal of the integration circuit;

[0031] The microprocessor is used to process the sampling signal of the sampling channel and output a lightning current signal.

[0032] Furthermore, the sampling channel comprises:

[0033] A small-range sampling channel is used to sample the current integral signal within a preset small-range measurement range;

[0034] The large-range sampling channel is used to sample the current integration signal within a preset large-range measurement range.

[0035] Furthermore, the small-range sampling channel includes:

[0036] A first amplifier circuit, used to amplify the integrated signal output by the integration circuit with a small magnification factor;

[0037] The first sampling circuit is used to sample the amplified signal output by the first amplifying circuit.

[0038] Furthermore, the large-range sampling channel includes:

[0039] A second amplifier circuit is used to amplify the integrated signal output by the integration circuit with a large magnification factor;

[0040] The second sampling circuit is used to sample the amplified signal output by the second amplifying circuit.

[0041] Furthermore, the preset small-range measurement range is 0-1.5 kA.

[0042] Furthermore, the preset large-range measurement range is 1.5-100 kA.

[0043] Furthermore, the microprocessor is used to determine whether the current amplitude of the sampling signal of the small-range sampling channel exceeds the preset small-range measurement range. If so, it outputs the sampling signal of the large-range channel; if not, it outputs the sampling signal of the small-range channel.

[0044] The working principle of the present invention is based on the law of electromagnetic induction and electronic signal processing technology. The following is an introduction to the working process and principle of the lightning current monitoring device:

[0045] Rogowski coil induction: When the lightning current passes through the monitored conductor, the printed wire in the Rogowski coil will be arranged around the conductor to form a closed magnetic field path. According to the law of electromagnetic induction, the changing magnetic field will induce an electromotive force (voltage signal) in the printed wire of the Rogowski coil. This electromotive force is the differential signal of the lightning current and is proportional to the rate of change of the lightning current.

[0046] Integration circuit processing: The differential signal output by the Rogowski coil needs to be processed by an integration circuit to restore the original lightning current signal. The integration circuit is usually composed of an operational amplifier, which integrates the input differential signal to obtain a voltage signal corresponding to the original current waveform.

[0047] Sampling channel settings: Small-range sampling channel: includes the first amplifier circuit and the first sampling circuit, which are used to amplify and sample the current integration signal in the range of 0 to 1.5 kA at a small rate. Large-range sampling channel: includes the second amplifier circuit and the second sampling circuit, which are used to amplify and sample the current integration signal in the range of 1.5 to 100 kA at a large rate.

[0048] Signal amplification and sampling: The first amplification circuit and the second amplification circuit respectively amplify the signal output by the integration circuit at different magnifications to adapt to current signals of different ranges. The first sampling circuit and the second sampling circuit respectively sample the amplified signal and convert the analog signal into a digital signal for processing by the microprocessor.

[0049] Microprocessor processing and judgment: The microprocessor receives the digital signal of the sampling channel and performs further processing, such as digital filtering, amplitude calculation, etc. The microprocessor first determines whether the sampling signal amplitude of the small-scale sampling channel exceeds the preset small-scale measurement range (0-1.5kA). If the signal amplitude of the small-scale sampling channel exceeds the preset range, it means that the lightning current exceeds the upper limit of the small range. At this time, the microprocessor will output the sampling signal of the large-scale channel. If the signal amplitude of the small-scale sampling channel does not exceed the preset range, the microprocessor outputs the sampling signal of the small-scale channel.

[0050] Through the above content, the lightning current monitoring device of the present invention can accurately monitor and record the size of the lightning current, whether it is a small current or a large current, and can ensure the accuracy and reliability of the measurement.

[0051] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A lightning current monitoring device, characterized in that: include: A Rogowski coil, wherein the Rogowski coil is formed by evenly arranging printed conductors on a printed circuit board; An integration circuit, used for integrating the differential signal output by the Rogowski coil to restore the original signal; A sampling channel, used for sampling the integrated signal of the integration circuit; The microprocessor is used to process the sampling signal of the sampling channel and output a lightning current signal.

2. The lightning current monitoring device according to claim 1, characterized in that: The sampling channel comprises: A small-range sampling channel is used to sample the current integral signal within a preset small-range measurement range; The large-range sampling channel is used to sample the current integration signal within a preset large-range measurement range.

3. The lightning current monitoring device according to claim 2, characterized in that: The small-range sampling channel includes: A first amplifier circuit, used to amplify the integrated signal output by the integration circuit with a small magnification factor; The first sampling circuit is used to sample the amplified signal output by the first amplifying circuit.

4. The lightning current monitoring device according to claim 3, characterized in that: The large-range sampling channel includes: A second amplifier circuit is used to amplify the integrated signal output by the integration circuit with a large magnification factor; The second sampling circuit is used to sample the amplified signal output by the second amplifying circuit.

5. The lightning current monitoring device according to claim 4, characterized in that: The preset small-range measurement range is 0-1.5 kA.

6. The lightning current monitoring device according to claim 4, characterized in that: The preset large-range measurement range is 1.5-100 kA.

7. The lightning current monitoring device according to claim 4, characterized in that: The microprocessor is used to determine whether the current amplitude of the sampling signal of the small-range sampling channel exceeds the preset small-range measurement range. If so, it outputs the sampling signal of the large-range channel; if not, it outputs the sampling signal of the small-range channel.

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