RU224050U1 - ARC CHAMBER OF A HIGH-SPEED BREAKER - Google Patents

Abstract

The utility model relates to the field of electrical equipment engineering and can be used in a high-speed switch unit used both in electrical devices for general industrial purposes and in traction devices of electric trains. The arcing chamber contains a chamber mouth section, including horns and a hole formed by the above horns and configured to allow an electric arc to enter it, and a deion grid section, including deion grids with steel and insulating arc-resistant plates, an arc division horn and additional arc division horns. Moreover, the internal width of the chamber mouth section is 2-3 times less than the internal width of the deion grating section. The technical result is to reduce the size of the arc-extinguishing chamber of a high-speed circuit breaker while maintaining the efficiency of extinguishing the electric arc due to the rapid increase in arc resistance and large extraction of electric arc energy. 2 ill.

Description

The utility model relates to the field of electrical equipment engineering and can be used as part of a high-speed switch unit used both in electrical devices for general industrial purposes and in traction devices of electric trains.

In the prior art, an arc-extinguishing chamber is known (RU 2306629 C1, 09/20/2007) containing outer walls, between which arc-extinguishing horns are installed, deion gratings consisting of steel plates, between which there are air gaps, are installed at an angle to each other. Flame arresting grilles are installed along the deion gratings at the exit from the chamber. The outer walls of the arc-extinguishing chamber have holes in the area where the deion gratings are located.

The disadvantage of this device is the presence of a hole for the removal of ionized gases. Since the grids do not contain flame arrester plates or other solutions that prevent the arc from escaping, the arc will exit the chamber through the holes in the deion grids and short-circuit the deion grid plates.

The arc-extinguishing chamber of the high-speed circuit breaker VB-11 is known (https://electri4ka.com/et2_m_er2t_ed2t/et2_7.html). When the main contacts of the high-speed switch are opened, an electric arc is ignited between them; under the influence of the external magnetic field created by the arc-extinguishing coils and the electrodynamic forces acting on the arc, it moves from the contacts to the horns of the arc-extinguishing chamber, enters a narrowing gap and labyrinth. The arc is stretched and cooled, touching with the walls of the arc-extinguishing chamber. Then it moves along U-shaped fechral elements built into the labyrinth and slot of the arc chute. As a result of this process, the arc resistance increases, thereby limiting and then decreasing the arc current. Having passed through the labyrinth and fechral elements, the arc enters the deion lattice, its resistance increases even more and the arc goes out.

The labyrinth-slot design of the arc-extinguishing chambers of the switch with built-in fechral elements and deion gratings at the exit of the chambers did not ensure compliance with the requirements of NBZhT TsT 144-2003 as amended in 2009 and GOST 33798.3-2016 on the maximum switched on and off current of 20,000 A and switching on of switches in O-VO-VO mode when testing for ultimate switching capacity (O - opening the circuit breaker, BO - turning on and subsequent automatic shutdown). The switching capacity of these cameras was at the limit, and in the VO mode a supply of switching capacity is required, since the time of current rise increases and the shutdown process becomes more difficult. At extreme currents, these chambers did not hold the arc well; it came out of the chambers and shorted to the nearest grounded elements of the switch.

The solution to this problem is described in the article (“Deion gratings in the design of the arc-extinguishing chamber of high-speed circuit breakers of the BVB series” - Bulletin of VElNII No. 4(74), 2016), revealing the design of the arc-extinguishing chamber, which is a prototype of the utility model. The arcing chamber contains outer walls made of insulating material. Arc-extinguishing horns are fixed between the outer walls 1, two rows of steel plates (deion gratings) are installed at an angle to each other, and two rows of insulating plates are installed along the deion gratings at the exit from the chamber. Each insulating plate is adjacent to a steel plate. The number, dimensions of steel plates and the size of the gaps between them are selected in accordance with recommendations in the technical literature. The arc chute works as follows. When the contacts of the switch are opened, an electric arc is ignited between them, which, under the influence of the magnetic field forces created by the magnetic blast coils of the switch and the resulting electrodynamic forces of the current circuit from the contact area of the switch, is transferred to the arc extinguishing horns, enters the mouth of the chamber, is divided and stretched on the arc extinguishing horns along the deion gratings and enters into deion lattices. Divided by a grid of mutually insulated steel plates into a series of short arcs connected in series, the arc goes out. Insulating plates adjacent to the steel plates keep the arc from leaving the grid and shorting behind it.

The division of the arc into a number of short arcs has a significant effect on the switching capacity of the high-speed circuit breaker. The width of the chamber mouth opening is also important. If the width of the chamber in the area of the mouth opening is too large, the arc will cool less well against the walls of the chamber, therefore, its resistance will increase more slowly, due to which the arc will take longer to extinguish. If the width of the opening of the chamber mouth is too small, then the arc will enter the chamber mouth more slowly, and if the width is very small, it will stop altogether and not enter the chamber mouth.

Consequently, there is a need to create a device that makes it possible to extinguish the electric arc in circuits with a steady-state short-circuit current required by GOST 33798.3-2016 with limited dimensions of the switch unit located under the car.

The technical result of this utility model is to reduce the size of the arc-extinguishing chamber of a high-speed circuit breaker while maintaining the efficiency of extinguishing the electric arc due to the rapid increase in arc resistance and large extraction of electric arc energy.

The technical result is achieved by using an arc suppression chamber containing a section of the chamber mouth, including horns and a hole formed by the above horns and made with the possibility of an electric arc entering it, and a section of deion gratings, including deion gratings with steel and insulating arc-resistant plates, an arc division horn and additional arc dividing horns. Moreover, the internal width of the chamber mouth section is 2-3 times less than the internal width of the deion grating section.

The internal width of the chamber mouth section is 12-18 mm.

The essence of the utility model is illustrated by drawings, where

in fig. 1 shows an arc chute;

in fig. 2 cross-section of the arc chute.

Deion arc chutes are designed to extinguish the electric arc formed when the main contacts of a high-speed switch are opened.

The high-speed switch unit is located in the underbody space of the rail rolling stock and is made in the form of a high-speed switch placed in a casing with two arc-extinguishing chambers. This solution makes it possible to reduce the overall dimensions of the device compared to a block containing a switch with one chamber. The casing consists of a metal frame with a lid and a fiberglass casing with rubber seals to prevent moisture and dust from entering.

Inside the unit there is also a strip with terminals for connecting low-voltage wires, two electrical low-voltage interlocks, insulators, as well as a cable and an air duct.

The switch contains two arc-extinguishing chambers to extinguish electric arcs that occur when the main contacts open.

Each arc-extinguishing chamber contains a housing made of lateral, transverse and longitudinal insulating walls made of insulating material. Between the side walls there are horns 2, forming the mouth of the chamber 1, and an arc dividing horn 4, located opposite the mouth of the chamber 1. Moreover, the mouth of the chamber 1 forms a hole made with the possibility of an electric arc entering it. Between the arc division horn 4 and the horns 2 there are additional arc division horns 3. Moreover, the sharp ends of the arc division horn 4 and the additional arc division horns 3 are directed towards the mouth of the chamber. The arc division horn 4 and additional arc division horns 3 are designed to divide the arc into four arcs in the area in front of the deion gratings. On the sides of the arc division horn 4 and behind the additional arc division horns 3, deion gratings 5 are located at an angle to each other. They are made of mutually insulated steel plates 7, to the end part of which insulating arc-resistant plates 6, made of arc-resistant insulating material, are tightly adjacent. for example, Forterm NT500. There are gaps between the plates for the removal of ionized gas formed when the arc burns inside the chamber, extending between the insulating plates and limited by the transverse walls of the arc-extinguishing chamber. The arc-extinguishing chamber is divided into two sections: a chamber mouth section, including horns 2 and a hole formed by the above horns 2 and made with the possibility of an electric arc entering it (chamber mouth 1), and a deion grating section, including deion gratings 5 with steel 7 and insulating arc-resistant plates 6, arc division horn 4 and additional arc division horns 3. Moreover, the internal width A of the chamber mouth section is 2-3 times less than the internal width B of the deion grating section.

The electric arc is most effectively cooled when passing through the steel plates of the deionic grid, the length of which is limited by the dimensions of the high-speed switch unit. In connection with this, a decision was made to increase the width of the steel plates, which will reduce the length of the deion gratings, thereby maintaining the extinction of the electric arc.

In addition, changing the cross-section of the passage from a narrow to a wider one helps the arc enter the grate faster, since the arc, like a hot gas, tends to expand. This solution makes it possible to maintain the efficiency of the extinguishing chamber while reducing the dimensions of the arc extinguishing chamber.

The optimal width A for the greatest energy output and increasing the resistance of the electric arc and at the same time the rapid entry of the arc into the mouth and subsequent stretching in front of the grid is 12-18 mm. Moreover, the width B of the deion lattice section should be 2-3 times wider than the width of the chamber mouth. The diameter of the fixed arc barrel with a current of 5000 A is 8 mm. The maximum currents in the chambers can reach 8000 A. With a width A of less than 12 mm, the arc will enter the mouth of the chamber more slowly and there is a possibility that it will stop and not enter it. If the width of the chamber mouth is greater than 18 mm, the energy of the arc when passing through it does not have time to decrease, due to which the arc does not have time to cool. If the ratio of widths A and B is greater than 1:3, this will lead to an increase in the width of the arc chute and will not allow for its normal operation. If the ratio of widths A and B is less than 1:2, then the efficiency of arc extinction deteriorates.

The device works as follows.

The electric arc formed when the main contacts of the high-speed switch are opened, under the influence of the forces of the electromagnetic field and the resulting electrodynamic forces of the current circuit from the area of the main contacts of the switch is transferred to the horns 2 of the arc extinguishing chamber, then enters the mouth of the chamber. When moving along the chamber mouth section in the direction of the deion grating section, the energy and temperature of the electric arc decreases, due to which the ionizing ability of the arc decreases. Passing into the deion grating section of the arc extinguishing chamber, the arc is divided into 4 arcs and enters the deion gratings. The arc moves along the steel plates and, upon reaching the insulating arc-resistant plate-deion gratings, fades out. Ionized gases formed during the arc extinguishing process escape out through the gaps of the deionic lattice.

Claims (2)

1. An arc-extinguishing chamber containing a section of the chamber mouth, including horns (2) and a hole formed by the above horns (2) and configured to allow an electric arc to enter it, and a section of deion gratings, including deion gratings (5) with steel (7 ) and insulating arc-resistant plates (6), a fission horn (4) and additional fission horns (3), characterized in that the internal width of the chamber mouth section is 2-3 times less than the internal width of the deion grating section. 2. Arc chamber according to claim 1, characterized in that the internal width of the chamber mouth section is 12-18 mm.