Submarine cable trend and insulation performance integrated testing device and testing method applying same

Abstract

The invention relates to a submarine cable trend and insulation performance integrated testing device and a testing method using the same, solves the problems in the prior art, and adopts the technical scheme that the submarine cable trend and insulation performance integrated testing device comprises a connecting structure body, an instrument cabin arranged on the connecting structure body and a magnetic measurement array matched with the instrument cabin, the magnetic measurement array is arranged in the instrument cabin, the electric field measurement assembly is matched with the magnetic measurement array, the protective cylinder covers the peripheries of the magnetic measurement array and the electric field measurement assembly, the open end of the protective cylinder is matched with a shell of the instrument cabin, an inner cavity of the protective cylinder is a sealed inner cavity, the electric field measurement assembly is used for measuring electric field distribution, and the magnetic measurement array is used for measuring magnetic field distribution. Based on electromagnetic signal extraction of the submarine cable, an external detector is utilized to carry out routing inspection when needed, the correlation between the cable trend and the insulativity is established through measurement to obtain distribution characteristics of a space magnetic field and an electric field, and trend judgment and insulativity evaluation are carried out. And an integrated high-efficiency detection technical means is provided for ocean detection.

Description

Technical Field

[0001] The present invention relates to the field of submarine cable positioning and insulation detection, and in particular to a submarine cable orientation and insulation performance integrated testing device and a testing method using the same. Background Art

[0002] Submarine cables (referred to as cables or cable lines or cables) are operated in seawater immersion, long-term high voltage and other environments, which may cause insulation aging or even insulation breakdown, ultimately reducing the safety of submarine cables. In addition, with the large-scale development of the ocean, marine engineering construction, marine fisheries, marine transportation and other marine operations are increasing, which are easy to interfere with and damage submarine cables. Therefore, before operation, it is necessary to determine the direction of the submarine cable and evaluate the insulation performance to avoid cable damage or accidents.

[0003] At present, submarine cables are usually located by submarine cable positioning (generally based on acoustics, optics and beacons), and submarine cables are avoided during submarine operations, thereby reducing or avoiding accidents caused by cable damage, such as:

[0004] Patent CN202311627168.0 is an offshore submarine cable positioning method based on USBL and SINS / GPS systems. In the installation error adjustment stage, the whale optimization algorithm (WOA) is used to optimize the installation error of the ultra-short baseline (USBL) and strapdown inertial navigation (SINS) / global positioning system (GPS) combined positioning system. The SINS / GPS system is directly installed on the ship, and the USBL is installed on a ship-based six-degree-of-freedom stabilization device. At the same time, the position of the beacon relative to the USBL transducer is uniformly converted to the earth coordinate system to achieve precise positioning of the submarine cable.

[0005] Patent CN202111557175.9 submarine cable positioning method, device, computer equipment and computer program product, including controlling multiple acoustic wave signal generators to send test signals respectively, and recording the sending time of the test signal to obtain first time data; the test signal is an acoustic wave signal of a preset frequency; monitoring the sensing optical fiber built into the submarine cable; determining the submarine cable positioning point on the submarine cable; recording the time when the waveform of the preset frequency is monitored at the submarine cable positioning point to obtain second time data; determining the position coordinates of the submarine cable positioning point based on the first time data, the second time data and the position coordinates of multiple acoustic wave signal generators.

[0006] Patent CN202310097466.7, a deep-sea submarine cable positioning method based on DVL and single beacon. First, the submarine cable detection robot obtains accurate position information through the Beidou satellite navigation system on the water surface; secondly, when the submarine cable detection robot dives underwater, considering that the DVL cannot obtain low speed at this time, a single beacon acoustic positioning is used to complete the position solution of the underwater robot, and a maximum entropy extended Kalman filter algorithm is proposed for position solution; finally, when the submarine cable detection robot reaches the vicinity of the submarine cable, the DVL and single beacon fusion positioning method is adopted, and the positioning accuracy of the submarine cable is improved by the average weighted method.

[0007] It can be seen from the above technologies that these existing technologies are all methods that combine the sea surface and the sea surface to locate the cable. The technologies on the sea surface are basically the same, that is, they are implemented based on the strapdown inertial navigation combined with GPS. The biggest difference is the positioning technology strategy under the sea surface. The existing patents are all based on beacons. For example, patent CN202311627168.0 uses a USBL transducer to collect the signal of the cable beacon and calculates it to the global positioning system for positioning; patent CN202310097466.7 uses DVL and single beacon fusion positioning; patent CN201511028853.7 uses a single beacon acoustic positioning to complete the position solution.

[0008] The use of beacons increases the difficulty and cost of implementation, and a series of issues such as power supply and maintenance need to be considered. Moreover, as time goes by, the life of these beacons and detection devices is limited, and it is impossible to monitor the entire life cycle. In addition, these existing technologies can only locate the submarine cable, but cannot obtain the working status of the cable itself, including the most important insulation performance. Summary of the invention

[0009] The purpose of the present invention is to solve the above-mentioned problems existing in the prior art and to provide an integrated test device for the direction and insulation performance of a submarine cable and a test method using the same. The device adopts a method combining electric field and magnetic field sensor array measurements, based on the extraction of electromagnetic signals from the submarine cable itself, and uses an external detector to perform inspections when needed. The device establishes a correlation between the direction of the cable and the insulation by measuring the spatial magnetic field and electric field distribution characteristics, performs direction identification and insulation evaluation, and provides an integrated and efficient detection technology for ocean exploration, which is beneficial to ensuring the safe and reliable operation of the submarine cable, avoiding accidents caused by cable damage, and being able to promptly discover cable faults and repair and replace them in a timely manner.

[0010] The above technical purpose of the present invention is mainly solved by the following technical solutions: a submarine cable direction and insulation performance integrated test device, characterized in that it includes a connection seat, an instrument cabin arranged on the connection seat, a magnetic measurement array matched with the instrument cabin, an electric field measurement component matched with the magnetic measurement array, a protective tube covered on the periphery of the magnetic measurement array and the electric field measurement component, the open end of the protective tube is matched with the shell of the instrument cabin, so that the inner cavity of the protective tube is a sealed inner cavity, the electric field measurement component is used to measure the electric field distribution, and the magnetic measurement array is used to measure the magnetic field distribution. This technical solution adopts a method of combining electric field and magnetic field sensor array measurement, based on the electromagnetic signal extraction of the submarine cable itself, and uses an external detector to perform inspections when necessary. By measuring the spatial magnetic field and electric field distribution characteristics, the relationship between the cable direction and insulation is established, and the direction is judged and the insulation is evaluated, providing an integrated and efficient detection technology for ocean exploration, which is conducive to ensuring the safe and reliable operation of the submarine cable, avoiding accidents caused by cable damage, and being able to timely discover cable faults and repair and replace them in time.

[0011] The difference between this technical solution and the prior art is that it can not only effectively and accurately locate and detect the submarine cable based on the extraction of the electromagnetic signal of the submarine cable itself, but also accurately evaluate the insulation status of the submarine cable by obtaining the electric and magnetic field signals.

[0012] Specifically, the electric field measurement component is mainly used to measure the underwater electric field, the magnetic measurement array is mainly used to measure the magnetic field distribution, the protective tube is used to encapsulate and waterproof the electric field measurement component and the magnetic measurement array, the instrument cabin is used to place the electrode assembly measurement circuit and the magnetic measurement array processing, signal acquisition and data transmission circuit, the connecting structure is used to connect the submarine cable direction and insulation performance integrated test device with the underwater motion unit, and the submarine cable direction and insulation performance integrated test device is driven to move through the underwater motion unit.

[0013] As a further improvement and supplement to the above technical solution, the present invention adopts the following technical measures: the magnetic measurement array includes an end cap and an end plate, and a plurality of mounting columns are respectively arranged on the end cap and the end plate at both ends, and at least eight sensors are adjustable in position on the mounting columns, wherein the eight sensors are arranged at the eight vertices of a cube or a cuboid. Under normal circumstances, eight sensors can meet the requirements. In order to facilitate further optimization of the integrated test device for the direction and insulation performance of submarine cables and to facilitate maintenance and replacement of sensors, more sensors can be arranged. Therefore, the arrangement of more than eight sensors also falls within the protection scope of this technical solution.

[0014] Preferably, the center of the end cap and the center of the end plate are located on the axis of the protective tube, the end cap is arranged at one end of the instrument cabin, the end plate is arranged toward the protective tube, and the sensor is a three-axis magnetic sensor. In this technical solution, the three-axis magnetic sensor of the spatial array is used to measure the magnetic field around the cylindrical cable, which can make full use of the distribution characteristics of the magnetic field around the cylindrical cable. According to the concentric circles with the magnetic lines of force centered on the axis of the cable, the direction of the magnetic lines of force is along the tangent direction of the circumference, and the magnetic lines of force change from dense to sparse from the center of the cable axis to the outside. The magnetic flux density B is expressed as:

[0015] Where I is the current, μ is the magnetic permeability, and R is the distance from the center of the cable.

[0016] At the same time, by establishing reference coordinates on the sensor array, the measurement points of each sensor can be synthesized to obtain a magnetic vector. The axis formed by the intersection of the normal planes of the magnetic vectors is the central axis of the cable. The position and posture of the central axis relative to the sensor array coordinate system can be determined, thereby accurately determining the position and posture of the cable.

[0017] The present invention uses a group of magnetic sensor arrays evenly distributed in a cube (or rectangular parallelepiped) space to measure magnetic field characteristics to determine the direction of the cable, and arranges electrodes on the edges of the rectangular parallelepiped to capture changes in the spatial electric field to evaluate insulation.

[0018] The position and posture of the cable can be solved by any combination of three sensor test data in the sensor array. Eight sensors, each of which forms a group of three sensors, can be combined in any way, with a total of 56 combinations. The optimal solution of the 56 combinations can be calculated by the mean or minimum norm to prevent errors caused by individual combinations, so that the position and posture of the cable can be accurately detected.

[0019] Preferably, the electric field measurement assembly includes a support seat arranged on the end plate of the magnetic measurement array, an X-direction electrode, an X-direction reference electrode, a Y-direction electrode, a Y-direction reference electrode, a Z-direction electrode and a Z-direction reference electrode arranged orthogonally and equidistantly on the rectangular coordinate system XYZO arranged on the support seat and with point O as the origin, and the X-direction electrode and the X-direction reference electrode, the Y-direction electrode and the Y-direction reference electrode, the Z-direction electrode and the Z-direction reference electrode are all arranged symmetrically with point O as the symmetry point. The insulating medium of the submarine cable (such as the commonly used cross-linked polyethylene (XLPE)) is used to block the conductivity between the cables and between the cables and the external environment medium to prevent current leakage. The destructive factors of the insulating medium include high-voltage breakdown caused by charge accumulation, partial discharge, etc. No matter which factor, once the insulating medium is damaged, it is often accompanied by a change in the electric field distribution around the cable (for example, high-voltage breakdown is accompanied by a continuous enhancement of the surrounding electric field, and partial discharge is accompanied by a small pulse change of the electric field). The electric field is measured by the electric field measurement component, and the insulation performance is evaluated based on the trend of changes in the electric field strength, the severity of the changes, or the frequency of pulse-like changes. Generally speaking, a faster electric field trend and an increase in frequency mean a deterioration in the insulation condition.

[0020] Specifically, a rectangular coordinate system XYZO with point O as the origin is established. On the Z axis, the Z-direction electrode and the Z-direction reference electrode are installed symmetrically to point O. The sensitive electric field direction of the two electrodes is the Z axis. Similarly, the X-direction electrode and the X-direction reference electrode, the Y-direction electrode and the Y-direction reference electrode are arranged and installed on the X axis and the Y axis respectively to measure the X-direction electric field and the Y-direction electric field. The distances of the electrodes and the reference electrodes in each direction to the origin O of the coordinate system are equal. They are installed on the support seat, and the axis of the connecting column coincides with the axis of the protective tube.

[0021] Specifically, the orthogonal and equidistantly arranged electrodes can obtain the three-dimensional electric field strength at point O in space. By capturing the electric field strength signal, it is used to determine the local discharge intensity and frequency of the cable, and the insulation performance of the cable is evaluated accordingly. Before use, it is necessary to accumulate data in the evaluation database. The specific method is to artificially create the insulation damage level of the cable through accelerated aging and other means, and obtain the corresponding relationship database between the electric field change and the insulation level through testing, and then reverse it in subsequent use. In the electric field evaluation, since the distance has a huge impact on the electric field, it is necessary to unify the measurement distance. For this purpose, it is necessary to adjust the position and posture of the monitoring device and the cable line according to the cable position and posture information obtained by the magnetic field sensor array. The insulation status evaluation through electric field measurement is carried out under certain detector and cable postures to ensure that the evaluation results are not affected by these factors.

[0022] Preferably, the support seat includes a seat ring arranged on the OXY plane, and a special-shaped seat arranged on the OZY plane or the OZX plane, the special-shaped seat includes a semi-ring seat, a straight seat on the semi-ring seat that is axially folded and extended at one end toward the bottom of the protective tube, and a Z-shaped seat at the other end of the semi-ring seat, the end of the Z-shaped seat facing away from the semi-ring seat is fixed to the seat ring, a Z-direction reference electrode is arranged on the Z-shaped seat, a Z-direction electrode is arranged on the straight seat, and the X-direction electrode, X-direction reference electrode, Y-direction electrode and Y-direction reference electrode are all arranged on the seat ring and are arranged at 90° intervals.

[0023] Preferably, a connecting column is provided on the support seat, the connecting column is connected to the end plate, and the axis of the connecting column is colinear with the axis of the protective tube.

[0024] Preferably, the connecting column is arranged on a semi-annular seat on the supporting seat, and the connecting column faces away from the bottom of the protective tube.

[0025] The technical solution of the second technical subject of the present invention is: a test method using an integrated test device for submarine cable orientation and insulation performance, the steps of which include:

[0026] Based on the magnetic field measurement array, establishing a coordinate system on each sensor on the magnetic field measurement array;

[0027] In the coordinate system, each sensor outputs a magnetic flux density vector B i ;

[0028] According to Biotsafar's theorem, the magnetic flux density vector is generated by an infinitely long wire, with the origin O i The foot of the perpendicular to the wire is point A. i The vector R pointing to point A i With vector B i vertical;

[0029] According to the coordinates of point A (x i ,y i , z i ), we get the vector R i and (B ix , B iy , B iz );

[0030] According to the coordinates of point A (x i ,y i , z i ), vector R i and (B ix , B iy , B iz ), we get two equations:

[0031] Bix ·x i +B iy ·y i +B iz ·Z i =0 (1)

[0032]

[0033] Introduce two more sensors, whose coordinates are (x j ,y j , z j )、(x k ,y k , z k ), we get the equation:

[0034]

[0035] Through equations (1), (2) and (3), nine variables and nine constraint equations are obtained and solved to determine the position and posture of the cable conductor relative to the magnetic sensor array;

[0036] Among them, i, j, k are all integers and take values ​​between 1, 2, …, 8, and i≠j≠k.

[0037] Preferably, the vector R i With vector B i , we get the constraint equation: R i ·B i =0;

[0038] The coordinates of point A (x i ,y i , z i ), we get: B ix ·x i +B iy ·y i +B iz ·Z i =0,

[0039] The vector R i for,

[0040] Preferably, the test method using the integrated test device for submarine cable orientation and insulation performance also includes the following steps:

[0041] Accumulate cable insulation performance evaluation data and establish a cable insulation performance evaluation database;

[0042] Conduct electric field assessment: Use the cable position and posture information obtained by the magnetic field sensor array to monitor the position of the device and cable to adjust and unify the measurement distance of the electric field;

[0043] By arranging eight electrodes orthogonally and equidistantly, the three-dimensional electric field strength at point O in space is obtained. By capturing the electric field strength signal, it is used to determine the intensity and frequency of partial discharge of the cable, and the cable insulation performance is evaluated accordingly.

[0044] The present invention has the beneficial effects:

[0045] 1. The cable is positioned and its attitude and direction (referred to as positioning and attitude determination) is determined through the magnetic field measurement array component, and the insulation state of the cable is determined based on the positioning and attitude through the electric field measurement component, so that the submarine cable direction and insulation performance integrated test device can not only perform positioning and attitude determination based on the magnetic field and electric field, but also determine the insulation state of the cable, so that the submarine cable direction and insulation performance integrated test device has a multi-functional cable monitoring function;

[0046] 2. When the magnetic measurement array is used to realize the cable positioning and attitude determination, eight sensors are arranged orthogonally and equidistantly on the rectangular coordinate system XYZO with point O as the origin (i.e., 2×2×2 dimensions and distributed at the eight vertices of a cube), and the sensitive axes of the sensors are distributed in the eight edges of the cube respectively. Three of the sensors are used to realize the position and attitude determination of the cable relative to the sensor array coordinate system;

[0047] 3. When calculating the position and attitude through the magnetic measurement array, the infinite length wire magnetic field calculation formula is used to calculate the distance between the sensor and the cable. The two constraint equations to be solved are established by taking advantage of the characteristics that the direction is perpendicular to the cable line. Two more sensors are added to balance the equations and unknowns to complete the solution, thus realizing the positioning and attitude measurement of the cable.

[0048] 4. Through the eight array sensors, any three sensors can determine the cable position and posture. Through various combinations, multiple sets of position and posture solutions can be obtained. Averaging these solutions or taking the minimum deviation solution can obtain a better solution, thereby improving the accuracy and stability of detection;

[0049] 5. When the electric field measuring device is used to evaluate the insulation status of the cable, it is achieved through the six electrodes on the electric field measuring device. The six electrodes are divided into three pairs of measuring electrodes and reference electrodes, which are arranged on three orthogonal axes respectively. The intersection of each three axis is the center point of each pair of electrodes, so as to realize the three-axis measurement of the electric field;

[0050] 6. The evaluation method of cable insulation status is to capture electric field signals through electric field measurement components. Electric field measurement implements three-axis measurement. Before it is put into use, it is necessary to acquire the ability to judge through the changes in the amplitude and frequency of the electric field signal and the study of the insulation status. It is a technical means based on prior learning.

[0051] 7. The electric field measurement component is immersed in seawater after waterproofing treatment, and the magnetic field sensor array is waterproofed with a protective barrel. The instrument cabin is used to place the signal transmission and data processing, storage and communication circuits of the magnetic field sensor array of the electric field measurement component. The entire device is installed on an underwater submersible or other towed equipment through connecting structural parts to achieve stable positioning. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 The invention discloses a schematic structural diagram of a test device in an explosion state.

[0053] Figure 2 It is a structural schematic diagram of the magnetic field measurement array in the present invention.

[0054] Figure 3 It is a structural schematic diagram of the electric field measurement component in the present invention.

[0055] Figure 4 The present invention is a schematic diagram of position and attitude solution.

[0056] Figure 5 The invention discloses a flow chart of a testing method.

[0057] In the figure: 1. protective tube; 2. electric field measurement component; 3. magnetic measurement array; 4. instrument cabin; 5. connecting structure; 301. end cover; 302. end plate; 303. mounting column; 304. first magnetic sensor; 305. second magnetic sensor; 306. third magnetic sensor; 307. fourth magnetic sensor; 308. fifth magnetic sensor; 309. sixth magnetic sensor; 310. seventh magnetic sensor; 311. eighth magnetic sensor; 201. support seat; 202. Y-axis electrode; 203. X-axis electrode; 204. Z-axis electrode; 205. Y-axis reference electrode, 206. X-axis reference electrode; 207. Z-axis reference electrode; 208. connecting column. DETAILED DESCRIPTION

[0058] The technical solution of the present invention is further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0059] Example 1: Figure 1-Figure 3 As shown, the technical solution of the first technical subject of the present invention is:

[0060] A submarine cable direction and insulation performance integrated testing device, comprising a connecting seat, an instrument cabin 4 arranged on the connecting seat, a magnetic measurement array 3 matched with the instrument cabin 4, an electric field measurement component 2 matched with the magnetic measurement array 3, and a protective tube 1 covering the magnetic measurement array 3 and the electric field measurement component 2. The open end of the protective tube 1 cooperates with the shell of the instrument cabin 4 so that the inner cavity of the protective tube 1 is a sealed inner cavity. The electric field measurement component 2 is used to measure the electric field distribution, and the magnetic measurement array 3 is used to measure the magnetic field distribution.

[0061] This technical solution adopts a method that combines electric field and magnetic field sensor array measurements. It is based on the extraction of electromagnetic signals from the submarine cable itself and uses external detectors to conduct inspections when needed. By measuring the spatial magnetic field and electric field distribution characteristics, the relationship between the cable direction and insulation is established, and direction identification and insulation evaluation are performed. This provides an integrated and efficient detection technology for ocean exploration, which is conducive to ensuring the safe and reliable operation of submarine cables, avoiding accidents caused by cable damage, and being able to promptly discover cable faults and repair and replace them in a timely manner.

[0062] The difference between this technical solution and the prior art is that it can not only effectively and accurately locate and detect the submarine cable based on the extraction of the electromagnetic signal of the submarine cable itself, but also accurately evaluate the insulation status of the submarine cable by obtaining the electric and magnetic field signals.

[0063] Specifically, the electric field measurement component 2 is mainly used to measure the underwater electric field, and the magnetic measurement array 3 is mainly used to measure the magnetic field distribution. The protective tube 1 is used to encapsulate and waterproof the electric field measurement component 2 and the magnetic measurement array 3. The instrument cabin 4 is used to place the electrode assembly measurement circuit and the processing, signal acquisition and data transmission circuit of the magnetic measurement array 3. The connecting structure 5 is used to connect the integrated test device for the direction and insulation performance of the submarine cable with the underwater motion unit, and the integrated test device for the direction and insulation performance of the submarine cable is driven to move through the underwater motion unit.

[0064] That is to say, the electric field measurement component 2 is immersed in seawater after waterproofing treatment, the magnetic field sensor array is waterproofed by a protective barrel, and the instrument cabin 4 is used to place the signal transmission and data processing, storage and communication circuits of the magnetic field sensor array of the electric field measurement component 2. The entire device is installed on an underwater submersible or other towed equipment through connecting structural parts to achieve stable positioning.

[0065] Next, the above technical solution is further described:

[0066] In practical applications, the magnetic measurement array 3 includes an end cover 301, an end plate 302, a plurality of mounting posts 303 respectively arranged on the end cover 301 and the end plate 302 at both ends, and at least eight sensors adjustable in position arranged on the mounting posts, wherein the eight sensors (including a first magnetic sensor 304, a second magnetic sensor 305, a third magnetic sensor 306, a fourth magnetic sensor 307, a fifth magnetic sensor 308, a sixth magnetic sensor 309, a seventh magnetic sensor 310, and an eighth magnetic sensor 311) are arranged at eight vertices of a cube or a cuboid.

[0067] In this technical solution, under normal circumstances, eight sensors are sufficient to meet the requirements. In order to facilitate further optimization of the integrated test device for the direction and insulation performance of the submarine cable and to facilitate the maintenance and replacement of sensors, more sensors can be set. Therefore, setting more than eight sensors also falls within the protection scope of this technical solution.

[0068] In practical applications, the center of the end cover 301 and the center of the end plate 302 are located on the axis of the protective tube 1, the end cover 301 is arranged at one end of the instrument cabin 4, the end plate 302 is arranged toward the protective tube 1, and the sensor is a three-axis magnetic sensor.

[0069] In this technical solution, the three-axis magnetic sensor of the space array is used to measure the magnetic field around the cylindrical cable, which can make full use of the distribution characteristics of the magnetic field around the cylindrical cable. According to the concentric circles with the axis of the cable as the center, the direction of the magnetic lines of force is along the tangent direction of the circumference, and the magnetic lines of force change from dense to sparse from the center of the cable axis to the outside. The magnetic flux density B is expressed as:

[0070] Where I is the current, μ is the magnetic permeability, and R is the distance from the center of the cable.

[0071] At the same time, by establishing reference coordinates on the sensor array, the measurement points of each sensor can be synthesized to obtain a magnetic vector. The axis formed by the intersection of the normal planes of the magnetic vectors is the central axis of the cable. The position and posture of the central axis relative to the sensor array coordinate system can be determined, thereby accurately determining the position and posture of the cable.

[0072] The present invention uses a group of magnetic sensor arrays evenly distributed in a cube (or rectangular parallelepiped) space to measure magnetic field characteristics and determine the direction of the cable.

[0073] That is to say, when the position and attitude are solved by the magnetic measurement array 3, the infinite length wire magnetic field calculation formula is used to calculate the distance between the sensor and the cable, and the two constraint equations to be solved are established by utilizing the characteristics of the direction and the cable being skewed and perpendicular. The other two sensors are added to balance the number of equations and unknowns to complete the solution, thereby realizing the positioning and attitude measurement of the cable.

[0074] The position and posture of the cable can be solved by any combination of the three sensor test data in the sensor array.

[0075] For eight sensors, three sensors form a group and can be combined arbitrarily, for a total of fifty-six combinations. The optimal solution of the fifty-six combinations can be calculated by the mean or minimum norm to prevent errors caused by individual combinations, so as to accurately detect the position and posture of the cable.

[0076] like Figure 4 As shown, in actual application, the electric field measurement component 2 includes a support base 201 arranged on the end plate 302 on the magnetic measurement array 3, and an X-direction electrode 203, an X-direction reference electrode 206, a Y-direction electrode 202, a Y-direction reference electrode 205, a Z-direction electrode 204 and a Z-direction reference electrode 207 arranged on the support base 201 and orthogonally and equidistantly arranged on a rectangular coordinate system XYZO with point O as the origin. The X-direction electrode 203 and the X-direction reference electrode, the Y-direction electrode 202 and the Y-direction reference electrode, and the Z-direction electrode 204 and the Z-direction reference electrode are all symmetrically arranged relative to each other with point O as the symmetry point.

[0077] The insulating medium of the submarine cable (such as the commonly used cross-linked polyethylene (XLPE)) is used to block the conductivity between the cables and between the cables and the external environment medium to prevent current leakage. The destructive factors of the insulating medium include high-voltage breakdown caused by charge accumulation, partial discharge, etc. Regardless of the factor, once the insulating medium is damaged, it is often accompanied by a change in the electric field distribution around the cable (for example, high-voltage breakdown is accompanied by a continuous enhancement of the surrounding electric field, and partial discharge is accompanied by a small pulse-like change in the electric field). The electric field is measured by the electric field measurement component 2, and the insulation performance is evaluated based on the trend of the electric field strength change, the severity of the change, or the frequency of the pulse-like change. In general, a faster trend of the electric field and an increase in frequency mean a deterioration in the insulation condition.

[0078] In this technical solution, electrodes are arranged on the side lines of the rectangular parallelepiped to capture the changes in the spatial electric field to evaluate the insulation.

[0079] In the present technical solution, the insulation status of the cable is evaluated by an electric field measuring device through six electrodes on the electric field measuring device, wherein the six electrodes are divided into three pairs of measuring electrodes and reference electrodes, which are arranged on three orthogonal axes respectively, and each intersection of the three axes is the center point of each pair of electrodes, thereby realizing three-axis measurement of the electric field.

[0080] In this technical solution, the evaluation method of the cable insulation status is to capture the electric field signal through the electric field measurement component 2. The electric field measurement implements three-axis measurement. Before it is put into use, it is necessary to acquire the ability to judge through the changes in the amplitude and frequency of the electric field signal and the learning of the insulation status. It is a technical means based on prior learning.

[0081] Specifically, a rectangular coordinate system XYZO with point O as the origin is established. On the Z axis, the Z-direction electrode 204 and the Z-direction reference electrode are installed symmetrically to point O. The sensitive electric field direction of the two electrodes is the Z axis. Similarly, the X-direction electrode 203 and the X-direction reference electrode, the Y-direction electrode 202 and the Y-direction reference electrode are arranged and installed on the X axis and the Y axis respectively, for measuring the X-direction electric field and the Y-direction electric field. The distances of the electrodes and the reference electrodes in each direction to the origin O of the coordinate system are equal, and they are installed on the support seat 201, and the axis of the connecting column 208 coincides with the axis of the protective tube 1.

[0082] Specifically, the orthogonal and equidistantly arranged electrodes can obtain the three-dimensional electric field strength at point O in space. By capturing the electric field strength signal, it is used to determine the intensity and frequency of local discharge of the cable, and based on this, the insulation performance of the cable is evaluated.

[0083] Before use, it is necessary to accumulate data in the evaluation database. The specific method is to artificially create the insulation damage level of the cable through accelerated aging and other means, and obtain the corresponding relationship database between the electric field change and the insulation level through testing, and then reverse it in subsequent use. In the electric field evaluation, since the distance has a huge impact on the electric field, it is necessary to unify the measurement distance. For this purpose, it is necessary to adjust the position and posture of the monitoring device and the cable line according to the cable position and posture information obtained by the magnetic field sensor array. The insulation status evaluation through electric field measurement is carried out under certain detector and cable postures to ensure that the evaluation results are not affected by these factors.

[0084] In actual application, the support seat 201 includes a seat ring arranged on the OXY plane, and a special-shaped seat arranged on the OZY plane or the OZX plane. The special-shaped seat includes a semi-ring seat, a straight seat on the semi-ring seat that is axially folded and extended at one end toward the bottom of the protective tube 1, and a Z-shaped seat at the other end of the semi-ring seat. The end of the Z-shaped seat facing away from the semi-ring seat is fixed to the seat ring, a Z-direction reference electrode is arranged on the Z-shaped seat, and a Z-direction electrode 204 is arranged on the straight seat. The X-direction electrode 203, the X-direction reference electrode, the Y-direction electrode 202 and the Y-direction reference electrode are all arranged on the seat ring and are arranged at 90° intervals.

[0085] In practical applications, a connecting column 208 is provided on the support seat 201 , and the connecting column 208 is connected to the end plate 302 . The axis of the connecting column 208 is colinear with the axis of the protection tube 1 .

[0086] In practical applications, the connecting column 208 is disposed on a semi-annular seat on the supporting seat 201 , and the connecting column 208 faces away from the bottom of the protective tube 1 .

[0087] Example 2: Figure 4 and Figure 5 As shown, the technical solution of the second technical subject involved in the present technical invention is:

[0088] A test method using an integrated test device for submarine cable orientation and insulation performance, that is, a test method for testing a cable line using an integrated test device for submarine cable orientation and insulation performance involved in Example 1, the steps of which include:

[0089] Based on the magnetic field measurement array, establishing a coordinate system on each sensor on the magnetic field measurement array;

[0090] In the coordinate system, each sensor outputs a magnetic flux density vector B i ;

[0091] According to Biotsafar's theorem, the magnetic flux density vector is generated by an infinitely long wire, with the origin O i The foot of the perpendicular to the wire is point A. i The vector R pointing to point A i With vector B i vertical;

[0092] According to the coordinates of point A (x i ,y i , z i ), we get the vector R i and (B ix , B iy , B iz );

[0093] According to the coordinates of point A (x i ,y i , Z i ), vector R i and (B ix , B iy , B iz ), we get two equations:

[0094] B ix ·x i +B iy ·y i +B iz ·Z i =0 (1)

[0095]

[0096] Introduce two more sensors, whose coordinates are (x j ,y j , z j )、(x k ,y k , z k ), we get the equation:

[0097]

[0098] Through equations (1), (2) and (3), nine variables and nine constraint equations are obtained and solved to determine the position and posture of the cable conductor relative to the magnetic sensor array;

[0099] Among them, i, j, k are all integers and take values ​​between 1, 2, …, 8, and i≠j≠k.

[0100] Preferably, the vector R i With vector B i , we get the constraint equation: R i ·B i =0;

[0101] The coordinates of point A (x i ,y i , z i ), we get: B ix ·x i +B iy ·y i +B iz ·Z i =0,

[0102] The vector R i for,

[0103] In practical applications, when evaluating the insulation status of cables, it is necessary to acquire the ability to judge by learning the changes in the amplitude and frequency of the electric field signal and the insulation status. Therefore, the evaluation method of the cable insulation status is a technical method based on prior learning.

[0104] In the present technical solution, when a magnetic measurement array is used to realize cable positioning and attitude determination, eight sensors are arranged orthogonally and equidistantly (i.e., 2×2×2 dimensions and distributed at the eight vertices of a cube) on a rectangular coordinate system XYZO with point O as the origin, and the sensitive axes of the sensors are respectively distributed in the eight edges of the cube. Three of the sensors are used to realize the position and attitude determination of the cable relative to the sensor array coordinate system.

[0105] That is to say, through the eight arrays of sensors, any three sensors can be used to determine the cable position and posture. Through various combinations, multiple sets of position and posture solutions can be obtained. Averaging these solutions or taking the minimum deviation solution can obtain a better solution, thereby improving the accuracy and stability of detection.

[0106] In this technical solution, when solving the position and attitude through the magnetic measurement array, the infinite length wire magnetic field calculation formula is used to calculate the distance between the sensor and the cable, and the direction and the cable line are perpendicular to each other to establish two constraint equations to be solved. Two more sensors are added to balance the number of equations and unknowns to complete the solution, thereby realizing the positioning and attitude measurement of the cable.

[0107] Take this technical solution as an example:

[0108] The coordinate system x where the magnetic sensor is located 4 y 4 z 4 o 4 For example, the measured three-axis components (B 4x ,B 4y ,B 4z ) The resultant vector is B 4 According to Biotsafar's theorem, the magnetic flux density vector is generated by an infinitely long wire. 4 The foot of the perpendicular to the conductor L4 is point A. 4 The vector R pointing to point A 4 With B 4 Vertically, the following constraint equations hold:

[0109] R 4 ·B 4 =0

[0110] Assume that the coordinates of point A are (x 4 ,y 4 ,z 4 ),Right now:

[0111] B 4x ·x 4 +B 4y ·y 4 +B 4z ·z 4 =0(1)

[0112] And R can be calculated by the following formula: 4 :

[0113]

[0114] (x 4 ,y 4 ,z 4 )、(B4x ,B 4y ,B 4z ) into the equation:

[0115]

[0116] Formula (1) and Formula (2) form a system of equations with three variables and two equations, which has infinite solutions and is a straight line cluster. Therefore, the equations are expanded by introducing the measurement values ​​of two other sensors, such as sensor 306 and sensor 305. After expansion, there are nine variables and six equations. At the same time, considering (x 4 ,y 4 ,z 4 ), (x 3 ,y 3 ,z 3 ), (x 2 ,y 2 ,z 2 ) are points on the same conductor, so they are collinear, that is, there exists:

[0117]

[0118] Three constraint equations are added. Now, there are nine variables and nine constraint equations. By solving this set of equations, the position and posture of the cable conductor relative to the magnetic sensor array can be determined.

[0119] In summary, the above detector's position relative to the cable can be solved by any combination of the three sensor test data in the sensor array. Eight sensors can be combined in groups of three, with a total of 56 combinations. The optimal solution of the mean or minimum norm can be calculated for the 56 combinations to prevent errors caused by individual combinations.

[0120] In practical applications, in order to further improve accuracy, the test method using the submarine cable direction and insulation performance integrated test device also includes the following steps:

[0121] Accumulate cable insulation performance evaluation data and establish a cable insulation performance evaluation database;

[0122] Conduct electric field assessment: Use the cable position and posture information obtained by the magnetic field sensor array to monitor the position of the device and cable to adjust and unify the measurement distance of the electric field;

[0123] By arranging eight electrodes orthogonally and equidistantly, the three-dimensional electric field strength at point O in space is obtained. By capturing the electric field strength signal, it is used to determine the intensity and frequency of partial discharge of the cable, and the cable insulation performance is evaluated accordingly.

[0124] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. In the above embodiments, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A submarine cable direction and insulation performance integrated testing device, characterized in that The invention comprises a connection structure (5), an instrument cabin (4) arranged on the connection structure (5), a magnetic measurement array (3) matched with the instrument cabin (4), an electric field measurement component (2) matched with the magnetic measurement array (3), and a protective tube (1) arranged on the periphery of the magnetic measurement array (3) and the electric field measurement component (2), wherein the open end of the protective tube (1) matches with the shell of the instrument cabin (4) so ​​that the inner cavity of the protective tube (1) is a sealed inner cavity, the electric field measurement component (2) is used to measure the electric field distribution, and the magnetic measurement array (3) is used to measure the magnetic field distribution.

2. The integrated test device for submarine cable orientation and insulation performance according to claim 1 is characterized in that: The magnetic measurement array (3) comprises an end cover (301), an end plate (302), a plurality of mounting posts respectively arranged on the end cover (301) and the end plate (302) at two ends, and at least eight sensors adjustable in position arranged on the mounting posts, wherein the eight sensors are arranged at eight vertices of a cube or a cuboid.

3. The integrated test device for submarine cable orientation and insulation performance according to claim 2 is characterized in that: The center of the end cover (301) and the center of the end plate (302) are located on the axis of the protective tube (1); the end cover (301) is arranged at one end of the instrument cabin (4); the end plate (302) is arranged toward the protective tube (1); and the sensor is a three-axis magnetic sensor.

4. The integrated test device for submarine cable orientation and insulation performance according to claim 1, 2 or 3, characterized in that: The electric field measurement component (2) comprises a support base (201) arranged on an end plate (302) on the magnetic measurement array (3), an X-direction electrode (203), an X-direction reference electrode, a Y-direction electrode (202), a Y-direction reference electrode, a Z-direction electrode (204) and a Z-direction reference electrode (207) arranged on the support base (201) and arranged orthogonally and equidistantly on a rectangular coordinate system XYZO with point O as the origin, wherein the X-direction electrode (203) and the X-direction reference electrode, the Y-direction electrode (202) and the Y-direction reference electrode, the Z-direction electrode (204) and the Z-direction reference electrode (207) are all arranged symmetrically with point O as a symmetric point.

5. The integrated test device for submarine cable orientation and insulation performance according to claim 4 is characterized in that: The support seat (201) comprises a seat ring arranged on an OXY plane, and a special-shaped seat arranged on an OZY plane or an OZX plane, wherein the special-shaped seat comprises a semi-ring seat, a linear seat on the semi-ring seat which is axially folded and extended at one end thereof facing the bottom of the protective tube (1), and a Z-shaped seat at the other end of the semi-ring seat, wherein the end of the Z-shaped seat which is away from the semi-ring seat is fixed to the seat ring, a Z-direction reference electrode (207) is arranged on the Z-shaped seat, a Z-direction electrode (204) is arranged on the linear seat, and the X-direction electrode (203), the X-direction reference electrode, the Y-direction electrode (202), and the Y-direction reference electrode are all arranged on the seat ring and are arranged at 90° intervals.

6. The integrated test device for submarine cable orientation and insulation performance according to claim 4 is characterized in that: The support seat (201) is provided with a connecting column (208), the connecting column (208) is connected to the end plate (302), and the axis of the connecting column (208) is colinear with the axis of the protective tube (1).

7. The integrated test device for submarine cable orientation and insulation performance according to claim 6 is characterized in that: The connecting column (208) is arranged on a semi-annular seat on the supporting seat (201), and the connecting column (208) faces away from the bottom of the protective tube (1).

8. A test method using an integrated test device for submarine cable orientation and insulation performance, characterized in that: The steps include: Based on the magnetic field measurement array, establishing a coordinate system on each sensor on the magnetic field measurement array; In the coordinate system, each sensor outputs a magnetic flux density vector B i ; According to Biotsafar's theorem, the magnetic flux density vector is generated by an infinitely long wire, with the origin o i The foot of the perpendicular to the wire is point A. i The vector R pointing to point A i With vector B i vertical; According to the coordinates of point A (x i ,y i , z i ), we get the vector R i and (B ix , B iy , B iz ); According to the coordinates of point A (x i ,y i , z i ), vector R i and (B ix , B iy , B iz ), we get two equations: B ix ·x i +B iy ·y i +B iz ·z i =0 (1) Introduce two more sensors, whose coordinates are (x j ,y j , z j )、(x k ,y k , z k ), we get the equation: Through equations (1), (2) and (3), nine variables and nine constraint equations are obtained and solved to determine the position and posture of the cable conductor relative to the magnetic sensor array; Among them, i, j, k are all integers and take values ​​between 1, 2, …, 8, and i≠j≠k.

9. The testing method using the integrated testing device for submarine cable orientation and insulation performance according to claim 8 is characterized in that: By vector R i With vector B i , we get the constraint equation: R i ·B i =0; The coordinates of point A (x i ,y i , z i ), we get: B ix ·x i +B iy ·y i +B iz ·z i =0, The vector R i for, 10. The testing method using the integrated testing device for submarine cable orientation and insulation performance according to claim 9 is characterized in that: Also included are the following steps: Accumulate cable insulation performance evaluation data and establish a cable insulation performance evaluation database; Conduct electric field assessment: Use the cable position and posture information obtained by the magnetic field sensor array to monitor the position of the device and cable to adjust and unify the measurement distance of the electric field; By arranging eight electrodes orthogonally and equidistantly, the three-dimensional electric field strength at point O in space is obtained. By capturing the electric field strength signal, it is used to determine the intensity and frequency of partial discharge of the cable, and the cable insulation performance is evaluated accordingly.

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