Grounding protection structure of cable insulation on-line monitoring system

Abstract

The utility model discloses a grounding protection structure of a cable insulation on-line monitoring system, which comprises two steel beams, a zero sequence current transformer is arranged above the two steel beams, a cable penetrates through the center of the zero sequence current transformer, a grounding wire is arranged on the surface of the cable, and the grounding wire is connected with the zero sequence current transformer. The grounding wire penetrates through the interior of the zero sequence current transformer, penetrates through the space between the two steel beams and extends to the position below the steel beams, U-shaped clamping plates are movably installed on the outer surfaces of the steel beams, and semicircular clamping rings are rotatably installed on the surfaces of the U-shaped clamping plates. According to the utility model, the grounding wire passes through the lower part from the upper part of the zero sequence current transformer and is fixed and protected through the half clamping ring, so that the situations that the leakage transformer cannot monitor a current signal and a relay protection device is rejected to operate and mistakenly operates due to the fact that the grounding wire is in contact with a steel beam are avoided; effective monitoring and evaluation of the insulation state of the power cable are realized.

Description

Technical Field

[0001] The utility model relates to the technical field of cable insulation monitoring, in particular to a grounding protection structure of a cable insulation online monitoring system. Background Art

[0002] The cable insulation online monitoring system is based on the characteristics of the three-phase cable in one sheath, and the partial discharge signal A, B, C three-phase partial discharge waveform of the cable outer sheath grounding wire. The judgment of whether the cable has partial discharge defects is highly correlated with the voltage waveform of each phase. Through the phase conversion algorithm, it can be judged whether there is partial discharge phenomenon in the cable;

[0003] The leakage current sensor and HFCT partial discharge sensor of the current cable insulation online monitoring system are installed on the exposed grounding wire of the cable on the load side of the 6Kv switch cabinet, and the exposed grounding wire has no insulating material sheath. When current flows through the cable core, an induced potential is generated on the metal sheath. When the sheath is open, the three-phase is unbalanced, the line has overvoltage, or a short circuit fault occurs, the induced potential is greater, causing the insulation of the cable outer sheath to break down, and the leakage current of the exposed grounding wire of the cable sheath increases accordingly. At this time, the monitoring signal cannot be effectively transmitted.

[0004] The grounding wire of the existing cable insulation online monitoring system usually passes through the bottom of the zero-sequence current transformer and then is directly laid on the metal casing. As a result, the leakage transformer on the exposed grounding wire cannot detect the current signal and the relay protection device refuses to operate or malfunctions. Therefore, it does not meet the existing needs. We propose a grounding protection structure for the cable insulation online monitoring system. Utility Model Content

[0005] The purpose of the utility model is to provide a grounding protection structure of a cable insulation online monitoring system to solve the problem that the grounding wire of the cable insulation online monitoring system proposed in the above background technology usually passes through the bottom of the zero-sequence current transformer and then is directly laid on the metal casing, causing the leakage transformer on the exposed grounding wire to fail to monitor the current signal and the relay protection device to refuse to operate or malfunction.

[0006] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a grounding protection structure of a cable insulation online monitoring system, comprising a steel beam, a zero-sequence current transformer is arranged above two of the steel beams, a cable is passed through the center of the zero-sequence current transformer, a grounding wire is arranged on the surface of the cable, the grounding wire passes through the interior of the zero-sequence current transformer and passes between the two steel beams and extends to the bottom of the steel beam, a U-shaped clamping plate is movably installed on the outer surface of the steel beam, and a semicircular clamping ring is rotatably installed on the surface of the U-shaped clamping plate.

[0007] Preferably, a rotating rod is fixedly installed on the outer side of the semicircular clamping ring, and the rotating rod is rotatably inserted into the interior of the U-shaped clamping plate. The inner surface of the semicircular clamping ring is provided with a spring groove, and a movable rod is slidably installed inside the spring groove. A compression spring is movably installed between the movable rod and the inside of the spring groove, and a semi-clamping ring is fixedly installed on the outer end of the movable rod, and the grounding wire movably passes through the interior of the semi-clamping ring.

[0008] Preferably, two positioning plates are provided on the outer surface of the semi-clamping ring, and two positioning grooves are fixedly installed on the outer surface of the semi-clamping ring, and the positioning grooves are slidably inserted into the interior of the positioning plates.

[0009] Preferably, three wire ends are provided at the top of the cable, and two assembly plates are fixedly mounted on the outer surface of the zero-sequence current transformer.

[0010] Preferably, a leakage current transformer and a HFCT partial discharge sensor are provided below the steel beam, the grounding wire runs through the leakage current transformer and the HFCT partial discharge sensor, and the bottom end of the grounding wire is connected to the ground.

[0011] Preferably, the semi-clamping ring is made of rubber.

[0012] Compared with the prior art, the beneficial effects of the utility model are:

[0013] 1. The utility model passes the grounding wire from the top of the zero-sequence current transformer through the bottom, and fixes and protects it through a semi-clamping ring, so as to avoid the leakage transformer failing to detect the current signal and the relay protection device refusing to operate or malfunctioning due to the grounding wire contacting the steel beam, thereby realizing effective monitoring and evaluation of the insulation state of the power cable;

[0014] 2. The utility model uses the cooperation of the semicircular clamping ring and the semi-clamping ring to clamp the grounding wire when the device is in use, thereby fixing the position of the grounding wire and preventing the grounding wire from contacting the steel beam, thereby preventing the grounding wire from being grounded prematurely and affecting the monitoring of the leakage current transformer and the HFCT partial discharge sensor;

[0015] 3. The utility model cooperates with the compression spring and the half clamping ring so that the device can adjust the distance between the two half clamping rings through the compression spring, and then can adapt to different sizes of grounding wires for clamping, which is convenient for the use of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0017] Figure 2 It is a schematic diagram of the half-section structure of the utility model as a whole;

[0018] Figure 3 It is a cross-sectional side view of the position of the semicircular snap-in ring of the utility model;

[0019] Figure 4 For this utility model Figure 3 Schematic diagram of the local structure of part A;

[0020] Figure 5 It is a partial structural schematic diagram of the semi-clamping ring of the utility model.

[0021] In the figure: 1. steel beam; 2. zero-sequence current transformer; 3. cable; 4. wire end; 5. assembly plate; 6. grounding wire; 7. leakage current transformer; 8. HFCT partial discharge sensor; 9. U-shaped clamping plate; 10. semicircular clamping ring; 11. rotating rod; 12. spring groove; 13. compression spring; 14. movable rod; 15. semi-clamping ring; 16. positioning plate; 17. positioning groove. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0023] See also Figures 1 to 5 The utility model provides an embodiment: a grounding protection structure of a cable insulation online monitoring system, including a steel beam 1, a zero-sequence current transformer 2 is arranged above two steel beams 1, a cable 3 is passed through the center of the zero-sequence current transformer 2, a grounding wire 6 is arranged on the surface of the cable 3, the grounding wire 6 passes through the inside of the zero-sequence current transformer 2 and passes between the two steel beams 1, and extends to the lower position of the steel beam 1, and a U-shaped clamping plate 9 is movably installed on the outer surface of the steel beam 1, and a semi-circular clamping ring 10 is rotatably installed on the surface of the U-shaped clamping plate 9. Through the cooperation of the semi-circular clamping ring 10 and the semi-clamping ring 15, when the device is in use, the semi-circular clamping ring 10 and the semi-clamping ring 15 can be used to clamp the grounding wire 6, thereby fixing the position of the grounding wire 6, avoiding the grounding wire 6 from contacting the steel beam 1, and avoiding the grounding wire 6 from being grounded prematurely to affect the monitoring of the leakage current transformer 7 and the HFCT partial discharge sensor 8.

[0024] The outer side of the semicircular clamping ring 10 is fixedly installed with a rotating rod 11, and the rotating rod 11 is rotated and inserted into the inside of the U-shaped clamping plate 9. The inner surface of the semicircular clamping ring 10 is provided with a spring groove 12, and the inside of the spring groove 12 is slidably installed with a movable rod 14. A compression spring 13 is movably installed between the movable rod 14 and the inside of the spring groove 12. The outer end of the movable rod 14 is fixedly installed with a semi-clamping ring 15, and the grounding wire 6 movably passes through the inside of the semi-clamping ring 15. The material of the semi-clamping ring 15 is rubber. Through the cooperation of the compression spring 13 and the semi-clamping ring 15, the device can adjust the distance between the two semi-clamping rings 15 through the compression spring 13, and then can adapt to different sizes of grounding wires 6 for clamping, which is convenient for the use of the device.

[0025] Two positioning plates 16 are provided on the outer surface of the half clamping ring 15 . Two positioning grooves 17 are fixedly installed on the outer surface of the half clamping ring 15 . The positioning grooves 17 are slidably inserted into the interior of the positioning plates 16 .

[0026] Three wire ends 4 are arranged at the top of the cable 3 , and two assembly plates 5 are fixedly mounted on the outer surface of the zero-sequence current transformer 2 .

[0027] A leakage current transformer 7 and a HFCT partial discharge sensor 8 are provided below the steel beam 1, and a grounding wire 6 runs through the leakage current transformer 7 and the HFCT partial discharge sensor 8, and the bottom end of the grounding wire 6 is connected to the ground. By passing the grounding wire 6 from the top of the zero-sequence current transformer through the bottom and fixing and protecting it with a semi-clamping ring 15, it is prevented that the leakage transformer cannot detect the current signal and the relay protection device refuses to operate or malfunctions due to the grounding wire 6 contacting the steel beam 1, thereby achieving effective monitoring and evaluation of the insulation state of the power cable.

[0028] When the grounding protection structure of the cable insulation online monitoring system is in use, the cable 3 can be first passed through between the steel beam 1 and the zero-sequence current transformer 2, and the grounding wire 6 can be passed from the top of the zero-sequence current transformer 2 to the bottom of the steel beam 1. At this time, one of the U-shaped clamping plates 9 is installed on the surface of the steel beam 1, so that the semicircular clamping ring 10 is aligned with the position of the grounding wire 6, and the semicircular clamping ring 10 is rotated by the rotating rod 11 so that the angle of the semicircular clamping ring 10 corresponds to the angle of the grounding wire 6. At this time, another U-shaped clamping plate 9 is installed on the surface of another steel beam 1, and the two half clamping rings 15 are pressed inwardly so that the half clamping rings 15 are retracted to the inner side of the spring groove 12. The half clamping ring 15 is then rotated to keep the angles of the two half clamping rings 10 consistent. At this time, the half clamping ring 15 is released, and the half clamping ring 15 is ejected by the elastic potential energy of the compression spring 13 to clamp the grounding wire 6 in the middle of the half clamping ring 10. At the same time, the positioning groove 17 is inserted into the interior of the positioning plate 16, so that the two half clamping rings 15 are laterally fixed. At this time, due to the blocking of the other half clamping ring 15 by the positioning groove 17, the two half clamping rings 15 cannot be separated laterally, thereby improving the stability of the device. Then the grounding wire 6 is passed through the leakage current transformer 7 and the HFCT partial discharge sensor 8 in sequence and connected to the ground.

[0029] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

Claims

1. A grounding protection structure of an online cable insulation monitoring system, comprising a steel beam (1), characterized in that: A zero-sequence current transformer (2) is arranged above the two steel beams (1), a cable (3) passes through the center of the zero-sequence current transformer (2), a grounding wire (6) is arranged on the surface of the cable (3), the grounding wire (6) passes through the interior of the zero-sequence current transformer (2) and passes between the two steel beams (1), and extends to the position below the steel beam (1), the outer surface of the steel beam (1) is movably mounted with a U-shaped clamping plate (9), and the surface of the U-shaped clamping plate (9) is rotatably mounted with a semicircular clamping ring (10).

2. The grounding protection structure of the cable insulation online monitoring system according to claim 1 is characterized by: A rotating rod (11) is fixedly installed on the outer side of the semicircular clamping ring (10), and the rotating rod (11) is rotatably inserted into the interior of the U-shaped clamping plate (9). The inner surface of the semicircular clamping ring (10) is provided with a spring groove (12), and a movable rod (14) is slidably installed inside the spring groove (12). A compression spring (13) is movably installed between the movable rod (14) and the interior of the spring groove (12), and a semi-clamping ring (15) is fixedly installed on the outer end of the movable rod (14), and the grounding wire (6) movably passes through the interior of the semi-clamping ring (15).

3. The grounding protection structure of the cable insulation online monitoring system according to claim 2 is characterized in that: The outer surface of the semi-clamping ring (15) is provided with two positioning plates (16), and the outer surface of the semi-clamping ring (15) is fixedly provided with two positioning grooves (17), and the positioning grooves (17) are slidably inserted into the interior of the positioning plates (16).

4. The grounding protection structure of the cable insulation online monitoring system according to claim 1 is characterized in that: The top of the cable (3) is provided with three wire ends (4), and the outer surface of the zero-sequence current transformer (2) is fixedly mounted with two assembly plates (5).

5. The grounding protection structure of the cable insulation online monitoring system according to claim 1 is characterized in that: A leakage current transformer (7) and an HFCT partial discharge sensor (8) are provided below the steel beam (1); the grounding wire (6) movably penetrates the inside of the leakage current transformer (7) and the HFCT partial discharge sensor (8); and the bottom end of the grounding wire (6) is connected to the ground.

6. The grounding protection structure of the cable insulation online monitoring system according to claim 2, characterized in that: The semi-clamping ring (15) is made of rubber.

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