High-voltage cable sheath grounding box

Abstract

The utility model discloses a high-voltage cable sheath grounding box which comprises a grounding box body. A current protector and a monitoring device are correspondingly arranged in the grounding box body; the current protector and the monitoring device are respectively positioned on each circuit of the cross interconnection circuit; the current protectors are respectively connected in series with a main grounding wire of the cable sheath in a crossed and interconnected manner; the monitoring device has the functions of partial discharge signal monitoring, magnetic field intensity monitoring and voltage monitoring, and is respectively connected with the current protector and the signal junction box and grounded. According to the invention, the current protector is arranged in the grounding box, so that the cable sheath ring current is effectively reduced, and sheath ring current increase caused by long-distance cable radiation or multi-loop cable laying is inhibited; the monitoring device is arranged in the grounding box, so that secondary monitoring is achieved, meanwhile, follow-up cable monitoring does not need to be provided with other sensors, cable outer sheath monitoring, insulation monitoring and anti-theft and anti-cutting monitoring can be achieved, cable sheath ring current is effectively reduced, and normal and stable operation of a line is guaranteed.

Description

TECHNICAL FIELD

[0001] The utility model relates to cable transmission electric technology field, concretely is a high -voltage cable sheath grounding box. BACKGROUND

[0002] When high-voltage single-core cable carries out long-distance power transmission, in order to avoid induced voltage being too high, the segmented connection mode is usually adopted, specifically: in a loop, every three sections will form a group of cross-interconnected loops, in principle, when three sections are completely equal, through the cross-interconnection of three phases, the induced potential will be completely offset, so that the grounding current is zero, but due to the restriction of the implementation site and other conditions, the actual three sections are inconsistent in length, or when the load current of three phases is not equal, the cross-interconnection of three phases passing through the outer sheath of the cable cannot be completely offset, forming the cable metal sheath circulating current, and the current is often too large, resulting in serious sheath heating and reducing the power transmission capacity of the cable itself. In order to limit the induced voltage and fault overvoltage on the metal sheath of the power cable, avoid the circulating current in the sheath, one end of the cable sheath should be directly grounded, and the other end should be grounded through the protector. If the line is long, the cable sheath can be divided into three sections (or multiple sections in three sections) for mutual insulation, and each section of the sheath is cross-connected and grounded through the protector. However, when the actual long-distance cable or multi-loop cable is running, the induced current is relatively large, 1. Excessive heating circulating current will generate a lot of heat at the cable joint, and long-term operation will cause problems such as cable insulation aging, joint loosening, etc., thereby causing accidents. 2. High temperature and current damage to the cable insulation material will cause greater failure, even cause cable short circuit or poor contact, and further affect the normal operation of the power grid. CONTENT OF THE UTILITY MODEL

[0003] The application provides a high-voltage cable sheath grounding box, which effectively reduces the cable sheath circulating current by arranging a current protector in the grounding box, suppresses the increase of the sheath circulating current caused by long-distance cable radiation or multi-loop cable laying, reduces the energy transmission and outer sheath heating problems; By arranging a monitoring device in the grounding box, secondary monitoring is realized, and subsequent cable monitoring does not need to install other sensors, only needs to configure the monitoring device to realize the outer sheath monitoring, insulation monitoring and anti-cutting monitoring of the cable, thereby effectively reducing the cable sheath circulating current and ensuring the normal and stable operation of the line.

[0004] A high-voltage cable sheath induction compensation and monitoring device, comprising a grounding box body;

[0005] The current protector and the monitoring device are arranged in the grounding box body correspondingly;

[0006] The current protector and the monitoring device are respectively located on each circuit of the cross-interconnected circuit, and the current protector and the monitoring device are integrated in the grounding box body.

[0007] The current protectors are connected in series to the total grounding line of the cable sheath cross interconnection respectively;

[0008] The monitoring device has partial discharge signal monitoring, magnetic field intensity monitoring and voltage monitoring functions, one end of the monitoring device is connected with the current protectors respectively, the other end of the monitoring device is grounded respectively, and the monitoring device is connected with the signal terminal box of the grounding box body respectively.

[0009] Preferably, the monitoring device comprises a partial discharge signal monitoring module, a magnetic field intensity monitoring module, a voltage monitoring module and a connector.

[0010] The partial discharge signal monitoring module, the magnetic field intensity monitoring module and the voltage monitoring module are connected with the connector respectively.

[0011] The connector is connected with the signal terminal box and the current protectors respectively, and the connector is grounded.

[0012] Preferably, the partial discharge signal monitoring module is a partial discharge nickel magnetic core open-close type partial discharge sensor.

[0013] The magnetic field intensity monitoring module is a silicon steel sheet open-close type circulating current sensor.

[0014] The voltage monitoring module is a capacitance induction sheath voltage sensor.

[0015] Preferably, the partial discharge nickel magnetic core open-close type partial discharge sensor comprises a resistor, a nickel magnetic core, a first coil and a capacitor.

[0016] The resistor is located between one end of the first coil and the capacitor.

[0017] The first coil is wound on the nickel magnetic core on one side, one end of the first coil is connected with the resistor, and the other end of the first coil is connected with the other end of the capacitor.

[0018] Preferably, the number of turns of the first coil is determined according to the properties of the nickel magnetic core.

[0019] Preferably, the first coil is a high-temperature wire.

[0020] Preferably, the silicon steel sheet open-close type circulating current sensor comprises a silicon steel sheet and a second coil.

[0021] The second coil is wound on both sides of the silicon steel sheet respectively, and both ends of the second coil are connected with plugs respectively.

[0022] Preferably, the ratio of the coils wound on both sides of the silicon steel sheet is 1000:1.

[0023] Preferably, the capacitor is made of red copper.

[0024] Preferably, the current protector comprises a parallel inductor and zinc oxide valve;

[0025] One end of the inductor and zinc oxide valve is grounded respectively, and the other end of the inductor and zinc oxide valve is connected to the

[0026] Monitoring device respectively.

[0027] Compared with the prior art, the application has the beneficial effects that:

[0028] The current suppressor and the monitoring device are correspondingly arranged in the grounding box, the current suppressor and the monitoring device are arranged on each circuit of the cross interconnection circuit respectively, the circulating current of the cable sheath is suppressed by the current suppressor, the increase of the circulating current of the sheath caused by long-distance cable radiation or multi-loop cable laying is suppressed, thereby avoiding the problems that the induced current is relatively large due to the actual long-distance cable or multi-loop laying cable operation, the transmission of energy is reduced, the outer sheath is heated, excessive heating causes a large amount of heat at the cable joint, causes the cable insulation to age, the joint to be loose, the insulation to be damaged, the high temperature and the current of the cable insulation material to be damaged, and the normal operation of the power grid is affected; the monitoring device with the integration of partial discharge, sheath circulating current and sheath voltage is arranged, the current suppressor is directly connected with the cable shielding layer and is connected to the total grounding row, the sensor of the monitoring device is correspondingly installed at the grounding position of each phase current suppressor, is clamped on the grounding wire, and is used for detecting the current, voltage and partial discharge of the primary equipment, realizes the secondary monitoring of the current on each circuit of the cross interconnection circuit, and realizes the outer sheath monitoring, insulation monitoring and anti-cutting monitoring of the cable without installing other sensors while double-protecting the cable operation. BRIEF DESCRIPTION OF DRAWINGS

[0029] Fig. 1 It is a structure schematic view of a high-voltage cable sheath grounding box in the embodiment of the application;

[0030] Fig. 2 It is a schematic view of a current protector in a high-voltage cable sheath grounding box in the embodiment of the application;

[0031] Fig. 3 It is a structure schematic view of a monitoring device in a high-voltage cable sheath grounding box in the embodiment of the application;

[0032] In the figure: 1, grounding box body; 2, current protector; 3, monitoring device; 4, signal junction box; 5, nickel magnetic core; 6, silicon steel sheet; 7, capacitor; 8, connector. DETAILED DESCRIPTION

[0033] A high-voltage cable sheath grounding box, comprising a grounding box body;

[0034] A current protector and a monitoring device are correspondingly arranged in the grounding box body;

[0035] The current protector and the monitoring device are respectively arranged on each circuit of the cross-connection circuit, and the current protector and the monitoring device are integrated in the grounding box body;

[0036] The current protector is respectively connected in series with the total grounding line of the cable sheath cross-connection;

[0037] The monitoring device has partial discharge signal monitoring, magnetic field intensity monitoring and voltage monitoring functions, one end of the monitoring device is respectively connected with the current protector, the other end of the monitoring device is respectively grounded, and the monitoring device is respectively connected with the signal terminal box of the grounding box body.

[0038] Further, the monitoring device comprises a partial discharge signal monitoring module, a magnetic field intensity monitoring module, a voltage monitoring module and a connector;

[0039] The partial discharge signal monitoring module, the magnetic field intensity monitoring module and the voltage monitoring module are respectively connected with the connector;

[0040] The connector is respectively connected with the signal terminal box and the current protector, and the connector is grounded.

[0041] Further, the partial discharge signal monitoring module is a partial discharge nickel magnetic core open-close type partial discharge sensor;

[0042] The magnetic field intensity monitoring module is a silicon steel sheet open-close type circulating current sensor;

[0043] The voltage monitoring module is a capacitance induction sheath voltage sensor.

[0044] Further, the partial discharge nickel magnetic core open-close type partial discharge sensor comprises a resistor, a nickel magnetic core, a first coil and a capacitor;

[0045] The resistor is arranged between one end of the first coil and the capacitor;

[0046] The first coil is wound on one side of the nickel magnetic core, one end of the first coil is connected with the resistor, and the other end of the first coil is connected with the other end of the capacitor.

[0047] Further, the number of turns of the first coil is determined according to the properties of the nickel magnetic core.

[0048] Further, the coil is a high-temperature wire.

[0049] Further, the silicon steel sheet open-close type circulating current sensor comprises a silicon steel sheet and a second coil.

[0050] The second coil is wound on the two sides of the silicon steel sheet respectively, and the two ends of the second coil are connected with the plug respectively.

[0051] Further, the ratio of the coils wound on the two sides of the silicon steel sheet is 1000:1.

[0052] Further, the capacitor adopts red copper.

[0053] Further, the current protector comprises an inductor and a zinc oxide valve in parallel;

[0054] One end of the inductor and the zinc oxide valve is connected with the ground respectively, and the other end of the inductor and the zinc oxide valve is connected with the monitoring device respectively.

[0055] It should be noted that:

[0056] In the present application, by connecting a current protector in series at the direct ground of the cross interconnection, the circulating current can be effectively inhibited.

[0057] In the current protector, the zinc oxide valve functions to, when a single-phase short-circuit fault occurs, the induced voltage flowing through the metal sheath of the cable increases, the instantaneous circulating current increases, and then a very high voltage is formed at the two ends of the inductor. In order to avoid burning the inductor, and to avoid causing harm to the maintenance personnel due to the high voltage formed at the two ends of the inductor, the zinc oxide valve is used to protect the high voltage formed to be timely conducted to the ground. The two devices work in cooperation to achieve the double effects of inhibiting the circulating current of the cable sheath and protecting.

[0058] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0059] Please refer to Figs. 1-3 The present embodiment provides a high-voltage cable sheath grounding box, which comprises a grounding box body 1.

[0060] The current protector and the monitoring device are correspondingly arranged in the grounding box body.

[0061] The current protector 2 and the monitoring device 3 are respectively located on the A-phase, B-phase and C-phase circuits of the cross interconnection circuit, and the current protector 2 and the monitoring device 3 are integrated in the grounding box body 1.

[0062] The current protector is connected in series on the A-phase, B-phase and C-phase circuits, and one end is connected with the total grounding line of the grounding box respectively.

[0063] One end of the monitoring device 3 is connected with the other end of the current protector 2 respectively, and the other end of the monitoring device 3 is grounded respectively, and the monitoring device 3 is connected with the signal terminal box 4 of the grounding box respectively.

[0064] In the embodiment, the monitoring device 3 is fused by the partial discharge nickel magnetic core open-close type partial discharge sensor, the magnetic field intensity monitoring module is the silicon steel sheet open-close type circulating current sensor, and the voltage monitoring module is the capacitor induced shielded voltage sensor, thereby forming the fused monitoring device with the functions of partial discharge signal monitoring, magnetic field intensity monitoring and voltage monitoring.

[0065] The monitoring device 3 comprises a shell, and a partial discharge nickel magnetic core open-close type partial discharge sensor, a silicon steel sheet open-close type circulating current sensor, a capacitor induced shielded voltage sensor and a connector arranged in the shell.

[0066] The partial discharge nickel magnetic core open-close type partial discharge sensor, the silicon steel sheet open-close type circulating current sensor and the capacitor induced shielded voltage sensor are connected with the current protector and the signal terminal box of the grounding box through the connector respectively.

[0067] The partial discharge nickel magnetic core open-close type partial discharge sensor, the silicon steel sheet open-close type circulating current sensor and the capacitor induced shielded voltage sensor are connected with the connector respectively; the connector is installed in the shell, the connector is connected with the signal terminal box of the grounding box and the current protector respectively, and the connector is grounded.

[0068] In the embodiment, the connector is a five-core aviation plug.

[0069] In the embodiment, the partial discharge nickel magnetic core open-close type partial discharge sensor comprises a resistor R1, a nickel magnetic core 5, a first coil L1,

[0070] and a capacitor C1.

[0071] The nickel magnetic core 5 is installed in the shell.

[0072] The resistor R1 is located between the first coil L1 and one end of the capacitor C1.

[0073] The first coil L1 is wound on the nickel magnetic core 5 on one side, one end of the first coil L1 is connected with the resistor R1, the other end of the first coil L1 is connected with the other end of the capacitor C1, one end (i.e. A1) of the connector is connected with the circuit between the resistor R1 and the capacitor C1, and the other end of the connector is connected with the circuit between the first coil L1 and the capacitor C1 (i.e. A2).

[0074] The first coil L1, the resistor R1 and the capacitor C1 form an integration circuit, form a coupling link of partial discharge signals, and ensure accurate transmission of the signals from the high-voltage equipment to the measuring system.

[0075] The number of turns of the first coil L1 is determined according to the properties of the nickel magnetic core, and the first coil L1 is a high-temperature wire.

[0076] In the embodiment, the silicon steel sheet open-close type circulating current sensor comprises a silicon steel sheet 6 and a second coil L2.

[0077] The silicon steel sheet 6 is installed in the shell.

[0078] The second coil L2 is wound on both sides of the silicon steel sheet 6, and the two ends (i.e., A3 and A4) of the coil L2 are connected to the connector 8, so as to monitor the magnetic field intensity.

[0079] The ratio of the coils wound on both sides of the silicon steel sheet 6 is 1000:1, so that when the current needs to be measured, the switch is closed, at this time, the primary current flows through the primary winding, and at the same time, the corresponding current is generated in the secondary winding. When the current does not need to be measured, the switch is opened, at this time, the primary current does not flow through the primary winding, thereby avoiding the influence of the current generated in the secondary winding on the measurement.

[0080] In the embodiment, the capacitor 7 is made of red copper, which can provide better conductivity, thereby reducing the internal resistance and heat loss of the capacitor; the capacitor 7 is made of red copper, is wound on the outer diameter of the cable according to the outer diameter size of the cable grounding wire, and is tightly attached to the cable, so as to couple the grounding wire induced voltage, that is, the red copper is used to realize effective coupling of the cable grounding wire induced voltage due to its good conductivity and electromagnetic characteristics, and A5 reference voltage selects the grounding box as a reference point. The capacitor does not block the central gap of the shell, thereby avoiding affecting the coupling of the circulating current and the partial discharge.

[0081] In the embodiment, the current protector 2 comprises a parallel inductor l1 and a zinc oxide valve piece u1.

[0082] One end of the inductor l1 and the zinc oxide valve piece u1 is grounded, and the other end of the inductor l1 and the zinc oxide valve piece u1 is connected to the monitoring device 3.

[0083] In the embodiment, the current protector mainly comprises an inductor l1 and a zinc oxide valve piece u1, the size of the inductor l1 is designed according to the voltage grade of the primary cable, and the through-flow capacity is >100A; the integrated piece u1 (i.e., the zinc oxide valve piece) is configured according to the selected voltage grade of the cable.

Claims

1. A high-voltage cable sheath grounding box, characterized in that, Including the grounding box body; The grounding box body is equipped with a current protector and a monitoring device. The current protector and monitoring device are respectively located on each circuit of the cross-interconnected circuit, and the current protector and monitoring device are integrated in the grounding box; The current protectors are connected in series on the main grounding wire of the cross-interconnection of the cable sheaths; The monitoring device has partial discharge signal monitoring, magnetic field strength monitoring and voltage monitoring functions. One end of the monitoring device is connected to the current protector, and the other end of the monitoring device is grounded. The monitoring device is connected to the signal junction box of the grounding box body.

2. A high-voltage cable sheath grounding box according to claim 1, characterized in that, The monitoring device includes: a partial discharge signal monitoring module, a magnetic field strength monitoring module, a voltage monitoring module, and a connector; The partial discharge signal monitoring module, the magnetic field strength monitoring module, and the voltage monitoring module are respectively connected to the connector; The connectors are connected to the signal junction box and the current protector, respectively, and the connectors are grounded.

3. A high-voltage cable sheath grounding box according to claim 2, characterized in that, The partial discharge signal monitoring module is a partial discharge nickel magnetic core open-close type partial discharge sensor; The magnetic field strength monitoring module is a silicon steel sheet openable circulating current sensor; The voltage monitoring module is a capacitive sensing sheath voltage sensor.

4. A high-voltage cable sheath grounding box according to claim 3, characterized in that, The partial discharge nickel magnetic core open-close type partial discharge sensor includes a resistor, a nickel magnetic core, a first coil, and a capacitor; The resistor is located between the first coil and one end of the capacitor; The first coil is wound on one side of a nickel magnetic core. One end of the first coil is connected to a resistor, and the other end of the first coil is connected to the other end of a capacitor.

5. A high-voltage cable sheath grounding box according to claim 4, characterized in that, The number of turns of the first coil is determined by the properties of the nickel magnetic core.

6. A high-voltage cable sheath grounding box according to claim 4, characterized in that, The first coil is a high-temperature wire.

7. A high-voltage cable sheath grounding box according to claim 3, characterized in that, The silicon steel sheet opening and closing circulating current sensor includes a silicon steel sheet and a second coil; The second coil is wound around both sides of the silicon steel sheet, and the two ends of the second coil are connected to plugs.

8. A high-voltage cable sheath grounding box according to claim 7, characterized in that, The ratio of coils wound on both sides of the silicon steel sheet is 1000:

1.

9. A high-voltage cable sheath grounding box according to claim 3, characterized in that, The capacitor is made of copper.

10. A high-voltage cable sheath grounding box according to claim 1, characterized in that, The current protector includes a parallel inductor and a zinc oxide valve plate; One end of the inductor and the zinc oxide valve plate are grounded, and the other end of the inductor and the zinc oxide valve plate are connected to the monitoring device.

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