CN201072427Y - A Pulse Current Measurement Device Based on Flexible Rogowski Coil - Google Patents

Abstract

The utility model relates to a pulse current measuring device based on a flexible Rogowski coil, which belongs to the technical field of electrical high voltage measurement. Including: a flexible Rogowski coil for pulse current measurement of the measured current-carrying conductor; an integrator for integrating and restoring the signal output by the flexible Rogowski coil to obtain an analog signal proportional to the derivative of the measured pulse current; A data sampling module used to perform analog conditioning on the analog signal output by the integrator to obtain a discrete sampling signal; a digital-to-analog conversion module used to convert the analog signal output by the integrator into a discrete digital signal; used for A/D The digital signal output by the conversion module is processed to obtain the central processing unit of the measured pulse signal; the wireless communication module is used to communicate with the outside world; the global positioning system module is used to calibrate the clock time of the central processing unit. The measuring device of the utility model is cheap, and is convenient for large-scale measurement of the waveform of the natural lightning current in the field.

Description

A Pulse Current Measurement Device Based on Flexible Rogowski Coil

technical field

The utility model relates to a pulse current measuring device based on a flexible Rogowski coil, in particular to the measurement of lightning current, and belongs to the technical field of electrical high-voltage measurement.

Background technique

Lightning is an atmospheric discharge phenomenon that often occurs in nature. When a strong lightning strike occurs, a lightning current of up to hundreds of kA will be generated in its discharge channel. The generation process of lightning current is often accompanied by strong electromagnetic phenomena, which will bring serious harm to power transmission, electronic communication, air transportation and other fields. In order to effectively carry out research on lightning protection, lightning formation mechanism and other related aspects, how to accurately measure the waveform of lightning current is an urgent problem to be solved at present.

The research on the characteristic parameters of lightning current has been paid more attention in the electric power industry, while the traditional research methods basically rely on simulation and simulation technology, due to the lack of actual lightning current parameters in nature (such as waveform, amplitude, rise time, duration etc.), coupled with the inaccuracy of the established model, the results of the simulation are often wrong, which will mislead the design of lightning protection. The most direct way to obtain lightning current parameters is to measure. At present, some developed countries have installed lightning monitoring devices on a few transmission lines and communication towers, and captured several lightning current waveforms during operation. In contrast, the research work done in my country on lightning current measurement is relatively small.

The Rogowski coil is a method of testing pulse current invented by Russian scientists. It is often used in high voltage laboratories to test pulse current in combination with an oscilloscope. Because the oscilloscope is expensive, does not have a good communication port, and can only record the waveform automatically once, and needs human intervention to record the second waveform, this kind of measurement device is difficult to apply in large quantities, especially in field applications. Moreover, the structure of most existing Rogowski coils is a hard shell structure, that is, the shell is a very thick metal shielding shell. When in use, the measured structure needs to be untied and passed through the Rogowski coil, that is, the coil cannot be opened. .

Contents of the invention

The purpose of this utility model is to propose a pulse current measuring device based on a flexible Rogowski coil, using a flexible Rogowski coil, combined with a high-speed data acquisition device, using the GPS global positioning system, and by means of a GPRS wireless data communication module, to measure the pulse current function.

The pulse current measurement device based on the flexible Rogowski coil proposed by the utility model includes:

The flexible Rogowski coil is used for pulse current measurement of the measured current-carrying conductor, the measured current-carrying conductor passes through the flexible Rogowski coil, and the output end of the flexible Rogowski coil is connected to the integrator;

The integrator is used to integrate and restore the signal output by the flexible Rogowski coil to obtain an analog signal proportional to the derivative of the measured pulse current, and the output terminal of the integrator is connected to the input terminal of the data sampling module;

The digital-to-analog conversion module is used for conditioning the analog signal output by the integrator, using A/D to convert the analog signal into a discrete digital signal, and then temporarily storing the digital signal in the memory;

The central processing unit is used for calculating and processing the digital signal output by the A/D conversion module to obtain the measured pulse signal, and the central processing unit is connected with the wireless communication module and the global positioning system module respectively;

The wireless communication module is used for communicating with the outside world, and the wireless communication module is connected with the central processing unit;

The global positioning system module is used for calibrating the clock time of the central processing unit, and the global positioning system module is connected with the central processing unit.

The Rogowski coil in the above measurement device includes: a casing, a metal shielding layer, a flexible skeleton, a coil, a conductive core wire and an integrator. The bushing, the metal shielding layer and the flexible frame are sequentially fixed concentrically from outside to inside to form a ring, and one side of the ring is an opening. The coil is wound on the flexible frame, and the conductive core wire is embedded in the flexible frame. One end of the coil is connected to one end of the integrator in the measuring device, and the other end of the coil is connected to the other end of the integrator in the measuring device through the conductive core wire in the flexible frame. connected at one end.

The pulse current measurement device based on the flexible Rogowski coil proposed by the utility model has the advantage of using the mature high-speed sampling technology for the device, which is cheap compared with the special measurement device in the laboratory, and is convenient for wide application, such as large-scale in the field Measure the natural lightning current waveform. The device of the utility model uses the GPRS wireless transmission module to transmit the digital signal to the remote terminal, which is beneficial to install the device in an inaccessible area, and reduces the manpower and material resources required to artificially extract the lightning current waveform. At the same time, the device of the utility model adopts the GPS global satellite positioning system to locate the lightning strike point, and provides a time reference for the measurement system to record the lightning strike time. The flexible Rogowski coil is adopted in the measuring device of the utility model, and is designed as an open type. The structure is like a line, which can be bent at will. When in use, it is not necessary to untie the measured structure, as long as the flexible coil is wound around the measured structure. One turn (or more turns), and then connect the first end of the flexible coil through the connector, so that the Rogowski coil has good flexibility, easy to install and disassemble, compact and light, very convenient and simple to install, suitable for field use, and has Compared with some rigid Rogowski coils, the application range of Rogowski coils is greatly expanded.

Description of drawings

Fig. 1 is a schematic structural diagram of a pulse current measuring device proposed by the present invention.

Fig. 2 is a structural schematic diagram of the flexible Rogowski coil used in the measuring device of the present invention.

Fig. 3 is a schematic circuit diagram of the integrator in the flexible coil of the present invention.

In Figure 2, 1 is a current-carrying conductor, 2 is a heat-shrinkable sleeve, 3 is a metal shielding layer, 4 is a flexible skeleton, 5 is a coil wound on a flexible skeleton, and 6 is a conductive core wire, which is used as a coil loop. 7 is an integrator.

Detailed ways

The pulse current measurement device based on the flexible Rogowski coil proposed by the utility model has a structure as shown in Figure 1, including: a flexible Rogowski coil for measuring the pulse current of the measured current-carrying conductor, and the measured current-carrying conductor passes through the flexible Rogowski coil, the output end of the flexible Rogowski coil is connected to the integrator;

The integrator is used to integrate and restore the signal output by the flexible Rogowski coil to obtain an analog signal proportional to the derivative of the measured pulse current. The output terminal of the integrator is connected to the input terminal of the data sampling module. The integrator can be composed of composed of resistors and capacitors;

The digital-to-analog conversion module is used for conditioning the analog signal output by the integrator, using A/D to convert the analog signal into a discrete digital signal, and then temporarily storing the digital signal in the memory;

The central processing unit is used for calculating and processing the digital signal output by the A/D conversion module to obtain the measured pulse signal, and the central processing unit is connected with the wireless communication module and the global positioning system module respectively;

The wireless communication module is used for communicating with the outside world, and the wireless communication module is connected with the central processing unit;

The global positioning system module is used for calibrating the clock time of the central processing unit, and the global positioning system module is connected with the central processing unit.

、金属屏蔽层、柔性骨架

、线圈5、导电芯线

和积分器7。套管

、金属屏蔽层3和柔性骨架依次由外向内同心相对固定成为圆环，在圆环的一侧为一开口。线圈5绕在柔性骨架

上，导电芯线

埋在柔性骨架

中，线圈5的一端与积分器7的一端相连接，线圈5的另一端通过柔性骨架

中的导电芯线

与积分器7的另一端相连接。The Rogowski coil in the above-mentioned measuring device has a structure as shown in Figure 2, including: sleeve

, metal shielding layer , flexible skeleton

, coil 5, conductive core wire

and integrator 7. casing

, metal shielding layer 3 and flexible skeleton They are concentrically fixed sequentially from outside to inside to form a ring, and one side of the ring is an opening. The coil 5 is wound on a flexible skeleton

upper, conductive core wire

Buried in flexible skeleton

Among them, one end of the coil 5 is connected to one end of the integrator 7, and the other end of the coil 5 passes through the flexible skeleton

Conductive core wire in

Connect with the other end of the integrator 7.

In one embodiment of the present utility model, used digital-to-analog conversion module selects the ADS901 chip that U.S. BB (BURR BROWN) company produces, and the storage memory in the digital-to-analog conversion module selects the CY7C4251 chip that U.S. Cypress Company produces. The central processing unit used is the C8051F040 single-chip microcomputer produced by Cygnal Company of the United States. The MC39I GPRS module produced by Siemens is selected for use. The GPS module used is the GPSLD-1W wireless module produced by Nokia Corporation.

In the measuring device of the utility model, the casing of the Rogowski coil is made of heat-shrinkable material; the flexible skeleton is made of soft insulating material, such as silicon rubber.

The integrator in the measuring device of the utility model is a passive integrator, which is composed of resistors and capacitors connected in a T shape, as shown in Figure 3.

The working principle of the utility model device is: the measured current-carrying conductor passes through the center of the flexible Rogowski coil. According to the law of electromagnetic induction, the output voltage of the flexible Rogowski coil is in a differential relationship with the measured current. The current conductors are coupled by magnetic field without electrical connection, which can realize the isolation between high and low voltage, and protect the safety of subsequent acquisition equipment. In order to restore the measured current, passive analog integration of the differential voltage is required, and the integrated voltage signal is proportional to the measured current.

When the device is applied to lightning current measurement, the device can be installed on the power transmission line or the top of the pole tower, etc., so that the lightning rod passes through the center of the flexible Rogowski coil. Since the flexible Rogowski coil is usually installed on the transmission line or the tower, the signal after integral restoration needs to go through a long transmission cable to the digital recorder. Perform quantization processing on the restored signal, and convert the analog signal into a digital signal.

Traditional lightning current measurement devices generally store the measured waveforms in a memory, and after a period of time, the staff will extract the data. The device of the utility model uses a GPRS wireless transmission module to transmit digital signals to a remote terminal, which is beneficial for installing the device in inaccessible areas and reduces the manpower and material resources required for artificially extracting lightning current waveforms.

At the same time, due to the wide distribution of transmission lines, in order to accurately identify the recorded lightning current waveform, the utility model device uses the GPS global satellite positioning system to locate the lightning strike point, and can provide a time reference for the measurement system to record the lightning strike time.

为用来保护线圈并起绝缘作用的热缩套管，可以从市场上的普通化工商店购买，

是柔性罗氏线圈的骨架，本实用新型的一个实施例中，采用硅橡胶电缆作为线圈的骨架，

是硅橡胶电缆的导电芯线，此时作为柔性罗氏线圈的回线。柔性线圈设计成开口式，首末端通过接插件进行连接，以方便使用。使柔性罗氏线圈首末端相连的接插件可以使用由法国安普公司生产的BNC型接口。According to the characteristics of the measured pulse current, a flexible Rogowski coil with wide frequency band and wide dynamic range is designed for the pulse current measuring device of the utility model, which is easy to install and disassemble, and the subsequent processing circuit is simple and reliable. In the flexible Rogowski coil shown in Figure 2,

The heat-shrinkable sleeve used to protect the coil and insulate it can be purchased from general chemical stores in the market,

It is the skeleton of the flexible Rogowski coil. In one embodiment of the present invention, a silicon rubber cable is used as the skeleton of the coil.

It is the conductive core wire of the silicone rubber cable, which is used as the return wire of the flexible Rogowski coil at this time. The flexible coil is designed as an open type, and the first end is connected by a connector for convenience. The connector that connects the head and the end of the flexible Rogowski coil can use the BNC type interface produced by the French AMP company.

The flexible Rogowski coil in the measuring device of the utility model has selected a suitable supporting frame material. The lightning current measuring device is usually installed outdoors, the working conditions are relatively harsh, and the temperature range is relatively large, so the skeleton material should choose a material with better temperature characteristics. In this utility model, silicon rubber is used as the skeleton material of the Rogowski coil. Silicone rubber has high temperature resistance, high pressure resistance, waterproof, anti-corrosion and other properties, and can work at -60 ° C ~ +180 ° C. In one embodiment of the utility model, a silicon rubber cable is used as the flexible skeleton, which not only has good flexibility and is easy to install and disassemble, but also uses the core wire of the cable as the return wire of the Rogowski coil.

For the flexible Rogowski coil in the measuring device of the utility model, appropriate coil parameters must be selected. According to the amplitude and frequency of the measured current, the parameters of the Rogowski coil need to be calculated, such as the outer diameter and length of the skeleton, the wire diameter and the number of turns of the winding wire, etc. In one embodiment of the utility model, the enamelled copper wire with a wire diameter of 0.1-0.5mm is uniformly and densely wound on a silicon rubber cable with an outer diameter of 0.1-1.0mm, and the enameled wire is welded to the core wire of the cable at the end of the coil together. The core wire and enameled wire of the cable at the head end of the coil are connected to the shielded cable as the output end of the coil. In order to protect the enameled wire wound on the skeleton, a layer of heat shrinkable sleeve can be put on the outer layer of the coil, and a suitable rubber joint can be installed at the beginning and end of the coil to form a loop. Using the core wire of the silicone rubber cable as the loop of the coil can also offset the influence of the magnetic field perpendicular to the coil direction on the measurement results; the rapidly changing external voltage will superimpose high-frequency oscillation on the output of the Rogowski coil through stray capacitive coupling. Winding a layer of copper foil on the outer layer of the coil can effectively reduce the oscillation amplitude, but there should be enough gaps between adjacent copper foils, otherwise the circulating current in the shielding layer will weaken the useful magnetic field, and the copper foil should be in contact with the coil's A certain output end is connected as the signal ground wire; in order to reduce the interference of the external magnetic field on the signal transmission circuit, the transmission cable should use a twisted-pair shielded wire.

In order to obtain a waveform proportional to the measured current, it is also necessary to integrate the output voltage signal of the flexible Rogowski coil. In the utility model, the Rogowski coil works in an external integral state, so a passive integral circuit composed of a resistor and a capacitor is adopted, wherein the resistor must ensure no inductance, and the capacitor should have a small leakage current and high temperature stability. In order to realize the integration function, the product of the resistance value R and the capacitance value C should be much larger than the period of the integrated signal. The schematic diagram of the passive integration circuit is shown in Figure 3.

Claims (6)

1. impulse current measurement mechanism based on flexible Luo-coil is characterized in that this measurement mechanism comprises:

Flexible Luo-coil is used for tested current is carried out impulse current measurement, and tested current passes flexible Luo-coil, and the flexible Luo-coil output terminal links to each other with integrator;

Integrator is used for the signal of above-mentioned flexible Luo-coil output is carried out the integration reduction, and obtaining and the proportional simulating signal of measured pulse electric current, the output terminal of integrator links to each other with the input end of data sampling module;

D/A converter module, the analog signal conversion that is used for above-mentioned integrator output is a discrete digital signal, and digital signal is stored in the reservoir;

Central processing unit is used for the digital signal of A/D modular converter output is carried out calculation process, and to obtain the measured pulse signal, central processing unit links to each other with GPS module with wireless communication module respectively;

Wireless communication module is used for and extraneous communication, and wireless communication module links to each other with central processing unit;

GPS module is used for the clock time of central processing unit is demarcated, and GPS module links to each other with central processing unit.

2. measurement mechanism as claimed in claim 1 is characterized in that wherein said Luo-coil comprises: sleeve pipe, metal screen layer, flexible back bone, coil, conductive core line and integrator; Described sleeve pipe, metal screen layer and the flexible back bone concentric relative fixed of ecto-entad successively become annulus, are an opening in a side of annulus; Described coil is on flexible back bone, described conductive core line is embedded in the flexible back bone, one end of coil is connected with an end of integrator in the measurement mechanism, and the other end of coil is connected with the other end of integrator in the measurement mechanism by the conductive core line in the flexible back bone.

3. measurement mechanism as claimed in claim 2 is characterized in that wherein said sleeve pipe made by material contracting with heat.

4. measurement mechanism as claimed in claim 2 is characterized in that wherein said flexible back bone made by soft insulating material.

5. measurement mechanism as claimed in claim 2 is characterized in that wherein said flexible back bone made by silicon rubber.

6. measurement mechanism as claimed in claim 2 is characterized in that wherein said integrator is made up of the resistance and the electric capacity that become T shape to connect.

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