CN211741394U - Detection head and alternating voltage detection device - Google Patents
Detection head and alternating voltage detection device Download PDFInfo
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- CN211741394U CN211741394U CN201922277920.9U CN201922277920U CN211741394U CN 211741394 U CN211741394 U CN 211741394U CN 201922277920 U CN201922277920 U CN 201922277920U CN 211741394 U CN211741394 U CN 211741394U
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Abstract
The utility model provides a detection head and an alternating voltage detection device, wherein the detection head comprises an insulating shell and a detection electrode positioned in the insulating shell; the insulation shell is provided with a wiring hole for the cable to be detected to run, the detection electrode is arranged adjacent to the wiring hole, the insulation shell passes through the wiring hole and is assembled to the cable to be detected, the detection electrode and the cable to be detected form an electrodeless capacitor, and alternating voltage on the cable to be detected is converted into a detection signal through electric field coupling between capacitor electrodes. The utility model discloses a can constitute the detection electrode of an electrodeless electric capacity with the cable that awaits measuring, will alternating voltage on the cable that awaits measuring converts into the detected signal, because testing process does not have any direct contact with the system that awaits measuring, and whole measurement process does not have any influence to cable that awaits measuring and relevant system, and the security is higher.
Description
Technical Field
The embodiment of the utility model provides a relate to the alternating current detection area, more specifically say, relate to a detect head and alternating voltage detection device.
Background
At present, the detection of alternating voltage is mainly realized by an alternating voltage sensor, and the existing alternating voltage sensors sample voltage signals to be detected in a direct contact mode and then send the voltage signals to a subsequent processing circuit;
the used sampling mode of current voltage sensor mainly is resistance partial pressure and voltage transformer (PT) mode, no matter be resistance partial pressure mode or PT transformer mode, all is the low pressure that the alternating voltage on the circuit that awaits measuring is converted into follow-up circuit and can be handled after through the direct contact sampling, and this kind of mode has advantages such as convenient detection, simple structure, low cost, detection precision height, but these two kinds of modes have the security problem that can not avoid under its failure mode: the divider resistor may be broken down to cause short circuit, the voltage transformer may have turn-to-turn short circuit, and the like, and these faults are common in the use process, which finally causes the input impedance of the sensor to be reduced and even short circuit, thereby affecting the normal operation of the line or system to be measured. For the fields with high requirements on safety, such as railways, chemical industry, coal, military and the like, the influence caused by the short circuit can bring serious consequences and even threaten the safety of life and property. In order to reduce the failure rate of the alternating voltage sampling device, the sampling device needs to implement severe device production, quality control process and a large number of screening experiments before use, and needs to be regularly maintained and checked after use, which consumes a large amount of manpower and material resources, but still cannot completely avoid the influence on a system to be tested after the sampling device fails.
SUMMERY OF THE UTILITY MODEL
The to-be-solved technical problem of the utility model lies in, adopt resistance partial pressure and PT mutual-inductor mode detection voltage to the aforesaid to break down easily to influence the problem of the circuit or the normal work of system that awaits measuring, provide one kind and detect head and alternating voltage detection device.
The technical solution of the present invention to solve the above technical problems is to provide a detection head, which comprises an insulating housing and a detection electrode located in the insulating housing; the insulation shell is provided with a wiring hole for the cable to be detected to run, the detection electrode is arranged adjacent to the wiring hole, the insulation shell passes through the wiring hole and is assembled to the cable to be detected, the detection electrode and the cable to be detected form an electrodeless capacitor, and alternating voltage on the cable to be detected is converted into a detection signal through electric field coupling between capacitor electrodes.
Preferably, the insulating housing has a first connection terminal thereon, and the detection electrode is electrically connected to the first connection terminal.
Preferably, the detection head further comprises a shielding case, the shielding case is in a cylindrical shape with openings at two ends in the insulating shell, and the detection electrode is located in an area enclosed by the shielding case.
Preferably, the detection electrode is assembled in the insulating shell through pouring sealant, and the detection electrode is parallel to the central axis of the wiring hole.
Preferably, the detection electrode is made of a cylindrical conductive material, and the detection electrode is disposed around the wiring hole.
Preferably, the first connection terminal comprises a socket located at a side of the wire routing hole, and a central axis of the socket is parallel to a central axis of the wire routing hole.
The utility model also provides an alternating voltage detection device, which is used for detecting the alternating voltage on the cable to be detected and comprises a signal processing circuit, a power supply and the detection head; the input end of the signal processing circuit is electrically connected with the detection electrode and converts a detection signal on the detection electrode into a voltage to be output; the power supply is connected to the power supply input interface of the signal processing circuit and provides working voltage for the signal processing circuit.
Preferably, the signal processing circuit and the power supply are integrated into a detection host, and the detection host comprises a second connection terminal electrically connected with the signal processing circuit; the signal processing circuit is in conductive connection with the detection electrode through a cable connecting the first wiring terminal and the second wiring terminal.
Preferably, the signal processing circuit includes a signal amplifying unit, a digital filtering and compensating unit and an output transmitting unit, which are respectively powered by the power supply, and the signal amplifying unit linearly amplifies the detection signal from the detection electrode to a preset amplitude value, the digital filtering and compensating unit filters and digitally compensates the amplified detection signal, and the output transmitting unit converts the filtered and compensated signal into a voltage signal of a preset format for output.
Preferably, the alternating voltage detection device includes a plurality of detection heads respectively installed on cables to be detected of different phases, the detection host includes a plurality of second connection terminals respectively electrically connected with the signal processing circuit, and the signal processing circuit is electrically connected with the first connection terminals of the plurality of detection heads through a plurality of cables respectively connected to the plurality of second connection terminals.
The utility model discloses a detect head and alternating voltage detection device, through can constitute an electrodeless electric capacity's detection electrode with the cable that awaits measuring, will alternating voltage on the cable that awaits measuring converts into the detected signal, because testing process and the system that awaits measuring do not have any direct contact, whole measurement process does not have any influence to cable that awaits measuring and relevant system, and the security is higher. And, through set up first binding post at insulating casing for need not to break off the cable that awaits measuring and can detect. Furthermore, the utility model discloses still set up shield cover shielding same frequency interference detecting the head for measure the lower limit and can reach 50mV, cooperation insulating casing has improved measuring range greatly.
Drawings
Fig. 1 is a schematic structural diagram of a detection head according to an embodiment of the present invention;
fig. 2 is a schematic end structure diagram of a detection head provided in an embodiment of the present invention;
fig. 3 is a schematic cross-sectional structure diagram of a detection head according to an embodiment of the present invention;
fig. 4 is a schematic diagram of an ac voltage detecting apparatus according to an embodiment of the present invention;
fig. 5 is a schematic diagram of an ac voltage detecting apparatus for single cable voltage detection according to an embodiment of the present invention;
fig. 6 is a schematic diagram of an ac voltage detecting apparatus for detecting voltage of a two-phase cable according to an embodiment of the present invention;
fig. 7 is a schematic diagram of an ac voltage detecting apparatus for detecting voltage of a three-phase cable according to an embodiment of the present invention;
fig. 8 is a schematic diagram of an ac voltage detecting apparatus for detecting voltage of another three-phase cable according to an embodiment of the present invention;
fig. 9 is a schematic diagram of a signal processing circuit in an ac voltage detecting apparatus according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
As shown in fig. 1-3, the embodiment of the present invention provides a structural schematic diagram of a detection head, which can be used to assist in detecting the ac voltage on the cable to be detected. The detection head of the present embodiment includes an insulating housing 11 and a detection electrode 12, and the detection electrode 12 is located in the insulating housing 11, wherein the insulating housing 11 may be formed by processing insulating materials such as ABS, PC, ABS + PC, and ceramics, and the detection electrode 12 may be specifically copper, copper alloy, or other types of conductive materials. The insulating housing 11 is provided with a wire feeding hole 13 for the cable to be detected to be routed, the detection electrode 12 and the wire feeding hole 13 are arranged adjacently (the inner space of the wire feeding hole 13 is separated from the detection electrode 12 by an insulating layer), and when the insulating housing 11 is assembled to the cable to be detected through the wire feeding hole 13 (namely, the cable to be detected passes through the wire feeding hole 13), the detection electrode 12 and the cable to be detected form an electrodeless capacitor (the detection electrode 12 and the cable to be detected respectively form an electrode of the capacitor), and the alternating voltage on the cable to be detected is converted into a detection signal through the electric field coupling between the capacitor electrodes (namely, the alternating voltage on the cable to be detected is coupled to the detection electrode 12 through the electric field between the capacitor electrodes), so that the auxiliary detection of the voltage. Also, in order to increase the intensity of the detection signal to realize high-precision detection, the detection electrode 12 may have a large surface area.
The detection head enables the cable to be detected and the detection electrode to form an electrodeless capacitor through the insulating shell 11, so that alternating voltage on the cable to be detected can be converted into a detection signal, detection of the alternating voltage on the cable to be detected is achieved, the detection process is free of any direct contact with a system to be detected, the whole measurement process is free of any influence on the cable to be detected and related systems, and safety is high. Due to the 'DC-AC blocking' characteristic of the capacitor, the detection head can only measure an AC voltage signal but cannot measure a DC voltage signal.
In addition, by selecting proper materials and designing the structure, the capacitance value of the capacitor of the detection head can be controllably changed within a certain range under the field use environment, so that a relatively stable and compensable sampling voltage signal can be obtained.
In an embodiment of the present invention, the insulation shell 11 of the detection head may have a first connection terminal 14 thereon, and the detection electrode 12 is electrically connected to the first connection terminal 14, for example, the first connection terminal 14 may include a socket, so as to facilitate connection. By being connected to the first connection terminal 14, the detection electrode 12 can be electrically connected to obtain a detection signal on the detection electrode 12. Specifically, the end portion of the detection electrode 12 may be soldered to a Printed Circuit Board (PCB) 15, and accordingly, the conductive portion of the first connection terminal 14 is also soldered to the PCB 15, thereby achieving conductive connection with the detection electrode 12.
The insulating housing 11 may be a double-layer cylindrical structure, that is, it includes an outer sleeve and an inner sleeve, which are made of insulating material and can be integrally injection-molded. The outer sleeve and the inner sleeve may be cylindrical, the wire hole 13 is located in the inner sleeve, and the detection electrode 12 is installed in a cavity between the inner sleeve and the outer sleeve (i.e., the detection electrode 12 and the wire hole 13 are separated by the inner sleeve), for example, the detection electrode 12 may be encapsulated in the cavity by a potting adhesive. Also, in order to improve the detection accuracy, the detection electrode 12 may be parallel to the central axis of the wiring hole 13. Of course, the detecting electrode 12 can be integrally injection-molded with the insulating housing 11 if the material is selected to allow.
In order to better realize the electric field coupling with the cable to be detected and improve the strength of the detection signal, the detection electrode 12 may be made of a cylindrical conductive material, and the detection electrode 12 is disposed around the wiring hole 13. Specifically, the potential difference between the detection electrode 12 and the cable to be measured can be represented by the following calculation formula (1):
wherein, UAFor the voltage on the cable to be tested, UBTo sense the voltage at the electrodes, RARadius of cable to be measured, RBThe radius of the cylindrical surface on which the detection electrode 12 is located is l, which is the height of the detection electrode 12 (i.e., the length of the detection electrode 12), and λ, which is the amount of charge per unit length of the detection electrode 12.
In another embodiment of the present invention, the detection head may further include a shielding case (for example, made of a metal material), and the shielding case is in a cylindrical shape with openings at both ends in the insulating housing 11. The detection electrode 12 and the wiring hole 13 are respectively positioned in the area enclosed by the shielding case, and the detection electrode 12 and the shielding case are separated by an insulating layer. Correspondingly, the first connection terminal 14 may include a radio frequency connector and an inner pin (the inner pin may be welded to the printed circuit board 15) located in the radio frequency connector, the shielding case is connected to the radio frequency connector of the first connection terminal 14, and the detection electrode 12 is electrically connected to the inner pin of the first connection terminal 14, so that external interference signals may be shielded by the shielding case and the radio frequency connector, the lower measurement limit of the detection head may reach 50mV, and the detection accuracy is greatly improved. The radio frequency connector can ensure the shielding performance of the shielding cover, and particularly, the radio frequency connector can be coaxially connected with the inner needle in a plugging mode or other modes.
The detection electrode 12, the shield, the printed circuit board 15 and the first connection terminal 14 can form a relatively independent module and are assembled in a cavity between the outer sleeve and the inner sleeve of the insulating shell 11, so that the integration level of the detection head is improved, and the assembly is facilitated.
In order to facilitate connection with an external device, in the above-described inspection head, the insertion port of the first connection terminal 14 may be located at a side portion of the wiring hole 13, and a central axis of the insertion port may be parallel to a central axis of the wiring hole 13.
As shown in fig. 4, the embodiment of the present invention further provides an ac voltage detection device, which is used to detect the ac voltage on the cable 30 to be detected, and it is not necessary to add hardware in the system where the cable to be detected is located, and it is not necessary to disconnect the system where the cable to be detected is located. The detection device of the present embodiment includes a signal processing circuit 21, a power supply 22, and the detection head 10 as described above. The input end of the signal processing circuit 21 is electrically connected to the detection electrode 12 of the detection head 10, and converts the detection signal on the detection electrode 12 into a voltage for output; the power supply 22 is connected to the power supply input interface of the signal processing circuit 21 and supplies an operating voltage to the signal processing circuit 21.
In the ac voltage detecting apparatus, the detecting head 10 can be directly mounted on the cable 30 to be detected, that is, the cable 30 to be detected passes through the wiring hole 13 of the detecting head 10; the signal processing circuit 21 and the power supply 22 may be integrated into a detection host 20, and the detection host 20 includes a second connection terminal electrically connected to the signal processing circuit 21. When the voltage of the cable 30 to be detected needs to be detected, the second connection terminal can be connected to the first connection terminal 14 through the cable, so that the signal processing circuit 21 is electrically connected with the detection electrode 12, and the detection signal is obtained from the detection electrode 12.
The signal processing circuit 21 may specifically include a signal amplifying unit, a digital filtering and compensating unit, and an output transmitting unit, and the signal amplifying unit, the digital filtering and compensating unit, and the output transmitting unit are respectively powered by the power supply 22. The input end of the signal amplification unit is connected to the second connection terminal so as to collect weak voltage signals from the detection electrode 12 of the detection head 10 and amplify the weak voltage signals, and in order to ensure that alternating voltage signals with different amplitudes are collected linearly, the signal amplification unit can adopt devices with linear working modes such as resistors and integrated operational amplifiers, and the like, so that the sampled signals can be linearly amplified to preset amplitudes. Because the signal quantity collected by the detection head 10 is very weak and is easily interfered by external signals, the digital filtering and compensating unit can be used for filtering and collecting the signals, and can specifically adopt a digital band-pass filter for filtering. Meanwhile, due to the influence of inherent characteristics such as frequency characteristics and temperature characteristics of the capacitor, the capacitor of the detection head 10 generates measurement errors on different voltage acquisition amounts with different frequencies, capacitance values of the capacitor influenced by environmental temperature changes, and the like, so that the digital filtering and compensating unit also needs to correct the sampling signal in a digital compensation mode to offset the measurement errors and ensure the measurement accuracy. The output transmitting unit is used for transmitting the filtered and compensated voltage signal into a required signal (namely, a voltage signal with a preset format) and outputting the required signal, for example, the required signal CAN be converted into a standard industrial analog signal, various standard or non-standard transmission protocols such as digital RS485/RS232/CAN and the like, a wireless interface, a cloud (including Bluetooth, NB-IOT, GPRS) and the like.
The alternating voltage detection device can be used for detecting the voltage of a single cable, and as shown in fig. 5, the alternating voltage detection device only comprises one detection head 10, and the detection host 20 only comprises one second connection terminal; the ac voltage detection device can be used to detect the voltage of the two-phase cable L, N, and as shown in fig. 6, the ac voltage detection device includes two detection heads 10 respectively mounted on the L, N-phase cable to be detected, and the detection host 20 includes two second connection terminals respectively electrically connected to the signal processing circuit; the ac voltage detection device can be used to detect the voltage of the three-phase cable A, B, C, and as shown in fig. 7, the ac voltage detection device includes three detection heads 10 respectively mounted on the A, B, C-phase cable to be detected, and the detection host 20 includes three second connection terminals respectively electrically connected to the signal processing circuit; the ac voltage detection device can be used to detect the voltages of the three-phase cable A, B, C and the zero line N, and as shown in fig. 8, the ac voltage detection device includes four detection heads 10 respectively installed on the A, B, C-phase cable to be detected and the zero line N, and the detection host 20 includes four second connection terminals respectively electrically connected to the signal processing circuit.
The following describes a topology structure of a signal amplifying unit in the signal processing circuit 21, which is applied to the voltage detection signal processing of the two-phase cable to be tested, with reference to fig. 9. The signal amplification unit comprises a precision instrument amplifier consisting of double operational amplifiers, and the input end of the signal amplification unit can be customized into current input type negative feedback.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention should be covered by the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A detection head is characterized by comprising an insulating shell and a detection electrode positioned in the insulating shell; the insulation shell is provided with a wiring hole for the cable to be detected to run, the detection electrode is arranged adjacent to the wiring hole, the insulation shell passes through the wiring hole and is assembled to the cable to be detected, the detection electrode and the cable to be detected form an electrodeless capacitor, and alternating voltage on the cable to be detected is converted into a detection signal through electric field coupling between capacitor electrodes.
2. The head of claim 1, wherein the dielectric housing has a first terminal thereon, and the sensing electrode is electrically connected to the first terminal.
3. The head according to claim 1, wherein the head further comprises a shield case in a cylindrical shape having openings at both ends thereof in the insulating housing, and the detection electrode and the wiring hole are respectively located in an area surrounded by the shield case.
4. The head according to claim 1, wherein the detection electrode is fitted in the insulating housing by potting adhesive, and the detection electrode is parallel to a central axis of the wiring hole.
5. The head of claim 4, wherein the sensing electrode is formed of a cylindrical conductive material and is disposed around the wiring hole.
6. The probe according to claim 2, wherein the first connection terminal includes a socket at a side of the wiring hole, and a central axis of the socket is parallel to a central axis of the wiring hole.
7. An alternating voltage detection device for detecting an alternating voltage on a cable to be detected, wherein the detection device comprises a signal processing circuit, a power supply and a detection head according to any one of claims 1 to 6; the input end of the signal processing circuit is electrically connected with the detection electrode and converts a detection signal on the detection electrode into a voltage to be output; the power supply is connected to the power supply input interface of the signal processing circuit and provides working voltage for the signal processing circuit.
8. The ac voltage detecting device according to claim 7, wherein the signal processing circuit and the power supply are integrated into a detecting host, and the detecting host comprises a second connection terminal electrically connected to the signal processing circuit; the signal processing circuit is in conductive connection with the detection electrode through a cable connecting the first wiring terminal and the second wiring terminal.
9. The ac voltage detecting apparatus according to claim 7, wherein the signal processing circuit includes a signal amplifying unit, a digital filtering and compensating unit, and an output transmitting unit, which are respectively powered by the power supply, and linearly amplifies the detection signal from the detection electrode to a preset amplitude by the signal amplifying unit, filters and digitally compensates the amplified detection signal by the digital filtering and compensating unit, and converts the filtered and compensated signal to a voltage signal output of a preset format by the output transmitting unit.
10. The ac voltage detecting device according to claim 8, wherein the ac voltage detecting device includes a plurality of detecting heads respectively attached to cables to be detected of different phases, the detecting main unit includes a plurality of second connecting terminals respectively electrically connected to the signal processing circuit, and the signal processing circuit is electrically connected to the first connecting terminals of the plurality of detecting heads through a plurality of cables respectively connected to the plurality of second connecting terminals.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922277920.9U CN211741394U (en) | 2019-12-16 | 2019-12-16 | Detection head and alternating voltage detection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922277920.9U CN211741394U (en) | 2019-12-16 | 2019-12-16 | Detection head and alternating voltage detection device |
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| Publication Number | Publication Date |
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| CN211741394U true CN211741394U (en) | 2020-10-23 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201922277920.9U Active CN211741394U (en) | 2019-12-16 | 2019-12-16 | Detection head and alternating voltage detection device |
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| CN (1) | CN211741394U (en) |
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