WO2015103979A1

WO2015103979A1 - Outdoor low-voltage fuse disconnector

Info

Publication number: WO2015103979A1
Application number: PCT/CN2015/070275
Authority: WO
Inventors: Yujun Wang; Xing Liu; Bo Chen
Original assignee: S&C Electric (China) Company Ltd.
Priority date: 2014-01-07
Filing date: 2015-01-07
Publication date: 2015-07-16
Also published as: CN103715003A

Abstract

An outdoor low-voltage fuse disconnector comprises terminals (11,12), a fuse body (2), stationary contacts (31, 32), an operating handle (6), insulators(19, 29), and a bottom plate (10). The fuse body (2) is mounted in a fuse body carrier(4).The bottom plate(10) is fixed with the left terminal (11), a rotation bracket (13) and the left stationary contact(31) via the left insulator (19), and the bottom plate (10) is fixed with the right terminal (12) and the right stationary contact (32) via the right insulator (29). The fuse body (2) is a contact fuse body, a metal grid arc extinguishing chamber (5) is provided below the right stationary contact (32), and a closing holding mechanism (8) is provided to hold the operating handle (6) in a closing position. When the fuse body carrier (4) is pulled down, the fuse body (2) will be pulled out along as a moving contact of the disconnector, forming an observable visible air isolation gap at the supply side and the load side. The disconnector is low in temperature rise and long in service life, strong in short-circuit current limiting capacity and breaking capacity high in reliability, easy to match, safe in isolation, convenient to operate and maintain, safe and reliable in outdoor operation and economical and effective.

Description

Outdoor Low-voltage Fuse Disconnector

Technical Field

This utility model relates to a disconnector for a low-voltage power distribution system, particularly to an outdoor low-voltage fuse disconnector.

Background Art

Nowadays, in many low-voltage power distribution networks, alow-voltage fuse link isolator is used for the protection and isolation of a pole-mounted distribution transformer’s low-voltage side line. But such an isolator cannot switch the load current of the circuit, and the low-voltage fuse link is a sheet of copper with a narrow cross section, for which there is no corresponding product standards, and its protective characteristic curve and breaking performance are unstable, which cannot guarantee a safe and reliable operation, and its long-term operating temperature is very high, which causes the temperature of adjacent contacts to rise when the heat is conducted to them, so that oxidation of its surface increases, ultimately increasing the contact resistance and ablating the contacts. Meanwhile, in the actual operation, it is often operated with load, intensifying the burning of the surfaces of the stationary and moving contacts, which causes the contact resistance to increase sharply after closing, leading to an ultra-high temperature rise and the burning of the equipment.

In other low-voltage power distribution networks, an outdoor low-voltage power distribution box is used for the protection of the pole-mounted distribution transformer’s low-voltage side line, wherein an indoor plastic-case-type interrupter is installed in the power distribution box, and itis hung on poles or at the bottom of the distribution transformer. Many problems exist: the problems such asthe corrosion of the case, the aging of the equipmentand vulnerability to external forces are difficult to solve, no visible safe isolation gap is available in the open position of the switch, which is unable to provide line staff with safe isolation protection.

The current low-voltage fuse link is an open bare piece of thin copper with no other means for arc extinguishing, when fault current flows by, the arc burns freely in the air, producing ionized gas and metal vapors that can cause personal injury, fire, explosion and other hazards, and causing heating of adjacent metal conductor； an uncontrolled arc causes short-circuit in other circuits, resulting in line outage which causes huge economic losses to the production and living. The open fuse link has no measures for current limiting, energy is spread into the air viathe arc, and the arc extincts as the current naturally crosses zero； long arcing time and large electric power caused by the peak short-circuit current has great impact on the heating and forced deformation of the lines and equipment. There is no corresponding product standards for low-voltage fuse links, thus its time-current characteristic curve is not definitely regulated, and the products of different manufacturers vary widely, which leads to no coordinated protection between the upper and the lower level. After one fuse link is blown and replaced, a new fuse link does not have the same characteristics as the original one, causing poor interchangeability. The isolator has no arc extinguishing device, and cannot operate with load. Indoor plastic-case-type interrupter is installed in the outdoor power distribution box, and operates for a long period of time under conditions of high temperature, low temperature, or a hot-and-humid circulating environment, thus its plastic case and the frame are easy to age, deform, until the interrupter can no longer operate, and loses its function； the case corrodes, resulting in rain water getting into the interrupter, leading to short circuit, and causing malfunction.

Disclosure of the Invention

On the basis of the above-mentioned drawbacks, this utility model provides an outdoor low-voltage fuse disconnector, which solves the problems in prior art that the product has a high temperature rise and a short life, meanwhile the disconnector has a strong capability to limit the short-circuit current and carry out a sectionalization, and it is highly reliable, easy to coordinate with, safe to perform an isolation, convenient to operate and maintain, safe and reliable for outdoor operation, economical and effective.

An outdoor low-voltage fuse disconnector according to this utility model comprises a left terminal 11, a right terminal 12, a fuse body 2, a left stationary contact 31, a right stationary contact 32, an operating handle 6, a left insulator 19, a right insulator 29, and a bottom plate 10, wherein the fuse body 2 is mounted in a fuse body carrier 4, the operating handle 6 is riveted on the fuse carrier 4, and the disconnector is characterized in that the bottom plate 10 is fixed with the left terminal 11, a rotation bracket 13 and the left stationary contact 31 via the left insulator 19, and the bottom plate 10 is fixed with the right terminal 12 and the right stationary contact 32 via the right insulator 29, wherein the fuse body 2 is a contact fuse body with the contact silver-plated, a metal grid arc extinguishing chamber 5 is provided below the right stationary contact 32, and a closing holding mechanism 8 which holds the operating handle 6 in a closing position is provided between the right terminal 12 and the operating handle 6, when the fuse body carrier 4 is pulled down, the fuse body 2 will be pulled out along as a moving contact of the disconnector, forming an observable visible air isolation gap at the supply side and the load side. The contact is silver-plated, which can resist corrosion and is oflow contact resistance, and used for protection of the lines and equipment； an internal indicating device for indicating the blowout of the fuse body is optional； the arc extinguishing chamber uses metal grids to divide an arc into many segments, and the arc is extinguished stably and reliably through the aids of the restoring strength of the initial media depending on near cathode effect and the thermal conductivity of the metal grids； the closing holding mechanism holds the operating handle in the closing position, preventing any accidental opening, and providing the opening operation with the desired instant opening speed.

The fuse body is inserted into and fixed on the fuse body carrier, constituting the moving armof the disconnector. The left terminal and the right terminal are double-apertured flat terminals with the surfaces silver-plated, providing the clamp connection of the equipment with a large contact surface to ensure a reliable connection. The left stationary contact and the right stationary contact are silver-plated with multifinger contact, thus the contact resistance is small and the temperature rise of the contact is low, ensuring that the contact spring will not be annealed and slack, so that it is anti-aging and can significantly improve operation safety, the fuse body carrier is glass-fiber-reinforced engineering plastic with strong anti-aging properties and high mechanical strength, the left insulator 1 and the right insulator are of silicon rubber material, with high mechanical strength, hydrophobicity, and flame retarding, anti-aging and anti-UV properties, the operating handle is formed by curving stainless steel material, thus it is ofvery high strength and stiffness, and a pull-hole is provided at its tail to improve the visibility and operability, the bottom plate is made of thick steel plate with hot galvanizing treatment on the surface, thus it is not easily deformed and the installation and fixation are reliable, ensuring a safe and stable operation of the disconnector.

The disconnector solves the problems in prior art that the product has a high temperature rise and a short life, and can operate safely and reliably for decades； it has a strong capability to limit the short-circuit current, so as to protect the lines and equipment from the heat and the thermal shock caused by the fault current, thus to prolong its service life； it has a strong capability to perform a sectionalization, operating safely and silently to break a high short-circuit current quickly, without producing an external arc； it has high reliability, wherein the fuse body is sealed within a ceramic tube, avoiding influence from the external environment, when replaced with a new fuse body, the new fuse body ensures that the protection it provides restores to the initial level； the closing holding mechanism of the disconnector can prevent any accidental opening and dropout of the disconnector by itself, and can provide an opening speed not depending on the operator； its compact structure offers a fault protection, a load switching and a safe isolation with low cost； standard characteristics of the fuse body and a high level current-limiting ensure an effective coordination between the fuse body and other protective equipment, and can also ensure a coordinated protection after the replacement of the fuse body； the plastic case of the metal grid arc extinguishing chamber can withstand the pressure generated by the heat of the arc and absorb the heat of the arc, when the fuse body carrier 4 is pulled down, the fuse body will be pulled out along as a moving contact of the disconnector, forming an observable visible air isolation gap at the supply side and the load side, and providing safe isolation measures for line maintenance staff； its operation can be maintained conveniently, since the product is designed fully in accordance with the outdoor rain, ultraviolet radiation and other operation environments, it is mounted directly on the cross arm of the pole, and does not require any protective cover. The outdoor contact fuse body, the metal grid arc extinguishing chamber, the silicon rubber insulators, as well as the design of the contact structure, and the metal material with anticorrosion treatment, ensure the overall safety and reliability of the product.

Description of Drawings

Figure 1 is a schematic diagram of the disconnector.

Embodiments

Below the utility model is further described referring to the drawing.

An outdoor low-voltage fuse disconnector according to this utility model comprises a left terminal 11, a right terminal 12, a fuse body 2, a left stationary contact 31, a right stationary contact 32, an operating handle 6, a left insulator 19, a right insulator 29, and a bottom plate 10, wherein the fuse body 2 is mounted in a fuse body carrier 4, the operating handle 6 is riveted on the fuse body carrier 4, and the disconnector is characterized in that the bottom plate 10 is fixed with the left terminal 11, a rotation bracket 13 and the left stationary contact 31 via the left insulator 19, and the bottom plate 10 is fixed with the right terminal 12 and the right stationary contact 32 via the right insulator 29, wherein the fuse body 2 for protection of the lines and equipment is a contact fuse body with the contact silver-plated, which can resist corrosion and is of low contact resistance, and an internal indicating device for indicating the blowout of the fuse body is optional, ametal grid arc extinguishing chamber 5 is provided below the right stationary contact 32, wherein the arc extinguishing chamber uses metal grids to divide the arc into a number of segments, and the arc is extinguished stably and reliably through the aids of the restoring strength of the initial media depending on near cathode effect and the thermal conductivity of the metal grids, a closing holding mechanism 8 is provided between the right terminal 12 and the operating handle 6, the closing holding mechanism 8 holds the operating handle 6 in a closing position, preventing any accidental opening, and provides the opening operation with the desired instant opening speed.

The fuse body 2 is inserted into and fixed on the fuse body carrier 4, constituting the moving arm of the disconnector. The left terminal 11 and the right terminal 12 are double-apertured flat terminals with the surfaces silver-plated, providing the clamp connection of the equipment with a large contact surface to ensure a reliable connection. The left stationary contact 31 and the right stationary contact 32 are silver-plated with multifinger contact, thus the contact resistance is small and the temperature rise of the contact is low, ensuring that the contact spring will not be annealed and slack, so that it is anti-aging and can significantly improve operation safety, the fuse body carrier 4 is glass-fiber-reinforced engineering plastic with strong anti-aging properties and high mechanical strength, the left insulator 19 and the right insulator 29 are of silicon rubber material, with high mechanical strength, hydrophobicity, and flame retarding, anti-aging and anti-UV properties, the operating handle 6 is formed by curving stainless steel material, thus it is of very high strength and stiffness, and a pull-hole 7 is provided at its tail to improve the visibility and operability, the bottom plate 10 is made of thick steel plate with hot galvanizing treatment on the surface, thus it is not easily deformed and the installation and fixation are reliable, ensuring a safe and stable operation of the disconnector.

Specifically, when in use, the hook of a hook rod is put into the pull-hole 7 of the operating handle 6 and pulled down, thus the moving arm (constituted by the fuse body 2 and the fuse body carrier 4) is pulled out from the closing holding mechanism, at this point, the metal grid arc extinguishing chamber 5 cuts offthe operating current, and forms a visible gap between the left stationary contact 31 and the right stationary contact 32, to isolate the supply. When to replace the fuse body 2, the hook of the hook rod is put into the hole of the moving arm near the rotation bracket 13, then the moving arm can be removed by lifting the hook up and moving it outwards, and then the fuse body 2 can be removed by hand from the slot of the fuse body carrier 4 on the removed moving arm, after that a new fuse body 2 can be mounted； after mounting, the moving arm is remounted onto the rotation bracket 13, and the hook of the hook rod is put into the pull-hole 7 of the operating handle 6, then the moving arm is pushed up, when the closing position is reached, the moving arm is held by the closing holding mechanism, thus the installation is complete, when fault current occurs in the line, the fuse body 2 is blown and limits the short-circuit current, so as to protect the lines and equipment.

Based on the structure and working principle of the outdoor low-voltage fuse disconnector of this utility model as described above, a person having ordinary skill in the art would understand that this utility model is not limited to the above-mentioned specific embodiments, any modification and substitution by employing common knowledge in the art on the basis of this utility model shall fall within the protection scope of this utility model.

Claims

An outdoor low-voltage fuse disconnector comprising a left terminal (11) , a right terminal (12) , a fuse body (2) , a left stationary contact (31) , a right stationary contact (32) , an operating handle (6) , a left insulator (19) , a right insulator (29) , and a bottom plate (10) , wherein the fuse body (2) is mounted in a fuse body carrier (4) , the operating handle (6) is riveted on the fuse body carrier (4) , characterized in that the bottom plate (10) is fixed with the left terminal (11) , a rotation bracket (13) and the left stationary contact (31) via the left insulator (19) , and the bottom plate (10) is fixed with the right terminal (12) and the right stationary contact (32) via the right insulator (29) , wherein the fuse body (2) is a contact fuse body with the contact silver-plated, a metal grid arc extinguishing chamber (5) is provided below the right stationary contact (32) , and a closing holding mechanism (8) which holds the operating handle (6) in a closing position is provided between the right terminal (12) and the operating handle (6) , when the fuse body carrier (4) is pulled down, the fuse body (2) will be pulled out along as a moving contact of the disconnector, forming an observable visible air isolation gap at the supply side and the load side.
The outdoor low-voltage fuse disconnector according to claim 1, characterized in that the fuse body (2) is inserted into and fixed on the fuse body carrier (4) , constituting a moving arm of the disconnector.
The outdoor low-voltage fuse disconnector according to claim 1, characterized in that the left terminal (11) and the right terminal (12) are double-apertured flat terminals with the surfaces silver-plated.
The outdoor low-voltage fuse disconnector according to claim 1, characterized in that the left stationary contact (31) and the right stationary contact (32) are silver-plated with multifinger contact, the fuse body carrier (4) is glass-fiber-reinforced engineering plastic, the left insulator (19) and the right insulator (29) are of silicon rubber material.
The outdoor low-voltage fuse disconnector according to claim 1, characterized in that the operating handle (6) is formed by curving stainless steel material, and a pull-hole (7) is provided at its tail.