CN212410750U - Data acquisition device suitable for single-phase earth fault line selection - Google Patents
Data acquisition device suitable for single-phase earth fault line selection Download PDFInfo
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- CN212410750U CN212410750U CN202020706876.9U CN202020706876U CN212410750U CN 212410750 U CN212410750 U CN 212410750U CN 202020706876 U CN202020706876 U CN 202020706876U CN 212410750 U CN212410750 U CN 212410750U
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Abstract
The utility model discloses a data acquisition device suitable for single-phase earth fault route selection relates to single-phase earth fault route selection technical field. The device comprises a PCB circuit board and a TMR sensor group, wherein the PCB circuit board is formed by splicing and connecting a left PCB board and a right PCB board through electric terminals, and the left PCB board and the right PCB board are clamped on a conductor to be tested after being surrounded; the TMR sensor group consists of four groups of TMR sensors, wherein two TMR sensors are attached to the front side and the back side of the same PCB; the PCB circuit board is provided with a signal processing circuit and is connected with an upper computer through a data interface, and the TMR sensor is electrically connected with the signal processing circuit. When the device is used, the left PCB and the right PCB are clamped on the conductor to be tested, the device is convenient to disassemble and assemble and does not need to be installed after the power of the device is cut off, the measurement range is wide, the result is accurate, the installation is simple and easy, and the cost is low. The four groups of eight TMR sensors are used, high-precision measurement is carried out on the current in a mode of firstly carrying out differential amplification and then carrying out mean value operation, and the success rate of line selection is effectively improved.
Description
Technical Field
The utility model relates to a single-phase earth fault route selection technical field, concretely relates to data acquisition device suitable for single-phase earth fault route selection.
Background
The single-phase earth fault refers to a 10kV to 35kV low-current earth fault and is the most frequently occurring fault type in power distribution network faults. The resulting impact not only affects the normal power supply to the user, but also may cause irreversible damage to the equipment, affecting socioeconomic performance. Therefore, how to quickly identify a fault and locate a fault area of a single-phase ground fault is always a key content of research in the electrical field, including research on single-phase ground fault line selection.
The common current transformer can detect the change of current, but after single-phase earth fault happens, the symmetry of line voltage can still be ensured by supplying power, the current change is small during fault, and even the continuous power supply to the load is not influenced in a short period. Therefore, the normal current transformer monitoring current mode is difficult to identify the influence of the fault, and the difference between the fault phase and the non-fault phase cannot be judged. The traditional measurement scheme is to comprehensively judge the zero sequence voltage or zero sequence power direction of the system, and the equipment adopts zero sequence CT and other equipment to perform data acquisition work of single-phase earth fault line selection, but the equipment is inconvenient to install, generally needs to be installed and enters a power distribution network to work after the equipment is powered off, and the success rate of line selection is low.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a data acquisition device suitable for single-phase earth fault route selection solves current route selection device and can only install and the low problem of route selection success rate after the equipment outage.
In order to solve the technical problem, the utility model adopts the following technical scheme: the utility model provides a data acquisition device suitable for single-phase earth fault route selection which characterized in that: the TMR sensor group comprises a PCB (printed Circuit Board) and a TMR sensor group, wherein the PCB is formed by splicing and connecting a left PCB and a right PCB through electric terminals, and the left PCB and the right PCB are encircled and then clamped on a conductor to be tested; the TMR sensor group consists of four groups of TMR sensors, wherein two TMR sensors are attached to the front side and the back side of the same PCB; the PCB circuit board is provided with a signal processing circuit and is connected with an upper computer through a data interface, and the TMR sensor is electrically connected with the signal processing circuit.
The TMR sensor group has the further technical scheme that the distances from the TMR sensor to the center of the conductor to be measured are all consistent, and the sensing directions of the TMR sensor groups are opposite.
The further technical scheme is that the included angle formed by the connecting line of the centers of the adjacent TMR sensors and the center of the conductor to be measured is 90 degrees.
A further technical scheme is that the left PCB and the right PCB are semi-annular, the end faces of the left PCB and the right PCB are provided with electric terminals matched with each other, the outer side wall of the left PCB and the right PCB is provided with a shielding layer, and the data interface is arranged on one of the left PCB and the right PCB and is electrically connected with the signal processing circuit.
The signal processing circuit is composed of a differential amplifier, an average value adder, a program control gain amplifier and an AD converter which are electrically connected in sequence, wherein the differential amplifier is electrically connected with the TMR sensor group, the AD converter is connected with an AD data interface of a data interface, the program control gain amplifier is connected with the program control gain interface of the data interface, and the signal processing circuit further comprises a power module for providing a power supply.
The further technical scheme is that the differential amplifier is provided with four paths, and each path is correspondingly connected with one group of TMR sensors.
The working principle is as follows: four groups of TMR sensors, two of each group are tightly attached to the front and back sides of the same printed circuit board and are positioned at the radial distance L of the conductor to be measured, the included angle between the connecting line of each group of central points and the radial central point of the conductor and the connecting line of the adjacent group is 90 degrees, the four groups are wrapped around the current-carrying conductor in a circular shape, and the sensitive directions of the two sensors of each group are opposite.
The differential amplifier has four paths and corresponds to four groups of sensors respectively. The output of each group of sensors should ideally be equal in magnitude and opposite in polarity. And (3) differentially amplifying the input voltages with opposite polarities by using a differential amplification circuit, and outputting measurement results of the four groups of sensors, namely U1, U2, U3 and U4.
The average adder uses a high-bandwidth dual-power operational amplifier to add the gains of one fourth of U1, U2, U3 and U4 respectively, so as to achieve the effect of averaging by an analog circuit.
Amplification circuit and AD sampling: the obtained average voltage is amplified by controllable gain using a high-bandwidth PGA (programmable gain amplifier), and the gain can be controlled by an external interface command. The amplified voltage enters a high-frequency AD for sampling, and a sampling measurement value is uploaded to an upper computer through an AD data interface.
Compared with the prior art, the beneficial effects of the utility model are that:
(1) control two PCB boards pass through the connection that electric terminal can peg graft, during the use will control two PCB integrated circuit boards connect on the conductor that awaits measuring can, easy dismounting just need not to install again after the equipment outage, and measuring range is wide, and the result is accurate, and the installation is simple and easy, and is with low costs.
(2) And the current is measured with high precision by using four groups of eight TMR sensors in a mode of firstly carrying out differential amplification and then carrying out mean value operation. The influence of external interference, noise of individual devices, slight change of the shape and position of the lead and the like on the measurement result is effectively reduced, the measurement precision is high, and the success rate of line selection is effectively improved.
(3) The data interface is provided with an AD data transmission interface and a program control gain amplifier interface, the AD data interface can acquire acquired data, and the program control gain amplifier interface can reduce gain through the interface after a grounding line selection fault occurs so as to realize rapid checking of fault current; and when no fault occurs, the high-precision monitoring of the normal operation current can be realized by increasing the gain.
Drawings
Fig. 1 is the assembly schematic diagram of the middle PCB and the TMR sensor of the present invention.
Fig. 2 is a schematic diagram of a frame of the signal processing circuit according to the present invention.
Fig. 3 is a waveform diagram of a simulated fault current generated using PSCAD.
Fig. 4 is a measurement result diagram of the data acquisition device of the present invention.
In the figure: the device comprises a 1-PCB, a 101-left PCB, a 102-right PCB, a 2-TMR sensor, a 3-electrical terminal, a 4-conductor to be tested, a 5-data interface and a 6-shielding layer.
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.
Fig. 1 and 2 show a data acquisition device suitable for single-phase earth fault line selection, which comprises a PCB circuit board 1 and a TMR sensor group, wherein the PCB circuit board 1 is composed of a left PCB board 101 and a right PCB board 102, the left PCB board 101 and the right PCB board 102 are both in a semi-ring shape, a cylindrical shielding layer 6 is arranged on the outer side wall, and the shielding layer 6 is a layer of high-permeability material parallel to the axial direction of the PCB circuit board 1. The end faces of the left PCB 101 and the right PCB 102 are provided with adaptive electrical terminals 3, and one of the PCBs is provided with a data interface 5. During the use, surround the back joint on the conductor 4 that awaits measuring with semi-annular left PCB board 101 and right PCB board 102, two PCB boards realize connecting after electric terminal 3 pegs graft.
The TMR sensor group is composed of four groups of TMR sensors 2, each group is two and pastes the positive and negative of same PCB circuit board 1 relatively, TMR sensor 2 is all unanimous to 4 central distances of conductor to be measured, the sensitive direction of group TMR sensor 2 is opposite, the line of TMR sensor 2 center to 4 centers of conductor to be measured and adjacent TMR sensor 2 center to 4 centers of conductor to be measured are the contained angle that becomes 90, four groups of TMR sensors 2 are circular parcel around 4 conductors to be measured.
The PCB circuit board 1 is provided with a signal processing circuit, the signal processing circuit is composed of a differential amplifier, an average value adder, a program control gain amplifier and an AD converter which are electrically connected in sequence, the differential amplifier is electrically connected with the TMR sensor group, the AD converter is connected with an AD data interface of the data interface 5, and the digital signal after AD sampling on the board is output. The programmable gain amplifier is connected with a programmable gain interface of the data interface 5, and an external control system can input instructions through the interface to control the gain of the programmable gain amplifier.
The signal processing circuit also comprises a power supply module for supplying power. The data interface 5 is connected with an upper computer, and the upper computer can directly read data and can also perform secondary processing and analysis on the data. The differential amplifier is provided with four paths, and each path is correspondingly connected with one group of TMR sensors 2.
When the TMR sensor is used, the left PCB 101 and the right PCB 102 are clamped on the conductor 4 to be measured and powered on, the power module of the device starts to work after being powered on, the TMR sensor 2 in the same group actually measures magnetic fields in opposite directions of the same point, the voltages with the same magnitude and opposite polarities are transmitted to a differential amplifier, the differential amplifier circuit carries out differential amplification on input voltage, and measurement results of the four groups of sensors, namely U1, U2, U3 and U4, are output. The differential amplifier and the two TMR sensors 2 here can protect the signal from small interfering signals. Meanwhile, the differential mode is used for measuring signals, so that the influence of the device on the measurement result when the device is subjected to common-mode interference such as power supply fluctuation, ripple waves and the like can be effectively reduced.
The average adder uses a high-bandwidth dual-power operational amplifier to add the gains of one fourth of U1, U2, U3 and U4 respectively, so as to achieve the effect of averaging by an analog circuit. The signal then passes through a PGA (programmable gain amplifier) to a high frequency, high accuracy AD converter. And finally, combining the data interface of the AD and the gain control interface of the programmable gain amplifier to serve as a data interface 5 of the equipment, and carrying out data transmission on the data interface 5 and an upper computer.
The device manufactured based on the composition principle is used for carrying out preliminary measurement and waveform restoration on the fault current simulated under the laboratory condition. In this experiment, a waveform file of a simulated fault current was generated using PSCAD, and as shown in fig. 3, an automatic trigger mode was set with a trigger frequency of 100 times per second and a current maximum of 13.7A. The waveform file is sent to a waveform generator in the above-described mode, and measurement is performed after the measurement circuit is connected. And the waveform of the measurement result is displayed on an oscilloscope. The result of the final measurement is reduced to a waveform as shown in fig. 4.
It should be noted that, this equipment is designed for measuring single-phase earth fault route selection, and normal distribution network operating current and fault current are about 1000A and above, therefore this equipment's range is great, has the more obvious inaccurate condition of measurement when measuring the experimental current. But still can see from the enlarged measurement result picture that the measurement result is basically the same with the characteristics of the original waveform, simultaneously according to this experiment, when measuring the situation of 14.7A electric current at most, the absolute error is not more than 1A, therefore can conjecture that when measuring 1000A heavy current, the measurement precision should be within 0.5%, completely satisfy the measurement requirement to single-phase earth fault route selection.
Although the invention has been described herein with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this invention. More particularly, various variations and modifications are possible in the component parts and/or arrangements within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, other uses will also be apparent to those skilled in the art.
Claims (6)
1. The utility model provides a data acquisition device suitable for single-phase earth fault route selection which characterized in that: the TMR sensor group is characterized by comprising a PCB (printed circuit board) 1 and a TMR sensor group, wherein the PCB (1) is formed by a left PCB (101) and a right PCB (102) which are connected in a plug-in mode through an electric terminal (3), and the left PCB (101) and the right PCB (102) are clamped on a conductor (4) to be detected after being surrounded; the TMR sensor group is composed of four groups of TMR sensors (2), and two of each group are oppositely attached to the front and back surfaces of the same PCB (1); the PCB circuit board (1) is provided with a signal processing circuit and is connected with an upper computer through a data interface (5), and the TMR sensor (2) is electrically connected with the signal processing circuit.
2. The data acquisition device suitable for single-phase earth fault line selection according to claim 1, wherein: distances from the TMR sensor (2) to the center of the conductor (4) to be measured are consistent, and the sensitivity directions of the grouped TMR sensors (2) are opposite.
3. The data acquisition device suitable for single-phase earth fault line selection according to claim 2, wherein: and an included angle formed by the connecting line of the centers of the adjacent TMR sensors (2) and the center of the conductor (4) to be tested is 90 degrees.
4. The data acquisition device suitable for single-phase earth fault line selection according to claim 1, wherein: the left PCB (101) and the right PCB (102) are both semi-annular, the end faces of the left PCB and the right PCB are provided with electric terminals (3) matched with each other, the outer side wall of the left PCB is provided with a shielding layer (6), and a data interface (5) is arranged on one of the left PCB (101) and the right PCB (102) and is electrically connected with a signal processing circuit.
5. The data acquisition device suitable for single-phase earth fault line selection according to claim 1, wherein: the signal processing circuit is composed of a differential amplifier, an average value adder, a program control gain amplifier and an AD converter which are sequentially and electrically connected, the differential amplifier is electrically connected with the TMR sensor group, the AD converter is connected with an AD data interface of the data interface (5), the program control gain amplifier is connected with the program control gain interface of the data interface (5), and the signal processing circuit further comprises a power supply module for providing a power supply.
6. The data acquisition device suitable for single-phase earth fault line selection according to claim 5, wherein: the differential amplifier is provided with four paths, and each path is correspondingly connected with one group of TMR sensors (2).
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| Application Number | Priority Date | Filing Date | Title |
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| CN202020706876.9U CN212410750U (en) | 2020-04-30 | 2020-04-30 | Data acquisition device suitable for single-phase earth fault line selection |
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| CN202020706876.9U CN212410750U (en) | 2020-04-30 | 2020-04-30 | Data acquisition device suitable for single-phase earth fault line selection |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112964928A (en) * | 2021-02-24 | 2021-06-15 | 优利德科技(中国)股份有限公司 | Clamp-on ammeter without magnetism collecting iron core and automatic balance adjusting method |
| CN115728547A (en) * | 2022-10-10 | 2023-03-03 | 烟台东方威思顿电气有限公司 | Open TMR array sensor access type direct current electric energy meter and precision compensation method |
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2020
- 2020-04-30 CN CN202020706876.9U patent/CN212410750U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112964928A (en) * | 2021-02-24 | 2021-06-15 | 优利德科技(中国)股份有限公司 | Clamp-on ammeter without magnetism collecting iron core and automatic balance adjusting method |
| CN112964928B (en) * | 2021-02-24 | 2024-01-30 | 优利德科技(中国)股份有限公司 | Clamp ammeter without integrated magnet core and automatic balance adjustment method |
| CN115728547A (en) * | 2022-10-10 | 2023-03-03 | 烟台东方威思顿电气有限公司 | Open TMR array sensor access type direct current electric energy meter and precision compensation method |
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