Open type multifunctional alternating current acquisition device

Abstract

The invention discloses an open type multifunctional alternating current acquisition device which integrates the functions of current transformer measurement, protection and electric leakage acquisition and facilitates uninterruptible power operation of project transformation. The open type multifunctional alternating current acquisition device comprises a shell, a plurality of measurement coils, a plurality of protection coils, an electric leakage coil, a plurality of primary windings and a signal conversion circuit board, the shell is formed by clamping a frame-shaped shell and a cover plate, a plurality of strip-shaped assemblies fixed to the inner wall of the frame-shaped shell are arranged in the frame-shaped shell, an opening in one end of each strip-shaped assembly faces the cover plate, the shell is cut into an upper shell assembly and a lower shell assembly along the central cross section of the shell, and locking structures which are combined are arranged on the side faces of the upper shell assembly and the lower shell assembly respectively. The primary windings are respectively arranged in the strip-shaped assemblies, the measuring coil and the protection coil respectively surround the strip-shaped assemblies, and the electric leakage coil integrally surrounds the strip-shaped assemblies; the signal conversion circuit board is arranged in the frame-shaped shell, and the plurality of measuring coils, the plurality of protection coils and the electric leakage coil are electrically connected with the signal conversion circuit board respectively.

Description

Technical Field

[0001] The present invention relates to the technical field of current transformers, and particularly relates to an open-type multi-functional AC current acquisition device. Background Art

[0002] With the continuous expansion of the power scale and the rapid development of the power industry, the complexity of the power grid structure and the single-unit capacity have been further increased. Due to being affected by economy and environment to a certain extent, the safety problems of the power system have become more important. Once a safety problem occurs, it will cause long-term and large-scale power outages. Therefore, it is necessary to continuously research the safety monitoring and control of the power system to promote the development of the power industry. As an indispensable part of the power system, the current transformer can play the role of isolating high- and low-voltage electrical equipment and providing the AC current acquisition quantity to the protection and measurement devices.

[0003] The AC current transformers used in the prior art have the following defects: 1. The existing current transformers have a single function. If it is necessary to simultaneously meet metering, protection, and leakage monitoring requirements, multiple transformers need to be installed, which is cumbersome to install and has a high labor cost; 2. Conventionally, they are closed transformers. During the project transformation process, power-off installation is required, which affects the user's power consumption. In addition, it is necessary to disassemble the primary cable or copper busbar, and the transformation time is relatively long; 3. The transmission distance of the output current signal of the traditional current transformer is limited, and there are certain requirements for the diameter of the secondary wire; 4. The traditional current transformer needs to cooperate with a power meter to read data and cannot directly display it in real time on the background; 5. The installation of conventional transformers requires accessories such as metal support pieces, and the installation method is single. Summary of the Invention

[0004] The purpose of the present invention is to overcome the defects existing in the prior art and provide an open-type multi-functional AC current acquisition device that integrates the functions of current transformer measurement, protection, and leakage acquisition and facilitates power-off operation during project transformation.

[0005] To achieve the above purpose, the technical solution of the present invention is to design an open-type multi-functional AC current acquisition device, and the open-type multi-functional AC current acquisition device includes a housing, a plurality of measurement coils, a plurality of protection coils, a leakage coil, a plurality of primary windings, and a signal conversion circuit board; The housing is formed by snap-fitting a frame-shaped housing and a cover plate. A plurality of strip-shaped components fixed on the inner wall are arranged in the frame-shaped housing. One end of the strip-shaped component opens towards the cover plate. The housing is cut along its central cross-section into an upper housing component and a lower housing component. The sides of the upper housing component and the lower housing component are respectively provided with mating locking structures; The primary windings are respectively arranged in the strip-shaped components. The measurement coils and the protection coils respectively surround the strip-shaped components. The leakage coil integrally surrounds the plurality of strip-shaped components; The signal conversion circuit board is disposed inside the frame-shaped housing, and the plurality of measurement coils, the plurality of protection coils, and the leakage coil are electrically connected to the signal conversion circuit board respectively.

[0006] Furthermore, the housing is formed by an epoxy casting process, and the signal conversion circuit board, the measurement coils, the protection coils, and the leakage coil are fixed inside the housing by an epoxy casting structure.

[0007] Furthermore, the measurement coil includes an annular amorphous magnetic core, an enameled wire, and an insulating layer. The enameled wire is wound around the upper half of the annular amorphous magnetic core, and the insulating layer covers the annular amorphous magnetic core and the enameled wire.

[0008] Furthermore, the protection coil includes an annular silicon steel magnetic core, an enameled wire, and an insulating layer. The enameled wire is wound around the upper half of the annular silicon steel magnetic core, and the insulating layer covers the annular silicon steel magnetic core and the enameled wire.

[0009] Furthermore, the leakage coil includes, from inside to outside, an annular amorphous magnetic core, an enameled wire, an insulating layer, and a metal shielding layer. The enameled wire is wound around the upper half of the annular amorphous magnetic core.

[0010] Furthermore, the signal conversion circuit board is provided with an auxiliary power supply access terminal, a signal conversion circuit, and a signal output terminal.

[0011] Furthermore, at least one of a guide rail spring clip, a bottom plate mounting bracket, a guide rail mounting slot, and a copper bar fixing buckle is provided on the outer surface of the frame-shaped housing.

[0012] The advantages and beneficial effects of the present invention are as follows: By means of the measurement coils, protection coils, and leakage coils surrounding each primary winding that can be connected to the measured circuit, the acquisition of three current signals, namely power metering, line protection, and leakage measurement, can be carried out simultaneously. The functions of current transformer measurement, protection, and leakage acquisition are integrated into one, meeting various requirements. In addition, the housing adopts an open design, which is divided into an upper housing assembly and a lower housing assembly. The upper housing assembly and the lower housing assembly can be closed into a whole by fastening through a locking structure provided on the side. At the same time, the primary winding is integrated in a strip-shaped component inside the housing and can be directly connected to the measured circuit, enabling power-off-free operation during project transformation without the need to disassemble the primary cable, which is convenient for project transformation. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic structural diagram of an open-type multifunctional AC current acquisition device of the present invention; Figure 2 is an exploded schematic structural diagram of an open-type multifunctional AC current acquisition device of the present invention; Figure 3 Front view of an open - type multi - functional AC current acquisition device of the present invention; Figure 4 Side view of an open - type multi - functional AC current acquisition device of the present invention; Figure 5 Bottom view of an open - type multi - functional AC current acquisition device of the present invention; Figure 6 Top view of an open - type multi - functional AC current acquisition device of the present invention; Figure 7 Schematic diagram of the working principle of an open - type multi - functional AC current acquisition device of the present invention.

[0014] In the figure: 1. Housing; 2. Measuring coil; 3. Protection coil; 4. Leakage current coil; 5. Signal conversion circuit board; 6. Snap ring; 1.1 Frame - type housing; 1.2 Cover plate; 1.3 Locking structure; 1.4 Strip - shaped component; 1.5 Upper housing component; 1.6 Lower housing component; 1.1.1 Bottom plate mounting bracket; 1.1.2 Guide rail mounting bracket; 1.2.1 Copper busbar mounting bracket; 2.1 Measuring coil; 2.2 Measuring coil; 2.3 Measuring coil; 3.1 Protection coil; 3.2 Protection coil; 3.3 Protection coil; 4.1 Metal shielding layer; 5.1 Auxiliary power supply terminal; 5.2 Signal output terminal. Specific embodiments

[0015] The following combines the drawings and embodiments to further describe the specific embodiments of the present invention. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and cannot be used to limit the protection scope of the present invention.

[0016] According to Figures 1 to 7As shown in the figure, the present invention is an open - type multifunctional AC current acquisition device. The open - type multifunctional AC current acquisition device includes a housing 1, several measurement coils 2 (including measurement coil 2.1, measurement coil 2.2, measurement coil 2.3), several protection coils 3 (including protection coil 3.1, protection coil 3.2, protection coil 3.3), a leakage current coil 4, several primary windings, and a signal conversion circuit board 5. The housing 1 is formed by snap - fitting a frame - type housing 1.1 and a cover plate 1.2. Inside the frame - type housing 1.1, several strip - shaped components 1.4 are fixed on its inner wall. One end of the strip - shaped component 1.4 is open towards the cover plate 1.2. The housing 1 is cut along its central cross - section into an upper housing component 1.5 and a lower housing component 1.6, and locking structures 1.3 that match each other are respectively provided on the sides of the upper housing component 1.5 and the lower housing component 1.6. The primary windings are respectively arranged in each strip - shaped component 1.4. Each measurement coil and each protection coil respectively surround each strip - shaped component, and the leakage current coil 4 entirely surrounds several strip - shaped components. The signal conversion circuit board 5 is arranged inside the frame - type housing 1.1, and several measurement coils 2, several protection coils 3, and the leakage current coil 4 are respectively electrically connected to the signal conversion circuit board 5.

[0017] Combined with Figure 7 the schematic diagram shown, each primary winding is connected in series in the measured lines A, B, and C. I 1 is the primary current of the measured line currents A, B, and C. I 21 is the secondary current signal of the measurement coil. I 22 is the secondary current signal of the protection coil. I 23 is the secondary current signal of the leakage current coil. The number of turns of the primary winding of the multifunctional AC current acquisition device is denoted as N1, the number of turns of the secondary winding of the measurement coil is denoted as N21, the number of turns of the secondary winding of the protection coil is denoted as N22, and the number of turns of the secondary winding of the leakage current coil is denoted as N23.

[0018] Let Z 2 e 1 be the impedance of the secondary - loop measurement equipment and the connecting wires. Z 2 e 2 be the impedance of the secondary - loop protection equipment and the connecting wires. When the primary current flows into the acquisition device from the P1 end and flows out from the P2 end, and the secondary - loop measurement equipment and the secondary - loop protection equipment are connected, according to the electromagnetic induction law, the current I 1 flowing through the primary winding will generate induced electromotive force and induced current in each secondary winding (measurement coil, protection coil, leakage current coil). That is, when the primary winding current changes, the magnetic flux passing through the secondary winding will change, thereby generating induced currents I 21, I 22, I 23. According to the transformer current - transformation principle, the primary current I 1 and each secondary current satisfyI 1* N 1 = I 21* N 21 = I 22* N 22 = I 23* N 23. The primary current can be calculated through the known turns ratio and the measured secondary current. I 1. On the secondary side, measure the current of the coil. I 21 passes through the impedance of the secondary circuit measuring equipment and the connecting wires. Z 2 e 1 to form a closed loop; the current of the protection coil I 22, the current of the leakage coil I 23 passes through the impedance of the secondary circuit protection equipment and the connecting wires. Z 2 e 2 to form a closed loop. After these current signals are input into the signal conversion circuit board, subsequent processing can be carried out.

[0019] The secondary current signal collected by the measuring coil I 21 is mainly used to accurately measure the current value in the measured circuit. Transmit it to the signal conversion circuit board, and the MCU integrated on the signal conversion circuit board can calculate the primary side current I 1 magnitude in combination with parameters such as the turns ratio. The measured current value can be displayed in real time on the display module, which is convenient for the operator to intuitively understand the circuit current situation. It can also output the current value signal to an external acquisition device through the analog signal output interface or the RS485 communication interface, providing basic data for subsequent power metering, load analysis, etc., and helping to evaluate the working state and energy consumption of the electrical equipment.

[0020] The secondary current signal collected by the protection coil I 22 is mainly used for protection functions. When abnormal situations such as overcurrent and short circuit occur in the circuit, the current signal collected by this coil will change. After the MCU integrated on the signal conversion circuit board receives this change signal, it can output this change signal to the secondary circuit protection equipment to trigger a protection action, such as cutting off the circuit by controlling the switching equipment.

[0021] The secondary current signal collected by the leakage coil I 23 is mainly used to detect the leakage situation in the circuit. Under normal circumstances, the vector sum of the three-phase line currents is zero. When leakage occurs, the three-phase current balance is broken, and the leakage coil will induce a corresponding current signal. The MCU integrated on the signal conversion circuit board I 23 judges whether there is leakage and the degree of leakage. If leakage is detected, an alarm signal can be sent out in time.

[0022] In the embodiments of the present disclosure, by means of measurement coils, protection coils, and leakage coils that surround the primary windings that can be connected to the measured circuit, current signals for three functions, namely power metering, line protection, and leakage measurement, can be collected simultaneously. The functions of current transformer measurement, protection, and leakage collection are integrated into one, meeting various requirements. In addition, the housing adopts an open design and is divided into an upper housing assembly and a lower housing assembly. The upper housing assembly and the lower housing assembly can be fastened into a whole through a locking structure arranged on the side. At the same time, the primary windings are integrated into a strip-shaped assembly inside the housing and can be directly connected to the measured circuit, enabling power-off-free operation during project transformation without the need to disassemble the primary cable, which is convenient for project transformation.

[0023] In order to enhance the insulation between the measurement coils, protection coils, leakage coils, and the circuit, and enhance the salt spray resistance level of the device to meet the usage requirements in high voltage levels, high temperature and high humidity, salt spray resistance, and high altitude areas, a further preferred embodiment of the present invention is that the housing is formed by an epoxy casting process, and the signal conversion circuit board, measurement coils, protection coils, and leakage coils are fixed inside the housing by an epoxy casting structure.

[0024] In order to ensure the stability of measurement, improve the sensitivity and accuracy of measurement, a further preferred embodiment of the present invention is that the measurement coil includes a ring-shaped amorphous magnetic core, enameled wire, and an insulating layer. The enameled wire is wound around the upper half of the ring-shaped amorphous magnetic core, and the insulating layer covers the ring-shaped amorphous magnetic core and the enameled wire.

[0025] The amorphous magnetic core has the characteristics of high magnetic permeability, low coercivity, and low loss. The high magnetic permeability enables a large electromotive force to be induced under a small magnetic field change, which is beneficial to accurately measure small current changes and can improve the sensitivity and accuracy of measurement. By reasonably controlling the number of turns and layout wound on the upper half of the magnetic core, parameters such as the inductance of the coil can be adjusted to meet the requirements of the measurement circuit and achieve a better measurement effect. At the same time, considering the characteristics of the magnetic field distribution of the magnetic core, winding on the upper half can effectively utilize the magnetic flux change of the magnetic core and improve the induction efficiency.

[0026] In order to accurately sense the fault current signal and reduce costs, a further preferred embodiment of the present invention is that the protection coil includes a ring-shaped silicon steel magnetic core, enameled wire, and an insulating layer. The enameled wire is wound around the upper half of the ring-shaped silicon steel magnetic core, and the insulating layer covers the ring-shaped silicon steel magnetic core and the enameled wire.

[0027] The silicon steel magnetic core has a high saturation magnetic induction intensity and can withstand a large magnetic field intensity without saturation. The high saturation magnetic induction intensity characteristic of the silicon steel magnetic core enables it to accurately sense the fault current signal, providing a reliable basis for triggering the protection action of the secondary circuit protection equipment. The upper part winding can effectively utilize the magnetic flux change of the magnetic core, improving the induction efficiency. In addition, the price of silicon steel material is relatively low, with good cost-effectiveness, making it suitable for large-scale application in protection coils.

[0028] In order to improve the sensitivity and reliability of leakage detection, enhance the anti-interference ability and balance of the coil, a further preferred embodiment of the present invention is that the leakage coil is successively composed of an annular amorphous magnetic core, an enameled wire, an insulating layer, and a metal shielding layer from the inside to the outside, and the enameled wire is wound on the upper half of the annular amorphous magnetic core.

[0029] Leakage detection needs to be very sensitive to tiny current changes. The amorphous magnetic core can accurately sense the extremely tiny unbalanced current (leakage current) in the circuit, improving the sensitivity and reliability of leakage detection. Similarly, the upper part winding can effectively utilize the magnetic flux change of the magnetic core, improving the induction efficiency. In addition, the outer layer of the leakage coil 4 is wrapped with a metal shielding layer 4.1, enhancing the anti-interference ability and balance of the coil.

[0030] In order to improve the versatility of the device for transmitting signals, a further preferred embodiment of the present invention is that the signal conversion circuit board is provided with an auxiliary power supply access terminal 5.1, a signal conversion circuit, and a signal output terminal.

[0031] The signal conversion circuit can be an MCU integrated on the signal conversion circuit board. The auxiliary power supply access terminal 5.1 is used to access the external circuit, converting DC24V into a weak current to supply power to the signal conversion circuit board. The signal output terminals include an analog signal output interface, an RS485 communication interface, and a display module interface. The MCU integrated on the signal conversion circuit board can convert the current signal collected by the coil into an analog signal through a specific algorithm, and then output the analog signal to external metering equipment and protection equipment through the analog signal output interface. At the same time, the MCU integrated on the signal conversion circuit board can also convert the current signal collected by the coil into a digital signal through an analog-to-digital conversion module, and then output the digital signal to external metering equipment through the RS485 communication interface. The adoption of the RS485 communication interface to integrate the digital signal transmission function enables the device to have a longer signal transmission distance, stronger anti-interference ability, and safer and more reliable signal transmission. In addition, a status indicator light can also be integrated on the signal conversion circuit board, and the indicator light alarms when the temperature of the signal conversion circuit board is too high or the current data is abnormal.

[0032] In order to make the installation method of the device diverse and the device installation fast and convenient, a further preferred embodiment of the present invention is that a guide rail clip 6, a bottom plate mounting bracket 1.1.1, a guide rail mounting slot 1.1.2, and a copper bar fixing buckle 1.2.1 are provided on the outer surface of the frame-shaped housing 1.1.

[0033] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. An open-type multifunctional AC current acquisition device, characterized in that It includes a housing, several measuring coils, several protection coils, a leakage current coil, several primary windings and a signal conversion circuit board; The housing is formed by clamping a frame-shaped housing and a cover plate. Several strip-shaped components fixed on the inner wall are arranged in the frame-shaped housing. One end of the strip-shaped component opens towards the cover plate. The housing is cut along its central cross-section into an upper housing component and a lower housing component. The sides of the upper housing component and the lower housing component are respectively provided with mating locking structures; The primary windings are respectively arranged in the strip-shaped components. The measuring coils and the protection coils respectively surround the strip-shaped components. The leakage current coil integrally surrounds the several strip-shaped components; The signal conversion circuit board is arranged inside the frame-shaped housing. The several measuring coils, the several protection coils and the leakage current coil are respectively electrically connected to the signal conversion circuit board.

2. The open-type multifunctional AC current acquisition device according to claim 1, wherein The housing is formed by an epoxy casting process. The signal conversion circuit board, the measuring coils, the protection coils and the leakage current coil are fixed inside the housing by an epoxy casting structure.

3. The open-type multifunctional alternating current acquisition device according to claim 1, wherein The measuring coil includes an annular amorphous magnetic core, enameled wire and an insulating layer. The enameled wire is wound around the upper half of the annular amorphous magnetic core. The insulating layer covers the annular amorphous magnetic core and the enameled wire.

4. The open-type multi-functional AC current acquisition device according to claim 1, wherein, The protection coil includes an annular silicon steel magnetic core, enameled wire and an insulating layer. The enameled wire is wound around the upper half of the annular silicon steel magnetic core. The insulating layer covers the annular silicon steel magnetic core and the enameled wire.

5. The open-type multifunctional AC current acquisition device according to claim 1, wherein The leakage current coil is successively an annular amorphous magnetic core, enameled wire, insulating layer, and metal shielding layer from the inside to the outside. The enameled wire is wound around the upper half of the annular amorphous magnetic core.

6. The open-type multi-functional alternating current acquisition device according to claim 1, characterized in that, The signal conversion circuit board is provided with an auxiliary power supply access terminal, a signal conversion circuit and a signal output terminal.

7. The open-type multifunctional AC current acquisition device according to claim 1, wherein At least one of a guide rail spring clip, a bottom plate mounting bracket, a guide rail mounting slot, and a copper bus bar fixing buckle is provided on the outer surface of the frame-shaped housing.

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