FR2612683A1 - High-voltage circuit breaker with closure resistor - Google Patents

Abstract

The invention relates to a high-voltage circuit breaker with closure resistor. …<??>The subject is a high-voltage circuit breaker with closure resistor comprising, in a cylindrical insulating casing 1 filled with dielectric gas, a moving assembly including an arc contact 10 and a permanent contact 4 and a fixed assembly comprising an arc contact 24 and a permanent contact 23, and a closure resistor 50 coaxial with the casing, characterised in that it comprises a piece which is semi-mobile with respect to the fixed assembly, that is to say which can perform a translational motion of limited amplitude with respect to the said fixed assembly, the said piece being connected electrically to the closure resistor, the said piece comprising a tubular portion 37 provided with contact fingers 38 with two studs, the first set 39 of studs coming, during closure of the circuit breaker, into contact with the main moving contact 4, thus inserting the closure resistor 50, this insertion being followed by the placing in contact of the moving arc contact 10 and of the fixed arc contact 24, thus short-circuiting the said resistor, the second set of studs 40 coming, at the end of closure, into contact with the fixed main contact 23 thus short-circuiting the said resistor 50. …<??>Application to high-voltage circuit breakers. … …

Description

- 1 -

The present invention relates to a high voltage circuit breaker comprising a resistor associated with a mechanism for inserting this.

resistance when closing the circuit breaker.

Document FR.A 8106444 discloses a circuit breaker of the aforementioned type in which the insertion mechanism comprises a semi-movable tubular insertion part coaxial with the fixed main contacts and with the fixed arcing contacts and external to the latter. . During the closing of the circuit breaker, the insertion part is pushed by an insertion contact, also tubular, linked to the mobile assembly of the

circuit breaker.

The two tubular parts are provided at their ends coming into contact with tungsten end pieces to resist the wear produced by

the arc which is established on closing.

When closing, the semi-mobile insert is brought to the potential of the line protected by the circuit breaker and must therefore be placed at a sufficient distance from one part of the porcelain casing of the chamber. switch, on the other hand of the central metal parts of the device, to avoid any untimely ignition. It follows that the diameter of the circuit breaker cannot be less than the sum of the three insulation distances, respectively the porcelain insulation distance of the insertion tube, the insulation distance of the insertion tube-fixed main contact and the distance. fixed main contact - fixed arcing contact determined by dimensions

of the insulating blowing nozzle.

The increase in the breaking capacities of circuit breakers leads to the creation of interrupting chambers operating at constant voltages.

higher.

The arrangement which has been described is more difficult to achieve for

high arc-chamber voltages because the insulating distances

increase and require the use of coins and envelopes

insulators with a larger diameter and therefore very high cost.

An object of the invention is to provide a circuit breaker with a device

closing resistance insertion of reduced diameter.

Another object of the invention is to provide a circuit breaker in which the end of the insertion contacts is subjected to a wear - 2 - reduced by the fact that the current passes through it only for a very small time.

duration when the circuit breaker closes.

The present invention relates to a high-voltage circuit breaker with closing resistance, comprising in a cylindrical insulating casing filled with dielectric gas, a movable assembly comprising an arcing contact and a permanent contact, and a fixed assembly comprising a dielectric contact. 'arc and permanent contact, and a closing resistor

coaxial with the casing, characterized in that it comprises a semi-

movable relative to the fixed assembly, that is to say capable of carrying out a translational movement of limited amplitude relative to said fixed assembly, said part being electrically connected to the closing resistor, said part comprising a tubular portion provided with contact fingers with two pads, the first set of pads coming into contact with the moving main contact when the circuit breaker is closed, which inserts the closing resistor, this insertion being followed by contacting the contact d 'mobile arc and the fixed arcing contact which bypasses said resistance, the second set of pads coming, at the end of closing, into contact with the fixed main contact which ensures

the passage of permanent current.

Advantageously, the tubular portion comprises one end made of material resistant to the effects of the arc, cooperating with a ring made of similar material disposed in the vicinity of the movable main contact and

semi-movably linked to said movable assembly.

The invention will be well understood from the description given below.

of a preferred embodiment of the invention, with reference to the appended drawing in which: - Figure 1 is a partial view in axial section of the circuit breaker of the invention, the left half-section showing the device in full position open and the straight half-section in fully closed position, - Figure 2 is a sectional view along line II-II of Figure 1, - Figure 3 is a partial axial sectional view of the circuit breaker, the

left half-section representing the device in the starting position of

resistance, and the straight half-cut in the fully

closed.

26 1 2683

-3- The circuit breaker shown partially in the figures comprises an outer insulating casing 1 made of porcelain delimiting a volume 2 filled with dielectric gas such as sulfur hexafluoride, under a

pressure of a few bars.

The movable assembly comprises a tube 3 integral with an operating rod, not shown, and carrying a movable permanent contact 4, a blowing nozzle 5 made of insulating material and a semi-movable ring 6, intended for the insertion of a closing resistor, associated with a damping spring 7 and electrically connected to the tube 3 by a braid 8; the movable assembly also comprises a tube 9 terminated by fingers 10 constituting a movable arcing contact and an insulating nozzle 45. The tube 3 is connected to a first outlet of the

circuit breaker, not shown.

The fixed assembly comprises a tubular portion 21, connected to a

second socket not shown.

The tubular portion is extended by several arms directing towards the axis of the circuit breaker, such as the arm referenced 22 in FIGS. 1 and 2. There are, in the example described, two arms 22 which, on the one hand, support a crown 23 constituting a permanent fixed contact, on the other hand

a tube 24 constituting a fixed arcing contact.

The closing resistor 50, consisting of a stack of elements according to a known technique, is placed axially in an insulating support 25. The resistor is in contact with a metal block.

26 to which is fixed another metal block 27.

The block 27 carries a fixed guide tube 28 around which slides

the damping tube 29 on a shoulder of which rests an end

mated with a spring 30, the other end of which bears on the block 27.

The end of the tube 29 ends with two fixing sockets 36.

The stroke of the damping tube is limited by a core 31.

The resistance is inserted by an assembly which is now described: it comprises two arms 35 secured to the tube.

damping 29 by means of the plugs 36.

In the example of the figure these arms are two in number and are

place in the spaces left free between the arms 22.

The arms 35 are extended by a tubular portion 37 carrying at its interior contact fingers 38 having contact pads 39 and

at each of their ends.

The socket 36 also carries contact fingers 41 cooperating with

a contact rod 43 integral with the block 27.

The tube 37 is terminated by a crown 42 made of a material resistant to wear due to the electric arc, for example tungsten or tungsten alloy. The circuit breaker operates as follows: - in the closed position, the current passes through tube 21, contact 23,

fingers 40, 38, 39, contact 4 and tube 3.

- during a circuit breaker closing operation from the open position (left part of figure 1), the moving equipment

moves up the figure.

The first contact takes place between the crowns 6 and 42 (figure 3) and the current then passes through the tube 3, the braid 8, the crown 6, the crown 42, the tube 37, the arms 35, the fingers 41, the rods 43, the

block 27, block 26 and resistor 50.

The moving part continuing its course, the spring 7 is compressed and the contact between the rings 6 and 42 is shunted very quickly by

the contact between the pads 39 and the mobile main contact 4.

In this way, the wear of the tungsten rings 6 and 42 is limited.

since the current circulates in its entirety only for about a millisecond, the current then passing entirely through the pads 39

and contact 4.

The moving part continues its course and reaches a position where the arcing fingers 10 come into contact with the arcing contact tube 24; the resistor 50 is then short-circuited because the current passes directly from the tube 3 to the arms 22 through the fingers 10 and the tube 24; the pads 40 then come into contact with the contact

main fixed 23; which ensures the passage of the permanent current.

The closing movement is damped by the compression of the

spring 30 at the end of the stroke.

On opening, by its inertia and by the suction effect of the volume 51, the movable insertion device does not follow the very rapid movement of the contacts 4 and 10 so that it does not reach its position

normal opening until after the arc has been extinguished.

In the circuit breaker of the invention the arm-tube assembly constitutes

killing the closing resistor insertion device, also serves to pass permanent current when the circuit breaker is closed. The permanent current then flows through the coaxial tube 21 and outside the resistor 50 which makes it possible to obtain currents

high nominal.

It can be seen that in this device the rings 42 and 6 made of a material resistant to wear due to the electric arc can have diameters

low enough, this facilitates their realization and reduces their cost.

Indeed, the dielectric strength of the insulation space between the insertion tube 37 and the main contact 23 is in the direction

longitudinal and no longer in the radial direction.

The isolation or device is provided entirely by gas.

In addition, the presence of the contact pads 39 facilitates the switching.

tion and reduces the electrical wear of these crowns.

- 6 -

Claims (4)

CLAIMS: 1 / High-voltage circuit breaker with closing resistance, comprising in a cylindrical insulating envelope (1) filled with dielectric gas that, a mobile assembly comprising an arcing contact (10). and a permanent contact (4) and a fixed assembly comprising an arcing contact (24) and a permanent contact (23), and a closing resistor (50 ) coaxial with the casing, characterized in that it comprises a part that is semi-mobile relative to the fixed assembly, that is to say capable of carrying out a translational movement of limited amplitude relative to said fixed assembly, said part being electrically connected to the closing resistor, said part comprising a tubular portion (37) provided with contact fingers (38) with two studs, the first set of studs (39) coming, when the circuit breaker is closed, in contact with main contact movable (4), which inserts the closing resistor (50), this insert tion being followed by the placing in contact of the movable arcing contact (10) and of the fixed arcing contact (24) which bypasses said resistance, the second set of pads (40) coming, at the end of closing , in contact with the fixed main contact (23) which ensures the passage of the permanent current. 2 / A circuit breaker according to claim 1 characterized in that the tubular portion (37) comprises one end (42) of material resistant to the effects of the arc, cooperating with a ring (6) of similar material disposed in the vicinity of the movable main contact (4) and linked in such a way semi-mobile to said mobile assembly. 3 / circuit breaker according to one of claims 1 and 2 characterized in that that said semi-moving part comprises arms (35) fixed to a damping tube (29) provided with a spring (30), said arms supporting said tubular portion (37). 4 / A circuit breaker according to claim 3 characterized in that the electrical connection between said semi-moving part and the resistor (50) is made by means of contact fingers (41) cooperating with rods (43) connected to a metal block ( 27) in electrical contact with said resistance. / Circuit breaker according to one of claims 3 and 4 characterized in that that the main (23) and arcing (24) fixed contacts are supported by arms (22) between which pass the arms (35) of the semi- mobile.