A high voltage cable fault monitoring and protection system

Abstract

This utility model relates to a high-voltage cable fault monitoring and protection system, applicable to the fields of power generation, substation, and distribution. In this embodiment, the system includes a high-voltage cable, a first relay, a second relay, and a time-delay relay. By integrating components such as the first relay, the time-delay relay, and the second relay, the system can respond rapidly once a breakdown fault occurs in the high-voltage cable, ensuring the faulty circuit is disconnected within a very short time. Furthermore, while ensuring sufficient response time for insulation breakdown faults, this utility model uses the time-delay relay to allow sufficient time for fluctuations in induced current caused by current changes, preventing system malfunctions. The coil of the first relay acts as an additional load when a fault occurs. This helps to disperse and limit the magnitude of short-circuit current and induced current, preventing excessive current from causing physical damage such as overheating or melting of the cable.

Description

Technical Field

[0001] This utility model relates to the fields of power generation, substation and distribution, and in particular to a high-voltage cable fault monitoring and protection system. Background Technology

[0002] High-voltage cables are power cables used to transmit voltages between 1kV and 1000kV, and are mainly used in power transmission and distribution systems.

[0003] When high-voltage cables are in operation, they are affected by environmental corrosion, high-temperature operation, or human damage, which can lead to aging or damage and a decline in the insulation performance of the high-voltage cables. At this time, the insulation of the high-voltage cables has generated dendritic or water ripple discharge patterns. Although the conductor has not yet broken through the insulation layer, if it continues to develop, when the insulation performance of the high-voltage cables deteriorates to a potential difference sufficient to break through the insulation, a through channel will form between the conductor and the insulation of the high-voltage cables, resulting in an insulation breakdown fault and subsequently a single-phase or multi-phase short circuit accident.

[0004] Currently, traditional high-voltage cable fault monitoring methods mostly rely on manual inspections or simple current and voltage monitoring devices. These methods have drawbacks such as slow response speed and inability to provide real-time protection. Especially when a breakdown fault occurs in a high-voltage cable, the fault current can increase rapidly, posing a serious threat to the cable itself and connected load equipment. If the faulty circuit cannot be disconnected in time, it may lead to even more serious consequences.

[0005] To overcome the shortcomings of existing technologies, some high-voltage cable fault monitoring and protection systems based on relay protection have begun to appear on the market. These systems typically determine the presence of a fault by monitoring changes in the current in the cable and quickly disconnect the power supply when a fault is detected to protect the cable and the load equipment. However, these systems often suffer from problems such as slow protection action, high false trip rate, and inability to flexibly adjust protection strategies according to the severity of the fault. Utility Model Content

[0006] In view of this, the present invention aims to propose a high-voltage cable fault monitoring and protection system to solve the problems of insufficient protection for insulation breakdown faults, slow protection action, and high false trip rate in the prior art.

[0007] To achieve the above objectives, the technical solution of this utility model is implemented as follows:

[0008] This utility model provides a high-voltage cable fault monitoring and protection system, including:

[0009] The high-voltage cable includes a first relay, a second relay, and a time-delay relay. The high-voltage cable comprises at least one conductor and shielding layers surrounding each conductor. One end of each conductor is connected to one end of a normally closed contact of the second relay, the other end of which is connected to a first power supply terminal, and the other end of the conductor is connected to a load terminal. The shielding layer is connected to one end of the coil of the first relay near the first power supply terminal, and the other end of the coil is grounded. One end of the normally open contact of the first relay is connected to a second power supply terminal, and the other end is connected to one end of the coil of the time-delay relay, the other end of which is grounded. One end of the normally open contact of the time-delay relay is connected to a third power supply terminal, and the other end is connected to one end of the coil of the second relay, the other end of which is grounded. An insulating layer is provided between the shielding layer and the conductor.

[0010] Furthermore, the fault monitoring and protection system also includes an AC current sensor, a voltage acquisition system, and a current acquisition system;

[0011] The AC current sensor is disposed around the shielding layer and is located close to the first relay;

[0012] The first end of the AC current sensor is connected to the first end of the voltage acquisition system; the second end is connected to the first end of the current acquisition system; and the second end of the current acquisition system is connected to the second end of the voltage acquisition system.

[0013] Furthermore, the alternating current sensor is a Rogowski coil.

[0014] Furthermore, the voltage acquisition system includes an integrating circuit and a voltage acquisition unit;

[0015] The integrating circuit includes resistors, capacitors, and amplifiers;

[0016] The first end of the Rogowski coil is connected to one end of the resistor, and the other end of the resistor is connected to one end of the capacitor and the inverting input of the amplifier, respectively.

[0017] The second end of the Rogowski coil is connected to the non-inverting input of the amplifier and the second end of the voltage acquisition unit, respectively.

[0018] The output of the amplifier is connected to the other end of the capacitor and the first input of the voltage acquisition device.

[0019] Furthermore, the current acquisition system includes a current acquisition unit;

[0020] The first end of the current collector is connected to the second end of the Rogowski coil;

[0021] The second terminal of the current acquisition unit is connected to the non-inverting input terminal of the amplifier and the second terminal of the voltage acquisition unit.

[0022] Furthermore, the fault monitoring and protection system also includes a data uploading system and a data analysis terminal;

[0023] The output terminal of the current acquisition device is connected to the first input terminal of the data upload system;

[0024] The output terminal of the voltage acquisition unit is connected to the second input terminal of the data upload system;

[0025] The output of the data upload system is connected to the data analysis terminal.

[0026] Furthermore, the data transmission system includes an analog-to-digital converter and a communication management unit;

[0027] The output terminal of the current collector is connected to the first input terminal of the analog-to-digital converter;

[0028] The output terminal of the voltage acquisition unit is connected to the second input terminal of the analog-to-digital converter;

[0029] The output of the analog-to-digital converter is connected to the input of the communication management unit;

[0030] The output of the communication management unit is connected to the data analysis terminal.

[0031] Furthermore, the data transmission system also includes a switch;

[0032] The output of the communication management unit is connected to the first end of the switch; the second end of the switch is connected to the data analysis terminal.

[0033] Furthermore, the shielding layer is a metal shielding layer.

[0034] Furthermore, the time-delay relay is an energized time-delay relay.

[0035] Compared with the prior art, this utility model has the following advantages:

[0036] This invention integrates components such as a first relay, a time-delay relay, and a second relay to achieve real-time monitoring of the status of high-voltage cables. Once a breakdown fault occurs in the high-voltage cable, the system can respond rapidly, ensuring that the faulty circuit is disconnected within a very short time through preset current thresholds and delay settings, effectively preventing further damage to the cable itself and connected load equipment from the fault current.

[0037] Because the operating current on high-voltage cables often fluctuates significantly, large induced currents often appear in the metal shielding layer. To avoid relay malfunctions, this invention, while ensuring sufficient response time to insulation breakdown faults, uses a time-delay relay to allow sufficient time for fluctuations in induced current caused by current changes. Even if the first relay malfunctions, it will not accidentally disconnect the circuit connection between the first power supply terminal and the conductor.

[0038] In this invention, when the core current changes excessively, a large induced current appears on the shielding layer. When an insulation breakdown fault occurs in a high-voltage cable, a short-circuit current forms between the core and the shielding layer. By directly connecting the coil of the first relay to the shielding layer, this coil acts as an additional load when a fault occurs. This helps to disperse and limit the magnitude of the short-circuit current and the induced current, preventing excessive current from causing physical damage such as overheating or melting of the cable's metal layers (e.g., the shielding layer), thereby extending the cable's service life and reducing post-fault repair costs. In traditional fault monitoring systems, when a cable experiences a breakdown fault, the short-circuit current may directly impact the monitoring system's circuitry, leading to system damage or malfunction. This invention, by connecting the coil of the first relay as a load, can buffer the impact of the short-circuit current to a certain extent, enhancing the system's robustness and anti-interference capability.

[0039] The application of this system can significantly reduce the risk of single-phase or multi-phase short-circuit accidents caused by high-voltage cable faults, reduce the time and scope of power outages due to faults, and thus improve the safety and stability of the entire power system. This is of great significance for ensuring power supply, reducing economic losses, and improving user experience. Attached Figure Description

[0040] The accompanying drawings, which form part of this utility model, are used to provide a further understanding of the utility model. The illustrative embodiments of the utility model and their descriptions are used to explain the utility model and do not constitute an undue limitation of the utility model. In the drawings:

[0041] Figure 1 This is a schematic diagram of the overall structure of the first embodiment of the present utility model;

[0042] Figure 2 This is a schematic diagram of the overall structure of the second embodiment of the present invention;

[0043] Figure 3 This is a schematic diagram of the connection between the first relay and the time delay relay of this utility model;

[0044] Figure 4 This is a schematic diagram of the connection between the second relay and the time delay relay of this utility model;

[0045] Figure 5 This utility model relates to a single-core high-voltage cable;

[0046] Figure 6 This utility model relates to a three-core high-voltage cable;

[0047] Figure 7 This is the potential difference curve between the fault point and the shielding layer when a fault occurs in this utility model;

[0048] Figure 8 The current curve of the shielding layer when a fault occurs in this utility model;

[0049] Figure 9 This is the current curve of the shielding layer received by the Rogowski coil when a fault occurs in this utility model.

[0050] Explanation of reference numerals in the attached figures:

[0051] 1. Core wire; 2. Insulation layer; 3. Shielding layer; 4. Insulating sheath. Detailed Implementation

[0052] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments of the present invention can be combined with each other.

[0053] In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," and "back," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0054] Furthermore, in the description of this utility model, unless otherwise explicitly defined, the terms "installation," "connection," "joining," and "connector" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model in light of the specific circumstances.

[0055] The following will refer to the appendix. Figures 1 to 9 The present invention will be described in detail with reference to the embodiments.

[0056] Overall, such as Figure 1 , Figure 3 ,as well as Figure 4As shown, a high-voltage cable, a first relay, a second relay, and a time-delay relay are included. The high-voltage cable includes at least one conductor 1 and a shielding layer 3 surrounding each conductor 1. One end of conductor 1 is connected to one end of the normally closed contact of the second relay, the other end of the normally closed contact of the second relay is connected to a first power supply terminal, and the other end of conductor 1 is connected to a load terminal. The shielding layer 3 is connected to one end of the coil of the first relay near the first power supply terminal, and the other end of the coil of the first relay is grounded. One end of the normally open contact of the first relay is connected to a second power supply terminal, and the other end is connected to one end of the coil of the time-delay relay, and the other end of the coil of the time-delay relay is grounded. One end of the normally open contact of the time-delay relay is connected to a third power supply terminal, and the other end is connected to one end of the coil of the second relay, and the other end of the coil of the second relay is grounded. An insulating layer 2 is provided between the shielding layer 3 and the conductor 1.

[0057] This invention integrates components such as a first relay, a time-delay relay, and a second relay to achieve real-time monitoring of the status of high-voltage cables. Once a breakdown fault occurs in the high-voltage cable, the system can respond rapidly, ensuring that the faulty circuit is disconnected within a very short time through preset current thresholds and delay settings, effectively preventing further damage to the cable itself and connected load equipment from the fault current.

[0058] Because the operating current on high-voltage cables often fluctuates significantly, the metal shielding layer 3 often experiences large induced current. To avoid relay malfunctions, this invention, while ensuring sufficient response time to insulation breakdown faults, uses a time-delay relay to allow sufficient fluctuation time for induced current fluctuations caused by current changes. Even if the first relay malfunctions, it will not accidentally disconnect the circuit connection between the first power supply terminal and the conductor 1.

[0059] In this invention, when the current change in the conductor 1 is too large, a large induced current will appear on the shielding layer 3. When an insulation breakdown fault occurs in the high-voltage cable, a short-circuit current will form between the conductor 1 and the shielding layer 3. By directly connecting the coil of the first relay to the shielding layer 3, the coil acts as an additional load when a fault occurs. This helps to disperse and limit the magnitude of the short-circuit current and the induced current, preventing excessive current from causing physical damage such as overheating or melting of the cable's metal layers (such as the shielding layer 3), thereby extending the cable's service life and reducing repair costs after a fault. In traditional fault monitoring systems, when a cable breakdown fault occurs, the short-circuit current may directly impact the monitoring system's circuitry, leading to system damage or malfunction. This invention, by connecting the coil of the first relay as a load, can buffer the impact of the short-circuit current to a certain extent, enhancing the system's robustness and anti-interference capability.

[0060] The application of this system can significantly reduce the risk of single-phase or multi-phase short-circuit accidents caused by high-voltage cable faults, reduce the time and scope of power outages due to faults, and thus improve the safety and stability of the entire power system. This is of great significance for ensuring power supply, reducing economic losses, and improving user experience.

[0061] In this embodiment, the high-voltage cable can be a single-core high-voltage cable or a three-core high-voltage cable. When the high-voltage cable is a single-core high-voltage cable, such as... Figure 5 It includes a wire core 1 and shielding layers 3 respectively arranged around each wire core 1; one end of the wire core 1 is connected to a first power supply terminal and the other end is connected to a load terminal; the shielding layer 3 is grounded at the end closest to the first power supply terminal; an insulating layer 2 is arranged between the shielding layer 3 and the wire core 1; an insulating outer sheath is arranged around the shielding layer 3. In this embodiment, the insulation breakdown fault is the process of the wire core 1 forming a current loop between the breakdown insulating layer 2 and the insulating layer 2.

[0062] When the high-voltage cable is three-core, such as Figure 6 It includes a conductor 1 and shielding layers 3 respectively arranged around each conductor 1; one end of conductor 1 is connected to a first power supply terminal and the other end is connected to a load terminal; the shielding layer 3 is grounded at the end closest to the first power supply terminal; an insulation layer 2 is provided between the shielding layer 3 and the conductor 1; the high-voltage cable also includes an insulating outer sheath 4, which surrounds the shielding layers 3 of the three conductors 1. In this embodiment, the insulation breakdown fault is the process in which the conductor 1 breaks through the insulation layer 2 and forms a current loop between it and the shielding layer 3.

[0063] The functions of shielding layer 3 include:

[0064] Limiting the electric field: The shielding layer 3 can enhance the effect of limiting the electric field within the insulating layer 2, making the direction of the electric field consistent with the direction of the insulation radius (i.e., radial), thereby terminating the electric field on the metal strip, and there is no electric field outside the metal strip.

[0065] Preventing electromagnetic interference: Shielding layer 3 can prevent external electromagnetic interference from entering the high-voltage cable and prevent the signal energy transmitted inside the high-voltage cable from leaking into the external environment, ensuring that the signal is not affected or is minimally affected by electromagnetic noise generated by other equipment and environment during transmission, and maintaining the integrity and accuracy of the signal.

[0066] Grounding protection: If conductor 1 is damaged, the outflowing current can flow into the grounding grid through shielding layer 3, providing safety protection. Furthermore, shielding layer 3 can also shield electromagnetic fields, preventing the magnetic field generated by the current from affecting the normal operation of electrical components.

[0067] Homogenize the electric field: The shielding layer 3 can homogenize the electric field, reducing the risk of partial discharge and electrical breakdown of the insulating layer 2.

[0068] Protecting operators and equipment: In the event of a high-voltage cable breakdown fault, the high potential is rapidly and directly grounded to prevent electric shock to operators or patients, thus protecting personal safety.

[0069] Improving the insulation performance of high-voltage cables: By adding a shielding layer 3 of semi-conductive material to the conductor surface, partial discharge between the conductor and the insulation layer 2 is avoided, thereby improving the insulation performance of high-voltage cables.

[0070] The high-voltage cable shielding layer 3 plays a crucial role in limiting the electric field, preventing electromagnetic interference, providing grounding protection, and homogenizing the electric field, ensuring the safe and stable operation of the high-voltage cable. During grounding, the current flows through the shielding layer 3 into the grounding grid, providing safety protection. In this invention, the partial discharge current path is formed through the shielding layer 3, allowing for the measurement of the leakage current and determination of the partial discharge strength.

[0071] More specifically, the fault monitoring and protection system also includes AC current sensors, voltage acquisition systems, and current acquisition systems;

[0072] An alternating current sensor is disposed around the shielding layer 3 and is positioned close to the first relay.

[0073] The first terminal of the AC current sensor is connected to the first terminal of the voltage acquisition system; the second terminal is connected to the first terminal of the current acquisition system; and the second terminal of the current acquisition system is connected to the second terminal of the voltage acquisition system.

[0074] This invention enables real-time monitoring of the insulation performance of high-voltage cables, accurate prediction of insulation breakdown faults in high-voltage cables, rapid and precise location of fault points, and timely detection and handling of faults before the insulation layer 2 of the high-voltage cable breaks down.

[0075] More specifically, the alternating current sensor is a Rogowski coil.

[0076] More specifically, the voltage acquisition system includes an integrating circuit and a voltage acquisition unit;

[0077] An integrating circuit includes resistors, capacitors, and amplifiers;

[0078] The first end of the Rogowski coil is connected to one end of a resistor, and the other end of the resistor is connected to one end of a capacitor and the inverting input of the amplifier.

[0079] The second end of the Rogowski coil is connected to the non-inverting input of the amplifier and the second end of the voltage acquisition unit, respectively.

[0080] The amplifier's output is connected to the other end of the capacitor and the first input of the voltage acquisition unit.

[0081] More specifically, the current acquisition system includes a current acquisition unit;

[0082] The first terminal of the current collector is connected to the second terminal of the Rogowski coil;

[0083] The second terminal of the current acquisition unit is connected to the non-inverting input terminal of the amplifier and the second terminal of the voltage acquisition unit.

[0084] More specifically, the fault monitoring and protection system also includes a data upload system and a data analysis terminal;

[0085] The output of the current acquisition unit is connected to the first input of the data upload system.

[0086] The output of the voltage acquisition unit is connected to the second input of the data upload system;

[0087] The output of the data upload system is connected to the data analysis terminal.

[0088] More specifically, such as Figure 2 As shown, the data transmission system includes an analog-to-digital converter and a communication management unit;

[0089] The output of the current collector is connected to the first input of the analog-to-digital converter;

[0090] The output of the voltage acquisition unit is connected to the second input of the analog-to-digital converter;

[0091] The output of the analog-to-digital converter is connected to the input of the communication management unit;

[0092] The output of the communication management unit is connected to the data analysis terminal.

[0093] More specifically, the data transmission system also includes switches;

[0094] The output of the communication management unit is connected to the first end of the switch; the second end of the switch is connected to the data analysis terminal.

[0095] More specifically, the shielding layer 3 is a metallic shielding layer 3.

[0096] More specifically, a time-delay relay is an energized time-delay relay.

[0097] The working principle of this utility model for high-voltage cable faults includes:

[0098] like Figure 1As shown, the first power supply terminal supplies power to core 1 via a time-delay relay, which in turn supplies power to the load. When a breakdown fault occurs in the high-voltage cable at point G, core 1 breaks down the insulation layer 2 and discharges to the shielding layer 3, forming a current. This current then passes through points A and E in sequence to supply power to the coil of the first relay with adjustable drive current. When the current reaches the preset current, the first relay operates, and its normally open contact closes. The second power supply terminal supplies power to the coil of the time-delay relay via the normally open contact of the first relay. At this time, the time-delay relay operates after a preset delay, and its normally open contact closes. The third power supply terminal supplies power to the coil of the second relay via the normally open contact of the time-delay relay. The normally closed contact of the second relay opens, and the first power supply stops supplying power to core 1 to avoid interference to the end load.

[0099] In this embodiment, the first relay and the second relay are both high-voltage relays. More specifically, when the first power supply is an AC 10kV high-voltage relay, and the second and third power supplies are AC 220V input voltages, the coil of the first relay is configured with an input voltage of the first power supply voltage (AC 10kV) and the operating voltage of the auxiliary contacts is the second power supply voltage (AC 220V). Alternatively, it can be a relay powered by the first power supply (AC 10kV), in which case the coil of the second relay is configured with an input voltage of the third power supply voltage (AC 220V) and the operating voltage of the auxiliary contacts is the first power supply voltage (10kV). Further details are omitted here.

[0100] The working method of this utility model for high-voltage cable fault monitoring includes:

[0101] Step S1: Obtain the induced current data sent by the data transmission system;

[0102] Step S2: Extract the i-th abnormal current waveform and the (i+1)-th abnormal current waveform with the same current direction as the i-th abnormal current waveform from the induced current data, and calculate the time difference Δt between the two abnormal current waveforms. i Where i is an integer greater than 0;

[0103] Step S3: According to Formula 1

[0104]

[0105] Calculate the mean of time difference Where n is the time difference Δt between the i-th abnormal current waveform and the (i+1)-th abnormal current waveform with the same current direction as the i-th abnormal current waveform. i The total number;

[0106] Step S4, according to formula 2

[0107]

[0108] Calculate the distance L between the discharge location of the shielding layer 33 and the AC current sensor, where V is the propagation speed of the current in the shielding layer 33;

[0109] Step S5: Take the distance L between the discharge location of the shielding layer 33 and the AC current sensor as the distance between the fault location of the high-voltage cable and the AC current sensor.

[0110] More specifically, the method further includes, after determining the distance L between the fault location of the high-voltage cable and the AC current sensor:

[0111] An alarm signal is generated and the distance between the fault location of the high-voltage cable and the AC current sensor is output.

[0112] More specifically, after acquiring the induced current data sent by the data transmission system, the method further includes:

[0113] Acquire the induced voltage data sent by the data transmission system;

[0114] Output induced current data and induced voltage data.

[0115] The working principle of this utility model for high-voltage cable fault monitoring is as follows: Figure 7 As shown, in this embodiment, the fault point where the high-voltage cable experiences insulation breakdown is point G. Point A is the point on the shielding layer 33 corresponding to point G. Points B, C, and D are sampling points extending from one side of point A. As shown in the figure, with point G as the center, as the distance from point G increases, the potential difference between the shielding layer 3 and the conductor 11 of the high-voltage cable gradually decreases until it reaches zero. The potential difference at the fault point G is the highest, and the voltage relationship is UA0 > UB0 > UC0 > UD0. At this time, the copper conductor 11 of the high-voltage cable discharges to the shielding layer 3 through the fault point G (at this time, only the conductor 11 discharges to the shielding layer 3, but no insulation breakdown fault has occurred). Although the main insulation has not yet been broken down, there is already voltage, which is connected to the high-voltage cable braid and grounded through the shielding layer 3, forming a current path.

[0116] At this time, the aforementioned current is collected by the Rogowski coil, then by the current standby unit. After integration by the integrating signal composed of resistors, capacitors, and amplifiers, it is converted into a voltage signal and collected by the voltage acquisition unit. This voltage is then output to the data analysis terminal after passing through the analog-to-digital converter, communication management unit, and switch. The current acquisition unit is equipped with a filtering circuit to remove external stray signals and filter out the current signal output by the Rogowski coil. Figure 8 The current waveform output by shielding layer 3 when the fault occurs is shown below. After being acquired by the Rogowski coil, the current waveform output by the Rogowski coil is as follows: Figure 9As shown in the figure, the i-th abnormal current waveform extracted from the induced current data and its occurrence time t1 are shown, as well as the (i+1)-th abnormal current waveform with the same current direction as the i-th abnormal current waveform extracted from the induced current data and its occurrence time t1 are shown. 2， And calculate the time difference Δt between the two abnormal current waveforms. i .

[0117] The data analysis terminal obtains the induced voltage and induced current data sent by the data transmission system, calculates the discharge location of the shielding layer 3 based on the induced current data, and then determines the fault location of the high-voltage cable.

[0118] This invention monitors the induced current at the grounding point of the shielding layer 3 using an AC current sensor; it collects the induced voltage data from the AC current sensor using a voltage acquisition system; it collects the induced current data from the AC current sensor using a current acquisition system; and it transmits the induced voltage data from the voltage acquisition system and the induced current data from the current acquisition system to a data analysis terminal using a data transmission system. The data analysis terminal then obtains the induced voltage and induced current data sent by the data transmission system, calculates the discharge position of the shielding layer 3 based on the induced current data, and thus determines the fault location of the high-voltage cable. This enables real-time monitoring of the insulation performance of high-voltage cables, accurately predicts insulation breakdown faults, and allows for rapid and precise fault location. The fault location is detected before the insulation layer 2 of the high-voltage cable breaks down, and the fault location is quickly determined through fault ranging, allowing for timely handling. This prevents the fault from developing further and causing insulation breakdown leading to a grounding short circuit, which could affect the safe operation of production equipment and avoid production losses and personnel injuries.

[0119] This invention performs insulation testing on high-voltage cables to check for weak insulation and determine whether the insulation of the high-voltage cables is up to standard.

[0120] When leakage current is detected, the data analysis terminal is used to determine whether it is an abnormal current waveform. If not, the problem is eliminated. If it is, the current waveform is analyzed, traveling wave ranging is performed on the fault point, and the location of the partial discharge point is determined based on the ranging distance. The fault analysis system sends a pop-up notification to the maintenance personnel to eliminate the potential hazard. The entire process is handled before it develops into a fault, avoiding an accident and reducing economic losses for the country and the company.

[0121] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A high-voltage cable fault monitoring and protection system, characterized in that, include: A high-voltage cable, a first relay, a second relay, and a time-delay relay, wherein the high-voltage cable includes at least one conductor and a shielding layer disposed around each conductor; One end of the wire core is connected to one end of the normally closed contact of the second relay, the other end of the normally closed contact of the second relay is connected to the first power supply terminal, and the other end of the wire core is connected to the load terminal; the shielding layer is connected to one end of the coil of the first relay near the first power supply terminal, and the other end of the coil of the first relay is grounded; one end of the normally open contact of the first relay is connected to the second power supply terminal, and the other end is connected to one end of the coil of the time delay relay, and the other end of the coil of the time delay relay is grounded; one end of the normally open contact of the time delay relay is connected to the third power supply terminal, and the other end is connected to one end of the coil of the second relay, and the other end of the coil of the second relay is grounded; an insulating layer is provided between the shielding layer and the wire core.

2. The high-voltage cable fault monitoring and protection system according to claim 1, characterized in that: The fault monitoring and protection system also includes an AC current sensor, a voltage acquisition system, and a current acquisition system; The AC current sensor is disposed around the shielding layer and is located close to the first relay; The first end of the AC current sensor is connected to the first end of the voltage acquisition system; the second end is connected to the first end of the current acquisition system; and the second end of the current acquisition system is connected to the second end of the voltage acquisition system.

3. The high-voltage cable fault monitoring and protection system according to claim 2, characterized in that: The alternating current sensor is a Rogowski coil.

4. The high-voltage cable fault monitoring and protection system according to claim 3, characterized in that: The voltage acquisition system includes an integrating circuit and a voltage acquisition unit; The integrating circuit includes resistors, capacitors, and amplifiers; The first end of the Rogowski coil is connected to one end of the resistor, and the other end of the resistor is connected to one end of the capacitor and the inverting input of the amplifier, respectively. The second end of the Rogowski coil is connected to the non-inverting input of the amplifier and the second end of the voltage acquisition unit, respectively. The output of the amplifier is connected to the other end of the capacitor and the first input of the voltage acquisition device.

5. A high-voltage cable fault monitoring and protection system according to claim 4, characterized in that: The current acquisition system includes a current acquisition device; The first end of the current collector is connected to the second end of the Rogowski coil; The second terminal of the current acquisition unit is connected to the non-inverting input terminal of the amplifier and the second terminal of the voltage acquisition unit.

6. A high-voltage cable fault monitoring and protection system according to claim 5, characterized in that: The fault monitoring and protection system also includes a data upload system and a data analysis terminal; The output terminal of the current acquisition device is connected to the first input terminal of the data upload system; The output terminal of the voltage acquisition unit is connected to the second input terminal of the data upload system; The output of the data upload system is connected to the data analysis terminal.

7. A high-voltage cable fault monitoring and protection system according to claim 6, characterized in that: The data upload system includes an analog-to-digital converter and a communication management unit; The output terminal of the current collector is connected to the first input terminal of the analog-to-digital converter; The output terminal of the voltage acquisition unit is connected to the second input terminal of the analog-to-digital converter; The output of the analog-to-digital converter is connected to the input of the communication management unit; The output of the communication management unit is connected to the data analysis terminal.

8. A high-voltage cable fault monitoring and protection system according to claim 7, characterized in that: The data upload system also includes a switch; The output of the communication management unit is connected to the first end of the switch; the second end of the switch is connected to the data analysis terminal.

9. A high-voltage cable fault monitoring and protection system according to claim 1, characterized in that: The shielding layer is a metal shielding layer.

10. A high-voltage cable fault monitoring and protection system according to claim 1, characterized in that: The time delay relay is an energized time delay relay.

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