CN115980428A - Phase difference-based cable three-phase unbalanced current detection method - Google Patents
Phase difference-based cable three-phase unbalanced current detection method Download PDFInfo
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Abstract
The invention provides a phase difference-based cable three-phase unbalanced current detection method, which analyzes the phase difference of radial and tangential magnetic field signals generated by a three-core three-phase cable in different directions to obtain images of the phase difference of the radial and tangential magnetic field signals in different directions of the three-core three-phase cable, and monitors whether the three-phase current of the three-core three-phase cable meets the requirement of balance or not by taking the magnetic field phase difference image generated by the cable three-phase current balance as a reference so as to achieve the purpose of real-time monitoring. Meanwhile, the phase difference is used as a monitoring means of the three-core three-phase cable, so that long-term operation of the equipment can be ensured, the time period of regular calibration is greatly prolonged, and the workload of calibration work of the sensor is reduced; the phase difference can be judged by the phase difference of the two signals even if the signal amplitude exceeds the amplitude measuring range of the magnetic sensor and saturation distortion occurs as a monitoring means.
Description
Technical Field
The invention belongs to the field of current sensing, and relates to a phase difference-based method for detecting three-phase unbalanced current of a cable, which is used for detecting the phase difference of radial and tangential magnetic field signals generated in different directions of a three-core three-phase cable and judging whether three-phase current conducted by the three-core three-phase cable meets the three-phase balance requirement or not according to the phase difference.
Background
The current value is an important monitoring quantity for evaluating the operation state of the power grid in the power system, and the excessive three-phase unbalanced current can cause adverse effects on the healthy operation of the power grid. Only under the condition of ensuring three-phase balance, the loss in electric energy transportation can be reduced to the minimum, the minimum energy consumption is realized, and the effective energy conservation is realized. The existing common method is to use a pincerlike meter to perform fixed-point measurement at the neutral point of the transformer, but the method needs field detection, cannot display relevant conditions of the cable in real time, and cannot feed back the relevant conditions in time when the cable has problems. Although the problem of real-time performance can be solved for the measurement method based on the magnetic field signal amplitude, for the measurement of the amplitude, the long-term operation of the sensor can generate drift, so that the amplitude measurement is inaccurate, and the calibration work needs to be carried out regularly; amplitude-based magnetic sensors produce saturation distortion when the magnetic field is outside the amplitude measurement range. Therefore, a novel three-phase current balance state detection technology which can ensure real-time performance, is stable for a long time and has a large measurement range is needed.
The invention provides a method for monitoring the three-phase current of a three-core three-phase cable, which analyzes the phase difference of radial and tangential magnetic field signals of the three-core three-phase cable in different directions to obtain images of the phase difference of the radial and tangential magnetic field signals of the three-core three-phase cable in different directions, and monitors whether the three-phase current of the three-core three-phase cable meets the requirement of balance by taking the image of the magnetic field phase difference generated by the balance of the three-phase current of the cable as a reference so as to achieve the aim of real-time monitoring. Meanwhile, the phase difference is used as a monitoring means of the three-core three-phase cable, the influence of the output amplitude drift of the sensor is avoided, and the long-term operation of the equipment can be ensured, so that the time period of the periodic calibration is greatly prolonged, and the workload of the calibration work of the sensor is reduced; the phase difference is used as a monitoring means, and even if the signal intensity exceeds the amplitude measurement range of the magnetic sensor and saturation distortion is generated, the phase difference of the two signals can be used for judging.
Disclosure of Invention
The invention aims to provide a method for detecting three-phase unbalanced current of a cable based on phase difference, which takes the phase difference of radial and tangential generated magnetic field signals of three-core three-phase cables in different directions as a judgment reference on the basis of not increasing the complexity of equipment. The invention uses the analysis of the phase difference of the radial and tangential magnetic field signals generated by the three-core three-phase cable in different directions to draw phase difference images of the three-core three-phase cable in different directions, and then judges the three-phase balance of the three-core three-phase cable according to the phase difference images.
The working mechanism of the invention is as follows: after three-phase power is applied to the three-core three-phase cable (7), magnetic fields can be generated around the three-core three-phase cable, the size and the direction of the magnetic fields are different, so that the phase difference of magnetic field signals generated in the radial direction and the tangential direction of the three-core three-phase cable (7) in different directions is different, phase difference images of the three-core three-phase cable (7) in different directions are drawn by detecting the radial direction and the tangential direction phase difference of each direction in which the three-core three-phase cable (7) axially bypasses a circle through a magnetic sensor array (9) consisting of a plurality of vector magnetic sensors at equal angle intervals and formed by vector magnetic sensors (8), and when unbalanced current and balanced current are applied to the three-core three-phase cable (7), the generated phase images are obviously different, so that whether the three-phase current of the three-core three-phase cable (7) is balanced or not can be easily judged by taking the phase difference images drawn by the magnetic fields generated by the three-phase current in balance as a judgment basis.
A phase difference-based cable three-phase unbalanced current detection method is based on a three-core three-phase cable current detection device, wherein the three-core three-phase cable current detection device comprises a magnetic sensing system (1) and a phase detection system (2); the magnetic sensing system (1) and the phase detection system (2) are connected in sequence through leads.
The magnetic sensing system (1) comprises a magnetic sensor array (8) consisting of a plurality of vector magnetic sensors (7) and used for acquiring a magnetic field generated by a three-core three-phase cable (6); the three-core three-phase cable (6) comprises an A core (3), a B core (4) and a C core (5); when three-phase currents exist in the A core (3), the B core (4) and the C core (5) of the three-core three-phase cable (6), magnetic fields generated by the A core (3), the B core (4) and the C core (5) in the radial direction and the tangential direction of the three-core three-phase cable (6) in different directions are acquired by the magnetic sensor array (8).
Preferably, the magnetic sensing system (1) comprises n vector magnetic sensors (7); the n vector magnetic sensors (7) are distributed on a circumference which takes the central point of the three cores of the three-core three-phase cable (6) as the center of a circle and has a radius of R at equal intervals, namely, the distance between each vector magnetic sensor (7) and the axial core of the three-core three-phase cable (6) is the same; wherein R is more than or equal to d, and d represents 1/2 of the outer diameter of the three-core three-phase cable (6); n =360/θ and is an integer, θ representing the central angle between two adjacent sampling points;
preferably, the magnetic sensing system (1) comprises 1 vector magnetic sensor (7), a circular ring type track and a motor; the circular ring-shaped track is positioned at the periphery of the three-core three-phase cable (6), and the circle center of the circular ring-shaped track is superposed with the central point of three cores of the three-core three-phase cable (6); the vector magnetic sensor (7) is connected with the inner side of the circular ring type track in a sliding manner; the motor drives the vector magnetic sensor (7) to slide along the inner side of the circular ring-shaped track; the radius R of the circular ring-shaped track is larger than or equal to d, and d represents 1/2 of the outer diameter of the three-core three-phase cable (6);
the phase detection system (2) comprises a vector magnetic sensor signal receiving device (9) and a vector magnetic sensor signal processing device (10); the signals acquired by the magnetic sensor array (8) are read by a vector magnetic sensor signal receiving device (9), and the vector magnetic sensor signal processing device (10) is used for drawing images of the radial and tangential magnetic field phase differences of different directions acquired by the vector magnetic sensor signal receiving device (9).
The method for detecting the three-phase unbalanced current of the cable based on the phase difference specifically comprises the following steps:
step (1), building a test platform:
1-1, a magnetic sensor array (8) capable of detecting radial and tangential magnetic fields in different directions is installed at a proper position on a three-core three-phase cable (6);
1-2, starting a vector magnetic sensor signal receiving device (10), receiving radial and tangential magnetic field signals of different directions of the three-core three-phase cable (6) collected by the magnetic sensor array (8), and calculating phase differences of the radial and tangential magnetic fields of different directions.
Step (2), determining a three-core calibration position of the three-core three-phase cable (6):
2-1, only the current of the core A (3) in the three-core three-phase cable (6) is conducted, the current of the core B (4) and the current of the core C (5) are not conducted, and the position with the maximum magnetic induction intensity is found as the calibration position of the core A (3) in the three-core three-phase cable (6) through the magnetic induction intensity of a magnetic field received by the magnetic sensor array (8);
2-2, only the current of the B core (4) in the three-core three-phase cable (6) is conducted, the A core (3) and the C core (5) are not conducted, and the position with the maximum magnetic induction intensity is found as the calibration position of the B core (4) in the three-core three-phase cable (6) through the magnetic induction intensity of the magnetic field received by the magnetic sensor array (8);
2-3, only the current of the C core (5) in the three-core three-phase cable (6) is conducted, the A core (3) and the B core (4) are not conducted, and the position with the maximum magnetic induction intensity is found as the calibration position of the C core (5) in the three-core three-phase cable (6) through the magnetic induction intensity of a magnetic field received by the magnetic sensor array (8);
constructing a standard image with the position of the magnetic field sampling point as a horizontal coordinate and the phase difference as a vertical coordinate;
3-1, adjusting the currents of an A core (3), a B core (4) and a C core (5) in the three-core three-phase cable (6) to balance the three-phase currents;
3-2, radial and tangential magnetic fields in different directions are obtained by a magnetic sensor array (8) and are transmitted into a vector magnetic sensor signal receiving device (9);
a 3-3 vector magnetic sensor signal receiving device (9) acquires the phase difference of radial and tangential magnetic fields of the three-core three-phase cable (6) in different directions;
the 3-4 vector magnetic sensor signal receiving device (10) takes the position of a magnetic field sampling point as an abscissa, one of the three calibration positions of the three-core three-phase cable (6) determined in the step (2) is selected as an initial position, and a standard image S is drawn by taking the phase difference as an ordinate 0 ；
Step (4), detecting the three-phase current balance condition of the three-core three-phase cable (6) in real time:
4-1: under the condition that the calibration positions of the platform built in the step (1) and the three-core three-phase cable (6) in the step (2) are not changed, the magnetic sensor array (8) acquires radial and tangential magnetic fields of the three-core three-phase cable (6) in different directions in real time, and the vector magnetic sensor signal receiving device (9) acquires the radial and tangential magnetic fields according to the magnetic sensor array (8)The phase difference of radial and tangential magnetic fields of different directions of the three-core three-phase cable (6) is calculated by magnetic field signals, and then a real-time image S is drawn by a vector magnetic sensor signal receiving device (10) i ；
4-2: real-time image S i With the standard image S 0 Comparing, if the phase difference is the same as the standard image S, determining that the three-phase current is balanced, otherwise, determining that the phase difference corresponding to the position of the magnetic field sampling point is equal to the standard image S 0 And judging whether the absolute value of the difference value corresponding to the phase difference is less than or equal to a threshold value, if so, determining that the three-phase current is balanced, and otherwise, determining that the three-phase current is unbalanced.
Preferably, each azimuthal radial and tangential magnetic field of the three-core three-phase cable (7) is B x ，B y The method specifically comprises the following steps:
wherein A is a ,A b ,A c The amplitudes of the magnetic fields generated by the core A (3), the core B (4) and the core C (5) of the three-core three-phase cable (7) are respectively; alpha, beta and gamma are included angles of the A core (3), the B core (4) and the C core (5) of the three-core three-phase cable (7) and the vector magnetic sensor (7) relative to the horizontal direction; w is the angular frequency of the current;
magnetic fields generated by currents of the A core (3), the B core (4) and the C core (5) of the three-core three-phase cable (7) are combined to obtain the B core x 、B y Initial phase of magnetic field
The method comprises the following steps:
wherein A is xbc ,A ybc ,
Is composed of
So that the phase difference
Is shown as
The method has the beneficial effects that:
1. compared with the method using the magnetic field intensity as a standard, the method using the phase difference as the standard can reduce the workload of calibration and ensure the long-time stable operation of the sensor.
2. The requirement of cable detection on real-time performance can be met, and the cable condition can be detected in real time.
3. Compared with the method that the magnetic field intensity is used as the standard, the method provided by the invention uses the phase difference as the standard, and can greatly improve the detection range of the magnetic sensor on the three-phase unbalanced current.
Drawings
FIG. 1 is a schematic flow diagram of the process;
FIG. 2 is a detailed flow diagram of the present method;
FIG. 3 is a graph of results calculated according to the finite source analysis method; wherein a is a comparison graph of a result calculated according to the finite source analysis method when only one phase current is reduced and a result calculated according to the finite source analysis method when three phases are balanced, and b is a comparison graph of a result calculated according to the finite source analysis method when only one phase current is increased and a result calculated according to the finite source analysis method when three phases are balanced;
FIG. 4 is a graph showing the results of an actual experiment in which the present method is performed; wherein a is a comparison graph according to an actual experiment result and an actual experiment result when three phases are balanced when only one-phase current is reduced, and b is a comparison graph according to the actual experiment result and the actual experiment result when the three phases are balanced when only one-phase current is increased;
FIG. 5 is a radial and tangential magnetic field diagram of the method when different three-phase balance currents are introduced; wherein a is a radial magnetic field diagram and a tangential magnetic field diagram when three phases of the three-phase cable are all electrified with 2A current, b is a radial magnetic field diagram and a tangential magnetic field diagram when three phases of the three-phase cable are all electrified with 13A current, and c is a radial magnetic field diagram and a tangential magnetic field diagram when three phases of the three-phase cable are all electrified with 30A current.
Detailed Description
The method is further analyzed with reference to the accompanying drawings.
As shown in fig. 1, the three-core three-phase cable current detection device includes a magnetic sensing system 1 and a phase detection system 2; the magnetic sensing system 1 and the phase detection system 2 are connected in sequence through a lead.
As shown in fig. 2, the magnetic sensing system 1 includes a cable three-phase a core 3, a cable three-phase B core 4, a cable three-phase C core 5, a three-core three-phase cable 6, a vector magnetic sensor 7, and a magnetic sensor array 8 composed of a plurality of vector magnetic sensors equally angularly spaced; when three-phase currents exist in the cable three-phase A core 3, the cable three-phase B core 4 and the cable three-phase C core 5, a magnetic sensor array 8 consisting of a plurality of vector magnetic sensors which are equally angularly spaced and consists of vector magnetic sensors 7 acquires magnetic fields generated by the cable three-phase A core 3, the cable three-phase B core 4 and the cable three-phase C core 5 in different directions of the three-phase cable 6 in the radial direction and the tangential direction.
The phase detection system 2 comprises a vector magnetic sensor signal receiving device 9 and a vector magnetic sensor signal processing device 10; the signal obtained by the magnetic sensor array 8 consisting of a plurality of vector magnetic sensors with equal angle intervals and consisting of the vector magnetic sensors 7 is read by the vector magnetic sensor signal receiving device 9, the phase difference of the radial and tangential magnetic fields of the three-core three-phase cable 6 in different directions is obtained, and the phase difference is processed by the vector magnetic sensor signal processing device 10.
In the practical example, the vector magnetic sensors 7 are fluxgate sensors, and the magnetic sensor array 8 composed of a plurality of vector magnetic sensors with equal angular intervals is distributed on a circumference with the center point of the three cores of the three-core three-phase cable (6) as the center and the radius of the circumference being R, that is, each vector magnetic sensor (7) has the same distance from the axial core of the three-core three-phase cable (6); wherein R is 1/2 of the outer diameter of the three-core three-phase cable (6); the central angle between two adjacent sampling points is 5 degrees.
The magnetic sensing system (1) described in this embodiment includes 1 vector magnetic sensor (7), a circular ring type track, and a motor; the circular ring-shaped track is positioned at the periphery of the three-core three-phase cable (6), and the circle center of the circular ring-shaped track is superposed with the central point of three cores of the three-core three-phase cable (6); the vector magnetic sensor (7) is connected with the inner side of the circular ring type track in a sliding manner; the motor drives the vector magnetic sensor (7) to slide along the inner side of the circular ring-shaped track; the radius R of the circular ring-shaped track is 1/2 of the outer diameter of the three-core three-phase cable (6). According to the position shown in fig. 2, a fluxgate sensor is used for acquiring data for the three-core three-phase cable 6 at sampling points every 5 degrees. The magnetic sensor array 8 is equivalent to a magnetic sensor array consisting of a plurality of vector magnetic sensors which are equally angularly spaced. The vector magnetic sensor signal receiving device 9 adopts an oscilloscope, and directly reads the phase difference of two signals through radial and tangential magnetic field signals of different directions of a three-core three-phase cable 6 of a fluxgate sensor introduced into the oscilloscope; the vector magnetic sensor signal processing device 10 manually collects the phase differences in the respective directions of the three-core three-phase cable 6, and draws an image of the total phase difference.
In the experimental process, a circular ring type track with 5 degrees as a scale is added on the three-core three-phase cable 6, the vector magnetic sensor 7 is fixed on the circular ring type track, and the position of a sampling point is tangent to the three-core three-phase cable 6. The detected signal is passed to a vector magnetic sensor signal receiving device 9. And only the A core 3 of the three phases of the cable is electrified, different sampling point amplitudes displayed by the vector magnetic sensor signal receiving device 9 are found, the position with the maximum amplitude is the position right above the A core 3 of the three phases of the cable, and the positions right above the B core 4 of the three phases of the cable and the C core 5 of the three phases of the cable are found in the same method to serve as three calibration positions. The calibration position of the A core 3 of the three phases of the cable is recorded as an initial point, 20A current is introduced into the A core 3 of the three phases of the cable, the B core 4 of the three phases of the cable and the C core 5 of the three phases of the cable, every 5 degrees is sampled by the vector magnetic sensor signal receiving device 10 from the initial point, the phase difference of each sampling point is recorded, images with the initial point and each position as a horizontal coordinate and the phase difference as a vertical coordinate are drawn, and the images only changing the current values of the B core 5 of the three phases of the cable to be 22A, 21A, 19A and 18A are collected by the same method to carry out a comparison experiment.
As shown in fig. 3, which is a result calculated using a finite source analysis method.
As shown in fig. 4, the graph is the result of actual measurement.
As can be seen from the two diagrams, the phase diagram when the three phases are unbalanced is clearly different from the phase diagram when the three phases are balanced, and therefore, a method for detecting the three-phase balance of the cable by using the phase difference is feasible.
As shown in fig. 5, it can be seen from the radial and tangential magnetic field diagrams when different three-phase balance currents are applied, when the applied current reaches 30A and exceeds the range of the amplitude measurement of the magnetic sensor, and when saturation distortion occurs, the measurement result of the phase difference is still consistent with that when the applied current does not exceed the range of the amplitude measurement of the magnetic sensor, which fully proves that the detection range of the magnetic sensor for three-phase unbalanced currents can be greatly improved by using the phase difference as the detection standard.
Claims (4)
1. A phase difference-based cable three-phase unbalanced current detection method is based on a three-core three-phase cable current detection device, wherein the three-core three-phase cable current detection device comprises a magnetic sensing system (1) and a phase detection system (2); the magnetic sensing system (1) and the phase detection system (2) are connected in sequence through leads;
the magnetic sensing system (1) comprises a magnetic sensor array (8) consisting of a plurality of vector magnetic sensors (7) and used for acquiring a magnetic field generated by a three-core three-phase cable (6); the three-core three-phase cable (6) comprises an A core (3), a B core (4) and a C core (5); when three-phase currents exist in the A core (3), the B core (4) and the C core (5) of the three-core three-phase cable (6), magnetic fields generated by the A core (3), the B core (4) and the C core (5) in the radial direction and the tangential direction of the three-core three-phase cable (6) in different directions are acquired by the magnetic sensor array (8);
the phase detection system (2) comprises a vector magnetic sensor signal receiving device (9) and a vector magnetic sensor signal processing device (10); signals acquired by the magnetic sensor array (8) are read by a vector magnetic sensor signal receiving device (9), and the vector magnetic sensor signal processing device (10) is used for drawing images of the radial and tangential magnetic field phase differences of different directions acquired by the vector magnetic sensor signal receiving device (9);
characterized in that the method comprises the following steps:
step (1), building a test platform:
1-1, mounting a magnetic sensor array (8) capable of detecting radial and tangential magnetic fields in different directions on a three-core three-phase cable (6);
1-2, starting a vector magnetic sensor signal receiving device (10), receiving radial and tangential magnetic field signals of different directions of the three-core three-phase cable (6) collected by a magnetic sensor array (8), and calculating phase differences of the radial and tangential magnetic fields of different directions;
step (2), determining a three-core calibration position of the three-core three-phase cable (6):
2-1, only passing the current of the core A (3) in the three-core three-phase cable (6), not passing the current of the core B (4) and the core C (5), and finding out the position with the maximum magnetic induction intensity as the calibration position of the core A (3) in the three-core three-phase cable (6) according to the magnetic induction intensity of a magnetic field received by the magnetic sensor array (8);
2-2, only the current of the B core (4) in the three-core three-phase cable (6) is conducted, the A core (3) and the C core (5) are not conducted, and the position with the maximum magnetic induction intensity is found as the calibration position of the B core (4) in the three-core three-phase cable (6) through the magnetic induction intensity of the magnetic field received by the magnetic sensor array (8);
2-3, only the current of the C core (5) in the three-core three-phase cable (6) is conducted, the A core (3) and the B core (4) are not conducted, and the position with the maximum magnetic induction intensity is found as the calibration position of the C core (5) in the three-core three-phase cable (6) through the magnetic induction intensity of the magnetic field received by the magnetic sensor array (8);
constructing a standard image with the position of the magnetic field sampling point as a horizontal coordinate and the phase difference as a vertical coordinate;
3-1: the current of an A core (3), a B core (4) and a C core (5) in the three-core three-phase cable (6) is adjusted, so that the three-phase current is balanced;
3-2: radial and tangential magnetic fields in different directions are acquired by a magnetic sensor array (8) and are transmitted into a vector magnetic sensor signal receiving device (9);
a 3-3 vector magnetic sensor signal receiving device (9) acquires the phase difference of radial and tangential magnetic fields of the three-core three-phase cable (6) in different directions;
the 3-4 vector magnetic sensor signal receiving device (10) takes the position of a magnetic field sampling point as an abscissa, one of the three calibration positions of the three-core three-phase cable (6) determined in the step (2) is selected as an initial position, and a standard image S is drawn by taking the phase difference as an ordinate 0 ；
Step (4), detecting the three-phase current balance condition of the three-core three-phase cable (6) in real time:
4-1: under the condition that the calibration positions of the platform built in the step (1) and the three-core three-phase cable (6) in the step (2) are not changed, the magnetic sensor array (8) acquires radial and tangential magnetic fields of the three-core three-phase cable (6) in different directions in real time, the vector magnetic sensor signal receiving device (9) calculates the phase difference of the radial and tangential magnetic fields of the three-core three-phase cable (6) in different directions according to the magnetic field signals acquired by the magnetic sensor array (8), and then the vector magnetic sensor signal receiving device (10) draws a real-time image S i ；
4-2: real-time image S i With the standard image S 0 Comparing, if the phase difference is the same, determining that the three-phase current is balanced, otherwise, judging the phase difference corresponding to the position of the magnetic field sampling point again and the standard image S 0 And judging whether the absolute value of the difference value corresponding to the phase difference is less than or equal to a threshold value, if so, determining that the three-phase current is balanced, and otherwise, determining that the three-phase current is unbalanced.
2. Method according to claim 1, characterized in that the azimuthal radial and tangential magnetic fields of the three-core three-phase cable (7) are each B x ，B y The method specifically comprises the following steps:
wherein A is a ,A b ,A c The amplitudes of the magnetic fields generated by the core A (3), the core B (4) and the core C (5) of the three-core three-phase cable (7) are respectively; alpha, beta and gamma are included angles of the A core (3), the B core (4) and the C core (5) of the three-core three-phase cable (7) and the vector magnetic sensor (7) relative to the horizontal direction; w is the angular frequency of the current;
magnetic fields generated by the currents of the core A (3), the core B (4) and the core C (5) of the three-core three-phase cable (7) are combined to obtain the core B x 、B y Initial phase of magnetic field
The method comprises the following steps:
wherein A is xbc ,A ybc ,
Is composed of
So that the phase difference
Is shown as
3. A method according to claim 1, characterized in that said magnetic sensing system (1) comprises n vector magnetic sensors (7); the n vector magnetic sensors (7) are distributed on a circumference which takes the central point of the three cores of the three-core three-phase cable (6) as the center of a circle and has a radius of R at equal intervals, namely, the distance between each vector magnetic sensor (7) and the axial core of the three-core three-phase cable (6) is the same; wherein R is larger than or equal to d, and d represents 1/2 of the outer diameter of the three-core three-phase cable (6); n =360/θ and is an integer, θ representing the central angle between two adjacent sampling points.
4. A method according to claim 1, characterized in that the magnetic sensor system (1) comprises 1 vector magnetic sensor (7), a circular ring type track, an electric motor; the circular ring-shaped track is positioned on the periphery of the three-core three-phase cable (6), and the circle center of the circular ring-shaped track is superposed with the central point of three cores of the three-core three-phase cable (6); the vector magnetic sensor (7) is connected with the inner side of the circular ring type track in a sliding manner; the motor drives the vector magnetic sensor (7) to slide along the inner side of the circular ring-shaped track; the radius R of the circular ring-shaped track is larger than or equal to d, and d represents 1/2 of the outer diameter of the three-core three-phase cable (6).
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116500499A (en) * | 2023-06-26 | 2023-07-28 | 陕西雨唐连创科技有限公司 | Three-core cable fault detection device, system and method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116500499A (en) * | 2023-06-26 | 2023-07-28 | 陕西雨唐连创科技有限公司 | Three-core cable fault detection device, system and method |
| CN116500499B (en) * | 2023-06-26 | 2023-09-15 | 陕西雨唐连创科技有限公司 | Three-core cable fault detection device, system and method |
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