A new type of air-insulated cable joint casing structure for ring main unit

Abstract

The present invention proposes a novel air-insulated cable joint sleeve structure for a ring network cabinet, wherein the sleeve structure is an integrated sleeve comprising a grounding shielding net, a conductive rod, an insert, a cable air chamber, and a lightning arrester air chamber; the conductive rod is an integrated conductive rod in the shape of the letter F, one of the two horizontal branches having a first contact seat for connecting a cable in the cable air chamber at the end, and the other end having a second contact seat for connecting a lightning arrester in the lightning arrester air chamber at the end; the first contact seat and the second contact seat are both provided with high-voltage shielding rings, which are respectively used to make the electric field in the cable air chamber and the lightning arrester air chamber uniform, so that the cable air chamber and the lightning arrester air chamber form air insulation structures at the first contact seat and the second contact seat; the present invention replaces interface insulation with air insulation, which can solve the insulation problems caused by mechanical damage, insulation moisture, insulation medium aging, and poor manufacturing process under the existing interface insulation.

Description

Technical Field

[0001] The invention relates to the technical field of power supply and distribution system and medium voltage switch equipment, in particular to a novel air-insulated cable joint sleeve structure for a ring network cabinet. Background Art

[0002] In the application of power cables in power systems, cable joint failures account for 70% of cable failures. The European-style cable T-joints currently used on the market use insulating materials such as silicone rubber and EPDM rubber, and the lap joints use interface bonding, apply silicone grease to eliminate air gaps, and have high requirements for stress cones and T-head cone surfaces. Analysis of the causes of the problem can be roughly divided into the following categories: mechanical damage, insulation moisture, aging of the insulating medium, poor manufacturing process, etc., but analysis of the root causes of these problems found that they are all problems with interface insulation. Therefore, the development of a new type of non-interface insulation joint form can avoid the above problems. The solution described in the present invention is to design an integrated cable joint sleeve that uses air insulation instead of interface insulation epoxy casting. Summary of the invention

[0003] The present invention proposes a novel air-insulated cable joint sleeve structure for a ring network cabinet, which uses air insulation to replace interface insulation, and can solve the insulation problems caused by mechanical damage, insulation moisture, insulation medium aging, and poor manufacturing process in the existing interface insulation form.

[0004] The present invention adopts the following technical solutions.

[0005] A novel air-insulated cable joint sleeve structure for a ring main unit, the sleeve structure being an integrated sleeve comprising a grounding shielding net, a conductive rod, an insert, a cable air chamber, and a lightning arrester air chamber; the conductive rod being an integrated conductive rod in the shape of the letter F, one of its two horizontal branches having a first contact seat at the end thereof for connecting the cable in the cable air chamber, and the other end thereof having a second contact seat at the end thereof for connecting the lightning arrester in the lightning arrester air chamber; the first contact seat and the second contact seat are both provided with high-voltage shielding rings, which are respectively used to make the electric field in the cable air chamber and the lightning arrester air chamber uniform, so that the cable air chamber and the lightning arrester air chamber form air insulation structures at the first contact seat and the second contact seat.

[0006] The one-piece sleeve is an one-piece structure cast by epoxy material, and a metal layer for achieving full shielding of the accessible surface is sprayed on its surface.

[0007] The vertical branch of the integrated conductive rod in the shape of letter F is used to connect the copper busbar inside the gas box of the ring main unit.

[0008] The grounding shielding net is welded with grounding points along its circumferential direction for leading out test lines.

[0009] The capacitance of the grounding point of the grounded shield is matched to the charged display.

[0010] The first contact seat is a plug-in structure for plugging and unplugging a cable terminal; the second contact seat is a plug-in structure for plugging and unplugging a lightning arrester.

[0011] The vertical branch of the integrated conductive rod in the shape of the letter F is the rear part of the integrated sleeve, and is provided with a bracket fixed to the ring network cabinet.

[0012] The end of the vertical branch of the integrated conductive rod in the shape of the letter F is the fixed end of the integrated sleeve, which is fixed to the gas box with a flange. A semicircular protective baffle and an umbrella skirt are provided at the fixed end to increase the creepage distance and improve the insulation margin.

[0013] The ring main unit is a 10KV ring main unit; the inner side surface of the flange is provided with a groove for installing a sealing ring to achieve adhesion with the gas box surface and ensure air tightness.

[0014] The advantages of the present invention are:

[0015] 1. A cable joint sleeve structure for connecting a ring main unit with a cable is provided. The device has a simple structure, uses a plug-in joint instead of a copper terminal assembly structure, and has a simple assembly process.

[0016] 2. Use normal pressure sealed air insulation instead of interface insulation to effectively avoid interface air gap problems and eliminate silicone grease failure problems.

[0017] 3. The surface sprayed metal layer achieves full shielding of accessible surfaces, uniform electric field and reliable performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0019] Attached Figure 1 It is a cutaway schematic diagram of the present invention;

[0020] Attached Figure 2 It is a top view schematic diagram of the present invention;

[0021] Attached Figure 3 It is a schematic cross-sectional view of an integrated conductive rod in the shape of the letter F;

[0022] Attached Figure 4 It is a top view schematic diagram of the integrated conductive rod in the shape of the letter F;

[0023] Attached Figure 5 It is a schematic diagram of the ground shielding network;

[0024] Attached Figure 6 It is a top view schematic diagram of the ground shielding network;

[0025] Attached Figure 7This is a schematic diagram of the present invention when a cable terminal and a lightning arrester are plugged in;

[0026] In the figure: 1-fixed end; 2-M10 nut insert; 3-conductive rod; 4-grounding shielding net; 5-M8 insert;

[0027] 101 - lightning arrester air chamber; 102 - cable air chamber; 103 - second contact seat; 105 - high voltage shielding ring; 106 - first contact seat; 107 - grounding point; 108 - cable terminal; 109 - lightning arrester. DETAILED DESCRIPTION

[0028] As shown in the figure, a new type of air-insulated cable joint sleeve structure for a ring main unit is provided, wherein the sleeve structure is an integrated sleeve including a grounding shielding net 4, a conductive rod 3, an insert, a cable air chamber 102, and an arrester air chamber 101; the conductive rod is an integrated conductive rod in the shape of the letter F, and one of its two horizontal branches is provided at the end with a first contact seat 106 for connecting the cable in the cable air chamber, and the other end is provided with a second contact seat 103 for connecting the lightning arrester in the lightning arrester air chamber; the first contact seat and the second contact seat are both provided with high-voltage shielding rings, which are respectively used to make the electric field in the cable air chamber and the lightning arrester air chamber uniform, so that the cable air chamber and the lightning arrester air chamber form air insulation structures at the first contact seat and the second contact seat.

[0029] Inserts include M10 nut inserts and M8 inserts5.

[0030] The one-piece sleeve is an one-piece structure cast by epoxy material, and a metal layer for achieving full shielding of the accessible surface is sprayed on its surface.

[0031] The vertical branch of the integrated conductive rod in the shape of letter F is used to connect the copper busbar inside the gas box of the ring main unit.

[0032] The ground shielding net is welded with grounding points 107 along its circumferential direction for leading out test lines.

[0033] The capacitance of the grounding point of the grounded shield is matched to the charged display.

[0034] The first contact seat is a plug-in structure for plugging and unplugging the cable terminal 108 ; the second contact seat is a plug-in structure for plugging and unplugging the lightning arrester 109 .

[0035] The vertical branch of the integrated conductive rod in the shape of the letter F is the rear part of the integrated sleeve, and is provided with a bracket fixed to the ring network cabinet.

[0036] The end of the vertical branch of the integrated conductive rod in the shape of the letter F is the fixed end 1 of the integrated bushing, which is fixed to the gas box by a flange. A semicircular protective baffle and an umbrella skirt are provided at the fixed end to increase the creepage distance and improve the insulation margin.

[0037] The ring main unit is a 10KV ring main unit; the inner side surface of the flange is provided with a groove for installing a sealing ring to achieve adhesion with the gas box surface and ensure air tightness. Example

[0038] In this example, if Figure 1 As shown, a cable terminal connection with an air cavity, a lightning arrester connecting sleeve, a conductive copper rod (conductive rod 3) and a grounding shielding net 4, and a fixed threaded insert are cast as one through epoxy material 1, a high-voltage shielding ring is welded around the contact seat of the conductive copper rod (conductive rod 3), and the contact seat is used to insert the cable terminal and the lightning arrester. The high-voltage shielding ring makes the electric field in the sleeve cavity uniform, prevents partial discharge, prolongs the service life of the cable, and realizes air insulation instead of interface insulation; the grounding point of the grounding shielding net is welded in the circumferential direction of the shielding net, which is convenient for the test line to be led out;

[0039] Secondly, one end of the casing is equipped with an umbrella skirt and a protective baffle (semi-circular protective baffle). The metal layer is sprayed on the surface to achieve full shielding of the accessible surface and reliable grounding. One end is fixed to the air box through a flange, and the end is fixed to the copper rod (conductive rod 3). The air cavity and the cable terminal are assembled together to form a touchable, pluggable, fully insulated and fully sealed structure.

[0040] In this example, the air chambers of the cable air chamber and the lightning arrester air chamber include a metal shell; the metal shell is provided with an air vent; the air vent is provided with an exhalation valve that can filter moisture and impurities; the exhalation valve ensures pressure balance inside and outside the air chamber through air exchange.

[0041] The above structure is intended to illustrate the technical means of the present invention, but not to limit the technical scope of the present invention. Those skilled in the art can make obvious improvements to the present invention in combination with existing common knowledge, which all fall within the scope of protection of the present invention.

Claims

1. A new type of air-insulated cable joint sleeve structure for ring main unit, characterized in that: The bushing structure is an integrated bushing including a grounding shielding net, a conductive rod, an insert, a cable air chamber, and a lightning arrester air chamber; the conductive rod is an integrated conductive rod in the shape of the letter F, one of the two horizontal branches of which is provided with a first contact seat for connecting the cable in the cable air chamber at the end, and the other end is provided with a second contact seat for connecting the lightning arrester in the lightning arrester air chamber; the first contact seat and the second contact seat are both provided with high-voltage shielding rings, which are respectively used to make the electric field in the cable air chamber and the lightning arrester air chamber uniform, so that the cable air chamber and the lightning arrester air chamber form air insulation structures at the first contact seat and the second contact seat; The one-piece sleeve is an one-piece structure cast by epoxy material, and its surface is sprayed with a metal layer for achieving full shielding of the accessible surface; The surface of the one-piece sleeve is sprayed with a metal layer for a uniform electric field; The grounding shielding net is welded with grounding points along its circumference for leading out test lines; The first contact seat is a plug-in structure for plugging and unplugging the cable terminal; the second contact seat is a plug-in structure for plugging and unplugging the lightning arrester; The end of the vertical branch of the F-shaped integrated conductive rod is the fixed end of the integrated sleeve, which is fixed to the gas box by a flange. A semicircular protective baffle and an umbrella skirt are provided at the fixed end, and a metal layer for full shielding and reliable grounding of the accessible surface is sprayed on the surface; The ring main unit is a 10KV ring main unit; the inner side of the flange is provided with a groove for installing a sealing ring; The air chamber of the cable air chamber and the arrester air chamber comprises a metal shell; the metal shell is provided with an air vent; the air vent is provided with an exhalation valve capable of filtering moisture and impurities.

2. According to claim 1, a novel air-insulated cable joint sleeve structure for a ring main unit is characterized in that: The vertical branch of the integrated conductive rod in the shape of letter F is used to connect the copper busbar inside the gas box of the ring main unit.

3. According to the novel air-insulated cable joint sleeve structure for ring main unit in claim 1, it is characterized by: The capacitance of the grounding point of the grounded shield is matched to the charged display.

4. The novel air-insulated cable joint sleeve structure for ring main unit according to claim 1 is characterized in that: The vertical branch of the integrated conductive rod in the shape of the letter F is the rear part of the integrated sleeve, and is provided with a bracket fixed to the ring network cabinet.

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