Power supply cable insulation state monitoring method and device, and electronic equipment

Abstract

The embodiment of the invention relates to the technical field of rail transit, in particular to a power supply cable insulation state monitoring method and device and electronic equipment. The power supply cable insulation state monitoring method comprises the following steps: acquiring voltage to ground of a three-phase cable of each monitoring partition of a power supply cable to obtain a three-phase voltage vector; respectively determining an end point position of the three-phase voltage vector, a circumcircle center of a circumcircle and a circumcircle radius of the circumcircle; determining a distance per unit value according to the distance between each end point position and the center of the circumcircle; and determining the insulation state of each monitoring zone of the power supply cable according to the distance per unit value. According to the power supply cable insulation state monitoring method provided by the embodiment of the invention, the insulation state of the power supply cable can be monitored when the superconducting maglev train runs off line, manual routing inspection along the whole line is not needed, the implementation is simple, fault positioning can be realized at the early stage of insulation deterioration of the power supply cable, safety accidents are effectively avoided, and the working efficiency is improved. And the running reliability and safety of the maglev train are improved.

Description

Technical Field

[0001] This application relates to the technical field of rail transit, and in particular, to a method and device for monitoring the insulation state of a power supply cable, and an electronic device. Background Art

[0002] A maglev train is a train propelled by magnetic levitation force. It realizes non-contact suspension and guidance between the train and the track through electromagnetic force, and then uses the electromagnetic force generated by a linear motor to drive the train to run. Due to the magnetic force of its track, it is suspended in the air, reducing friction. When running, unlike other trains that need to contact the ground, it is only affected by air resistance. The speed of high-speed maglev trains can reach more than 400 kilometers per hour, while most medium and low-speed maglev trains are in the range of 100 - 200 kilometers per hour.

[0003] The superconducting maglev ground propulsion coils are laid over a long distance along the line, and it is difficult to conduct manual inspections. When the cable undergoes insulation aging, the characteristics are not obvious. However, as the service life increases, the cable will age rapidly, and then serious faults will occur.

[0004] Therefore, there is an urgent need for a method to monitor the insulation state of power supply cables. Summary of the Invention

[0005] This application provides a method and device for monitoring the insulation state of a power supply cable, and an electronic device in an embodiment.

[0006] In a first aspect of the embodiments of this application, a method for monitoring the insulation state of a power supply cable is provided, including:

[0007] Obtain the ground voltages of the three-phase cables in each monitoring section of the power supply cable to obtain three-phase voltage vectors;

[0008] Respectively determine the end positions of the three-phase voltage vectors, the circumcenter of the circumscribed circle, and the radius of the circumscribed circle of the circumscribed circle;

[0009] Determine the per-unit value of the distance according to the distance between each end position and the circumcenter;

[0010] Determine the insulation state of each monitoring section of the power supply cable according to the per-unit value of the distance.

[0011] In an optional embodiment of this application, the step of obtaining the ground voltages of the three-phase cables in each monitoring section of the power supply cable to obtain three-phase voltage vectors includes:

[0012] Input a current with a rated frequency and a rated amplitude for no less than a preset duration into the ground stator modules along the line through a ground converter;

[0013] Perform voltage sampling on the power supply cable to obtain the ground voltages of the three-phase cables in each monitoring section of the power supply cable;

[0014] Filter and phase-lock the ground voltage of the three-phase cable to obtain the three-phase voltage vector.

[0015] In an alternative embodiment of the present application, the three-phase voltage vector at least includes: the phase and amplitude of each phase voltage.

[0016] In an alternative embodiment of the present application, the determining the per-unit value of the distance according to the distance of each of the end positions from the circumcenter includes:

[0017] Determine a first distance from the circumcenter to the origin of the three-phase voltage vector;

[0018] Determine the ratio between the first distance and the radius of the circumcircle of the circumcircle to obtain the per-unit value of the distance; wherein, the per-unit value of the distance is used to characterize whether there is an insulation fault in the power supply cable.

[0019] In an alternative embodiment of the present application, the determining the insulation state of each of the monitoring zones of the power supply cable according to the per-unit value of the distance includes:

[0020] If the per-unit value of the distance in the current monitoring zone exceeds a preset threshold range, determine that the insulation state of the current monitoring zone is an insulation fault.

[0021] In an alternative embodiment of the present application, after the step of if the per-unit value of the distance in the current monitoring zone exceeds a preset threshold range, determine that the insulation state of the current monitoring zone is an insulation fault, the method further includes:

[0022] Determine a second distance from each of the end positions of the three-phase voltage vector to the circumcenter;

[0023] Locate the insulation fault in the current monitoring zone according to the second distance.

[0024] In an alternative embodiment of the present application, each of the monitoring zones in the power supply cable is powered by three-step commutation, and the method further includes:

[0025] Respectively determine the per-unit values of the distances of a plurality of consecutive monitoring zones; wherein, the plurality of monitoring zones at least includes consecutively: a first monitoring zone, a second monitoring zone, and an intermediate monitoring zone located between the first monitoring zone and the second monitoring zone;

[0026] Determine whether the intermediate monitoring zone is in abnormal insulation according to the per-unit values of the distances of the first monitoring zone and the second monitoring zone.

[0027] In the second aspect of the embodiments of the present application, a power supply cable insulation state monitoring device is provided, including:

[0028] An acquisition module, configured to acquire the ground voltages of the three-phase cables in each monitoring section of the power supply cable to obtain three-phase voltage vectors;

[0029] A first determination module, configured to respectively determine the end positions of the three-phase voltage vectors, the circumcenter of the circumscribed circle, and the radius of the circumscribed circle of the circumscribed circle;

[0030] A second determination module, configured to determine the per-unit value of the distance according to the distances between the respective end positions and the circumcenter;

[0031] A third determination module, configured to determine the insulation state of each monitoring section of the power supply cable according to the per-unit value of the distance.

[0032] In the third aspect of the embodiments of the present application, an electronic device is provided, including: a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, the steps of any one of the above methods are implemented.

[0033] In the fourth aspect of the embodiments of the present application, a computer-readable storage medium is provided, on which a computer program is stored, characterized in that when the computer program is executed by a processor, the steps of any one of the above methods are implemented.

[0034] In the first aspect, for the power supply cable insulation state monitoring method provided by the embodiments of the present application, a three-phase balanced current is input into the ground coil, the ground three-phase voltages at the input end of the power supply cable are detected by each trackside switch station on the ground, and the signal is processed such as filtering and phase locking by a processing device to obtain three-phase voltage vectors, and then the three-phase voltage vectors are projected onto a two-dimensional plane, and the per-unit value of the distance is determined by using the geometric relationship between the phases, and then the insulation state is determined through the per-unit value of the distance. The power supply cable insulation state monitoring method provided by the embodiments of the present application can monitor the insulation state of the power supply cable when the superconducting maglev train is not running online, without manual inspection along the whole line, the implementation is simple, fault location can be achieved at the initial stage of power supply cable insulation deterioration, the power supply cable can be replaced to achieve early condition-based maintenance, the cable can be replaced, safety accidents can be effectively avoided, the human and material costs can be reduced, the operation efficiency can be improved, and the reliability and safety of the maglev train operation can be improved.

[0035] In the second aspect, for the power supply cable insulation state monitoring method provided by the embodiments of the present application, a trackside switch station is set at each ground stator input section, the power supply cable is partitioned, and three-step commutation can be achieved through autonomous control of each partition, sampling and analysis of voltage signals can be realized, and fully automated monitoring can be completely achieved, with lower labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings described herein are used to provide a further understanding of the present application, and constitute a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application, and do not constitute an improper limitation of the present application. In the drawings:

[0037] Figure 1 is an overall schematic diagram of a high-speed superconducting maglev system provided by an embodiment of the present application;

[0038] Figure 2 is a flowchart of a method for monitoring the insulation state of a power supply cable provided by an embodiment of the present application;

[0039] Figure 3 is a detection simulation circuit diagram of a method for monitoring the insulation state of a power supply cable provided by an embodiment of the present application;

[0040] Figure 4 is a schematic diagram of three-phase voltage vectors in a method for monitoring the insulation state of a power supply cable provided by an embodiment of the present application;

[0041] Figure 5 is a flowchart of a method for monitoring the insulation state of a power supply cable provided by an embodiment of the present application;

[0042] Figure 6 is a flowchart of a method for monitoring the insulation state of a power supply cable provided by an embodiment of the present application;

[0043] Figure 7 is a flowchart of a method for monitoring the insulation state of a power supply cable provided by an embodiment of the present application;

[0044] Figure 8 is a flowchart of a method for monitoring the insulation state of a power supply cable provided by an embodiment of the present application;

[0045] Figure 9 is a schematic structural diagram of a device for monitoring the insulation state of a power supply cable provided by an embodiment of the present application;

[0046] Figure 10 is a schematic structural diagram of an electronic device provided by an embodiment of the present application. Detailed implementation manners

[0047] In the process of implementing the present application, the inventors found that there is an urgent need for a method to monitor the insulation state of power supply cables.

[0048] In view of the above problems, an embodiment of the present application provides a method and device for monitoring the insulation state of a power supply cable, and an electronic device.

[0049] The solutions in the embodiments of this application can be implemented using various computer languages. For example, object-oriented programming languages such as Java and interpreted scripting languages such as JavaScript.

[0050] In order to make the technical solutions and advantages in the embodiments of this application clearer and more understandable, the following further elaborates on the exemplary embodiments of this application with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, rather than an exhaustive list of all embodiments. It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other.

[0051] The following briefly describes the application environment of the power supply cable insulation state monitoring method provided by the embodiments of this application:

[0052] Please refer to Figure 1 , Figure 1 , which is a schematic diagram of the overall structure of the high-speed superconducting maglev system. The power supply cable insulation state monitoring method provided by the embodiments of this application is applied to the high-speed superconducting maglev system. The high-speed superconducting maglev system includes at least: tracks and processing equipment. Among them, the tracks are divided into multiple monitoring zones. The monitoring zones can be divided according to a fixed distance or according to stator segments, and can be flexibly adjusted according to the actual situation. The embodiments of this application do not make specific limitations. It should be explained that at least one set of three-phase stator coil modules is laid on both sides of the track ground of each stator segment, and electrical signal (such as voltage signal, current signal, power, etc.) acquisition devices are arranged at each stator end. The stator input current is controlled by three ground high-power converters. Substation switchyards (T1, T2, T3...) are set along the track ground. Each substation switchyard is equipped with a high-power switching switch to cooperate with the ground converter to achieve three-step commutation. The three-step commutation means conducting three-phase currents each time. For example, please refer to Figure 1 and Figure 2 . For the first time, connect the ABC section and disconnect the currents of other sections; for the second time, connect the BCD section and disconnect the currents of other sections; for the third time, connect the CDF section and disconnect the currents of other sections. As shown in Figure 1 , the three ground converters are used to supply power to the ground stator modules. Taking the power supply network formed by the 1# converter as an example, according to the on-off status of the switches, the power supply network can be divided into different intervals, namely ABC section, ABDE section, ABDFG section... According to the analysis of the three-phase-to-ground voltage of the power supply cable of the T4 switchyard, the insulation state of the power supply cable in the ABC section can be determined; according to the insulation state of the ABC section and the three-phase-to-ground voltage of the power supply cable of the T7 switchyard, the insulation state of the power supply cable in the BDE section can be determined, and so on. In this way, the insulation state can be monitored regularly, improving the monitoring efficiency.

[0053] The above-mentioned electrical signal acquisition device is signal-connected to the processing device, and is used to acquire the electrical signals of the three-phase stator coil module, and send the electrical signals to the processing device for analysis, calculation, judgment, etc.; the processing device is configured with a digital processing system for processing and analyzing the corresponding data, and then determining the insulation state, and positioning each insulation fault or insulation anomaly. The processing device can be a computer, a server, a laptop computer, a mobile phone, a wearable electronic device, or other electronic devices with data analysis and processing capabilities, etc. There is no specific limitation in the embodiments of the present application, and it can be flexibly selected or adjusted according to the actual situation.

[0054] Please refer to Figure 2 , in the following embodiments, the above-mentioned processing device is used as the execution main body, and the power supply cable insulation state monitoring method provided by the embodiments of the present application is applied to the above-mentioned processing device, and is used to specifically illustrate the insulation fault of the power supply cable as an example. A power supply cable insulation state monitoring method provided by an embodiment of the present application includes the following steps 201-step 204:

[0055] Step 201, obtain the ground voltages of the three-phase cables in each monitoring section of the power supply cable to obtain three-phase voltage vectors;

[0056] Step 202, respectively determine the end position of the three-phase voltage vector, the circumcenter of the circumscribed circle, and the radius of the circumscribed circle of the circumscribed circle;

[0057] Step 203, determine the per-unit value of the distance according to the distance from each end position to the circumcenter;

[0058] Step 204, determine the insulation state of each monitoring section of the power supply cable according to the per-unit value of the distance.

[0059] The working principle of the power supply cable insulation state monitoring method provided by the embodiments of the present application is briefly introduced as follows:

[0060] Figure 3 It is a schematic diagram of the principle of the cable in the power supply interval section and the ground stator circuit of the present invention. ZLi (i = a, b, c represents three phases) represents the impedance of the cable section, ZSi represents the impedance of the stator section, ZEi represents the comprehensive ground impedance of the entire section of the power supply cable, and Rm represents the high resistance for measurement. When the insulation of the power supply cable deteriorates in the initial stage, its ground impedance is still very large, which is several orders of magnitude of the line impedance. Therefore, the three-phase voltages of ABC and abc to point O' can be regarded as a balanced state. When the insulation of phase C deteriorates, the impedance ZEC will become smaller, so the three-phase voltages of abc to point O will no longer be balanced.

[0061] Three three-phase high-power converters on the ground output currents with rated frequency and rated amplitude according to the instructions, and three-phase voltages will be induced at the power supply cable ports. The three-phase voltages to the ground are sampled by the voltage sampling circuit in the substation by the trackside, and after filtering and phase-locking processing by the output processing system, the voltage vectors of each phase (such as phase θi and amplitude Di) can be obtained.

[0062] By detecting the voltages uio (i = a, b, c, respectively representing the three phases) of the three-phase cable cores to the ground in each monitoring area, the information of the three voltage vectors is obtained; taking the origin O(0, 0) as the starting point, the end coordinates Ui(xi, yi) of the three vectors, the coordinates O’(xo’, yo’) of the center of the circumscribed circle of the vectors, and the radius R of the circumscribed circle are calculated. According to the per-unit value characteristics of the distances between the coordinate positions, the insulation state of the power supply cable is determined. The end position (such as the projection coordinates) Ui(xi, yi) of the voltage vector of each phase in the two-dimensional plane can be expressed as (Di×cosθi, Di×sinθi), and the position of the center of the circumscribed circle determined by the voltage vector of the phase is:

[0063]

[0064]

[0065] The radius R of the circumscribed circle is:

[0066]

[0067] The first distance Loo’ from the center of the circumscribed circle to the origin of the three-phase voltage vectors (the starting points of the three voltage vectors) is:

[0068]

[0069] Among them, Loo’ is the first distance, k is the per-unit value of the distance, (xo’, yo’) is the coordinate of the center of the circumscribed circle, and R is the radius of the circumscribed circle.

[0070] Thus, the geometric characteristics of the three-phase voltage vectors of the power supply cable to the ground in the two-dimensional plane are obtained. Figure 4 This is the schematic diagram of the three-phase voltage vectors of the present invention, which characterizes the geometric relationship of the three-phase voltage vectors in the two-dimensional plane.

[0071] Determining the ratio of the first distance to the radius of the circumscribed circle (k = Loo’ / R) can obtain the per-unit value of the distance. The smaller the per-unit value k of the distance, the better the insulation performance of the power supply cable; on the contrary, when the per-unit value k of the distance exceeds the set threshold, it can be determined that the power supply cable has an insulation fault. At the same time, by comparing the magnitudes of the three voltage vectors, the phase with the weakest insulation state can be located.

[0072] In the embodiment of the present application, the end position of the three-phase voltage vector, the circumcenter of the circumscribed circle, and the radius of the circumscribed circle of the circumscribed circle in the two-dimensional plane are used as characteristic quantities of the insulation state. This characteristic quantity extraction method is simple and convenient, and can effectively improve the monitoring efficiency of the power supply cable insulation state monitoring method in the embodiment of the present application, and reduce the monitoring equipment cost and process cost.

[0073] In a first aspect, the power supply cable insulation state monitoring method provided by the embodiment of the present application inputs a three-phase balanced current into the ground coil, detects the three-phase voltage to the ground at the input end of the power supply cable through each trackside switch station on the ground, and uses a processing device to perform filtering, phase locking, etc. on the signal to obtain a three-phase voltage vector. Then, the three-phase voltage vector is projected onto a two-dimensional plane, and the distance per unit value is determined using the geometric relationship between the phases. Then, the insulation state is judged based on this distance per unit value. The power supply cable insulation state monitoring method provided by the embodiment of the present application can monitor the insulation state of the power supply cable when the superconducting maglev train is not running online, without manual inspection along the entire line. It is simple to implement, can locate faults at the initial stage of power supply cable insulation deterioration, replace the power supply cable, achieve early condition-based maintenance, replace the cable, effectively avoid safety accidents, reduce labor and material costs, improve operation efficiency, and improve the reliability and safety of maglev train operation.

[0074] In a second aspect, the power supply cable insulation state monitoring method provided by the embodiment of the present application sets a trackside switch station at each ground stator input section, divides the power supply cable into zones, and can achieve three-step commutation through autonomous control of each zone, realize sampling and analysis of voltage signals, and can fully achieve fully automated monitoring with lower labor costs.

[0075] Please refer to Figure 5 , in an optional embodiment of the present application, the above step 201, obtaining the three-phase cable voltages to the ground of each monitoring zone of the power supply cable to obtain a three-phase voltage vector, includes the following steps 501-step 503:

[0076] Step 501: Input a current with a rated frequency and rated amplitude for a preset duration or more into the ground stator modules along the line through a ground converter;

[0077] Step 502: Perform voltage sampling on the power supply cable to obtain the three-phase cable voltages to the ground of each of the monitoring zones of the power supply cable;

[0078] Step 503: Perform filtering and phase locking processing on the three-phase cable voltages to the ground to obtain the three-phase voltage vector.

[0079] The preset duration can be 20 cycles or other durations, which are not specifically limited in the embodiments of the present application. When the superconducting maglev train is in an offline state, the star connection point of the ground three-phase stator coil is closed, and the three ground three-phase high-power converters output a current with a rated frequency and a rated amplitude of no less than 20 cycles according to the instruction. The power supply cable port will induce a three-phase voltage, and the voltage sampling circuit in the substation beside the track can collect the three-phase voltage to the ground and send it to the processing device for further analysis and processing. For example, part of the clutter can be removed through filtering processing, and the required three-phase voltage can be determined through phase locking, and then the three-phase voltage vector can be obtained, such as the phase θi, amplitude Di, etc., which will not be enumerated here.

[0080] The three-phase cable voltage to the ground of each monitoring area of the power supply cable obtained by voltage sampling of the power supply cable; through filtering and phase-locking processing to obtain the three-phase voltage vector, the interference of excessive clutter can be avoided, and the reliability of insulation state determination can be improved.

[0081] In an optional embodiment of the present application, the above three-phase voltage vector at least includes: the phase and amplitude of each phase voltage.

[0082] By determining the distance per unit value of the distance from the center of the circumscribed circle through the phase and amplitude of each phase voltage, the phase is used to represent the geometric direction, and the amplitude is used to ensure the geometric length, and the obtained distance per unit value is more reliable, further improving the reliability of the power supply cable insulation state monitoring method in the embodiments of the present application.

[0083] Please refer to Figure 6 , in an optional embodiment of the present application, the above step 203, determining the distance per unit value according to the distance from each end position to the center of the circumscribed circle, includes the following steps 601-step 602:

[0084] Step 601: Determine the first distance from the center of the circumscribed circle to the origin of the three-phase voltage vector;

[0085] Step 602: Determine the ratio of the first distance to the radius of the circumscribed circle of the circumscribed circle to obtain the distance per unit value; wherein, the distance per unit value is used to represent whether the power supply cable has an insulation fault.

[0086] As in the above embodiment, the first distance Loo' and the distance per unit value k can be determined according to the following formula:

[0087]

[0088] k = Loo' / R

[0089] Wherein, Loo' is the first distance, k is the distance per unit value, (xo', yo') is the coordinate of the center of the circumscribed circle, and R is the radius of the circumscribed circle.

[0090] The smaller the per-unit value k of the distance is, the better the insulation performance of the power supply cable. On the contrary, when the per-unit value k of the distance exceeds the set threshold, it can be determined that the power supply cable has an insulation fault. At the same time, by comparing the magnitudes of the three voltage vectors, the phase with the weakest insulation state can be located. Based on the geometric characteristics of the end positions of the three-phase voltage vectors, the circumcenter of the circumscribed circle, and the radius of the circumscribed circle in the two-dimensional plane as the characteristic quantity of the insulation state, this characteristic quantity extraction method is simple and convenient, which can effectively improve the monitoring efficiency of the power supply cable insulation state monitoring method in the embodiments of the present application and reduce the monitoring equipment cost and process cost.

[0091] In an optional embodiment of the present application, the above step 204, determining the insulation state of each monitoring section of the power supply cable according to the per-unit value of the distance, includes:

[0092] If the per-unit value of the distance in the current monitoring section exceeds the preset threshold range, it is determined that the insulation state of the current monitoring section is an insulation fault.

[0093] The smaller the per-unit value k of the distance is, the better the insulation performance of the power supply cable. On the contrary, when the per-unit value k of the distance exceeds the set threshold, it can be determined that the power supply cable has an insulation fault. At the same time, by comparing the magnitudes of the three voltage vectors, the phase with the weakest insulation state can be located. The determination method is simple and efficient, which can effectively improve the monitoring efficiency of the power supply cable insulation state monitoring method in the embodiments of the present application.

[0094] Please refer to Figure 7 , in an optional embodiment of the present application, after the above step 204, if the per-unit value of the distance in the current monitoring section exceeds the preset threshold range, it is determined that the insulation state of the current monitoring section is an insulation fault, the method further includes the following steps 701-702:

[0095] Step 701, determining the second distance from each of the end positions of the three-phase voltage vectors to the circumcenter;

[0096] Step 702, locating the insulation fault of the current monitoring section according to the second distance.

[0097] The second distance Li from each of the end positions to the circumcenter can be calculated by the following formula:

[0098]

[0099] where Li is the second distance, (xo’, yo’) is the coordinate of the circumcenter of the circumscribed circle, and (xi’, yi’) is the end position of each phase in the three-phase voltage vector.

[0100] The fault phase can be located through the second distance Li, that is, the area with a distance Li from the center of the circumcircle is the fault area. Moreover, the smaller the value of the second distance Li of a certain phase among the three phases, the more serious the insulation damage of this phase. In the embodiment of the present application, the insulation fault of the current monitoring section can be located through the second distance from the end positions of the three-phase voltage vectors to the center of the circumcircle. The farther the coordinate origin of the three vectors is from the center of the circumcircle, the worse the insulation performance of the power supply cable. That is, based on the geometric characteristics of the three-phase-to-ground voltage vectors in the front and rear section segments, the embodiment of the present application can locate the phase and section segment of the power supply cable with insulation degradation, without manual inspection along the entire line. Fault location can be achieved at the initial stage of insulation deterioration of the power supply cable, the power supply cable can be replaced, early condition-based maintenance can be realized, the labor and material costs can be reduced, the operation efficiency can be improved, and the reliability and safety of maglev train operation can be enhanced.

[0101] Please refer to Figure 8 , in an optional embodiment of the present application, each of the monitoring sections in the power supply cable adopts three-step commutation power supply. The above power supply cable insulation state monitoring method further includes the following steps 801-step 802:

[0102] Step 801: Determine the per-unit values of the distances of a plurality of consecutive monitoring sections respectively; among them, the plurality of monitoring sections at least include consecutively: a first monitoring section, a second monitoring section, and an intermediate monitoring section located between the first monitoring section and the second monitoring section;

[0103] Step 802: Determine whether the intermediate monitoring section is in abnormal insulation according to the per-unit values of the distances of the first monitoring section and the second monitoring section.

[0104] It should be noted that the abnormal insulation in this embodiment is different from the above-mentioned insulation fault. This abnormal insulation does not necessarily mean a fault, but a fault must have abnormal insulation.

[0105] In this embodiment, the insulation status of the power supply cables along the whole line is detected in sections. Based on the position characteristics (distance per unit value) of the phase voltage vectors in the previous section (the first monitoring section), the insulation status of the power supply cables in this section is comprehensively determined. For example, if M and N are intermediate monitoring sections between two adjacent monitoring sections (the first monitoring section and the second monitoring section), when the distance per unit values k of the two adjacent monitoring sections (the first monitoring section and the second monitoring section) before and after the intermediate monitoring sections M and N are both within the threshold range, it indicates that the insulation status of the intermediate monitoring sections M and N is normal; when the distance per unit value k of the M monitoring section is within the threshold range and the distance per unit value k of the N monitoring section exceeds the threshold, it can be determined that the insulation of the N monitoring section is abnormal; when the distance per unit value k of the M monitoring section exceeds the threshold and the difference between the distance per unit value k of the N monitoring section and the distance per unit value k of the M monitoring section is not significant, it can be determined that the insulation of the N section is normal and the insulation of the M monitoring section is abnormal; when the distance per unit value k of the M monitoring section exceeds the threshold and the difference between the distance per unit value k of the N monitoring section and the distance per unit value k of the previous monitoring section is too large, it can be determined that the insulation of both the M and N sections is abnormal.

[0106] In the embodiment of the present application, it is determined whether the intermediate monitoring section is in abnormal insulation through the distance per unit values of the first monitoring section and the second monitoring section located before and after. It is possible to pre-monitor abnormal insulation before an insulation fault occurs, locate the fault at the initial stage of insulation deterioration of the power supply cable, replace the power supply cable, achieve early condition-based maintenance, replace the cable, effectively avoid safety accidents, reduce labor and material costs, improve operation efficiency, and enhance the reliability and safety of maglev train operation.

[0107] It should be understood that although the steps in the flowchart are shown in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless clearly stated in this article, there is no strict order limit for the execution of these steps, and these steps can be executed in other orders. Moreover, at least a part of the steps in the figure may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed alternately or in turn with at least a part of other steps or sub-steps or stages of other steps.

[0108] Please refer to Figure 9 , an embodiment of the present application provides a power supply cable insulation status monitoring device 900, including: an acquisition module 910, a first determination module 920, a second determination module 930, and a third determination module 940, where:

[0109] The acquisition module 910 is configured to acquire the voltages of the three-phase cables of each monitoring section of the power supply cable to obtain three-phase voltage vectors;

[0110] The first determination module 920 is configured to respectively determine the end positions of the three-phase voltage vectors, the circumcenter of the circumscribed circle, and the radius of the circumscribed circle of the circumscribed circle.

[0111] The second determination module 930 is configured to determine the per-unit value of the distance according to the distances between the respective end positions and the circumcenter of the circumscribed circle.

[0112] The third determination module 940 is configured to determine the insulation status of each monitoring section of the power supply cable according to the per-unit value of the distance.

[0113] In an alternative embodiment of the present application, the acquisition module 910 is specifically configured to input a current with a rated frequency and a rated amplitude for a preset duration or more to the ground stator modules along the line through a ground converter; perform voltage sampling on the power supply cable to obtain the voltages to the ground of the three-phase cables in each monitoring section of the power supply cable; perform filtering and phase-locking processing on the voltages to the ground of the three-phase cables to obtain the three-phase voltage vectors.

[0114] In an alternative embodiment of the present application, the first determination module 920 is specifically configured to: the three-phase voltage vectors at least include the phases and amplitudes of the voltages of each phase.

[0115] In an alternative embodiment of the present application, the second determination module 930 is specifically configured to determine a first distance from the circumcenter of the circumscribed circle to the origin of the three-phase voltage vectors; determine a ratio between the first distance and the radius of the circumscribed circle of the circumscribed circle to obtain the per-unit value of the distance; wherein, the per-unit value of the distance is used to characterize whether an insulation fault occurs in the power supply cable.

[0116] In an alternative embodiment of the present application, the second determination module 930 is specifically configured to: if the per-unit value of the distance in the current monitoring section exceeds a preset threshold range, determine that the insulation status of the current monitoring section is an insulation fault.

[0117] In an alternative embodiment of the present application, the second determination module 930 is further configured to determine a second distance from each end position of the three-phase voltage vectors to the circumcenter of the circumscribed circle; locate the insulation fault in the current monitoring section according to the second distance.

[0118] In an optional embodiment of the present application, each of the monitoring partitions in the power supply cable is powered by three-step commutation. The second determination module 930 is further configured to respectively determine the per-unit values of the distances of a plurality of consecutive monitoring partitions; wherein, the plurality of monitoring partitions at least include consecutively: a first monitoring partition, a second monitoring partition, and an intermediate monitoring partition located between the first monitoring partition and the second monitoring partition; and determine whether the intermediate monitoring partition is in insulation abnormality according to the per-unit values of the distances of the first monitoring partition and the second monitoring partition.

[0119] For the specific limitations of the above power supply cable insulation state monitoring device 900, reference may be made to the limitations of the above method in the foregoing text, which will not be elaborated herein. Each module in the above power supply cable insulation state monitoring device 900 can be implemented in whole or in part by software, hardware, and their combination. The above modules can be embedded in the processor in the electronic device in the form of hardware or be independent of the processor, or can be stored in the memory in the electronic device in the form of software, so as to facilitate the processor to call and execute the operations corresponding to the above respective modules.

[0120] In an embodiment, an electronic device is provided, and the internal structure diagram of the electronic device can be as Figure 10 shown. The electronic device includes a processor, a memory, a network interface, and a database connected through a system bus. Among them, the processor of the electronic device is used to provide computing and control capabilities. The memory of the electronic device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the electronic device is used to store data. The network interface of the electronic device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, it implements a power supply cable insulation state monitoring method as described above. It includes: including a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, it implements any step in the above power supply cable insulation state monitoring method.

[0121] In an embodiment, a computer-readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by the processor, it can implement any step in the above power supply cable insulation state monitoring method.

[0122] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memory, CD-ROM, optical memory, etc.) that contain computer-usable program code.

[0123] The present application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one or more of the flows Figure 1 or blocks.

[0124] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including instruction means that implement the functions specified in Figure 1 one or more of the flows Figure 1 or blocks.

[0125] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are performed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one or more of the flows Figure 1 or blocks.

[0126] Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to these embodiments once they learn the basic creative concepts. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present application.

[0127] Obviously, those skilled in the art can make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalent technologies, this application is also intended to include these modifications and variations.

Claims

1. A method for monitoring the insulation state of a power supply cable, characterized in that Including: Obtaining the ground voltages of the three-phase cables in each monitoring section of the power supply cable to obtain three-phase voltage vectors; Respectively determining the end positions of the three-phase voltage vectors, the circumcenter of the circumcircle, and the circumradius of the circumcircle; Determining the per-unit value of the distance according to the distance between each end position and the circumcenter; Determining the insulation status of each monitoring section of the power supply cable according to the per-unit value of the distance.

2. The power supply cable insulation state monitoring method according to claim 1, characterized in that The obtaining the ground voltages of the three-phase cables in each monitoring section of the power supply cable to obtain three-phase voltage vectors includes: Inputting a current with a rated frequency and a rated amplitude for no less than a preset duration into the ground stator modules along the line through a ground converter; Performing voltage sampling on the power supply cable to obtain the ground voltages of the three-phase cables in each monitoring section of the power supply cable; Performing filtering and phase-locked processing on the ground voltages of the three-phase cables to obtain the three-phase voltage vectors.

3. The power supply cable insulation state monitoring method according to claim 1, characterized in that The three-phase voltage vectors at least include: the phase and amplitude of each phase voltage.

4. The power supply cable insulation state monitoring method according to claim 1, characterized in that, The determining the per-unit value of the distance according to the distance between each end position and the circumcenter includes: Determining a first distance from the circumcenter to the origin of the three-phase voltage vector; Determining the ratio between the first distance and the circumradius of the circumcircle to obtain the per-unit value of the distance; wherein, the per-unit value of the distance is used to characterize whether an insulation fault occurs in the power supply cable.

5. The method for monitoring the insulation state of a power supply cable according to claim 4, characterized in that, The determining the insulation status of each monitoring section of the power supply cable according to the per-unit value of the distance includes: If the per-unit value of the distance in the current monitoring section exceeds a preset threshold range, determining that the insulation status of the current monitoring section is an insulation fault.

6. The method for monitoring the insulation state of a power supply cable according to claim 5, characterized in that, After the if the per-unit value of the distance in the current monitoring section exceeds a preset threshold range, determining that the insulation status of the current monitoring section is an insulation fault, the method further includes: Determining a second distance from each end position of the three-phase voltage vector to the circumcenter; Locating the insulation fault in the current monitoring section according to the second distance.

7. The power supply cable insulation state monitoring method according to claim 1, characterized in that Each monitoring section in the power supply cable uses a three-step commutation power supply, and the method further includes: Respectively determining the per-unit values of the distances of a plurality of consecutive monitoring sections; wherein, the plurality of monitoring sections at least continuously include: a first monitoring section, a second monitoring section, and an intermediate monitoring section located between the first monitoring section and the second monitoring section; Determining whether the intermediate monitoring section is in insulation abnormality according to the per-unit values of the distances of the first monitoring section and the second monitoring section.

8. A power supply cable insulation state monitoring device, characterized in that, Including: An obtaining module, configured to obtain the ground voltages of the three-phase cables in each monitoring section of the power supply cable to obtain three-phase voltage vectors; A first determining module, configured to respectively determine the end positions of the three-phase voltage vectors, the circumcenter of the circumcircle, and the circumradius of the circumcircle; A second determining module, configured to determine the per-unit value of the distance according to the distance between each end position and the circumcenter; A third determining module, configured to determine the insulation status of each monitoring section of the power supply cable according to the per-unit value of the distance.

9. An electronic device, comprising: It includes a memory and a processor, and the memory stores a computer program. It is characterized in that when the processor executes the computer program, the steps of the method described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, the steps of the method described in any one of claims 1 to 7 are implemented.

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