Method and system for testing insulation resistance of coiled secondary cables, terminal, and storage medium

Abstract

Method and system for testing insulation resistance of a spooled secondary cable, terminal, storage medium. The method includes: collecting the insulation standard value of the secondary circuit cable and the total length of the spooled cable, determining the maximum cable laying length in the station based on the in-station secondary cable channel design drawing, using the A* algorithm and the smoothing processing algorithm, and calculating the reference value of the insulation resistance of the spooled secondary cable; testing the insulation resistance of the spooled secondary cable to obtain the test value of the insulation resistance of the spooled secondary cable, including: the test value of the insulation resistance of a single cable core, the test value of the insulation resistance between cable cores, and the test value of the overall insulation resistance; comparing each test value of the insulation resistance of the spooled secondary cable with the reference value of the insulation resistance of the spooled secondary cable; if each test value of the insulation resistance of the spooled secondary cable is greater than the reference value of the insulation resistance of the spooled secondary cable, it is determined that the insulation resistance of the spooled secondary cable meets the standard; otherwise, it is determined that the insulation resistance of the spooled secondary cable does not meet the standard.

Description

Technical Field

[0001] The present invention belongs to the field of power cable detection, and specifically relates to a method and system, a terminal, and a storage medium for testing the insulation resistance of a coiled secondary cable. Background Art

[0002] Insulation resistance refers to the resistance corresponding to the leakage current flowing through the dielectric after a certain time polarization process ends when a DC voltage is applied to the dielectric. It is the most basic insulation index of electrical equipment and electrical circuits. The routine inspection during the factory shipment of conventional secondary cables includes testing the insulation resistance. When measuring a cable below 1000V, a 1000V insulation resistance tester is used; when measuring a cable of 1000V and above, a 2500V insulation resistance tester is used; when measuring a cable of 6kV and above, a 5000V insulation resistance tester is used. By measuring the main insulation resistance of the power cable, it is possible to check whether the cable insulation is aged, damp, and insulation defects exposed during the withstand voltage test.

[0003] On-site at the substation, testing the insulation resistance of secondary cables is an important part of the substation infrastructure commissioning, maintenance, and acceptance. Conducting on-site insulation resistance testing of secondary cables mainly targets the cables laid in the secondary circuit. For example, in the industry standard DL_T 995-2016 "Inspection Regulations for Relay Protection and Power Grid Safety Automatic Devices", it is stipulated that for the insulation inspection and testing of the secondary circuit: during the acceptance test of newly installed protection devices, all externally introduced circuits and cables are disconnected from the terminal block of the protection panel cabinet, and all terminals of the current, voltage, DC control, and signal circuits are respectively connected together. The insulation resistance between the circuit and the ground and between each circuit is measured with a 1000V insulation resistance meter, and its value should be greater than 10MΩ.

[0004] In the prior art, for the on-site insulation resistance test of secondary cables, most of the tests are carried out after the cables have been laid, with both ends connected to the corresponding devices and terminal blocks. Before the test, the circuit is disconnected, and a megohmmeter (insulation resistance tester) is used to test the insulation resistance of the secondary circuit. Although this method can effectively test the resistance of the circuit, if the cable fails the insulation resistance test, it needs to be replaced. After replacing it with a qualified cable and laying and connecting it again, the insulation test of the new circuit is carried out again. This process is relatively complex, requires repeated cable laying, has a large amount of work, and the insulation condition of the cable cannot be sensed before the laying and connection are completed. If the new cable still has problems, it will continue to be replaced, consuming a large amount of manpower and material resources, and the construction period will also be correspondingly delayed. In fact, if the insulation resistance of the coiled cable can be tested before the cable is laid, the cable condition can be mastered in advance, avoiding the cumbersome process and waste of replacing the cable after it has been laid and applied. However, in the prior art, the insulation acceptance standard of the cable circuit and the routine inspection of the coiled cable are not combined, that is, the coiled cable is not tested for insulation according to the requirements of the secondary circuit insulation inspection and test. Combining the experience of multiple units such as infrastructure commissioning, maintenance, and acceptance, it is found that if the coiled cable is tested by the method of factory routine inspection, even if the test result at that time is greater than 10 MΩ, the insulation of the secondary cable circuit after laying may be less than 10 MΩ, which cannot meet the requirements of the secondary circuit insulation standard. Summary of the Invention

[0005] To solve the deficiencies in the prior art, the present invention provides a method and system, a terminal, and a storage medium for testing the insulation resistance of coiled secondary cables. Based on the existing insulation resistance test standard for secondary circuits in substations, the insulation test of the coiled cable is carried out before the secondary cable is laid. After the coiled cable that passes the test is laid, the insulation of the secondary circuit also meets the requirements of industry standards.

[0006] The present invention adopts the following technical solutions.

[0007] The present invention proposes a method for testing the insulation resistance of coiled secondary cables, including:

[0008] Step 1, collecting the insulation standard value of the secondary circuit cable and the total length of the coiled cable;

[0009] Step 2, based on the design drawings of the secondary cable channels in the substation, determining the maximum laying length of the cables in the substation based on the A* algorithm and the smoothing processing algorithm;

[0010] Step 3, calculating the insulation resistance reference value of the coiled secondary cable by using the data obtained in Steps 1 and 2;

[0011] Step 4: Test the insulation resistance of the reel-mounted secondary cables to obtain the test values of the insulation resistance of the reel-mounted secondary cables. The test values of the insulation resistance of the reel-mounted secondary cables include: the test value of the insulation resistance of a single cable core, the test value of the insulation resistance between cable cores, and the test value of the overall insulation resistance.

[0012] Step 5: Compare each test value of the insulation resistance of the reel-mounted secondary cables with the reference value of the insulation resistance of the reel-mounted secondary cables. If each test value of the insulation resistance of the reel-mounted secondary cables is greater than the reference value of the insulation resistance of the reel-mounted secondary cables, it is determined that the insulation resistance of the reel-mounted secondary cables meets the standard; otherwise, it is determined that the insulation resistance of the reel-mounted secondary cables does not meet the standard.

[0013] Preferably, in Step 1, during the commissioning and acceptance of newly put into operation projects, the standard value of the insulation resistance of the secondary circuit cables is taken as 10 MΩ; during the regular inspection of secondary devices in the maintenance stage, the standard value of the insulation resistance of the secondary circuit cables is taken as 1 MΩ.

[0014] Preferably, in Step 2, within the entire station, for a certain secondary cable circuit, use the A* algorithm to determine each section of the path in the circuit and obtain the fitting function f(x, y) of each section of the path; the nodes at both ends of each section of the path include: the laying starting point, the laying ending point, and the midpoint during laying; among them, the midpoint during laying includes: the position where the laying path changes horizontally, the position where the laying path changes vertically, and the position of obstacles on the laying path;

[0015] The coordinate points of each node can be obtained from the design drawings of the secondary cable channels in the station.

[0016] Preferably, for any section of the path determined by the A* algorithm, in the two-dimensional plane, according to the nodes at both ends of this section of the path, smooth the fitting function f(x, y) of this section of the path within the range of the cable bending radius to obtain the smooth fitting function q(x, y, φ) on this section of the path, where the steering angle φ satisfies the following relational expression:

[0017]

[0018] In the formula,

[0019] x t and y t are the coordinates of any point on this section of the path,

[0020] x m and y m are the coordinates of the node on this section of the path close to the cable laying starting point side,

[0021] ρ is the cable bending radius.

[0022] Preferably, the length of each section of the path is calculated according to the smooth fitting function q(x, y, φ), and the sum of the lengths of each section of the path is used as the path length of a certain secondary cable loop.

[0023] Find the maximum value from the path lengths of the secondary cable loops in the whole substation as the maximum length L of the cable laying in the substation. max 。

[0024] Preferably, in step 3, the reference value of the insulation resistance of the coiled secondary cable satisfies the following relational expression:

[0025]

[0026] In the formula,

[0027] R p is the reference value of the insulation resistance of the coiled secondary cable.

[0028] R h is the standard value of the insulation resistance of the secondary circuit cable.

[0029] L max is the maximum length of the cable laying in the substation.

[0030] L p is the total length of the coiled cable.

[0031] K1 is the measurement reliability coefficient.

[0032] K2 is the loop correction coefficient.

[0033] Preferably, the measurement reliability coefficient K1 takes a value of 3, and the loop correction coefficient K2 takes a value of 2.5 - 3.

[0034] On the other hand, the present invention also proposes a test system for the insulation resistance of coiled secondary cables, and the system includes: a collection module, an insulation resistance calculation module, an insulation resistance test module, and a detection module.

[0035] The collection module is used to collect the insulation standard value of the secondary circuit cable and the total length of the coiled cable.

[0036] The insulation resistance calculation module includes: a maximum cable laying length calculation unit in the substation and an insulation resistance reference value calculation unit; the maximum cable laying length calculation unit in the substation is used to determine the maximum cable laying length in the substation according to the design drawings of the secondary cable channels in the substation based on the A* algorithm and the smoothing processing algorithm; the insulation resistance reference value calculation unit is used to calculate the reference value of the insulation resistance of the coiled secondary cable by using the data collected by the collection module and the maximum cable laying length in the substation determined by the maximum cable laying length calculation unit in the substation.

[0037] An insulation resistance test module is used to test the insulation resistance of a reel of secondary cables to obtain the insulation resistance test value of the reel of secondary cables. The insulation resistance test module includes: a single-cable-core insulation resistance test unit, an insulation resistance test unit between cable cores, and an overall insulation resistance test unit. The single-cable-core insulation resistance test unit outputs the insulation resistance test value of a single cable core, the insulation resistance test unit between cable cores outputs the insulation resistance test value between cable cores, and the overall insulation resistance test unit outputs the overall insulation resistance test value.

[0038] A detection module is used to compare the insulation resistance test value of a single cable core, the insulation resistance test value between cable cores, and the overall insulation resistance test value with the reference insulation resistance value of the reel of secondary cables. If each insulation resistance test value of the reel of secondary cables is greater than the reference insulation resistance value of the reel of secondary cables, it is determined that the insulation resistance of the reel of secondary cables meets the standard; otherwise, it is determined that the insulation resistance of the reel of secondary cables does not meet the standard and a warning is given.

[0039] On the other hand, the present invention also proposes a terminal, including a processor and a storage medium. The storage medium is used to store instructions. The processor is used to operate according to the instructions to execute the steps of the method for testing the insulation resistance of a reel of secondary cables.

[0040] On the other hand, the present invention also proposes a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the steps of the method for testing the insulation resistance of a reel of secondary cables are implemented.

[0041] The beneficial effect of the present invention is that, compared with the prior art, the method for testing the insulation resistance of a reel of secondary cables proposed by the present invention can test the insulation resistance of the reel of cables during arrival acceptance and before loop laying, which can reduce the impact of the overall insulation problem of the loop caused by insufficient insulation of the reel of cables itself. By applying the method proposed by the present invention to establish the operation standard for testing the insulation resistance of a reel of secondary cables before laying, the cut-off point of insulation testing can be advanced, the risk of non-compliance of insulation after laying of secondary cables can be reduced, and the waste and blindness of cable replacement due to non-compliance of insulation can also be reduced.

[0042] The present invention makes full use of the characteristic that the insulation resistance of secondary cables is inversely proportional to the effective measurement length of secondary cables. Taking the insulation resistance test of the cable corresponding to the maximum laying length in the substation as an example, the test efficiency and operability are improved.

[0043] The present invention uses the A* algorithm and performs curve smoothing within the allowable cable turning radius to obtain the path length of the secondary cable loop. The path length fully considers various factors such as the turning radius requirements and obstacle crossing requirements during cable laying. Therefore, it is more consistent with the actual cable laying path. Using the path length as the maximum length of in-station cable laying makes the calculation of the insulation resistance reference value of the coiled cable more accurate and reliable. At the same time, when calculating the insulation resistance reference value of the coiled cable, the differences between the insulation resistance test of the coiled secondary cable and the insulation resistance test of the secondary loop cable caused by the measurement instrument error and the influence of the secondary loop path are fully considered. Therefore, a measurement reliability coefficient and a loop correction coefficient are introduced to further improve the reliability and accuracy of the insulation resistance test of the coiled secondary cable.

[0044] The secondary coiled cable insulation resistance test system proposed by the present invention immediately gives a warning for coiled cables that do not meet the insulation requirements, that is, it informs the construction personnel that there is a risk that the insulation of the cable does not meet the standard after laying. Brief Description of the Drawings

[0045] Figure 1 is a flowchart of a method for testing the insulation resistance of a secondary coiled cable provided by the present invention;

[0046] Figure 2 is a schematic diagram of cable laying in an embodiment of the present invention. Detailed Embodiments

[0047] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. The embodiments described in this application are only a part of the embodiments of the present invention, rather than all embodiments. Based on the spirit of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0048] During the processes of substation infrastructure commissioning, maintenance, and acceptance, it is found that if the coiled cable is detected by the method of factory routine testing, even if the detection result at that time is greater than 10 MΩ, the insulation of the secondary loop after cable laying may be less than 10 MΩ, which cannot meet the insulation standard requirements of the secondary loop. Moreover, there are no standards and methods for testing the insulation resistance of coiled cables in the prior art. Therefore, the present invention provides a method for testing the insulation resistance of a coiled secondary cable, as Figure 1 shown, the testing method includes:

[0049] Step 1, collect the standard value of the insulation resistance of the secondary loop cable and the total length of the coiled cable.

[0050] In this embodiment, when conducting the insulation resistance test on the second - stage cables in coils on - site, first, collect on - site data, parameters, and prepare the test instruments. Among them, the collection of on - site data and parameters includes, but is not limited to: the standard value R of the insulation resistance of the second - stage circuit cables h , the total length L of the cables in coils p .

[0051] Among them, the standard value R of the insulation resistance of the second - stage circuit cables h can be determined according to the actual project situation. Taking the acceptance test of a newly installed protection device as an example, a 1000V insulation resistance meter is used to measure the insulation resistance between the circuit and the ground and between each circuit. The resistance value should be greater than 10MΩ. Therefore, R h = 10MΩ. When conducting regular inspections on the protection device, a 1000V insulation resistance meter is used to measure the insulation resistance between the circuit and the ground and between each circuit. The resistance value should be greater than 1MΩ. Therefore, R h = 1MΩ.

[0052] The total length L of the cables in coils p is determined by the total length marked on the cables in coils.

[0053] In terms of preparing the test instruments, mainly prepare a megohmmeter or an insulation resistance tester commonly used for cable insulation testing. A megohmmeter with a 1000V range is often used for cable insulation testing.

[0054] Step 2: According to the design drawings of the in - station second - stage cable channels, based on the A* algorithm and the smoothing algorithm, determine the maximum laying length of the in - station cables.

[0055] On the design drawings of the in - station second - stage cable channels, according to the usage scenarios of the cables in coils and combined with the in - station layout design, the laying length of each cable can be determined. There are multiple cables laid in the whole station. According to the calculation method provided in the national standard GB / T3048.5 - 2007 "Test Methods for Electrical Performance of Electric Wires and Cables - Part 5: Insulation Resistance Test", the calculation formula for the insulation resistance of each second - stage cable is as follows:

[0056]

[0057] In the formula,

[0058] R x is the insulation resistance of the second - stage cable,

[0059] K i is the insulation resistance constant,

[0060] L is the effective measurement length of the second - stage cable,

[0061] D is the outer diameter of the cable insulation,

[0062] d is the inner diameter of the second - stage cable insulation.

[0063] When conducting the insulation resistance test on the second - stage cables in reels, for the convenience of calculation, the influence of the cable core area is usually not considered. As can be seen from Equation (1), the insulation resistance of the second - stage cables is inversely proportional to the effective measurement length of the second - stage cables. However, there are hundreds of different effective measurement lengths of the second - stage cables within the whole substation. If the insulation test is carried out for each second - stage cable, it will lead to an extremely complex and time - consuming test process. In order to improve the insulation resistance test efficiency of the second - stage cables in reels within the substation, the cable corresponding to the maximum cable laying length within the whole substation can be selected as a representative for the insulation test. When the insulation resistance test of the cable corresponding to the maximum cable laying length within the substation is qualified, the insulation resistance tests of the remaining cables within the substation are all qualified. The present invention makes full use of the characteristic that the insulation resistance of the second - stage cables is inversely proportional to the effective measurement length of the second - stage cables, and takes the insulation resistance test of the cable corresponding to the maximum cable laying length within the substation as a representative, thus improving the test efficiency and operability.

[0064] Take Figure 2 the cable channel shown as an example. In the figure, the secondary circuit cables are laid from the on - site control cubicle or terminal box to the terminal blocks corresponding to the protection devices and air switches in the cubicle of the small room. Among them, L1 is the laying length of the secondary cables in the horizontal cable trench, and L2 is the sum of the laying length of the secondary cables in the vertical cable trench and the laying length of the secondary cables through pipes after leaving the cable trench. The cable laying length can be roughly estimated as the sum of L1 and L2.

[0065] However, when laying the second - stage cables on - site, the path of the secondary circuit is very complex. Different starting points and ending points make the actual laying length of the cables different. The obstacles on the laying path and the cable turning radius will also make the actual laying length different. Therefore, this rough estimate cannot obtain the accurate maximum cable laying length within the whole substation, which will affect the accuracy of the test.

[0066] For a certain secondary cable circuit, the present invention proposes to use the A* algorithm to determine each section of the path in this circuit and obtain the fitting function f(x, y) of each section of the path; the nodes at both ends of each section of the path include: the laying starting point, the laying ending point, and the mid - points on the laying path; among them, the mid - points on the laying path include: the position where the laying path changes in the horizontal direction, the position where the laying path changes in the vertical direction, and the position of the obstacles on the laying path.

[0067] For any section of the path, in the two - dimensional plane, according to the nodes at both ends of this section of the path, the fitting function f(x, y) of this section of the path is smoothed within the range of the cable turning radius to obtain the smoothed fitting function q(x, y, φ) on this section of the path, where the steering angle φ satisfies the following relational expression:

[0068]

[0069] In the formula,

[0070] x t and y t are the coordinates of any point on this section of the path.

[0071] x m and y m are the coordinates of the node on the side close to the starting point of cable laying of this section of the path.

[0072] ρ is the turning radius of the cable.

[0073] Calculate the length of each section of the path according to the smoothing fitting function q(x, y, φ), and take the sum of the lengths of each section of the path as the path length of this secondary cable circuit; find the maximum value from the path lengths of all secondary cable circuits in the substation as the maximum cable laying length L in the substation. max .

[0074] The present invention uses the A* algorithm and performs curve smoothing within the allowable range of the cable turning radius to obtain the path length of the secondary cable circuit. The path length fully considers various factors such as the turning radius requirement and the requirement of crossing obstacles in cable laying. Therefore, it is more consistent with the actual cable laying path. Using the path length as the maximum cable laying length in the substation makes the calculation of the reference value of the insulation resistance of the formed cable more accurate and reliable.

[0075] Step 3: Calculate the reference value of the insulation resistance of the formed secondary cable using the data obtained in Steps 1 and 2.

[0076] Considering the differences in the insulation resistance test of the formed secondary cable and the insulation resistance test of the secondary circuit cable caused by measurement instrument errors and the influence of the secondary circuit path, introduce a measurement reliability coefficient and a circuit correction coefficient, and perform derivation in combination with Equation (1), and it can be obtained that the reference value of the insulation resistance of the formed secondary cable satisfies the following relationship:

[0077]

[0078] In the formula,

[0079] R p is the reference value of the insulation resistance of the formed secondary cable.

[0080] R h is the standard value of the insulation resistance of the secondary circuit cable. In the commissioning and acceptance of newly commissioned projects, this value is taken as 10 MΩ according to the standard. During the regular inspection of secondary equipment during the maintenance stage, this value is taken as 1 MΩ according to the standard.

[0081] L max is the maximum cable laying length.

[0082] L p is the total length of the formed cable.

[0083] K1 is the measurement reliability coefficient, which is corrected according to the measured data and engineering experience, and the value is 3;

[0084] K2 is the loop correction coefficient, which is corrected according to the measured data and engineering experience, and the value is 2.5 - 3;

[0085] In this embodiment, take R h = 10 ΜΩ, L max = 0.5 km, assuming the total length of the coiled cable is 1.5 km. The reference value of the insulation resistance of this coiled cable calculated by using Equation (2) and meeting the requirements is:

[0086]

[0087] Step 4, test the insulation resistance of the coiled secondary cable to obtain the insulation resistance test value of the coiled secondary cable. The insulation resistance test value of the coiled secondary cable includes: the insulation resistance test value of a single cable core, the insulation resistance test value between cable cores, and the overall insulation resistance test value.

[0088] The test includes: the insulation resistance test of a single cable core, the insulation resistance test between cable cores, and the overall insulation resistance test.

[0089] Peel the two ends of the coiled cable, and use a specified test instrument (such as a 1000V megohmmeter or insulation resistance tester) to test the insulation of the cable core. Considering that a single cable contains multiple cable cores, it is necessary to test the insulation resistance of each cable core and the whole. Use a megohmmeter in the 1000V range to sequentially perform the insulation resistance test of a single cable core, the insulation resistance test between cable cores, and the overall insulation resistance test. Assume that this coiled cable contains 4 cable cores, then the test items of the whole coiled cable shall be carried out with reference to Table 1.

[0090] Table 1 Insulation Resistance Test Table of Secondary Coiled Cable

[0091]

[0092] The insulation resistance test of a single cable core refers to the insulation resistance test of a single core to the cable shield. The test method is to use a test instrument, with one test lead connected to the cable core and the other test lead connected to the cable shield. In this embodiment, the insulation resistance test of a single cable core mainly tests the insulation results of 4 cores to the shield, with one test lead connected to the cable core and the other test lead connected to the cable shield.

[0093] The insulation resistance test between cable cores refers to the insulation resistance test between different cable cores. The test method is to use a test instrument, with two test leads connected to different cable cores. In this embodiment, the insulation resistance test between cable cores mainly tests the insulation resistance between 4 cable cores, with two test leads connected to different cable cores for testing.

[0094] The overall insulation resistance test refers to the insulation resistance test of the entire coiled cable against the shielding layer. The test method is to short-circuit all the cable cores inside the coiled cable together, and use a test instrument. One test lead is connected to all the short-circuited cable cores, and the other test lead is connected to the cable shielding layer. In this embodiment, for the overall insulation resistance of the cable, 4 cable cores of the coiled cable are short-circuited together. One test lead is connected to all the short-circuited cable cores, and the other test lead is connected to the cable shielding layer.

[0095] After each insulation resistance test is completed, the cable needs to be discharged before the next insulation test starts to avoid inaccurate insulation tests caused by the influence of capacitive charges. Therefore, before the above 11 items of tests, the cable needs to be discharged.

[0096] Step 5: Compare the insulation resistance test values of each coiled secondary cable with the reference value of the insulation resistance of the coiled secondary cable; if the insulation resistance test values of each coiled secondary cable are all greater than the reference value of the insulation resistance of the coiled secondary cable, it is determined that the insulation resistance of the coiled secondary cable meets the standard; otherwise, it is determined that the insulation resistance of the coiled secondary cable does not meet the standard.

[0097] In this embodiment, when the insulation resistance test result values of the above 11 test items are all greater than 30 MΩ, it is determined that the insulation resistance of the coiled cable meets the standard and the coiled cable can be put into use for laying the secondary cable; otherwise, it indicates that there is a risk of insufficient insulation in this coil of cable and it is not recommended to be put into use.

[0098] The method for testing the insulation resistance of a secondary coiled cable proposed by the present invention can perform the insulation resistance test on the coiled cable during the arrival acceptance and before the loop laying, which can reduce the influence of the overall insulation problem of the loop caused by the insufficient insulation of the coiled cable itself. By using the method proposed by the present invention to establish the operation standard for the insulation resistance test of the secondary coiled cable before laying, the cut-off point of the insulation test can be advanced, reducing the risk that the insulation of the secondary cable does not meet the standard after laying, and also reducing the waste and blindness of cable replacement due to non-compliance of the insulation.

[0099] On the other hand, the present invention proposes a system for testing the insulation resistance of a secondary coiled cable, including: a collection module, an insulation resistance calculation module, an insulation resistance test module, and a detection module.

[0100] The collection module is used to collect the insulation standard value of the secondary circuit cable and the total length of the coiled cable;

[0101] The insulation resistance calculation module includes: a maximum in-station cable laying length calculation unit and an insulation resistance reference value calculation unit; the maximum in-station cable laying length calculation unit is used to determine the maximum in-station cable laying length based on the A* algorithm and the smoothing processing algorithm according to the in-station secondary cable channel design drawings; the insulation resistance reference value calculation unit is used to calculate the insulation resistance reference value of the secondary cables on a reel by using the data collected by the acquisition module and the maximum in-station cable laying length determined by the maximum in-station cable laying length calculation unit.

[0102] The insulation resistance test module is used to test the insulation resistance of the secondary cables on a reel to obtain the insulation resistance test value of the secondary cables on a reel; the insulation resistance test module includes: a single cable core insulation resistance test unit, an insulation resistance test unit between cable cores, and an overall insulation resistance test unit; the single cable core insulation resistance test unit outputs the insulation resistance test value of a single cable core, the insulation resistance test unit between cable cores outputs the insulation resistance test value between cable cores, and the overall insulation resistance test unit outputs the overall insulation resistance test value.

[0103] The detection module is used to compare the insulation resistance test value of a single cable core, the insulation resistance test value between cable cores, and the overall insulation resistance test value with the insulation resistance reference value of the secondary cables on a reel; if each insulation resistance test value of the secondary cables on a reel is greater than the insulation resistance reference value of the secondary cables on a reel, it is determined that the insulation resistance of the secondary cables on a reel meets the standard; otherwise, it is determined that the insulation resistance of the secondary cables on a reel does not meet the standard and a warning is given.

[0104] The secondary cable on-reel insulation resistance test system proposed by the present invention immediately gives a warning for the on-reel cable that does not meet the insulation requirements, that is, it informs the construction personnel that there is a risk that the insulation of the cable does not meet the standard after laying.

[0105] This disclosure can be a system, a method, and / or a computer program product. The computer program product can include a computer-readable storage medium having computer-readable program instructions thereon for causing a processor to implement various aspects of this disclosure.

[0106] A computer-readable storage medium can be a tangible device that can hold and store instructions for use by an instruction execution device. A computer-readable storage medium may be, for example—but not limited to—an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer-readable storage medium include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disc (DVD), a memory stick, a floppy disk, a mechanically encoded device such as a punched card or raised structures in grooves having instructions stored thereon, and any suitable combination of the foregoing. The computer-readable storage medium as used herein is not construed as being an instantaneous signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., an optical pulse through an optical fiber cable), or an electrical signal transmitted through a wire.

[0107] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to various computing / processing devices, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network may include a copper transmission cable, an optical fiber transmission, a wireless transmission, a router, a firewall, a switch, a gateway computer, and / or an edge server. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in a computer-readable storage medium in each computing / processing device.

[0108] The computer program instructions for performing the operations of the present disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine - related instructions, microcode, firmware instructions, state - setting data, or source code or object code written in any combination of one or more programming languages, including object - oriented programming languages such as Smalltalk, C++, etc., and conventional procedural programming languages such as the "C" language or similar programming languages. The computer - readable program instructions may be executed entirely on the user's computer, partially on the user's computer, executed as a stand - alone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., through the Internet using an Internet service provider). In some embodiments, by using the state information of the computer - readable program instructions to customize an electronic circuit, such as a programmable logic circuit, a field - programmable gate array (FPGA), or a programmable logic array (PLA), the electronic circuit can execute the computer - readable program instructions to implement various aspects of the present disclosure.

[0109] Aspects of the present disclosure are described herein with reference to the flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present disclosure. It should be understood that each block of the flowcharts and / or block diagrams, and combinations of blocks in the flowcharts and / or block diagrams, can be implemented by computer - readable program instructions.

[0110] These computer - readable program instructions can be provided to a processor of a general - purpose computer, a special - purpose computer, or other programmable data - processing apparatus to produce a machine such that the instructions, when executed by the processor of the computer or other programmable data - processing apparatus, create a means for implementing the functions / acts specified in one or more blocks of the flowchart and / or block diagram. These computer - readable program instructions can also be stored in a computer - readable storage medium, which causes a computer, a programmable data - processing apparatus, and / or other devices to operate in a particular manner, so that the computer - readable medium storing the instructions includes a manufacture that includes instructions for implementing various aspects of the functions / acts specified in one or more blocks of the flowchart and / or block diagram.

[0111] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices, causing a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other devices to generate a computer-implemented process, so that the instructions executed on the computer, other programmable data processing apparatus, or other devices implement the functions / actions specified in one or more boxes of the flowchart and / or block diagram.

[0112] The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagram may represent a module, a segment of a program, or a portion of an instruction, which contains one or more executable instructions for implementing the specified logical function. In some alternative implementations, the functions noted in the blocks may occur out of the order noted in the figures. For example, two consecutive blocks may in fact be executed substantially in parallel, or they may sometimes be executed in the reverse order, depending on the functionality involved. It should also be noted that each block of the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented by a dedicated hardware-based system that performs the specified functions or actions, or by a combination of dedicated hardware and computer instructions.

[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent replacements can still be made to the specific implementation manners of the present invention, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A method for testing the insulation resistance of a coiled secondary cable, characterized in that: The method includes: Step 1, collect the insulation standard value of the secondary circuit cable and the total length of the coiled cable; Step 2, according to the design drawings of the secondary cable channels in the station, based on the A* algorithm and the smoothing algorithm, determine the maximum length of the cable laying in the station, including: For any path determined by the A* algorithm, in the two-dimensional plane, according to the nodes at both ends of the path, smooth the fitting function f(x, y) of the path within the cable turning radius range to obtain the smoothed fitting function q(x, y, φ) on the path, where the steering angle φ satisfies the following relational expression: where x t , y t are the coordinates of any point on this section of the path, x m , y m are the coordinates of the node near the cable laying starting point on this section of the path, and ρ is the cable turning radius; Step 3, calculate the reference value of the insulation resistance of the coiled secondary cable using the data obtained in Steps 1 and 2; Step 4, test the insulation resistance of the coiled secondary cable to obtain the test value of the insulation resistance of the coiled secondary cable. The test value of the insulation resistance of the coiled secondary cable includes: the test value of the insulation resistance of a single cable core, the test value of the insulation resistance between the cable cores, and the test value of the overall insulation resistance; Step 5, compare each test value of the insulation resistance of the coiled secondary cable with the reference value of the insulation resistance of the coiled secondary cable; if each test value of the insulation resistance of the coiled secondary cable is greater than the reference value of the insulation resistance of the coiled secondary cable, it is determined that the insulation resistance of the coiled secondary cable meets the standard; otherwise, it is determined that the insulation resistance of the coiled secondary cable does not meet the standard.

2. The method for testing the insulation resistance of a coiled secondary cable according to claim 1, characterized in that: In Step 1, during the commissioning and acceptance of a newly put into operation project, the insulation resistance standard value of the secondary circuit cable is taken as 10 MΩ; during the regular inspection of the secondary device during the maintenance phase, the insulation resistance standard value of the secondary circuit cable is taken as 1 MΩ.

3. The method for testing the insulation resistance of a coiled secondary cable according to claim 1, characterized in that: In Step 2, within the entire station, for a certain secondary cable circuit, use the A* algorithm to determine each path in the circuit and obtain the fitting function f(x, y) of each path; The nodes at both ends of each path include: the laying starting point, the laying ending point, and the laying midpoint; among them, the laying midpoint includes: the position where the laying path changes horizontally, the position where the laying path changes vertically, and the position of the obstacle on the laying path; The coordinate points of each node can be obtained from the design drawings of the secondary cable channels in the station.

4. The method for testing the insulation resistance of a coiled secondary cable according to claim 1, characterized in that: Calculate the length of each path according to the smoothed fitting function q(x, y, φ), and take the sum of the lengths of each path as the path length of a certain secondary cable circuit; Find the maximum value from the path lengths of the secondary cable circuits within the entire station, and use it as the maximum cable laying length L within the station max .

5. The method for testing the insulation resistance of a coiled secondary cable according to claim 1, characterized in that: In Step 3, the reference value of the insulation resistance of the coiled secondary cable satisfies the following relational expression: In the formula, R p is the reference value of the insulation resistance of the secondary cable in a coil R h is the standard value of the insulation resistance of the secondary circuit cable L max is the maximum length of in-station cable laying; L p is the total length of the coiled cable; K1 is the measurement reliability coefficient; K2 is the loop correction coefficient.

6. The method for testing the insulation resistance of a coiled secondary cable according to claim 5, characterized in that: The measurement reliability coefficient K1 takes a value of 3, and the loop correction coefficient K2 takes a value of 2.5 - 3.

7. A reel secondary cable insulation resistance test system using the method according to any one of claims 1-6, the system comprising: A collection module, an insulation resistance calculation module, an insulation resistance test module, a detection module; characterized in that: The acquisition module is used to acquire the insulation standard value of the secondary circuit cable and the total length of the cabled cable. The insulation resistance calculation module includes: a maximum in-station cable laying length calculation unit and an insulation resistance reference value calculation unit. The maximum in-station cable laying length calculation unit is used to determine the maximum in-station cable laying length based on the A* algorithm and the smoothing processing algorithm according to the in-station secondary cable channel design drawings. The insulation resistance reference value calculation unit is used to calculate the insulation resistance reference value of the cabled secondary cable by using the data acquired by the acquisition module and the maximum in-station cable laying length determined by the maximum in-station cable laying length calculation unit. The insulation resistance test module is used to test the insulation resistance of the cabled secondary cable to obtain the insulation resistance test value of the cabled secondary cable. The insulation resistance test module includes: a single cable core insulation resistance test unit, an insulation resistance test unit between cable cores, and an overall insulation resistance test unit. The single cable core insulation resistance test unit outputs the single cable core insulation resistance test value, the insulation resistance test unit between cable cores outputs the insulation resistance test value between cable cores, and the overall insulation resistance test unit outputs the overall insulation resistance test value. The detection module is used to compare the single cable core insulation resistance test value, the insulation resistance test value between cable cores, and the overall insulation resistance test value with the insulation resistance reference value of the cabled secondary cable. If each insulation resistance test value of the cabled secondary cable is greater than the insulation resistance reference value of the cabled secondary cable, it is determined that the insulation resistance of the cabled secondary cable meets the standard; otherwise, it is determined that the insulation resistance of the cabled secondary cable does not meet the standard and a warning is given.

8. A terminal, comprising a processor and a storage medium; characterized in that: The storage medium is used to store instructions; The processor is used to operate according to the instructions to execute the steps of the method according to any one of claims 1-6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, the steps of the method according to any one of claims 1-6 are implemented.

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