Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
  • H01H33/70—Switches with separate means for directing, obtaining, or increasing flow of arc-extinguishing fluid
  • H01H33/72—Switches with separate means for directing, obtaining, or increasing flow of arc-extinguishing fluid having stationary parts for directing the flow of arc-extinguishing fluid, e.g. arc-extinguishing chamber
  • H01H33/74—Switches with separate means for directing, obtaining, or increasing flow of arc-extinguishing fluid having stationary parts for directing the flow of arc-extinguishing fluid, e.g. arc-extinguishing chamber wherein the break is in gas

Definitions

• the invention relates to a gas pressure switch according to the preamble of claim 1.
• a pressure gas switch is known from DE-OS 2039240, in which a fixed contact piece is located in a housing filled with extinguishing gas
• blowing nozzle 10 is arranged in the central axis of a tubular sleeve spaced from the housing and in which a blowing nozzle is fixedly connected to a movable contact piece, the mating contact piece with which it forms a switching point.
• the blow nozzle surrounds both switching elements in the switch-on position.
• the object of the invention according to claim 1 is to create a pressure gas switch which has the smallest possible external dimensions 25, can be produced as inexpensively as possible and in which reignitions are largely excluded.
• Such a sleeve can be located, for example, in an outdoor switch within a porcelain housing.
• a sleeve according to the invention could also be used in a metal-encapsulated, 35 gas-insulated high-voltage switchgear (fully insulated switchgear), where pressure waves can also occur when the device is switched off.
• There the sleeve is surrounded by an electrically conductive, earthed housing.
• An advantage that can be achieved with the invention according to claim 1 is that during the arc duration, extinguishing gas penetrates from the area between the sleeve and the housing into the interior of the sleeve through the radial openings in the part of the sleeve facing the switching point; this prevents the formation of negative pressure there, which could cause pressure waves and reignitions.
• the sleeve does not necessarily have to be arranged vertically.
• a saving of porcelain is only possible with a given dielectric strength of the pressure gas switch by reducing the switch diameter, because the length of the porcelain insulator practically determines the insulation strength, which is predetermined by the nominal voltage of the pressure gas switch.
• a simple to produce shape of the cross-sectional reducing element is specified in claim 4.
• the openings in the area of the sleeve facing the sound space are evenly distributed over the circumference according to claim 5; It has been shown that, in order to avoid reignitions, it is more favorable to arrange a plurality of smaller openings distributed over the circumference than to provide a few openings which are each correspondingly larger - with the same total area of the openings.
• a uniform distribution of the openings at the end of the sleeve facing away from the switching point has a favorable effect, because this protective measure allows hot protective gas to escape from the inside of the sleeve particularly well after the arc has arisen; it has also been found here that a uniform distribution of several small openings over the circumference of the sleeve is more favorable than the uniform arrangement of fewer, correspondingly larger openings.
• the total area of the openings which are arranged adjacent to the pressure wave barrier is preferably at least as large as the cross-sectional area which is arranged perpendicular to the longitudinal axis of the sleeve and extends between the socket and the inner wall of the sleeve.
• FIG. 1 shows in longitudinal section the essential elements of a pressure gas switch according to the invention (Fig. 1a); a cross section through the DruckgasstschLter is shown in Fig. 1b;
• Fig. 2 shows in section the areas with positive and negative pressure during the duration of the arc within a gas pressure switch according to the prior art, which has no pressure wave barrier and no openings at the lower end of the fixed contact carrier;
• Fig. 3 indicates the propagation of the pressure waves in one
• Fig. 1a a longitudinal section of a compressed gas switch according to the invention is shown in the open air version.
• Porcelain which is filled with the extinguishing gas SF ⁇ , is a fixed, tubular, conductive sleeve (2), which is attached with its end facing away from the WegsteLLe electrically conductive to an outwardly leading connection contact piece ( 3).
• a radial metal support (4) is attached to the inside of the sleeve (2) in the area facing the switching point, on which, facing the switching point, a pin-shaped, fixed switching piece (5) is attached.
• the socket (5) lies in the longitudinal axis of the sleeve (2 ) and ends approximately at the lower edge of the sleeve (2).
• the TuLpenutton (6) is fixed in a tubular, in the direction of the longitudinal axis of the housing (1) arranged, movable contact carrier (7).
• This contact carrier (7) is electrically conductive and has at its end facing the switching point on the outer edge of a nominal current contact piece (8) which, in the switched-on position, is encompassed by a nominal current contact (9) on the end of the fixed sleeve (2) facing the switching point.
• Switch (6) interrupted, and there arises an arc.
• the arc develops within a blow nozzle (10) which is attached to the sliding contact carrier (7).
• the fixed sleeve ( 2) and the movable contact carrier (7) are arranged at a small distance from the inner wall of the housing (1) made of porcelain.
• the smallest possible diameter of the housing (1) is advantageous to save the expensive material porcelain; on the other hand, when switching off, an electric field is formed between the nominal current contact (9) of the fixed sleeve (2) and the nominal current contact piece (8) of the movable contact carrier (7), which, if the diameter of the housing (1) is too small, causes a voltage breakdown in the air space outside the housing (1) can cause. A part of the field lines runs through the housing ( 1) and through the outside air surrounding it.
• the dielectric strength of air is lower than that of the shielding gas SF ⁇ , there may be a voltage breakdown in the air outside the housing (1) if the distance between the nominal current contacts and the inner wall of the housing (1) is too small.
• Near the end facing the switching point, e.g. B. at a short distance from the lower edge of the fixed sleeve (2) is arranged in its interior a cross-sectional element (11) in the form of a to the longitudinal axis of the sleeve (2) projecting edge, which is part of a
• the pressure wave barrier is not designed so that it closes the sleeve (2) in a completely sealing manner; rather, it limits the spread of pressure waves as an obstacle.
• the cross-section-reducing element (11) is located in the quarter of the sleeve (2) facing the switching point.
• the protruding edge surrounds the blowing nozzle (10) at a short distance in the switch-on position.
• the fixed pin-shaped contact piece ( 5 ) ends at the height of the cross-section-reducing element (11).
• openings in the wall of the fixed sleeve (2) namely openings (12) on the end of the sleeve (2) facing away from the switching point near the connection contact piece (3) and openings (13) on the end of the sleeve facing the switching point ( 2), slightly above the cross-section-reducing element (11). These openings (13) are located in the quarter of the sleeve (2) facing the switching point.
• the cross-section-reducing element (11) does not end exactly in the direction of the switching point with the edge of the sleeve (2) facing the switching point, but lies slightly above this edge and in the direction of the switching point after the openings (13).
• the movement is transmitted from a drive (not shown) to the displaceable contact carrier (7) via a switching rod (14). Between the movable switching piece (6) and the switching rod (14) there is a space which contains a pressure chamber, not shown, and a compression device for blowing the arc at low currents.
• FIG. 1b shows a cross section through the compressed gas switch perpendicular to the longitudinal axis of the sleeve (2), namely between the metal support (4) and the openings (13) arranged adjacent to the cross section reducing element (11).
• the inner wall of the sleeve (2) is approximately as large as the total area of all openings (13). This dimension largely ensures that sufficient arc extinguishing gas is generated by the Can flow in openings (13) in order to avoid the creation of a vacuum inside the sleeve (2).
• Fig. 2 shows the areas with overpressure (16) and with underpressure (17) within a pressure gas switch according to the prior art, which, apart from the missing openings (13) (according to Fig. 1a) in the area of the sleeve (2 ') and the missing cross-section-reducing element (11) (according to FIG. 1a) is identical in construction with a pressure gas switch according to the invention according to FIGS. 1a and 1b.
• the normal pressure is established inside the pressure gas switch after all the compensation processes caused by switching off have subsided.
• the jet of hot extinguishing gas is abruptly interrupted in the case of pressure gas switches without a compression device, whereas in the case of pressure gas switches with a compression device, residual gas still flows out of the pump and prevents the formation of negative pressure for a certain time.
• the pressure field shown in Fig. 2 then begins to equalize. Part of the excess pressure is released by the hot extinguishing gas escaping through the openings (12) in the area of the sleeve (2 1 ) facing away from the switching point.
• the substantial equalization of the pressure differences takes place in the form of pressure waves, which are noticeable in that reignitions can occur after about 20 to 50 ms after the arc has been extinguished. This time passes between the fading of the hot
• REPLACEMENT BLADE Backfire is caused by the penetration of a vacuum zone belonging to the pressure wave into the area between the contact pieces.
• the vacuum reduces the strength of the extinguishing gas.
• Fig. 3 indicates the pressure conditions after the extinction of the arc inside the sleeve (2 ').
• a location coordinate (18) which runs parallel to the central axis of the sleeve (2 ')
• the pressure distribution which runs symmetrically to the central axis, is shown in simplified form a short time after the arc has been extinguished.
• the spatial coordinate (18) denotes the normal line of the normal pressure of the extinguishing gas as it prevails after all the compensating processes in the interior of the housing (1) have subsided.
• An arrow (21) pointing away from the switching point indicates the direction of propagation of the pressure wave.
• the location of the pressure distribution in the sleeve (2 1 ), symmetrical to the longitudinal axis, is also shown above a location coordinate (22) that runs parallel to the central axis of the sleeve (2 1 ), namely after the reflection of the pressure wave at the upper end the sleeve (2).
• An arrow (25) pointing towards the switching point indicates the direction of propagation of the pressure wave.
• the pressure zone in such a pressure switch switches between the two contact pieces and can be there
• the likelihood of reignition is significantly lower, because the openings (13) prevent the creation of a pressure gradient inside the sleeve (2) and, as a result, the propagation of pressure waves.

Landscapes

• Arc-Extinguishing Devices That Are Switches (AREA)
• Circuit Breakers (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6421385

Family Applications (1)

Country Status (4)

Families Citing this family (1)

Citations (3)

• 1990
  • 1990-12-24 DE DE19904041702 patent/DE4041702C1/de not_active Expired - Fee Related
• 1991
  • 1991-12-18 JP JP4501661A patent/JPH06503916A/ja active Pending
  • 1991-12-18 WO PCT/EP1991/002442 patent/WO1992011652A1/de not_active Application Discontinuation
  • 1991-12-18 EP EP19920900805 patent/EP0564487A1/de not_active Withdrawn

Patent Citations (3)

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