High-voltage cable grounding ring current on-line monitoring system

Abstract

The utility model discloses a high-voltage cable grounding ring current on-line monitoring system, and belongs to the technical field of electric power systems. Comprising a centralized control center, a transformer substation, a control box and a grounding box, the grounding box is connected with the control box through a grounding wire, the control box is converged to a field bus through communication optical fibers to be connected with the transformer substation, the transformer substation is connected with the centralized control center through a network, and the centralized control center outputs through the network. According to the utility model, cable state parameters and tunnel environment parameters of each measurement point can be received in real time, the monitoring data can be sent to the transformer station level server, control commands sent by the transformer station level server can be received at the same time, and the communication anti-interference capability is strong. And when a cable metal sheath has a grounding fault, relatively large power frequency short-circuit current flows through the cable sheath and a grounding wire and lasts for a plurality of cycles, and the amplitude and direction of the first half-wave of the short-circuit current at the two ends of the cable are monitored, so that whether a breakdown point is on the cable can be accurately judged.

Description

Technical Field

[0001] The utility model relates to the technical field of power systems, in particular to an on-line monitoring system for high-voltage cable grounding loop current. Background Art

[0002] Power cables are cables used for transmitting and distributing electric energy. They are commonly used in urban underground power grids, outgoing lines of power stations, internal power supply of industrial and mining enterprises, and underwater transmission lines across rivers and seas. In power lines, the proportion of cables is gradually increasing. Power cables are cable products used to transmit and distribute high-power electric energy in the main lines of power systems, including power cables of various voltage levels from 1 to 500 kV and above, and various insulations.

[0003] In recent years, power cables have been widely used in power systems, especially in distribution networks. With the wide use of power cables, their drawbacks have gradually emerged. Due to factors such as the special structure of power cables and the complex environment they are in, the insulation of cables is reduced, which in turn leads to cable insulation failures. Traditional monitoring methods cannot detect cable insulation problems in a timely manner, so cable failures occur frequently. Therefore, researching effective on-line monitoring methods for power cables is crucial for ensuring the safe and reliable operation of cables. Summary of the Utility Model

[0004] The purpose of the utility model is to provide an on-line monitoring system for high-voltage cable grounding loop current, which solves the problem that traditional monitoring methods cannot detect cable insulation in a timely manner and avoids the frequent occurrence of cable failures.

[0005] To achieve the above purpose, the utility model provides an on-line monitoring system for high-voltage cable grounding loop current, including a centralized control center, a substation, a control box, and a grounding box. The grounding box is connected to the control box through a grounding wire. The control box is connected to the substation through communication optical fibers converging to the field bus. The substation is connected to the centralized control center through a network. The centralized control center outputs through a network.

[0006] Preferably, the centralized control center mainly includes a centralized control center server, which is used to receive the network signal of the substation and monitor through WEB and alarm through SMS.

[0007] Preferably, the substation mainly includes a control center server, which is used to receive the signal sent by the control box through communication optical fibers and output the signal to the centralized control center through a network.

[0008] Preferably, the control box includes a remote monitoring terminal and an AC / DC power supply. The remote monitoring terminal and the AC / DC power supply are connected to each other. Among them, the output voltage of the AC / DC is 24V, and its AC voltage is 220V.

[0009] Preferably, the grounding box includes a grounding box housing. Inside the grounding box housing, there are three groups of cables, namely Cable A, Cable B, and Cable C. Cable A, Cable B, and Cable C are arranged side by side, and one end of each of Cable A, Cable B, and Cable C is connected to the grounding end. The other ends of Cable A, Cable B, and Cable C are each provided with a current sensor connected to the busbar current collector. An on-line power-taking device is also connected to the outer end of the current sensor of Cable A. Grounding current collectors are sleeved on both sides of Cable A, Cable B, and Cable C. The busbar current collector, the on-line power-taking device, and the grounding current collector are all connected to the output acquisition sensor.

[0010] Preferably, the grounding current collectors in each group are connected by a single-core cable shielding layer cross-connected grounding wire.

[0011] Therefore, the high-voltage cable grounding loop online monitoring system of the present utility model with the above structure has the following beneficial effects:

[0012] The present utility model can integrate multiple monitoring functions, can receive the cable status parameters and tunnel environment parameters of each measurement point in real time, and send these monitoring data to the substation-level server. At the same time, it can receive the control commands sent by the substation-level server. The remote monitoring terminal and the substation or tunnel machine room-level server use optical fiber communication, and the communication has strong anti-interference ability.

[0013] When a grounding fault occurs in the cable metal sheath of the present utility model, a large power frequency short-circuit current will flow through the cable sheath and the grounding wire and last for several cycles. By monitoring the amplitude and direction of the first half-wave of the short-circuit current at both ends of the cable, it is possible to accurately determine whether the breakdown point is on the cable.

[0014] Next, through the drawings and embodiments, the technical solutions of the present utility model will be further described in detail. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic structural diagram of a high-voltage cable grounding loop online monitoring system of the present utility model;

[0016] Figure 2 It is a schematic structural diagram of a high-voltage cable grounding loop online monitoring system of the present utility model;

[0017] Figure 3 It is a schematic structural diagram of a high-voltage cable grounding loop online monitoring system of the present utility model;

[0018] Reference Numerals

[0019] 1. Grounding box housing, 2. Cable A, 3. Cable B, 4. Cable C, 5. Grounding terminal, 6. Grounding acquisition sensor, 7. Cross-connected grounding wire for single-core cable shielding layer, 8. On-line power-taking device, 9. Current sensor, 10. Busbar current collector, 11. Data acquisition sensor, 12. Remote control terminal. Detailed implementation manner

[0020] The technical solution of the present utility model will be further described below with reference to the drawings and embodiments.

[0021] Unless otherwise defined, the technical terms or scientific terms used in the present utility model should have the ordinary meaning understood by those with ordinary skills in the field to which the present utility model belongs. The "first", "second" and similar words used in the present utility model do not indicate any order, quantity or importance, but are only used to distinguish different components. The words such as "including" or "comprising" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. The words such as "connected" or "linked" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The "upper", "lower", "left", "right", etc. are only used to represent the relative position relationship. When the absolute position of the object to be described changes, the relative position relationship may also change accordingly.

[0022] Embodiment

[0023] As Figures 1 - 3 shown, the present utility model provides a high-voltage cable grounding loop online monitoring system, which includes a centralized control center, a substation, a control box and a grounding box. The grounding box is connected to the control box through a grounding wire. The control box is connected to the substation through a communication optical fiber converging to a field bus, and the substation is connected to the centralized control center through a network. The centralized control center outputs through a network.

[0024] The centralized control center mainly includes a centralized control center server, which is used to receive the network signal of the substation and monitor through WEB and alarm through text messages.

[0025] The substation mainly includes a control center server, which is used to receive the signal sent by the control box through the communication optical fiber and output the signal to the centralized control center through the network.

[0026] The control box includes a remote monitoring terminal and an AC / DC power supply. The remote monitoring terminal and the AC / DC power supply are connected to each other. Among them, the output voltage of the AC / DC is 24V, and its AC voltage is 220V.

[0027] The grounding box includes a grounding box housing 1. Inside the grounding box housing 1, there are three groups of cables, namely cable A 2, cable B 3, and cable C 4. Cable A 2, cable B 3, and cable C 4 are arranged side by side, and one end of each of cable A 2, cable B 3, and cable C 4 is connected to the grounding terminal 5. The other ends of cable A 2, cable B 3, and cable C 4 are each provided with a current sensor 9 connected to the busbar current collector 10. The outer end of the current sensor 9 of cable A 2 is also connected to an on-line power-taking device 8. Grounding current collectors 6 are sleeved on both sides of cable A 2, cable B 3, and cable C 4. The busbar current collector 10, the on-line power-taking device 8, and the grounding current collector 6 are all connected to the output acquisition sensor 11.

[0028] Each group of grounding current collectors 6 is connected by a single-core cable shielding layer cross-connected grounding wire 7.

[0029] The grounding box housing 1 is made of a stainless-steel waterproof chassis and can be directly installed on the wall of the cable maintenance well. The equipment uses an opening and closing type sensor, which is conducive to on-site installation. Current sensors are provided on cable A, cable B, and cable C to monitor the current and facilitate current acquisition.

[0030] The function of the centralized control center server is that each substation-level server transmits all monitoring data to the centralized control center server through the network and accepts its control instructions. The centralized control center server can conduct centralized monitoring, data analysis, management, and real-time control of the power tunnel environment and multiple cable state parameters under its jurisdiction.

[0031] The function of the substation or tunnel machine room-level server is to receive data sent by the remote monitoring terminal, and through data analysis, predict potential cable faults and fire warning and alarm states, water level height, and manhole cover opening and closing conditions in the tunnel. At the same time, corresponding control actions can be taken and control instructions can be sent to the remote monitoring terminal.

[0032] The function of the remote monitoring terminal is to receive the cable state parameters and tunnel environment parameters of each measurement point in real time, and send these monitoring data to the substation-level server. At the same time, it can receive the control commands sent by the substation-level server. The remote monitoring terminal and the substation or tunnel machine room-level server use optical fiber communication, and the communication anti-interference ability is strong.

[0033] The usage method is to connect the 220V power cord and communication line, power on, and the instrument will automatically start working. The leakage current transformer is clamped on the grounding wire of the single-phase cable, and the operating current transformer is clamped on the single-phase body of the cable. Connect the ABC leakage current transformers (100A / 5V) to the LC-A / LC-B / LC-C aviation connectors of the instrument according to the corresponding labels, and connect the ABC operating current transformers (20A / 5V) to the RC-A / RC-B / RC-C aviation connectors of the instrument. Connect the communication line to the communication aviation connector of the instrument.

[0034] After the grounding wire is stolen, the current changes suddenly, and an alarm text message is immediately sent to the mobile phone of the duty personnel to inform the location of the stolen grounding wire.

[0035] Report the damage condition of the cable outer sheath at any time to prevent the main insulation from being fatally damaged, and even immediately report the theft of the grounding wire. Monitoring the sheath insulation by continuously detecting the grounding current of the metal sheath is the only feasible method that does not change the line connection and does not affect the operation at present.

[0036] It can realize the transient overlimit monitoring of the grounding current, and requires to be able to latch and report it in order to provide reference indicators for the operation condition of the cable.

[0037] Therefore, the present utility model adopts the above-mentioned on-line monitoring system for the grounding loop current of high-voltage cables, which can integrate multiple monitoring functions. It can receive the cable state parameters and tunnel environment parameters of each measurement point in real time, and send these monitoring data to the substation-level server. At the same time, it can receive the control commands sent by the substation-level server. The remote monitoring terminal and the substation or tunnel machine room-level server use optical fiber communication, and the communication anti-interference ability is strong. And when a grounding fault occurs in the cable metal sheath, a large power frequency short-circuit current will flow through the cable sheath and the grounding wire and last for several cycles. By monitoring the amplitude and direction of the first half-wave of the short-circuit current at both ends of the cable, it is possible to accurately judge whether the breakdown point is on the cable.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present utility model and are not intended to limit them. Although the present utility model has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present utility model, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present utility model.

Claims

1. An on-line monitoring system for the grounding loop current of high-voltage cables, characterized in that: It includes a centralized control center, a substation, a control box and a grounding box. The grounding box is connected to the control box through a grounding wire. The control boxes are converged to the field bus through communication optical fibers and connected to the substation. The substation is connected to the centralized control center through a network, and the centralized control center outputs through the network.

2. The on-line monitoring system for the grounding loop current of a high-voltage cable according to claim 1, characterized in that: The centralized control center mainly includes a centralized control center server, which is used to receive the network signal of the substation, monitor through WEB and give an alarm through SMS.

3. An on-line monitoring system for the grounding loop current of a high-voltage cable according to claim 1, characterized in that: The substation mainly includes a control center server, which is used to receive the signal sent by the control box through the communication optical fiber and output the signal to the centralized control center through the network.

4. The on-line monitoring system for the grounding loop current of a high-voltage cable according to claim 1, characterized in that: The control box includes a remote monitoring terminal and an AC / DC power supply. The remote monitoring terminal and the AC / DC power supply are connected to each other. The output voltage of the AC / DC is 24V, and its AC voltage is 220V.

5. An on-line monitoring system for the grounding loop current of a high-voltage cable according to claim 1, characterized in that: The grounding box includes a grounding box shell. Inside the grounding box shell, there are three groups of cables, namely cable A, cable B and cable C. Cable A, cable B and cable C are arranged side by side, and one end of cable A, cable B and cable C is connected to the grounding end. The other ends of cable A, cable B and cable C are all provided with current sensors connected to the busbar current collector. An on-line power-taking device is also connected to the outer end of the current sensor of cable A. Grounding current collectors are sleeved on both sides of cable A, cable B and cable C. The busbar current collector, the on-line power-taking device and the grounding current collector are all connected to the output acquisition sensor.

6. An on-line monitoring system for the grounding loop current of a high-voltage cable according to claim 5, characterized in that: Each group of the grounding current collectors is connected by a single-core cable shielding layer cross-connected grounding wire.

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