CN114675128A - Submarine cable insulation fault on-line positioning method based on sheath current and voltage - Google Patents

Submarine cable insulation fault on-line positioning method based on sheath current and voltage Download PDF

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CN114675128A
CN114675128A CN202210263070.0A CN202210263070A CN114675128A CN 114675128 A CN114675128 A CN 114675128A CN 202210263070 A CN202210263070 A CN 202210263070A CN 114675128 A CN114675128 A CN 114675128A
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sheath
fault
voltage
cable
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李国锋
任乐朋
王志强
王进君
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Dalian University of Technology
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08—Locating faults in cables, transmission lines, or networks
    • G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
    • G01R31/083—Locating faults in cables, transmission lines, or networks according to type of conductors in cables, e.g. underground
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
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Abstract

A submarine cable insulation fault on-line positioning method based on sheath current and voltage belongs to the technical field of power cables. Firstly, a current sensor and a voltage sensor are arranged at the head and tail end sheath of each phase cable, and the current I of the head and tail end sheaths is collected1、I2And sheath voltage U1、U2The original data of (1). Secondly, monitoring the sheath current and the sheath voltage at the head end and the tail end of the submarine cable in real time, and processing the acquired data by using fast Fourier transform to obtain the amplitude and the phase of the sheath current and the sheath voltage. And finally, calculating and positioning the insulation fault point of the submarine cable according to the processed sheath current and sheath voltage data. The invention can reduce the safety risk and cost of using electrical equipment, improve the precision of fault positioning on the premise of ensuring safety, realize the precise positioning of cable insulation short-circuit fault, low-resistance fault and high-resistance fault, and the fault positioning is not influenced by power grid frequency fluctuation, power grid harmonic wave and ground potential deviation.

Description

Submarine cable insulation fault on-line positioning method based on sheath current and voltage
Technical Field
The invention belongs to the technical field of power cables, and particularly relates to an online positioning method for insulation faults of a submarine cable.
Background
With the further development and utilization of energy sources such as marine oil, offshore wind power and the like, a cross-sea power grid continuously extends and covers a sea drilling platform and a coastal island, and the application of submarine cables is more and more extensive. As the submarine cable is eroded by seawater and washed by sea waves for a long time and the marine environment is special and complex, more and more cases of submarine cable insulation faults exist, and once faults occur, the repair difficulty and the caused loss are huge. The on-line monitoring and fault location of the submarine cable have important significance for ensuring the safe and stable operation of the submarine cable.
The current submarine cable fault positioning method mainly comprises the following steps: 1. bridge method (off-line). The fault phase and the non-fault phase of the tested cable are in short circuit, two arms of the bridge are respectively connected with the fault phase and the non-fault phase, an adjustable resistor on the two arms of the bridge is adjusted, the bridge is balanced, and the fault distance can be obtained by utilizing the proportional relation and the known cable length. The measurement depends on a sound loop wire near a measured wire, and has a large requirement on the insulation resistance value of a fault point, and the measurement error is large. 2. Pulsed (off-line). The main principle is that pulse signals are injected into the head end or the tail end of a cable through an instrument, and the type and the position of a fault are judged by analyzing the reflection of the signals when electromagnetic waves encounter the fault in the transmission process of the cable. When the electromagnetic wave encounters impedance mismatching in the transmission process, such as a short-circuit point, an open-circuit point, a fault point, an intermediate joint and the like, reflection can occur to generate reflected waves, and the distance between the cable fault point and a pulse transmitting end can be calculated by measuring the time difference between the generated pulse and the reflected pulse. According to the difference of injected pulse voltage, the method is divided into a low-voltage pulse method and a high-voltage pulse method, wherein the low-voltage pulse method is simple and convenient to operate, but cannot be used for identifying high-resistance faults and flashover faults; the high-voltage pulse method is suitable for various fault types, but the test safety is poor and the waveform is difficult to identify due to the fact that high voltage is used during testing. 3. Flashover method (off-line). The main direct-current high voltage or impact high voltage is applied to a tested cable, multiple reflected waves are generated by using the instant discharge of a fault point, the time interval between the cyclic reflections is measured by using an instrument, and the distance between the fault position of the cable and a flashover generator is calculated. The method is divided into a direct-current high-voltage flashover method and an impact high-voltage flashover method according to different types of applied high voltage, wherein the direct-current high-voltage flashover method is simple in waveform and high in measurement accuracy, but is only suitable for flashover high-resistance faults; the impulse high-voltage flashover method is suitable for leakage high-resistance and low-resistance faults, but the measurement waveform is complex, the identification difficulty is high, and the accuracy is low.
Most of the existing fault location technologies of submarine cables are off-line, cable fault location is carried out through additional signals, the fault location device is high in cost and long in time consumption, the fault location cannot be determined immediately after the cable breaks down, real-time online measurement cannot be carried out, and the cable line is required to be powered off and processed usually. Therefore, it is necessary to provide a practical method capable of rapidly positioning the insulation fault of the submarine cable on line.
Disclosure of Invention
Aiming at the defects of the existing off-line fault positioning technology, the invention provides the on-line fault positioning method for the submarine cable insulation fault, which can be used for carrying out on-line monitoring on the submarine cable insulation fault to quickly determine the fault position, is convenient to implement and has low cost, and is based on the real-time measurement of the current and the voltage of the cable sheath.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
an on-line submarine cable insulation fault positioning method based on sheath current and voltage comprises the following steps:
the first step, the grounding mode of the submarine cable sheath is that two ends are directly grounded, and a current sensor and a voltage sensor are arranged at the sheath at the head end and the tail end of the cable. When any position of a certain phase of the submarine cable has an insulation fault, a fault channel between a cable conductor and a metal sheath can be equivalent to a fault resistor R f，RfThe values can be measured by an insulation resistance tester. Equivalent resistance R of fault channel through cablefAnd characteristic impedance Z of cablecThe comparison of (3) is to divide the cable insulation fault types into short-circuit fault, low-resistance fault and high-resistance fault, and R corresponding to different types of faults of the submarine cablefThe values are shown in table 1:
TABLE 1R corresponding to different fault types of submarine cablefValue of
Figure BDA0003551446380000021
Characteristic impedance Z of the submarine cablecCan be calculated from the following formula:
Figure BDA0003551446380000022
wherein R is0、L0Equivalent resistance, inductance per unit length, C for submarine cables0、G0Equivalent capacitance and conductance of the submarine cable in unit length, and omega is system angular frequency.
Secondly, collecting the current I of the first and the tail end sheath layers through a sensor aiming at the insulation fault between the submarine cable conductor and the metal sheath layer1、I2And sheath voltage U1、U2Any of the original signals may be represented by x (n).
And thirdly, processing the acquired original signal data by Fast Fourier Transform (Fast Fourier Transform) to respectively obtain the amplitude and the phase of the sheath current and the amplitude and the phase of the sheath voltage. The method comprises the following specific steps:
3.1) when submarine cable insulation fault, sheath current and sheath voltage have transient state process, and fault current mainly is power frequency current, carries out the FFT operation to the sheath current and the voltage signal that directly detect, and specific computational formula is:
Figure BDA0003551446380000031
Wherein, the first and the second end of the pipe are connected with each other,
Figure BDA0003551446380000032
is a twiddle factor; x (N) is a finite long sequence with the length of N, namely, the raw signals collected by the current sensor and the voltage sensor, and N is 0,1, …, N-1; x (k) is a signal spectrum obtained after FFT, including an amplitude spectrum and a phase spectrum.
3.2) through the analysis to signal amplitude spectrum and phase spectrum, obtain submarine cable head and end sheath electric current's amplitude and phase place, head and end sheath voltage's amplitude and phase place, cable head and end sheath electric current and sheath voltage can be expressed as:
Figure BDA0003551446380000033
wherein, I1、I2First and last end sheath current, x1、x2Amplitude of head and tail sheath current, y1、y2The phase of the first and the tail end sheath current; u shape1、U2Head and end sheath voltage, m1、m2Amplitude of head and tail end sheath voltage, t1、t2The phase of the first and the last sheath voltage.
And fourthly, calculating and positioning the insulation fault point of the submarine cable according to the processed sheath current and sheath voltage data. The specific calculation formula of the distance measurement and the positioning of the fault point is as follows:
Figure BDA0003551446380000034
wherein, I1And I2For sheath current, U, at the head and tail ends of submarine cables1And U2For the sheath voltage, R, at the head and tail ends of the submarine cables0The equivalent impedance of the metal sheath per unit length of the submarine cable, i is the length of the submarine cable line, l fThe distance between the insulation fault point of the submarine cable and the head end of the cable. Through the fault point distance measurement and positioning formula, the distance between the fault point and the head end is accurately positioned by combining related known parameters and processed sheath voltage and current data, and the accurate positioning of the submarine cable insulation fault is realized.
Furthermore, the submarine cable in the first step is a three-core cable, no insulating joint is arranged in the middle of the cable, the two ends of the metal sheath are directly grounded, and a current sensor and a voltage sensor are required to be installed at the sheath at the head end and the tail end of any phase of cable. The sensor at the head end and the tail end of the cable can accurately acquire sheath current and sheath voltage data in real time, so that the data can be conveniently processed and analyzed subsequently, and the fault position of the cable can be further determined.
In the second step and the third step, real-time monitoring and data acquisition are carried out on the sheath current and the sheath voltage at the head end and the tail end of the submarine cable, the acquired original signal data are processed through fast Fourier transform, the amplitude and the phase of a sheath current signal and the amplitude and the phase of a sheath voltage signal are obtained, noise signals in the data are eliminated, and a more accurate calculation result is obtained.
The invention has the beneficial effects that: according to the method, the current and the voltage of the protective layer at the head end and the tail end of the submarine cable are monitored in real time, the acquired data are processed by utilizing fast Fourier transform, and then the online positioning and the distance measurement of fault points are realized, the safety risk and the cost of using electrical equipment are reduced, the precision of fault positioning is improved on the premise of ensuring the safety, the precise positioning of cable insulation short-circuit faults, low-resistance faults and high-resistance faults is realized, and the fault positioning is not influenced by power grid frequency fluctuation, power grid harmonic waves and ground potential deviation.
Drawings
FIG. 1 is a flow chart of the method for on-line locating the insulation fault of the submarine cable based on sheath current and voltage according to the present invention;
FIG. 2 is a schematic view of the two ends of the metal sheath of the submarine cable according to the present invention directly grounded;
FIG. 3 is a schematic diagram of on-line monitoring of sheath current and sheath voltage for an undersea cable in accordance with the present invention;
fig. 4 is an equivalent circuit diagram of an insulation fault of a submarine cable according to the present invention.
Detailed Description
The invention will be further described with reference to the accompanying drawings.
The submarine cable insulation fault on-line positioning process based on sheath current and voltage is shown in fig. 1, and comprises the following steps:
(a) the grounding mode of the submarine cable sheath is that two ends are directly grounded, a current sensor and a voltage sensor are arranged at the sheath at the head end and the tail end of any phase cable, and the data acquisition of sheath current and sheath voltage is carried out aiming at different types of insulation faults of the submarine cable;
(b) monitoring sheath current and sheath voltage at the head end and the tail end of the submarine cable in real time, and processing the acquired data by using fast Fourier transform to obtain the amplitude and the phase of the sheath current and the amplitude and the phase of the sheath voltage;
(c) and calculating and positioning fault points according to the processed sheath current and sheath voltage data.
The schematic diagram of the direct grounding of the two ends of the metal sheath of the submarine cable is shown in fig. 2. In order to suppress the voltage induced in the cable sheath, the cable metal sheath is grounded. The common metal sheath grounding modes include single-end grounding, double-end grounding, midpoint grounding, cross interconnection grounding and the like, and the specific grounding mode is selected according to the actual engineering requirement on the site. Because of the laying environment and conditions, the submarine cable cannot adopt a conventional cross interconnection grounding mode, and only can adopt a mode of directly grounding metal protective layers at two ends of a landing section of the submarine cable. The technical scheme of the invention aims at the submarine cable with two ends of the sheath directly grounded, the middle of the cable is not provided with an insulating joint, a current sensor and a voltage sensor are arranged between the metal sheath at the head end and the tail end of the cable and the ground, I1And I2Sheath current, U, monitored for the head and tail ends of the submarine cable1And U2The sheath voltage monitored for the submarine cable head and tail ends.
In the schematic diagram of on-line monitoring of sheath current and sheath voltage of submarine cable shown in fig. 3, when insulation fault occurs at any position of a certain phase of submarine cable, a fault channel is formed between the cable conductor and the metal sheath, which can be equivalent to a fault resistance R fAt this time, the fault resistance is much smaller than the main insulation resistance. Because the existence of the fault channel can cause the current and the voltage of the sheath at the head end and the tail end of the cable to be increased, and the current and the voltage of the sheath at the head end and the tail end, which correspond to different insulation fault positions of the cable, are also different, the invention realizes the online positioning of the fault point of the submarine cable based on the difference.
After the insulation fault occurs between the submarine cable conductor and the metal sheath, the cable is installed by using the metal sheath at the head end and the tail endThe current sensor and the voltage sensor are arranged to collect and monitor sheath current and voltage data, and the schematic diagram is shown in fig. 3. A faulty cable can be equated to a circuit as shown in fig. 4, where the cable fault path equivalent resistance is RfThe equivalent resistance of the cable head end protective layer grounding is R1The equivalent resistance of the cable end sheath grounding is R2The equivalent resistance and inductance per unit length of the cable are R0And L0Equivalent capacitance per unit length and conductance of cable C0And G0The equivalent resistance of the metal sheath per unit length of the cable is Rs0Rated AC voltage source is U, equivalent load is ZLThe equivalent voltage of the fault point protective layer is Uf. Let the total length of the submarine cable line be l, and the insulation fault point be lf。
If the current and voltage of the sheath at the head end of the submarine cable are known, the equivalent voltage U of the sheath at the fault point fCan be expressed as:
Uf＝I1Rs0lf+U1
the current and the voltage of the sheath at the tail end of the submarine cable are known, and then the equivalent sheath voltage U of the fault pointfCan be expressed as:
Uf＝I2Rs0(l-lf)+U2
the two types are combined to eliminate the equivalent sheath voltage U of the fault pointf：
I2Rs0(l-lf)+U2＝I1Rs0lf+U1
Because the length l of the submarine cable line and the equivalent resistance R of the metal sheath in the unit length of the cables0As known, after obtaining the amplitude and phase of the sheath current at the head end and the tail end of the cable and the amplitude and phase of the sheath voltage, the distance l between the insulation fault point of the cable and the head end can be obtainedf:
Figure BDA0003551446380000061
The amplitude and the phase of the sheath current at the head end and the tail end of the cable, the amplitude and the phase of the sheath voltage and related known parameters are obtained in the previous steps through the formula, so that the distance between the insulation fault point and the head end of the cable can be accurately calculated, and the fault point of the submarine cable can be positioned on line.
The above scheme is implemented according to the following steps:
(1) a current sensor and a voltage sensor are arranged at the sheath at the head end and the tail end of the submarine cable, when an insulation fault occurs at any position of a certain phase of the submarine cable, a fault channel between a cable conductor and the metal sheath can be equivalent to a fault resistor Rf，RfThe values can be measured by an insulation resistance tester. Equivalent resistance R through cable fault channelfAnd characteristic impedance Z of cablecThe cable insulation fault types are classified into a short-circuit fault, a low-resistance fault and a high-resistance fault. Characteristic impedance Z of submarine cable cCan be calculated from the following formula:
Figure BDA0003551446380000062
wherein R is0、L0Equivalent resistance, inductance per unit length, C for submarine cables0、G0Equivalent capacitance and conductance of the submarine cable in unit length, and omega is system angular frequency.
(2) Aiming at the insulation fault between the submarine cable conductor and the metal sheath, the current I of the first and the tail end sheaths is collected in real time by a sensor1、I2And sheath voltage U1、U2The original data of (1).
(3) The collected data are transmitted to a host, the data are processed in real time through fast Fourier transform, the amplitude and the phase of a sheath current signal and the amplitude and the phase of a sheath voltage signal are obtained, the position of a cable insulation fault point is calculated through a formula, and a fault positioning result is stored.
FFT calculation:
Figure BDA0003551446380000071
wherein the content of the first and second substances,
Figure BDA0003551446380000072
is a twiddle factor; x (N) is a finite long sequence with the length of N, namely, raw signals collected by a current sensor and a voltage sensor, wherein N is 0,1, …, N-1; x (k) is a signal spectrum obtained after FFT, including an amplitude spectrum and a phase spectrum.
And analyzing the signal amplitude spectrum and the signal phase spectrum to obtain the amplitude and the phase of the sheath current signal at the head end and the tail end of the submarine cable and the amplitude and the phase of the sheath voltage signal. The sheath current and the sheath voltage at the head and tail ends of the cable can be expressed as
Figure BDA0003551446380000073
Wherein, I1、I2First and last end sheath current, x1、x2Amplitude of head and tail sheath current, y1、y2The phase of the first and the tail end sheath current; u shape1、U2Head and end sheath voltage, m1、m2Amplitude of head and tail end sheath voltage, t1、t2The phase of the first and the last sheath voltage.
Secondly, fault positioning: based on the processed data of the current and the voltage of the sheath at the head end and the tail end of the cable, calculating by using a fault positioning formula to obtain the distance l between the cable insulation fault point and the head end of the cablef：
Figure BDA0003551446380000074
Wherein R iss0The equivalent impedance of the metal sheath in the unit length of the submarine cable, wherein l is the length of the cable line, and l is obtained by calculationfIn order to include both amplitude and phase characteristic parameters, the amplitude is selected to characterize the fault location.
According to the submarine cable insulation fault online positioning method based on sheath current and voltage, the sheath current and the sheath voltage at the head end and the tail end are monitored in real time, and the acquired data are processed by using fast Fourier transform, so that fault point online positioning and distance measurement are realized, and the safety risk and cost of using electrical equipment are reduced. On the premise of ensuring safety, the precision of fault positioning is improved, the accurate positioning of cable insulation short-circuit faults, low-resistance faults and high-resistance faults is realized, and the fault positioning is not influenced by power grid frequency fluctuation, power grid harmonic waves and ground potential deviation.
The online positioning method for the insulation fault of the submarine cable is verified by the following specific examples:
in this example, a 35kV crosslinked polyethylene insulated (XLPE) submarine cable is taken as an example, the submarine cable length is 12km, and the nominal section of the cable is 185mm2The submarine cable metal sheath is a lead alloy sheath with an equivalent resistance of 2.2 × 10-4Ω/m。
Equivalent resistance R of submarine cable unit length0And an inductance L0And (3) calculating:
Figure BDA0003551446380000081
Figure BDA0003551446380000082
wherein, the angular frequency ω is 2 pi f, and f is the system frequency; r isc、rsThe radius of the cable conductor and the inner radius of the shielding layer; rho c and rho s are the resistivity of the cable conductor and the resistivity of the shielding layer; mu.s0Is a vacuum magnetic permeability.
Equivalent capacitance C of submarine cable unit length0And conductance G0And (3) calculating:
Figure BDA0003551446380000083
Figure BDA0003551446380000084
wherein ε is the dielectric constant of the dielectric; epsilon0Is a vacuum dielectric constant of ∈0＝8.86×10-12F/m; σ is the conductivity of the dielectric.
In the embodiment, different types of insulation faults of the submarine cable occur at 2000m, 4500m, 6000m, 8400m and 10000m respectively, current and voltage data of a sheath at the head end and the tail end of the cable are collected through a current sensor and a voltage sensor, the collected data are processed through fast Fourier transform, the amplitude and the phase of a sheath current signal and the amplitude and the phase of a sheath voltage signal are obtained, and the distance between the cable insulation fault point and the head end of the cable is further calculated. The results of the online positioning method for the different types of insulation faults of the submarine cable are shown in table 2, and the table 2 shows that the online positioning method is suitable for positioning short-circuit faults, low-resistance faults and high-resistance faults, has higher positioning precision and has fault positioning errors within 0.5 percent.
TABLE 2 different types of insulation fault positioning results for submarine cables
Figure BDA0003551446380000091
The above-mentioned embodiments only express the embodiments of the present invention, but not should be understood as the limitation of the scope of the invention patent, it should be noted that, for those skilled in the art, many variations and modifications can be made without departing from the concept of the present invention, and these all fall into the protection scope of the present invention.

Claims (3)

1. An submarine cable insulation fault on-line positioning method based on sheath current and voltage is characterized by comprising the following steps:
the method comprises the following steps that firstly, two ends of a submarine cable sheath are directly grounded, and a current sensor and a voltage sensor are arranged at the sheath at the head end and the tail end of the cable; when the submarine cable is out of any position of a certain phaseIn the case of insulation failure, the failure path between the cable conductor and the metal sheath can be equivalent to a failure resistance Rf，RfThe value can be measured by an insulation resistance tester; equivalent resistance R through cable fault channelfAnd characteristic impedance Z of cablecThe comparison of (1) and (4) divides the cable insulation fault types into short-circuit fault, low-resistance fault and high-resistance fault;
characteristic impedance Z of the submarine cablecCan be calculated from the following formula:
Figure FDA0003551446370000011
wherein R is0、L0Equivalent resistance, inductance per unit length, C for submarine cables 0、G0Equivalent capacitance and conductance of the submarine cable in unit length, wherein omega is the angular frequency of the system;
secondly, aiming at the insulation fault between the submarine cable conductor and the metal sheath, acquiring the current I of the sheath at the head end and the tail end through a sensor1、I2And sheath voltage U1、U2Any of the original signals can be represented by x (n);
thirdly, processing the acquired original signal data by using Fast Fourier Transform (FFT), and respectively obtaining the amplitude and the phase of sheath current and the amplitude and the phase of sheath voltage;
3.1) when submarine cable insulation fault, there is transient process sheath current and sheath voltage, and fault current mainly is power frequency current, carries out the FFT operation to directly detected sheath current and voltage signal, and specific computational formula is:
Figure FDA0003551446370000012
wherein, the first and the second end of the pipe are connected with each other,
Figure FDA0003551446370000013
is a twiddle factor; x (N) is a finite element of length NA long sequence, namely, raw signals collected by a current sensor and a voltage sensor, wherein N is 0,1, …, and N-1; x (k) is a signal spectrum obtained after FFT, including an amplitude spectrum and a phase spectrum;
3.2) through the analysis to signal amplitude spectrum and phase spectrum, obtain submarine cable head and end sheath electric current's amplitude and phase place, head and end sheath voltage's amplitude and phase place, cable head and end sheath electric current and sheath voltage can be expressed as:
Figure FDA0003551446370000021
Wherein, I1、I2First and last end sheath currents, x1、x2Amplitude of head and tail sheath current, y1、y2The phase of the first and the tail end sheath current; u shape1、U2Head and end sheath voltage, m1、m2Amplitude of head and tail end sheath voltage, t1、t2The phase of the first and the tail end sheath voltage;
fourthly, calculating and positioning the insulation fault point of the submarine cable according to the processed sheath current and sheath voltage data; the specific calculation formula of the distance measurement and the positioning of the fault point is as follows:
Figure FDA0003551446370000022
wherein, I1And I2For sheath current, U, at the head and tail ends of submarine cables1And U2For the sheath voltage, R, at the head and tail ends of the submarine cables0The equivalent impedance of the metal sheath per unit length of the submarine cable, i is the length of the submarine cable line, lfThe distance between the submarine cable insulation fault point and the cable head end is calculated; through the fault point distance measurement and positioning formula, the distance between the fault point and the head end is accurately positioned by combining related known parameters and processed sheath voltage and current data, and the accurate positioning of the submarine cable insulation fault is realized.
2. The method for on-line location of insulation fault of submarine cable according to claim 1, wherein in the first step, R is associated with different types of fault of submarine cable fThe values are shown in table 1:
TABLE 1 corresponding R of different fault types of submarine cablefValue of
Figure FDA0003551446370000023
3. The method for on-line location of insulation fault of submarine cable according to claim 1, wherein the submarine cable in the first step is a three-core cable, there is no insulation joint in the middle of the cable, the metal sheath is grounded by directly grounding the two ends, and a current sensor and a voltage sensor are installed at the sheath at the head and tail ends of any phase of cable.
CN202210263070.0A 2022-03-17 2022-03-17 Submarine cable insulation fault on-line positioning method based on sheath current and voltage Pending CN114675128A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116718875A (en) * 2023-08-10 2023-09-08 国网江苏省电力有限公司电力科学研究院 Positioning method and instrument for sheath layer grounding in high-voltage cable single-end grounding system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116718875A (en) * 2023-08-10 2023-09-08 国网江苏省电力有限公司电力科学研究院 Positioning method and instrument for sheath layer grounding in high-voltage cable single-end grounding system
CN116718875B (en) * 2023-08-10 2023-12-15 国网江苏省电力有限公司电力科学研究院 Positioning method and instrument for sheath layer grounding in high-voltage cable single-end grounding system

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