EP0067460B1 - High-voltage power circuit breaker - Google Patents

Description

The invention relates to a high-voltage circuit breaker according to the preamble of patent claim 1.

Such a switch is known from French patent application FR-A-2 292 325. In the known switch, a heating volume cut out in a nozzle-shaped hollowed-out insulating material body and the compression space of a piston-cylinder compression device open into the extinguishing section located between the contact pieces. This does mean that even when switching large currents, fresh extinguishing gas from the compression space in the area of the nozzle constriction of the insulating material body is extremely quickly available for blowing the switching arc, but the end of the extinguishing path facing away from the nozzle constriction is only relatively hot and ion-rich gas from the in the insulating material body provided heating volume is supplied. This gas does not have optimal extinguishing properties, so that a re-ignition of the switching arc after a current zero crossing cannot be ruled out easily.

Switches are also known from European patent application EP-A-0 021 951 and German patent application DE-A-2 404 721, in which the switching arc drawn between the contact pieces during a switching operation has a current flowing through it which is to be switched off under the effect of the magnetic field Coil rotates around an axis. As a result, the heating effect of the switching arc is increased in a quenching chamber and, when the current to be switched off is zero, heated gas is available for blowing the switching arc. In order to enable adequate switching of the switching arc when switching small currents, a piston-cylinder compression device is provided in each of these switches, through which gas is sucked out of the quenching chamber through the quenching path located between the contact pieces. With this switch, at least in the initial phase of the quenching process, only hot quenching gas is used to blow the switching arc, so that a re-ignition of the switching arc after a zero current cannot be ruled out.

German patent application DE-A-2 349 263 also describes a switch with a combustion chamber in which an auxiliary arc lying in series with the switching arc is ignited during a switching operation. This auxiliary arc heats up the gas in the combustion chamber, which supports the drive of the switch. This switch has a piston-cylinder compression device for blowing the switching arc. With this switch, comparatively fresh gas is available for blowing the switching arc, but such a switch is relatively complex.

In a switch disclosed in French patent application FR-A-2 156 219, the blowing of the switching arc is improved in that a piston-cylinder device conveys gas from a compression chamber into the extinguishing section located between the contact pieces, which gas then flows through the extinguishing section is received by a suction chamber of the piston-cylinder device. Such a switch is comparatively complicated and requires a relatively strong drive to actuate the piston-cylinder device.

In a switch known from Swiss patent 568 649, although the drive can be made relatively weak by utilizing the pressure surge generated by the switching arc gases and the energy of the pressure surge can also be used to support the blowing, this switch has a pneumatic deflection of the switching arc gases necessary multi-chamber system with several valves pressurized by the hot extinguishing gases.

Finally, switches are known from French patent application FR-A-2 373 141 and German patent application DE-A-2 741 022, in which the quenching gas located in a closed chamber is essentially heated and compressed by an arc rotating under the action of a magnetic field becomes. With switch-off currents, the gas pressure in the heating chamber rises sharply and, above a predetermined pressure value, a wall delimiting the heating chamber is moved into a further closed chamber. As a result, fresh quenching gas located in this chamber is compressed and then used to extinguish the switching arc. With this switch, at least in the initial phase of the extinguishing process, only hot extinguishing gas is supplied. In addition, the strength of the extinguishing gas blowing depends on the strength of the current to be switched off.

It is an object of the invention to develop a switch of the generic type with simple means in such a way that a re-ignition of the switching arc after the zero current is almost avoided.

This object is achieved by the characterizing features of claim 1.

The circuit breaker according to the invention is characterized in that a comparatively large proportion of comparatively fresh quenching gas is available for switching arcing in all switching cases. This enables particularly effective blowing of the switching arc and improves the extinguishing capacity.

Further advantageous configurations of the circuit breaker according to the invention are specified in the dependent claims 2 to 4.

Exemplary embodiments of the invention are shown in simplified form below with reference to the drawing.

• Fig. 1 eine Aufsicht auf einen Schnitt durch eine erste Ausführungsform des erfindungsgemässen Hochspannungsleistungsschalters,
• Fig. 2 eine Aufsicht auf einen Schnitt durch eine zweite Ausführungsform des erfindungsgemässen Hochspannungsleistungsschalters und
• Fig. 3 eine Aufsicht auf einen Schnitt durch eine dritte Ausführungsform des erfindungsgemässen Hochspannungsleistungsschalters.

It shows:

• 1 is a plan view of a section through a first embodiment of the high-voltage circuit breaker according to the invention,
• Fig. 2 is a plan view of a section through a second embodiment of the high-voltage circuit breaker according to the invention and
• Fig. 3 is a plan view of a section through a third embodiment of the high-voltage circuit breaker according to the invention.

In all figures, the respective high-voltage circuit breaker is indicated in the switch-on position on the left-hand side, whereas a switch-off phase of the relevant high-voltage circuit breaker is shown on the right-hand side. Furthermore, the same parts are provided with the same reference numerals in all the figures.

1 shows a top view of a section through the contact arrangement of a high-voltage circuit breaker according to the invention. A movable contact piece 1 designed as a nozzle tube engages with contact fingers of a fixed contact piece 2 (see left side). An annular electrode 3 is arranged below the fixed contact piece 2 and is electrically conductively connected to one end of a coil 4. The other end of the coil is in electrically conductive connection with the contact piece 2. The coil 4 is attached to an insulating body 5, in which annular spaces 6, 7 and 8 are provided. The annular space 6 is connected to a further annular channel 12 via an annular mouth 9, the annular space 8 via an annular channel 10 and an annular mouth 11. The annular spaces 6 and 7 are connected to one another via an opening 13 provided in a wall 14. The annular spaces 7 and 8 are separated from one another by an annular piston 15. This beef piston 15 is connected via webs 16 to the movable contact piece 1 and is part of a compression device for extinguishing gas, which is provided in all the spaces and channels specified. Check valves 20 are provided on the annular space 8, which prevent a pressure drop in the annular space 8 when the compression device is actuated and enable the inflow of fresh extinguishing gas when switched on.

• Beim Ausschalten wird das Kontaktstück 1 nach unten bewegt. Gleichzeitig bewegt sich auch der Ringkolben 15 der Kompressionsvorrichtung nach unten und komprimiert im Ringraum 8 befindliches Löschgas, wobei Rückschlagventile 18 einen Druckabfall in den Ringräumen 6 und 7 verhindern. Sobald sich die Kontaktstücke 1 und 2 voneinander getrennt haben, wird sich zwischen ihnen ein Lichtbogen17 bilden. Mit zunehmendem Abstand zwischen den Kontaktstücken 1 und 2 wandert der Fusspunkt des Lichtbogens 17 vom feststehenden Kontaktstück 2 zur ringförmigen Elektrode 3 und schaltet hierbei die nun vom Abschaltstrom durchflossene Spule 4 ein (vergleiche die rechte Seite von Fig. 1). Das magnetische Feld der Spule bewirkt eine Rotation des Lichtbogens 17 um eine Kontaktstückachse. Hierbei wird Löschgas in der Hochstromphase stark erhitzt, wodurch zugleich auch der Druck des Löschgases ansteigt.

The mode of operation of the high-voltage circuit breaker according to the invention according to FIG. 1 is now as follows:

• When switching off, the contact piece 1 is moved down. At the same time, the annular piston 15 of the compression device also moves downward and compresses extinguishing gas located in the annular space 8, check valves 18 preventing a pressure drop in the annular spaces 6 and 7. As soon as the contact pieces 1 and 2 have separated from one another, an arc 17 will form between them. With increasing distance between the contact pieces 1 and 2, the base point of the arc 17 moves from the fixed contact piece 2 to the ring-shaped electrode 3 and thereby switches on the coil 4 through which the cutoff current now flows (compare the right side of FIG. 1). The magnetic field of the coil causes the arc 17 to rotate about a contact piece axis. Here, extinguishing gas is strongly heated in the high-current phase, which also increases the pressure of the extinguishing gas.

The heated, high-pressure quenching gas is stored in the annular space 6. A portion of the extinguishing gas stored in the annular space 6 passes through the opening 13 into the annular space 7, in which it exerts a force acting on the annular piston 15 in the switching-off direction and thus supporting the switch drive. This prevents the annular piston 15 from working against the pressure build-up of the extinguishing gas caused by heating and thus resulting in a drive deceleration.

At the same time, the fresh quenching gas located in the annular space 8 is compressed and flows when the heating effect of the arc 17 diminishes when the current zero point is approached, in the direction indicated by arrows via the annular channel 10 to the annular channel 12 and mixes there with the one from the annular space 6 flowing heated extinguishing gas. The mixing of the fresh and the hot extinguishing gas is further supported by the fact that the annular spaces 6 and 8 are separated from one another by the annular wall 14 and that the wall 14 has an edge 19 projecting into the annular channel 12. The edge 19 creates a turbulent boundary layer between fresh and hot extinguishing gas and thereby promotes their mixing.

From the ring channel 12, the extinguishing gas, which is under high pressure but has cooled considerably, is passed into the extinguishing section located between the movable contact piece 1 and the ring electrode 3, where it blows the arc particularly effectively up far beyond the zero current point and then via the nozzle-shaped opening of the contact piece 1 enters an expansion room.

2 shows a further exemplary embodiment of the switch according to the invention.

In contrast to Fig. 1, a top view of a section through the contact arrangement of a switch is shown, in which the heating of the extinguishing gas is not caused by a rotating, but by an arc drawn between the movable contact piece 1 and a fully cylindrical contact piece 2. Here, the insulating body 5 is designed as a nozzle. Compared to the dimensions of the annular space 6, which acts as a heating volume, the annular piston 15 has a small cross-section, so that when fresh extinguishing gas is compressed in the annular space 8, due to the strong pressure increase in the high-current phase when switching strong currents, there is no drive braking. Shortly before the zero current crossing, the fresh and the heated extinguishing gas are mixed in the annular channel 12 and, due to the presence of two nozzles, namely the nozzle-shaped insulating body 5 and the nozzle-shaped hollow contact piece 1, the arc 17 is blown twice.

The embodiment of the high-voltage circuit breaker according to the invention shown in FIG. 3 essentially corresponds to the embodiment according to FIG. 2, but like the switch according to FIG Annulus 7 limited. With this out In the embodiment of the high-voltage circuit breaker according to the invention, it has proven to be particularly advantageous to design the annular piston 15 in such a way that this area is the larger area of the differential piston.

Claims (4)

1. High-voltage circuit breaker comprising moving contact member (1) and at least one further contact member (2, electrode 3), which contact members (1, 2, electrode 3) delimit during a switching process a quenching section in which an arc (17) is burning, comprising a piston-cylinder compression device in the compression space (annular space 8) of which cold quenching gas is condensed and whose part changing the volume of the compression space (annular space 8) is rigidly connected to the moving contact member (1), comprising a heating volume (annular space 6) in which quenching gas, which is compressed by the arc (17) as a result of heating, is stored and comprising at least one nozzle through the opening of which compressed quenching gas flows during a switching process from the quenching section into an expansion space, characterised in that the compression space (annular space 8) and the heating volume (annular space 6) open into a common annular duct (12) which is a part of a mixing device for hot and cold quenching gas and connects the compression space (annular space 8) and the heating volume (annular space 6) to the quenching section, and that the openings (11, 9) of the compression space (annular space 8) and of the heating volume (annular space 6) in the annular duct (12) are separated from each other by an annular wall (14) which is provided with an edge (19) which projects into the annular duct (12) and by means of which a turbulent boundary layer forms between the hot and the cold quenching gas as the current to be switched off approaches its zero transition.

2. High-voitage circuit breaker according to Ciaim 1, characterised in that the annular duct (12) is delimited by the mowing contact member (1) and a body (5) of insulating material joined to the moving contact member (1).

3. High-voltage circuit breaker according to Claim 1, characterised in that the compression space (annular space 8) is subdivided by an annular piston (15) of the compression device into two annular spaces (7, 8) having oppositely variable volumes, one annular space (8) of which is connected to the annular duct (12) and the other annular space (7) of which is connected to the heating volume (annular space 6).

4. High-voltage circuit breaker according to Claim 3, characterised inthatthe annular piston (15) is constructed as a differential piston, the larger piston area of which delimits the annular space (7) which is joined to the heating volume (annular space 6).

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