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CN-121484721-B - High-reliability ring main unit

CN121484721BCN 121484721 BCN121484721 BCN 121484721BCN-121484721-B

Abstract

The invention provides a high-reliability ring main unit, which comprises an air box, a cable chamber and a mechanism chamber, wherein a vacuum arc extinguishing chamber, a moving contact assembly, an upper fixed contact, a lower fixed contact and a grounding module are arranged in the air box, the upper fixed contact and the lower fixed contact are selectively connected with the moving contact assembly, the moving contact assembly comprises a moving contact body, a high-temperature-resistant contact insert arranged on the moving contact body, a pressure regulating spring for providing contact pressure for the moving contact body, and a high-temperature-resistant heat insulation gasket arranged between the moving contact body and the pressure regulating spring, the grounding module is hermetically arranged on the inner wall of the air box and is provided with a conductive overlap surface respectively connected with an internal circuit of the cabinet and an external circuit of the cabinet, and the cable chamber comprises a side plate assembly, an impact-resistant door plate assembly and a partition plate structure for separating the cable chamber from the mechanism chamber. The invention relates to the technical field of ring main units, in particular to the field of intelligent power grids and high-voltage power transmission and distribution equipment.

Inventors

  • ZHONG JUNJIE
  • YANG XIANLIN
  • OU DENGCAI
  • SONG LUYU
  • ZHANG WEI
  • DENG DONG
  • YAO GUANG
  • XU YONGJUN
  • HAN YU
  • ZENG GUOHUI
  • ZENG RONGHUA
  • WEI CHUNXIAO

Assignees

  • 长园电力技术有限公司

Dates

Publication Date
20260512
Application Date
20260107

Claims (9)

  1. 1. The high-reliability ring main unit comprises an air box (1), a cable chamber (2) and a mechanism chamber (3), and is characterized in that a vacuum arc extinguishing chamber (11), a moving contact assembly (12), an upper fixed contact (13) and a lower fixed contact (14) which are selectively connected with the moving contact assembly (12) and a grounding module (15) are arranged in the air box (1), the moving contact assembly (12) comprises a moving contact body (121), a high-temperature-resistant contact insert (122) arranged on the moving contact body (121), a pressure regulating spring (123) for providing contact pressure for the moving contact body (121) and a high-temperature-resistant heat insulation gasket (124) arranged between the moving contact body (121) and the pressure regulating spring (123), the grounding module (15) is hermetically arranged on the inner wall of the air box (1) and is provided with a conductive lap joint surface (151) which is respectively connected with a grounding loop in the cabinet and a grounding loop, the cable chamber (2) comprises a side plate assembly (21), an impact-resistant assembly (22) and a middle plate (21) and a partition plate (21) which separates the cable chamber (2) from the mechanism chamber (3) and the mechanism chamber (23) to form a middle plate (212) from the side plate (21) to the outside in turn, the partition plate structure (23) is provided with a pressure release channel (231), and the impact-resistant door plate assembly (22) comprises an outer door plate (221), a first air layer (222), a first high-temperature-resistant plate (223), a second air layer (224) and an inner metal plate (225) which are sequentially arranged from outside to inside, so as to form a systematic internal arc protection system; A mechanism chamber bottom bracket (25) which is integrally designed is arranged between the cable chamber (2) and the mechanism chamber (3), and a top high temperature resistant plate (251) and a positive high temperature resistant plate (252) are arranged on one side of the mechanism chamber bottom bracket (25) facing the cable chamber (2); The anti-impact door plate assembly (22) is arranged on one side, close to the mechanism chamber (3), of the cable chamber (2), a reinforcing rib (226) is arranged on the inner side of the outer door plate (221), the first high-temperature-resistant plate (223) is arranged on the reinforcing rib (226) to form a first air layer (222), the inner metal plate (225) is arranged on the first high-temperature-resistant plate (223) through a heightening mounting piece (227) to form a second air layer (224), side high-temperature-resistant plates (26) are arranged on the inner sides of the left side and the right side of the anti-impact door plate assembly (22) in the cable chamber (2), the edges of the left side and the right side of the inner metal plate (225) are buckled on the side high-temperature-resistant plates (26), and the upper end edge of the inner metal plate (225) is buckled on one side, facing the cable chamber (2), of the mechanism chamber bottom support (25).
  2. 2. The high-reliability ring main unit as claimed in claim 1, wherein the high-temperature-resistant contact insert (122) on the moving contact body (121) is a copper-tungsten alloy insert (1221), a tungsten alloy insert (141) is arranged at the closing end of the lower fixed contact (14), and the copper-tungsten alloy insert (1221) is in face-to-face lap joint with the tungsten alloy insert (141) during closing.
  3. 3. The high-reliability ring main unit according to claim 2, wherein the movable contact assembly (12) is provided with at least four copper tungsten alloy inserts (1221), and the total closing contact area of the four copper tungsten alloy inserts (1221) during closing is not less than 6 square centimeters.
  4. 4. The high-reliability ring main unit according to claim 1, wherein the pressure regulating spring (123) is made of spring steel added with zirconium element, and the high-temperature-resistant heat insulation gasket (124) is a mica gasket.
  5. 5. The high-reliability ring main unit according to claim 1, wherein the installation surface of the grounding module (15) is provided with a sealing rubber ring (152), the conductive part of the grounding module (15) is a cuboid conductor with a cross-sectional area of 3.4 square centimeters, the two ends of the cuboid conductor form the conductive overlapping surfaces (151), and the distance between the two conductive overlapping surfaces (151) is 2.3 centimeters.
  6. 6. The high-reliability ring main unit according to claim 1, wherein the outer side plate (211) has a portion protruding toward the inside of the cable chamber (2), the intermediate layer (212) is an air layer formed between the outer side plate (211) and the high-temperature resistant plate (213), and the reinforcing plate (214) is attached to the inner side surface of the high-temperature resistant plate (213).
  7. 7. The high-reliability ring main unit according to claim 1, wherein a gap between the inner metal plate (225) and the side high-temperature resistant plate (26) is smaller than 0.2 cm, and a gap between the inner metal plate (225) and the mechanism chamber base (25) is smaller than 0.2 cm.
  8. 8. The high-reliability ring main unit according to claim 1, wherein the partition plate structure (23) comprises a middle partition plate (232) and a rear bottom sealing plate (233), the pressure release channel (231) is a pressure release hole (2311) formed in the rear bottom sealing plate (233), and the pressure release plate (2312) is installed on the pressure release hole (2311).
  9. 9. The high-reliability ring main unit according to claim 8, wherein a bowl-shaped protection plate (24) protruding from the inside to the outside is arranged on the inner rear side of the cable chamber (2), and the bowl-shaped protection plate (24) is tightly fixed with a rear frame of the cable chamber (2).

Description

High-reliability ring main unit Technical Field The invention relates to the technical field of ring main units, in particular to a high-reliability ring main unit, which belongs to the field of intelligent power grids and high-voltage power transmission and distribution equipment. Background With the continuous expansion of the power distribution network scale and the large-scale access of new energy power generation equipment, the short-circuit current level of the power grid is continuously increased, and higher requirements are put on the short-circuit tolerance and fault protection capability of power distribution equipment such as a ring main unit, and therefore, various improved schemes aiming at improving the reliability of the ring main unit have appeared in the prior art, such as simplifying the structure by optimizing the access mode of an arc extinguishing chamber, adding protection plates in the cabinet to enhance the mechanical strength, or adopting arc ablation resistant contact materials to prolong the service life. However, the existing improvement scheme focuses on optimization of single components or local functions, and systematic defects still exist when high-level short-circuit current and internal arc faults are handled, on one hand, the traditional contact system is easily affected by electric repulsive force (Hall force) to generate vibration and local overheating under the condition of high peak short-circuit current, fusion welding risks exist, and a pressure regulating mechanism of the traditional contact system can possibly fail at high temperature, on the other hand, the conventional grounding circuit design can cause high connection point resistance and overheat fusing hidden trouble under fault current, and in addition, the traditional protection structure of a cable chamber is mainly subjected to impact and ablation passively, lacks systematic design for actively conducting arc energy, is difficult to effectively inhibit explosive damage in a very short time, and thus threatens the integrity of equipment and personnel safety. Particularly, under the background that the current intelligent power grid is rapidly built, new energy is connected in a large scale and a high-voltage power transmission system with the voltage higher than 750 kilovolts is continuously developed, the short-circuit capacity of the power grid is greatly increased, and unprecedented challenges are presented for the tolerance capability and the active protection performance of power distribution equipment such as a ring main unit and the like under extreme working conditions. The local optimization scheme of the traditional ring main unit is difficult to meet the strict requirements of a large-scale power grid safety guarantee and defense system on key equipment, such as high reliability, long service life and maintenance free. Accordingly, the inventor has demanded a highly reliable ring main unit to solve the above-mentioned problems. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a high-reliability ring main unit, and aims to solve the systematic technical problems that in the prior art, the ring main unit is easy to melt and weld unstably, the reliability of a grounding loop is insufficient, and a cable chamber lacks an internal arc protection system for active dredging, so that high tolerance and operation safety of equipment are difficult to cooperatively guarantee under the working condition of high short-circuit current. The high-reliability ring main unit comprises an air box, a cable chamber and a mechanism chamber, wherein a vacuum arc extinguishing chamber, a moving contact component, an upper fixed contact, a lower fixed contact and a grounding module are arranged in the air box, the upper fixed contact and the lower fixed contact are selectively connected with the moving contact component, the moving contact component comprises a moving contact body, a high-temperature-resistant contact insert arranged on the moving contact body, a pressure regulating spring for providing contact pressure for the moving contact body, and a high-temperature-resistant heat insulation gasket arranged between the moving contact body and the pressure regulating spring, the grounding module is hermetically arranged on the inner wall of the air box and is provided with a conductive lap joint surface for respectively connecting a grounding loop in the air box with a grounding loop outside the cabinet, the cable chamber comprises a side plate component, an impact-resistant door plate component and a partition plate structure for separating the cable chamber from the mechanism chamber, the side plate component comprises an outer side plate, an intermediate layer for forming an air gap, a high-temperature-resistant plate and a reinforcing plate, the partition plate is provided with an impact-resistant channel, the door plate comprises a first air-resistant layer, an inner-pressur