CN112415433A - Long-lead short-circuit fault point positioning device and method - Google Patents

Long-lead short-circuit fault point positioning device and method Download PDF

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Publication number
CN112415433A
CN112415433A CN201910772276.4A CN201910772276A CN112415433A CN 112415433 A CN112415433 A CN 112415433A CN 201910772276 A CN201910772276 A CN 201910772276A CN 112415433 A CN112415433 A CN 112415433A
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short
point
circuit fault
control mcu
test
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CN201910772276.4A
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李威远
洪若昕
朱效锐
金豫
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East China Normal University
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East China Normal University
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08Locating faults in cables, transmission lines, or networks
    • G01R31/081Locating faults in cables, transmission lines, or networks according to type of conductors

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  • General Physics & Mathematics (AREA)
  • Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)

Abstract

The invention provides a long lead short circuit fault point positioning device, which comprises: the device comprises a main control MCU, a constant current source, a high-precision instrument amplifier, a high-precision ADC and a display screen; wherein the master control MCU is STM32H 743; the constant current source is used as an excitation signal and is connected to one end of the test point; the amplifier for the high-precision instrument is connected to the two test points to amplify the differential mode voltage of the two test points; the output end of the amplifier for the high-precision instrument is connected to the input end of the high-precision ADC, and the differential mode voltage between the two amplified test points is measured; after the differential mode voltage is measured, the communication between the high-precision ADC and the main control MCU is completed through an SPI protocol, and after the main control MCU receives data, the position of a short-circuit fault point and a distance test point is reversely deduced; the display screen is used for displaying.

Description

Long-lead short-circuit fault point positioning device and method
Technical Field
The invention relates to the field of fault detection, in particular to a long-conductor short-circuit fault point positioning device and method.
Background
Short-circuit failure is one of the most prone failure modes, and the conventional measurement of the short-circuit failure point is as follows: the utility model discloses a short-circuit fault detection device, including the universal meter, the short-circuit fault detection device is used to detect the short-circuit fault of long wire, and the short-circuit fault detection device is used to detect the short-circuit fault of long wire.
At present, no long-lead short-circuit fault point positioning device exists in the market.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides the long-lead short-circuit fault point positioning device and method which are simple in structure, low in cost, convenient to use and accurate in test.
The invention has the main functions of detecting the short circuit of the long lead, simultaneously accurately analyzing the position of a short-circuit fault point and displaying the distance from the test point on a display screen.
In order to realize the functions, the invention provides the following technical scheme: the utility model provides a long wire short circuit fault point positioner, includes a master control MCU, MCU is STM32H743, a constant current source, a high accuracy is amplifier for the appearance, a high accuracy ADC, and a display screen is used for showing.
The functionality of the present invention is thus implemented. The idea of the invention is that the length of the wire can be analyzed by measuring the resistance of the wire between the measuring points, thereby reversely deducing the position of the short-circuit point. In order to measure the size of the wire resistance, a constant current source is adopted as an excitation signal and connected to one end of a test point, an amplifier for the high-precision instrument is connected to two test points to amplify the differential mode voltage of the two test points, the output end of the amplifier for the high-precision instrument is connected to the input end of a high-precision ADC, and the amplified differential mode voltage between the two test points is measured. After the differential mode voltage is measured, the communication between the high-precision ADC and the master control MCU is completed through the SPI protocol, and after the master control MCU receives the data, the position of the short-circuit fault point and the distance test point is reversely deduced.
The long lead is made of uniform materials and has good linearity, so that resistivity information of the long lead needs to be obtained before testing, 3cm and 5cm leads are clamped between two testing points respectively before formal measurement, voltage values of corresponding position points are stored according to the prompt of a display screen, a straight line is determined according to the theorem of two points, and the main control MCU obtains the corresponding relation between the distance and the voltage values according to the voltage values of the two points. When the position of the short-circuit point is tested, the two ends of the wire are clamped between the two test points, at the moment, the constant current source is electrified, after the voltage of the short-circuit point is stable, the distance between the short-circuit point and the test point A is calculated according to the measured voltage and is displayed on the display screen, and at the moment, a user can quickly find the position of the short-circuit fault point according to the numerical value displayed on the display screen to perform quick troubleshooting.
Drawings
FIG. 1 is a schematic diagram of the overall scheme of the present invention;
FIG. 2 is a schematic view of an interface according to the present invention;
FIG. 3 is a circuit diagram of a constant current source of the present invention;
FIG. 4 is a circuit diagram of an amplifier for a high-precision instrument according to the present invention;
FIG. 5 is a circuit diagram of a high-precision ADC according to the present invention;
FIG. 6 is a code flow diagram of the present invention;
Detailed Description
The invention is further described in detail with reference to the following specific examples and the accompanying drawings. The procedures, conditions, experimental methods and the like for carrying out the present invention are general knowledge and common general knowledge in the art except for the contents specifically mentioned below, and the present invention is not particularly limited.
Referring to the attached figure 1, the main body of the invention is a constant current source, a high-precision instrument amplifier, a high-precision ADC, a main control MCU and a display screen.
Referring to fig. 2, in addition to identifying the position of the short-circuit point, the interface of the present invention is further provided with three touch buttons, namely, a "3 cm" acquisition, a "5 cm" acquisition, and a "start test". After a user starts the machine, the test point is clamped at the positions of 3cm and 5cm, the 3cm acquisition button is pressed after the 3cm position is clamped, the 5cm acquisition button is pressed after the 5cm position is clamped, at the moment, the voltage values at the positions of 3cm and 5cm are stored by the main control MCU, and the relation between the coordinate and the voltage is calculated. And clamping the long lead at A, B, pressing a 'start test' button, reading the voltage value of the high-precision AD by the main control MCU, deducing the distance from the short circuit point to the test point according to the calculated formula, and displaying the distance at the corresponding position of the display screen. And the display screen is communicated with the main control MCU through a serial port.
Referring to fig. 3, as shown in the schematic diagram of the constant current source, the AD5060 is a programmable 16-bit DAC, the magnitude of the output current of the constant current source can be precisely controlled by the MCU, and the communication mode between the AD5060 and the master MCU is SPI. REF3220 is a reference source chip of TI company, and its excellent low temperature drift characteristic can be used as a reference source of the AD5060, thereby ensuring that the output value of the constant current source is stable. According to the ohm theorem, the differential mode voltage of the two test points is stable when the same short-circuit fault point is ensured.
Referring to fig. 4, a schematic diagram of the amplifier for high-precision instruments is shown, the amplifier for high-precision instruments uses AD8227 manufactured by ADI corporation, and has excellent common mode rejection ratio, and can amplify differential mode voltage in microvolt level, thereby meeting the requirement of high precision in the present invention. The gain of the AD8227 can support an external resistance setting, which can be set by R1 and R2 in fig. 4. In the invention, the differential mode signals of the two test points are amplified by 20 times so as to ensure the precision of 1 cm.
Referring to fig. 5, the high-precision ADC is AD7793 manufactured by ADI corporation, suitable for high-precision measurement applications, and incorporates a low-noise 24-bit ADC with three differential analog inputs. An internal reference source may be used, also supporting an external reference source, several diodes in fig. 5 providing protection for the input pins of AD 7793.
Referring to fig. 6, the work flow of the master MCU is as follows. After the computer is started, when a 3cm acquisition key on the touch screen is pressed, a voltage value of 3cm is stored, when a 5cm acquisition key on the touch screen is pressed, a voltage value of 5cm is stored, and if a start test key is pressed before the voltage value of 3cm and the voltage value of 5cm are acquired, the key is judged to be invalid, and the computer returns to the previous state. When the voltage value at the position of 3cm and the voltage value at the position of 5cm are both collected, the relationship between the distance and the voltage value is calculated by the main control MCU according to the two values, the relation is judged to be effective after the 'start test' button is pressed, and the main control MCU can display the distance between the current short-circuit fault point and the test point and display the distance on the display screen.
Examples of the embodiments
The actual measurement result of the device for testing the short-circuit fault point is shown in table 1, and the error of the short-circuit fault point is judged to be within 1 cm.
TABLE 1 test example of short-circuit failure points
Figure BDA0002173964140000031
The protection of the present invention is not limited to the above embodiments. Variations and advantages that may occur to those skilled in the art may be incorporated into the invention without departing from the spirit and scope of the inventive concept, and the scope of the appended claims is intended to be protected.

Claims (3)

1. A long wire short circuit fault point positioning device is characterized by comprising: the device comprises a main control MCU, a constant current source, a high-precision instrument amplifier, a high-precision ADC and a display screen; wherein,
the master control MCU is STM32H 743;
the constant current source is used as an excitation signal and is connected to one end of the test point;
the amplifier for the high-precision instrument is connected to the two test points to amplify the differential mode voltage of the two test points; the output end of the amplifier for the high-precision instrument is connected to the input end of the high-precision ADC, and the differential mode voltage between the two amplified test points is measured;
after the differential mode voltage is measured, the communication between the high-precision ADC and the main control MCU is completed through an SPI protocol, and after the main control MCU receives data, the position of a short-circuit fault point and a distance test point is reversely deduced;
the display screen is used for displaying.
2. A long-conductor short-circuit fault point locating method, wherein the long-conductor short-circuit fault point locating device according to claim 1 is used, and the method comprises: in order to measure the size of the wire resistance, a constant current source is adopted as an excitation signal and is connected to one end of a test point, an amplifier for a high-precision instrument is connected to two test points to amplify the differential mode voltage of the two test points, the output end of the amplifier for the high-precision instrument is connected to the input end of a high-precision ADC, and the amplified differential mode voltage between the two test points is measured; after the differential mode voltage is measured, the communication between the high-precision ADC and the master control MCU is completed through the SPI protocol, and after the master control MCU receives the data, the position of the short-circuit fault point and the distance test point is reversely deduced.
3. The method for locating the short-circuit fault point of the long lead as claimed in claim 2, wherein before formal measurement, 3cm and 5cm leads are respectively clamped between two test points, the voltage value of the corresponding position point is stored according to the prompt of a display screen, a straight line is determined according to the theorem that two points, and the main control MCU obtains the corresponding relation between the distance and the voltage value according to the voltage values of the two points; when the position of the short-circuit point is tested, the two ends of the wire are clamped between the two test points, at the moment, the constant current source is electrified, after the voltage of the short-circuit point is stable, the distance between the short-circuit point and the test point A is calculated according to the measured voltage and is displayed on the display screen, and at the moment, a user can quickly find the position of the short-circuit fault point according to the numerical value displayed on the display screen to perform quick troubleshooting.
CN201910772276.4A 2019-08-21 2019-08-21 Long-lead short-circuit fault point positioning device and method Pending CN112415433A (en)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100102824A1 (en) * 2007-04-18 2010-04-29 Mario Tremblay Electrical network fault location by distributed voltage measurements
CN102707190A (en) * 2012-01-10 2012-10-03 成都唐源电气有限责任公司 Direct-current-side short-circuit fault distance measuring device and method of metro tractive power supply system
CN102967796A (en) * 2012-10-31 2013-03-13 陕西海泰电子有限责任公司 Detecting method for short dot position of cable
CN105425100A (en) * 2015-11-04 2016-03-23 上海电气电站设备有限公司 Method for measuring degree of turn-to-turn short-circuit fault of rotor and accurately positioning same
CN106353643A (en) * 2016-11-09 2017-01-25 雷细军 Resistance proportion cable fault tester
CN106405326A (en) * 2016-08-25 2017-02-15 华南理工大学 Time-domain fault range finding method for co-tower double-loop DC power transmission line based on single-loop electrical quantity

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100102824A1 (en) * 2007-04-18 2010-04-29 Mario Tremblay Electrical network fault location by distributed voltage measurements
CN102707190A (en) * 2012-01-10 2012-10-03 成都唐源电气有限责任公司 Direct-current-side short-circuit fault distance measuring device and method of metro tractive power supply system
CN102967796A (en) * 2012-10-31 2013-03-13 陕西海泰电子有限责任公司 Detecting method for short dot position of cable
CN105425100A (en) * 2015-11-04 2016-03-23 上海电气电站设备有限公司 Method for measuring degree of turn-to-turn short-circuit fault of rotor and accurately positioning same
CN106405326A (en) * 2016-08-25 2017-02-15 华南理工大学 Time-domain fault range finding method for co-tower double-loop DC power transmission line based on single-loop electrical quantity
CN106353643A (en) * 2016-11-09 2017-01-25 雷细军 Resistance proportion cable fault tester

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Application publication date: 20210226