Power cable state on-line monitoring platform and power cable fault data identification method

Abstract

The invention discloses a power cable state on-line monitoring platform, which acts on a multi-phase power cable, and the multi-phase power cable comprises a cable A phase, a cable B phase and a cable C phase. The power cable state online monitoring platform comprises a magnetic induction sensor module, a data processing unit, a serial output port, a LoRa module, a relay server and a receiving terminal. The invention further discloses a power cable fault data identification method, and according to the method, the fault type and the fault position of the multiphase power cable are judged according to the data collected by the power cable state on-line monitoring platform in combination with the data of the multiphase power cable in normal use and the preset degree coefficient. Compared with the prior art, the online monitoring platform provided by the invention is installed in a power cable line section, and by adopting the method provided by the invention, on the premise that an outer insulating layer of the cable is not damaged, rapid identification and positioning of faults can be realized, the state of the power cable can be fed back in real time, and the measurement precision is high.

Description

Technical Field

[0001] The present invention belongs to the technical field of cable line fault detection, and in particular relates to an online monitoring platform for power cable status and a power cable fault data identification method. Background Art

[0002] Cable lines have the advantages of high power supply reliability, good safety, and not occupying ground space. They have become the main direction of urban distribution network construction and are gradually being widely used in power grids of industrial and mining enterprises such as steel, petrochemical, and coal mines. The cable laying environment in the distribution network system is complex and hidden, with many branches. Once a cable fault occurs, it is difficult to locate, which brings many inconveniences to the troubleshooting and maintenance of the fault.

[0003] In the prior art, the common practice is to use distribution network automation systems or fault indicators and other equipment to locate the fault section, and then use offline distance measurement equipment to locate the fault point after the equipment is powered off. More specifically, the main fault location methods of existing power cables include: impedance method, single-ended traveling wave method and double-ended traveling wave method; the advantage of the traditional impedance method compared to the single-ended traveling wave method is higher startup reliability, and the disadvantage is lower ranging accuracy; the double-ended traveling wave method is prone to false startup due to the operation of the distribution network switch, and the fault location accuracy needs to be improved; the single-ended traveling wave method is prone to ranging failure due to the difficulty in identifying the wave head when the line parameters do not match; the above three solutions cannot be put into large-scale use in the distribution network due to their inherent defects.

[0004] The disadvantage of the prior art is that the existing high-voltage power cable fault location solution has the problem of low positioning accuracy and poor accuracy. Summary of the invention

[0005] The technical problem to be solved by the present invention is to address the deficiencies in the above-mentioned prior art and disclose an online monitoring platform for power cable status and a power cable fault data identification method to solve the technical problems of low positioning accuracy and poor accuracy in the existing solutions for locating high-voltage power cable faults.

[0006] The technical solution adopted by the present invention to solve its technical problems is: an online monitoring platform for the status of power cables, the online monitoring platform for the status of power cables acts on a multi-phase power cable, the multi-phase power cable comprises: cable A phase, cable B phase and cable C phase; the online monitoring platform for the status of power cables comprises: a magnetic induction sensor module, a data processing unit, a serial output port, a LoRa module, a relay server and a receiving terminal; the magnetic induction sensor module comprises an A phase magnetic induction sensor module Sa, a B phase magnetic induction sensor module Sb and a C phase magnetic induction sensor module Sc which are electrically connected to the data processing unit respectively; the A phase magnetic induction sensor module Sa is used to be installed on the outer layer of the cable core of the cable A phase to collect the induced electromotive force Ea of the cable A phase; the B phase magnetic induction sensor module Sb is used to be installed on the outer layer of the cable core of the cable B phase to collect the induced electromotive force Eb of the cable B phase; the C phase magnetic induction sensor module Block Sc is used to be installed on the outer layer of the cable core of phase C of the cable to collect the induced electromotive force Ec of phase C of the cable; the data processing unit is used to calculate the characteristic parameters of each detection point of the multi-phase power cable according to Ea, Eb and Ec, and provide cable operation status evaluation according to the characteristic parameters in combination with the fault identification algorithm, and output power cable operation data to the serial output port; the serial output port is respectively connected to the data processing unit and the LoRa module; and the serial output port is used to transmit the data calculated by the data processing unit to the LoRa module; the LoRa module is respectively connected to the serial output port and the relay server, and the LoRa module is used to send the data characteristic quantity to the relay server; the relay server is used to collect and summarize the data characteristic quantity sent by the LoRa module, and send the information to the receiving terminal. When it is determined that fault information occurs, the fault information is transmitted to the receiving terminal.

[0007] Preferably, the power cable status online monitoring platform also includes a power supply unit, which is electrically connected to the data processing unit, the LoRa module and the serial output port, respectively, and is used to supply power to the data processing unit and the serial output port; the serial output port is wirelessly connected to the LoRa module.

[0008] Preferably, the multi-phase power cable includes: further including a cable D phase, and the magnetic induction sensor module includes a D-phase magnetic induction sensor module Sd electrically connected to the data processing unit respectively.

[0009] Preferably, when the A-phase magnetic induction sensor module Sa is installed on the outer layer of the cable core of the cable phase A, the A-phase magnetic induction sensor module Sa maintains a fixed angle with the cable core of the cable phase A; when the B-phase magnetic induction sensor module Sb is installed on the outer layer of the cable core of the cable phase B, the B-phase magnetic induction sensor module Sb maintains a fixed angle with the cable core of the cable phase B; when the C-phase magnetic induction sensor module Sc is installed on the outer layer of the cable core of the cable phase C, the C-phase magnetic induction sensor module Sc maintains a fixed angle with the cable core of the cable phase C.

[0010] The present invention also discloses a method for identifying power cable fault data, comprising: judging the fault type and fault location of the multi-phase power cable according to the data collected by the above-mentioned online power cable status monitoring platform, and combining the data of the multi-phase power cable during normal use and a preset degree coefficient; the fault types include: phase-to-phase short circuit, single-phase ground short circuit, unbalanced fault and phase failure fault; the fault location is any phase in the multi-phase power cable.

[0011] Preferably, the power cable fault data identification method comprises the following steps:

[0012] S1, collecting the induced potential of each magnetic induction sensor point of the power cable, and calculating the characteristic parameters of each detection point of the power cable according to the induced potential of each detection point of the power cable;

[0013] S2, determining the operating status of each detection point of the power cable according to the characteristic parameters of each magnetic induction sensor point of the power cable and the fault judgment criteria, and sending the characteristic parameters and operating status of each detection point of the power cable to the LoRa module;

[0014] S3. Determine the overall operating state of the power cable according to the characteristic parameters and operating state of each detection point of the power cable. When it is determined that the overall operating state of the power cable is a phase-to-phase short circuit fault or a single-phase short circuit fault, determine the short circuit fault location according to the section positioning algorithm, and then send the overall operating state of the power cable and the short circuit fault location to the receiving terminal.

[0015] Preferably, the preset degree coefficients are k1, k2, and k3; the fault type is determined according to the following method:

[0016] According to the effective values ​​of the induced potential collected by the magnetic induction sensors Sa, Sb, and Sc, if the effective value of the induced potential of any phase increases by more than k1 times compared with the effective value of the induced potential of the phase during normal operation, and the unbalance degree of the induced potential is more than k2 times during normal operation, it is determined that a phase-to-phase short circuit fault occurs in the power cable;

[0017] If the relative amount of the induced potential zero sequence collected by the magnetic induction sensors Sa, Sb, and Sc increases by more than k3 times compared with normal operation, and the induced potential unbalance is greater than k1, it is determined that a single-phase grounding short circuit fault occurs in the power cable;

[0018] If the relative amount of the induced potential zero sequence collected by the magnetic induction sensors Sa, Sb, and Sc does not increase, and the induced potential unbalance degree is greater than k1 and less than k2, it is determined that an unbalanced fault occurs in the power cable;

[0019] If the relative amount of the zero-sequence induced potential collected by the magnetic induction sensors Sa, Sb, and Sc does not increase and the unbalance degree of the induced potential is greater than k2, it is determined that a phase failure occurs in the power cable.

[0020] Preferably, when it is determined that a phase-to-phase short circuit fault has occurred in the power cable, the location of the fault is determined by the following method: compare the effective values ​​of the induced potential of the magnetic induction sensors Sa, Sb, and Sc; if the effective value of the induced potential of the magnetic induction sensor Sb is the largest, the fault phase is cable phase A and cable phase B; if the effective value of the induced potential of the magnetic induction sensor Sc is the largest, the fault phase is cable phase B and cable phase C; if the effective value of the induced potential of the magnetic induction sensor Sa is the largest, the fault phase is cable phase A and cable phase C.

[0021] Preferably, when it is determined that a single-phase ground short-circuit fault occurs in the power cable, the location of the fault is determined by the following method: compare the effective values ​​of the induced potentials of the magnetic induction sensors Sa, Sb, and Sc; if the effective value of the induced potential of the magnetic induction sensor Sc is the smallest, the fault phase is cable phase A; if the effective value of the induced potential of the magnetic induction sensor Sa is the smallest, the fault phase is cable phase B; if the effective value of the induced potential of the magnetic induction sensor Sb is the smallest, the fault phase is cable phase C.

[0022] Preferably, when it is determined that a phase failure occurs in the power cable, the location of the fault is determined by the following method: compare the effective values ​​of the induced potentials of the magnetic induction sensors Sa, Sb, and Sc; if the effective value of the induced potential of the magnetic induction sensor Sc is the largest, the fault phase is cable phase A; if the effective value of the induced potential of the magnetic induction sensor Sa is the largest, the fault phase is cable phase B; if the effective value of the induced potential of the magnetic induction sensor Sb is the largest, the fault phase is cable phase C.

[0023] Compared with the prior art, installing the power cable status online monitoring platform of the present invention in the power cable line section can realize online monitoring of the status of the power cable line and short-circuit fault location; the present invention can monitor the power cable current online, and can obtain the steady-state value of the cable current in real time without destroying the outer insulation layer of the cable, and can provide real-time feedback on the power cable status, with higher measurement accuracy. By combining the imbalance degree and the zero-sequence relative quantity, the basis for fault judgment is more sufficient, and other operating states such as normal operation, open circuit, and unbalanced operation are identified and monitored, thereby improving the accuracy of fault identification. Field applications have shown that the use of this device combined with relevant fault location algorithms can realize rapid identification and location of faults under complex working conditions. The power cable status online monitoring platform of the present invention can realize online monitoring and locate the fault location, can be put into use on a large scale in distribution networks, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 When implementing the method of the present invention: a schematic diagram of the installation position of the magnetic induction device;

[0025] Figure 2 A schematic diagram of data collection and processing performed by the online power cable status monitoring platform of the present invention;

[0026] Figure 3 It is an overall schematic diagram of the power cable status online monitoring platform of the present invention in a power system. DETAILED DESCRIPTION

[0027] The present invention is described in detail below in conjunction with the various embodiments shown in the accompanying drawings, but it should be noted that these embodiments are not limitations of the present invention, and any equivalent transformations or substitutions in functions, methods, or structures made by ordinary technicians in the field based on these embodiments are all within the scope of protection of the present invention.

[0028] The following is combined with Figure 1-3 The power cable status online monitoring platform and the power cable fault data identification method of the present invention are further described.

[0029] The invention discloses an online monitoring platform for power cable status. The online monitoring platform for power cable status acts on a multi-phase power cable. The multi-phase power cable comprises: a cable A phase, a cable B phase and a cable C phase. The online monitoring platform for power cable status comprises: a magnetic induction sensor module, a data processing unit, a serial output port, a LoRa module, a relay server and a receiving terminal. The magnetic induction sensor module comprises an A-phase magnetic induction sensor module Sa, a B-phase magnetic induction sensor module Sb and a C-phase magnetic induction sensor module Sc which are electrically connected to the data processing unit respectively. The A-phase magnetic induction sensor module Sa is used to be installed on the outer layer of the cable core of the cable A phase to collect the induced electromotive force Ea of the cable A phase. The B-phase magnetic induction sensor module Sb is used to be installed on the outer layer of the cable core of the cable B phase to collect the induced electromotive force Eb of the cable B phase. The C-phase magnetic induction sensor module Sc is used to be installed on the outer layer of the cable core of the cable B phase to collect the induced electromotive force Eb of the cable B phase. The device is installed on the outer layer of the cable core of phase C of the cable to collect the induced electromotive force Ec of phase C of the cable; the data processing unit is used to calculate the characteristic parameters of each detection point of the multi-phase power cable according to Ea, Eb and Ec, and provide cable operation status evaluation according to the characteristic parameters in combination with the fault identification algorithm, and output the power cable operation data to the serial output port; the serial output port is respectively connected to the data processing unit and the LoRa module; and the serial output port is used to transmit the data calculated by the data processing unit to the LoRa module; the LoRa module is respectively connected to the serial output port and the relay server data, and the LoRa module is used to send the data characteristic quantity to the relay server; the relay server is used to collect and summarize the data characteristic quantity sent by the LoRa module, and send the information to the receiving terminal. When it is determined that fault information occurs, the fault information is transmitted to the receiving terminal.

[0030] In this embodiment, three coils are fixedly installed at equal intervals on the power cable to detect current imbalance and zero-sequence relative quantity, which are used to characterize the characteristic quantity of induced electromotive force of the cable operating state. The characteristic quantity of the cable operating state is found, and the cable fault type and fault point are quickly located, thereby improving the fault detection accuracy and fault identification accuracy, reducing the labor intensity of staff patrolling and troubleshooting, shortening the scope and duration of power outages, improving on-site work efficiency, and technically improving the quality of service.

[0031] According to a specific embodiment of the present invention, the power supply unit is electrically connected to the data processing unit, the LoRa module and the serial output port respectively, and is used to supply power to the data processing unit and the serial output port; the serial output port is wirelessly connected to the LoRa module.

[0032] According to a specific embodiment of the present invention, the multiphase power cable includes: further comprising a cable D phase, the magnetic induction sensor module including a D phase magnetic induction sensor module Sd electrically connected to the data processing unit respectively.

[0033] According to a specific embodiment of the present invention, when the A-phase magnetic induction sensor module Sa is installed on the outer layer of the cable core of cable phase A, the A-phase magnetic induction sensor module Sa maintains a fixed angle with the cable core of cable phase A; when the B-phase magnetic induction sensor module Sb is installed on the outer layer of the cable core of cable phase B, the B-phase magnetic induction sensor module Sb maintains a fixed angle with the cable core of cable phase B; when the C-phase magnetic induction sensor module Sc is installed on the outer layer of the cable core of cable phase C, the C-phase magnetic induction sensor module Sc maintains a fixed angle with the cable core of cable phase C.

[0034] The present invention also discloses a method for identifying power cable fault data, comprising: judging the fault type and fault location of the multi-phase power cable according to the data collected by the aforementioned power cable status online monitoring platform, and combining the data of the multi-phase power cable during normal use and a preset degree coefficient; the fault types include: phase-to-phase short circuit, single-phase ground short circuit, unbalanced fault and phase failure fault; the fault location is any phase in the multi-phase power cable.

[0035] According to a specific embodiment of the present invention, a method for identifying power cable fault data includes the following steps:

[0036] S1, collecting the induced potential of each magnetic induction sensor point of the power cable, and calculating the characteristic parameters of each detection point of the power cable according to the induced potential of each detection point of the power cable.

[0037] S2, determine the operating status of each detection point of the power cable according to the characteristic parameters of each magnetic induction sensor point of the power cable and the fault judgment criteria, and send the characteristic parameters and operating status of each detection point of the power cable to the LoRa module.

[0038] S3. Determine the overall operating state of the power cable according to the characteristic parameters and operating state of each detection point of the power cable. When it is determined that the overall operating state of the power cable is a phase-to-phase short circuit fault or a single-phase short circuit fault, determine the short circuit fault location according to the section positioning algorithm, and then send the overall operating state of the power cable and the short circuit fault location to the receiving terminal.

[0039] According to a specific implementation of the present invention, the preset degree coefficients are k1, k2, and k3. The fault type is determined according to the following method:

[0040] According to the effective values ​​of the induced potential collected by the magnetic induction sensors Sa, Sb, and Sc, if the effective value of the induced potential of any phase increases by more than k1 times compared with the effective value of the induced potential of that phase during normal operation, and the unbalance degree of the induced potential is more than k2 times that of normal operation, it is determined that an interphase short circuit fault has occurred in the power cable.

[0041] If the relative amount of the zero-sequence induced potential collected by the magnetic induction sensors Sa, Sb, and Sc increases by more than k3 times compared to normal operation, and the unbalance degree of the induced potential is greater than k1, it is determined that a single-phase grounding short circuit fault has occurred in the power cable.

[0042] If the relative amount of the zero-sequence induced potential collected by the magnetic induction sensors Sa, Sb, and Sc does not increase and the unbalance degree of the induced potential is greater than k1 and less than k2, it is determined that an unbalanced fault occurs in the power cable.

[0043] If the relative amount of the zero-sequence induced potential collected by the magnetic induction sensors Sa, Sb, and Sc does not increase and the unbalance degree of the induced potential is greater than k2, it is determined that a phase failure occurs in the power cable.

[0044] Determine the fault location according to the following method:

[0045] When it is determined that the power cable has a phase-to-phase short circuit fault, the fault location is determined by the following method: compare the effective values ​​of the induced potential of the magnetic induction sensors Sa, Sb, and Sc. If the effective value of the induced potential of the magnetic induction sensor Sb is the largest, the fault phase is cable phase A and cable phase B. If the effective value of the induced potential of the magnetic induction sensor Sc is the largest, the fault phase is cable phase B and cable phase C. If the effective value of the induced potential of the magnetic induction sensor Sa is the largest, the fault phase is cable phase A and cable phase C.

[0046] When it is determined that a single-phase ground short circuit fault occurs in the power cable, the fault location is determined by the following method: compare the effective values ​​of the induced potentials of the magnetic induction sensors Sa, Sb, and Sc. If the effective value of the induced potential of the magnetic induction sensor Sc is the smallest, the fault phase is cable phase A. If the effective value of the induced potential of the magnetic induction sensor Sa is the smallest, the fault phase is cable phase B. If the effective value of the induced potential of the magnetic induction sensor Sb is the smallest, the fault phase is cable phase C.

[0047] When it is determined that a phase failure occurs in the power cable, the location of the fault is determined by the following method: compare the effective values ​​of the induced potentials of the magnetic induction sensors Sa, Sb, and Sc; if the effective value of the induced potential of the magnetic induction sensor Sc is the largest, the fault phase is cable phase A; if the effective value of the induced potential of the magnetic induction sensor Sa is the largest, the fault phase is cable phase B; if the effective value of the induced potential of the magnetic induction sensor Sb is the largest, the fault phase is cable phase C.

[0048] It should be noted that:

[0049] (1) The present invention uses an online monitoring device and a fault judgment method to describe a three-phase power cable A, B, and C as an example, and the online monitoring and fault judgment devices of other types of power cables can be generalized and are not limited to the three detection modules and detection points of the present invention.

[0050] (2) The preset k1, k2, and k3 of the present invention are not fixed natural numbers, but can be dynamically modified according to the actual situation on site. Specifically, they are set according to the set value on site, and the set value = (line voltage / square root of 3) × 10%. In this embodiment, k1, k2, and k3 can be set to k1 < k2 < k3.

[0051] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

[0052] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An online monitoring platform for power cable status, characterized in that: The power cable status online monitoring platform acts on a multi-phase power cable, and the multi-phase power cable includes: cable A phase, cable B phase and cable C phase; the power cable status online monitoring platform includes: a magnetic induction sensor module, a data processing unit, a serial output port, a LoRa module, a relay server and a receiving terminal; the magnetic induction sensor module includes an A-phase magnetic induction sensor module Sa, a B-phase magnetic induction sensor module Sb and a C-phase magnetic induction sensor module Sc which are electrically connected to the data processing unit respectively; the A-phase magnetic induction sensor module Sa is used to be installed on the outer layer of the cable core of the cable A phase to collect the induced electromotive force Ea of the cable A phase; the B-phase magnetic induction sensor module Sb is used to be installed on the outer layer of the cable core of the cable B phase to collect the induced electromotive force Eb of the cable B phase; the C-phase magnetic induction sensor module Sc is used to be installed on the outer layer of the cable core of the cable C phase layer to collect the induced electromotive force Ec of phase C of the cable; the data processing unit is used to calculate the characteristic parameters of each detection point of the multi-phase power cable according to Ea, Eb and Ec, and provide cable operation status evaluation according to the characteristic parameters in combination with the fault identification algorithm, and output power cable operation data to the serial output port; the serial output port is respectively connected to the data processing unit and the LoRa module; and the serial output port is used to transmit the data calculated by the data processing unit to the LoRa module; the LoRa module is respectively connected to the serial output port and the relay server data, and the LoRa module is used to send the data characteristic quantity to the relay server; the relay server is used to collect and summarize the data characteristic quantity sent by the LoRa module, and send the information to the receiving terminal. When it is determined that fault information occurs, the fault information is transmitted to the receiving terminal.

2. The power cable status online monitoring platform according to claim 1 is characterized in that: The power cable status online monitoring platform also includes a power supply unit, which is electrically connected to the data processing unit, the LoRa module and the serial output port respectively, and is used to supply power to the data processing unit and the serial output port; the serial output port is wirelessly connected to the LoRa module.

3. The power cable status online monitoring platform according to claim 2 is characterized in that: The multi-phase power cable includes: a cable D phase, and the magnetic induction sensor modules include D-phase magnetic induction sensor modules Sd electrically connected to the data processing units respectively.

4. The power cable status online monitoring platform according to claim 3 is characterized in that: When the A-phase magnetic induction sensor module Sa is installed on the outer layer of the cable core of the cable phase A, the A-phase magnetic induction sensor module Sa maintains a fixed angle with the cable core of the cable phase A; when the B-phase magnetic induction sensor module Sb is installed on the outer layer of the cable core of the cable phase B, the B-phase magnetic induction sensor module Sb maintains a fixed angle with the cable core of the cable phase B; when the C-phase magnetic induction sensor module Sc is installed on the outer layer of the cable core of the cable phase C, the C-phase magnetic induction sensor module Sc maintains a fixed angle with the cable core of the cable phase C.

5. A method for identifying power cable fault data, characterized in that: include: According to the data collected by the online power cable status monitoring platform described in any one of 1-4, combined with the data of the multi-phase power cable when in normal use and the preset degree coefficient, determine the fault type and fault location of the multi-phase power cable; The types of faults include: phase-to-phase short circuit, single-phase ground short circuit, unbalanced fault and open phase fault; The fault location is any phase in the multi-phase power cable.

6. The method for identifying power cable fault data according to claim 5, characterized in that: The steps include: S1, collecting the induced potential of each magnetic induction sensor point of the power cable, and calculating the characteristic parameters of each detection point of the power cable according to the induced potential of each detection point of the power cable; S2, determining the operating status of each detection point of the power cable according to the characteristic parameters of each magnetic induction sensor point of the power cable and the fault judgment criteria, and sending the characteristic parameters and operating status of each detection point of the power cable to the LoRa module; S3. Determine the overall operating state of the power cable according to the characteristic parameters and operating state of each detection point of the power cable. When it is determined that the overall operating state of the power cable is a phase-to-phase short circuit fault or a single-phase short circuit fault, determine the short circuit fault location according to the section positioning algorithm, and then send the overall operating state of the power cable and the short circuit fault location to the receiving terminal.

7. The method for identifying power cable fault data according to claim 6, characterized in that: The preset degree coefficients are k1, k2, and k3; the fault type is determined according to the following method: According to the effective values ​​of the induced potential collected by the magnetic induction sensors Sa, Sb, and Sc, if the effective value of the induced potential of any phase increases by more than k1 times compared with the effective value of the induced potential of the phase during normal operation, and the unbalance degree of the induced potential is more than k2 times during normal operation, it is determined that a phase-to-phase short circuit fault occurs in the power cable; If the relative amount of the induced potential zero sequence collected by the magnetic induction sensors Sa, Sb, and Sc increases by more than k3 times compared with normal operation, and the induced potential unbalance is greater than k1, it is determined that a single-phase grounding short circuit fault occurs in the power cable; If the relative amount of the induced potential zero sequence collected by the magnetic induction sensors Sa, Sb, and Sc does not increase, and the induced potential unbalance degree is greater than k1 and less than k2, it is determined that an unbalanced fault occurs in the power cable; If the relative amount of the zero-sequence induced potential collected by the magnetic induction sensors Sa, Sb, and Sc does not increase and the unbalance degree of the induced potential is greater than k2, it is determined that a phase failure occurs in the power cable.

8. The method for identifying power cable fault data according to claim 7, characterized in that: When it is determined that a phase-to-phase short circuit fault occurs in the power cable, the location of the fault is determined by the following method: compare the effective values ​​of the induced potential of the magnetic induction sensors Sa, Sb, and Sc. If the effective value of the induced potential of the magnetic induction sensor Sb is the largest, the fault phase is cable phase A and cable phase B; if the effective value of the induced potential of the magnetic induction sensor Sc is the largest, the fault phase is cable phase B and cable phase C; if the effective value of the induced potential of the magnetic induction sensor Sa is the largest, the fault phase is cable phase A and cable phase C.

9. The method for identifying power cable fault data according to claim 7, characterized in that: When it is determined that a single-phase ground short circuit fault occurs in the power cable, the location of the fault is determined by the following method: compare the effective values ​​of the induced potential of the magnetic induction sensors Sa, Sb, and Sc; if the effective value of the induced potential of the magnetic induction sensor Sc is the smallest, the fault phase is cable phase A; if the effective value of the induced potential of the magnetic induction sensor Sa is the smallest, the fault phase is cable phase B; if the effective value of the induced potential of the magnetic induction sensor Sb is the smallest, the fault phase is cable phase C.

10. The method for identifying power cable fault data according to claim 7, characterized in that: When it is determined that a phase failure occurs in the power cable, the location of the fault is determined by the following method: compare the effective values ​​of the induced potentials of the magnetic induction sensors Sa, Sb, and Sc; if the effective value of the induced potential of the magnetic induction sensor Sc is the largest, the fault phase is cable phase A; if the effective value of the induced potential of the magnetic induction sensor Sa is the largest, the fault phase is cable phase B; if the effective value of the induced potential of the magnetic induction sensor Sb is the largest, the fault phase is cable phase C.

Images