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
  • H01H33/006—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means adapted for interrupting fault currents with delayed zero crossings
• • 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
  • H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
  • H01H33/66—Vacuum switches
  • H01H33/666—Operating arrangements
  • H01H33/6661—Combination with other type of switch, e.g. for load break switches
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H87/00—Protective devices in which a current flowing through a liquid or solid is interrupted by the evaporation of the liquid or by the melting and evaporation of the solid when the current becomes excessive, the circuit continuity being reestablished on cooling

Definitions

• the invention is based on a method for switching off a short-circuit current in a power distribution network and on a device for carrying out the method according to the preamble of claim 9.
• a switchgear is known from patent specification EP 0 593 902 B1, which can be used in an electrical power distribution network.
• This switchgear has a series connection of a disconnector with a vacuum interrupter, which is arranged in an insulating gas-filled housing. The always opens first when switching off
• Vacuum interrupter and interrupts the current, and only then does the isolator open without current.
• the isolator always switches on without power and only then the vacuum interrupter. Accordingly, the vacuum interrupter serves here as a circuit breaker and the isolator only performs the task of creating a isolating section, which in the open state must hold the voltage then present.
• Such a switchgear is suitable for use in the areas of the energy distribution network where none special demands are placed on their switching capacity.
• this switchgear is not intended and not suitable for use as a generator switch, since it has no means to force the zero-current crossings in the vicinity of the generator in the event of generator-fed short-circuits, without which it is not possible to switch off the short-circuits.
• the invention solves the problem of specifying a simple method for quickly switching off short-circuit currents in the area close to the generator and showing a device for carrying out this method.
• the circuit breaker vaporizes the asymmetrical component so effectively even with simple means in the case of strongly asymmetrical short-circuit currents which initially have no current zero crossing that current zero crossings occur after a comparatively short period of time, as a result of which premature cancellation the short-circuit current is made possible.
• This early cancellation of the short-circuit currents advantageously limits the secondary damage and also the duration of the electrodynamic stress on the switchgear.
• the circuit breaker has a vacuum interrupter and, connected in series with it, a switching device which is constructed similarly to a disconnector.
• This switchgear which is designed as a type of isolator, is equipped with particularly erosion-proof contacts, and is specially designed to generate the highest possible arc voltage, which attenuates the asymmetrical component of the short-circuit current when it is switched off, so that the time until the first zero crossing is advantageously shortened.
• the circuit breaker has a vacuum interrupter and, connected in series with it, a switching device which works as a current limiter.
• This current limiter is designed to generate as high a voltage drop as possible when large short-circuit currents occur, which dampens the asymmetrical component of the short-circuit current during the switching-off process, so that the time until the first zero crossing thereof is advantageously shortened.
• the current limiter works so effectively that a more effective damping of the asymmetrical component of the short-circuit current is possible than in the first embodiment of the circuit breaker.
• FIG. 1 is a schematic representation of a phase of a first embodiment of a circuit breaker in the open state
• FIG. 2 shows a schematic representation of a phase of a second embodiment of a circuit breaker in the switched-off state
• FIG. 3 shows a schematic illustration of a phase of a third embodiment of a circuit breaker in the switched-off state
• FIG. 5 shows a schematic representation of a phase of a fourth embodiment of a circuit breaker in the switched-off state
• Fig. 6 is a schematic representation of a phase of a fifth embodiment of a circuit breaker in the open state.
• the circuit breaker 1 shows a schematic representation of a phase of a first embodiment of a circuit breaker 1 in the switched-off state.
• the circuit breaker 1 has a series connection of a vacuum interrupter 2 with a further switching device 3 per phase.
• the vacuum switching chamber 2 is connected to the switching device 3 in an electrically conductive manner by means of a connecting piece 4.
• On the side facing away from the switching device 3, the vacuum switching chamber 2 is electrically conductively connected to a connecting terminal 5.
• the switching device 3 is electrically conductively connected to a connecting terminal 6 on the side facing away from the vacuum switching chamber 2.
• the connection terminals 5 and 6 serve to connect the circuit breaker 1 to the power supply network.
• the circuit breaker 1 is driven by a drive, not shown.
• a conventional energy storage drive can be provided as the drive, for example.
• This circuit breaker 1 is only suitable for comparatively small nominal currents, since it has only one power current path and no separate nominal current path. However, it is also possible, if the circuit breaker 1 is designed for a comparatively large current carrying capacity, to connect two or more vacuum interrupters 2 in parallel. If the vacuum interrupters 2 have to withstand higher voltages, a corresponding series connection of vacuum interrupters 2 is also possible.
• FIG. 2 shows a schematic illustration of a phase of a second embodiment of a circuit breaker 1 in the switched-off state.
• This embodiment differs differs from the embodiment shown in FIG. 1 in that a parallel nominal current path 7 is provided, which is equipped with nominal current contacts 8.
• the nominal current path 7 can be interrupted by means of these nominal current contacts 8.
• the nominal current path 7 is always first opened by a drive (not shown) during the switching-off process, whereupon the current to be switched off commutates to the power current path 9 running parallel to the nominal current path 7 and leading directly through the switching device 3 and the vacuum switching chamber 2.
• the drive actuates all three switching points in a precisely timed sequence. It is also possible to actuate the switching device 3 and the vacuum interrupter chamber 2 each with separate drives, and to achieve the movement of the nominal current contacts 8 by coupling with one of these drives.
• FIG. 3 shows a schematic illustration of a phase of a third embodiment of a circuit breaker 1 in the switched-off state.
• This embodiment differs from the embodiment shown in FIG. 2 in that a parallel nominal current path 10 is provided for the switching device 3, which is equipped with nominal current contacts 11, and that a separate parallel nominal current path 12 is also provided for the vacuum interrupter 2, which has nominal current contacts 13 is populated.
• the nominal current paths 10 and 12 can be interrupted by means of these nominal current contacts 11 and 13, respectively.
• Embodiments are also conceivable in which a parallel nominal current path is provided either to the switching device 3 alone or to the vacuum switching chamber 2 alone.
• a higher-level system protection 14 is indicated schematically, which all necessary measurement and Includes control devices that are necessary to ensure proper operation of the power distribution network, for example, it detects the occurrence of short circuits in the high-voltage network and then triggers the circuit breaker 1 in the event of a fault. This action of the system protection 14 on the circuit breaker 1 is symbolized by a dashed line of action 15.
• the drive (not shown) is designed such that when switching off, the switching device 3 and the vacuum switching chamber 2 are generally actuated and opened at the same time.
• the vacuum interrupter 2 opens after the switching device 3 with a time delay in order to burn up at the contacts of the vacuum interrupter
• the switching device 3 When switching on, the switching device 3 is generally closed first and only then does the vacuum switching chamber 2 definitely close the circuit. However, depending on the type of switching device 3, other time sequences are also possible.
• the rated current contacts 8, 11 and 13 always open first during the switching-off process, so that the current commutates to the respective power current path 9, in which the final interruption of the current then occurs he follows.
• the power current path 9 is always closed first and only then the respective nominal current contacts 8, 11 and 13.
• the switching device 3 here has particularly erosion-resistant erosion contacts which are specially designed to withstand the switch-off arc for a sufficiently long time.
• the switching device 3 is shown here schematically with a disconnection point, but it makes sense to provide the switching device 3 with a plurality of disconnection points connected in series, because in this way a high arc voltage falling across the switching device 3 is achieved, since the over add the arc voltages falling to the individual separation points.
• the switching device 3 can be arranged in an insulating gas or in air, wherein the corresponding insulating medium can be used with or without pressurization. Since the switching device 3 has a particularly high occurrence
• the switching device 3 is not intended for switching processes that require a switching capacity of the switching device 3, it has the task m this circuit breaker 1 to generate a high arc voltage during the switching process, which is required for the damping of the predominant part of the asymmetrical component of the short-circuit current to be switched off becomes. This damping considerably reduces the time constant for the asymmetry of the short-circuit current to subside. In the switched-off state, however, the isolating path of the switching device 3 additionally supports the dielectric strength of the vacuum interrupter 2 of the circuit breaker 1.
• the current profile curve A shows the uninfluenced profile of the short-circuit current after the occurrence of the short circuit at time T 0 . It is clear It can be seen that the short-circuit current in the phase shown is so strongly asymmetrical that no current zero crossings occur at first. The first zero crossing occurs here only after about two and a half periods at the time Ti, which means that only after this comparatively long period of time would there be a first possibility for switching off the short-circuit current. If an arcing fault is fed by this short-circuit current, this causes secondary damage which increases with the duration of this arcing.
• the circuit breaker 1, in particular its switching device 3, is designed such that a comparatively high arc voltage dropping across it is generated when it is switched off.
• This high arcing voltage acts on the course of the short-circuit current after opening the circuit breaker 1 at time T 2 and evaporates its asymmetry, so that instead of the theoretical current curve A, the actual current curve B is reached.
• the time span until the first zero crossing of the short-circuit current, which is at time T 3 in this current profile curve B is considerably shortened compared to the corresponding time period in the current profile curve A.
• the short-circuit current can therefore be canceled much earlier, so that consequently the unavoidable secondary damage and other loads are advantageous can be kept small.
• the short-circuit current will be canceled at the latest at time T 4 .
• Circuit breaker currents in the area of a high-voltage network close to the generator are switched off with the aid of circuit breaker 1 in the following steps: a) Detecting a short circuit and triggering circuit breaker 1 for switching off the short circuit current by higher-level system protection 14, b) Opening one in circuit breaker 9 of circuit breaker 1 arranged switching device 3 and formation of a first arc in at least one isolating path of the switching device 3, c) opening of the vacuum switching chamber 2 connected in series with the switching device 3 in the power circuit path 9 of the circuit breaker 3 and formation of a second arc in the vacuum switching chamber 2, d) damping the predominant part of the asymmetrical component of the short-circuit current to be switched off by the arc voltage dropping across the switching device 3, e) supporting the damping of the asymmetrical component the short-circuit current to be switched off due to the arc voltage dropping across the vacuum switching chamber 2, f) extinguishing the second arc through the vacuum switching chamber 2 in one current zero crossing and simultaneous exting
• FIG. 5 shows a schematic illustration of a phase of a fourth embodiment of a circuit breaker 1 in the switched-off state.
• the circuit breaker 1 has a series connection of a vacuum interrupter 2 per phase with a further switching device designed as a current limiter 16.
• the vacuum interrupter 2 is by means of a Connectors 4 electrically connected to the current limiter 16.
• the vacuum interrupter 2 On the side facing away from the current limiter 16, the vacuum interrupter 2 is electrically conductively connected to a connecting terminal 5.
• the current limiter 16 is connected on the side facing away from the vacuum switching chamber 2 via a further connecting piece 17 to a system isolator 18 which is electrically conductively connected to a connecting terminal 6.
• the connection terminals 5 and 6 are used to connect the circuit breaker 1 to the
• the circuit breaker 1 is driven by a drive, not shown.
• a conventional energy storage drive can be provided as the drive for the vacuum interrupter chamber 2, the current limiter 16 does not require a drive.
• the current limiter 16 is self-healing, i.e. after switching off the circuit, it automatically becomes conductive again, so that the vacuum interrupter 2 must hold the entire recurring voltage. If comparatively high voltages have to be controlled, then it makes sense to connect a circuit breaker 18 in series to the circuit breaker 1, which is opened immediately after switching off and which then holds the applied voltage.
• the circuit breaker 1 is only suitable for comparatively small nominal currents in this embodiment, since it has only one power current path and no separate nominal current path.
• circuit breaker 1 is designed for a comparatively large current carrying capacity, to connect two or more vacuum interrupters 2 in parallel. If the vacuum interrupters 2 have to withstand higher voltages, a corresponding series connection of vacuum interrupters 2 is also possible.
• FIG. 6 shows a schematic illustration of a phase of a fifth embodiment of a circuit breaker 1 in the switched-off state.
• This embodiment differs 5 in that the circuit breaker 1 is provided with a parallel nominal current path 7 which is equipped with nominal current contacts 8.
• the nominal current path 7 can be interrupted by means of these nominal current contacts 8.
• the rated current path 7 is always opened first by a drive, not shown, during which the current to be switched off commutates to the power current path 9 which runs parallel to the nominal current path 7 and runs directly through the current limiter 16 and the vacuum switching chamber 2.
• the drive actuates the two switching points in a precisely timed sequence. It is also possible to actuate the rated current contacts 8 and the vacuum interrupter 2 with separate drives.
• circuit breaker 18 in series with the circuit breaker 1, which, when the operating voltage is high, holds the voltage securely after the switch-off.
• the system isolator 18 is opened when de-energized and is de-energized before being switched on, possibly at the same time as the nominal current contacts 8.
• a current limiter 16 is used in the circuit breaker 1, for example if a particularly favorably designed current limiter is provided, the current profile curve C shown in FIG. 4 results for the current to be switched off.
• the current limiter 16 already acts before the circuit breaker 1, in In this case, the vacuum interrupter 2, that is to say before the time T 2 , on the current profile and significantly flattens and limits the current increase.
• the effect of the voltage drop across the current limiter 16 already begins at time T 5 .
• the arc voltages of the large number of arcs which form in the current limiter 16 after its response current has been exceeded add up to a comparatively high voltage drop, and this large voltage drop acts steaming on the current rise and steaming off its asymmetry.
• the time span until the first zero crossing of the short-circuit current is significantly shortened compared to the corresponding time span with the theoretical current curve A and also with respect to the current curve B.
• the short-circuit current can accordingly be canceled much earlier, so that consequently the unavoidable secondary damage and other loads can be kept advantageously small.
• the current limiter 16 does not require a separate mechanical drive; it is triggered by the fault current itself in a timely manner. After the current has been switched off, the current limiter 16 automatically returns to the initial state and is fully ready for the next switch-off.
• Circuit breaker 1 can not only be used as a generator switch in the area of the power supply network close to the generator, they can also be used as a distribution switch in all other network nodes, in particular the embodiments of the circuit breaker 1 without separate rated current paths can advantageously take over such protective functions.
• the circuit breaker 1 can be used both in conventional high-voltage switchgear and in metal-enclosed gas-insulated switchgear. NAME LIST

Landscapes

• High-Tension Arc-Extinguishing Switches Without Spraying Means (AREA)
• Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)
• Gas-Insulated Switchgears (AREA)

Applications Claiming Priority (3)

Publications (1)

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• 2000
  • 2000-04-05 DE DE2000116950 patent/DE10016950A1/de not_active Withdrawn
  • 2000-11-02 CN CN 00819596 patent/CN1452776A/zh active Pending
  • 2000-11-02 WO PCT/CH2000/000585 patent/WO2001078097A1/de not_active Application Discontinuation
  • 2000-11-02 JP JP2001575454A patent/JP2003530672A/ja not_active Withdrawn
  • 2000-11-02 EP EP00969159A patent/EP1269504A1/de not_active Withdrawn
  • 2000-11-02 AU AU2000278981A patent/AU2000278981A1/en not_active Abandoned
  • 2000-11-02 RU RU2002129359/09A patent/RU2002129359A/ru not_active Application Discontinuation

Non-Patent Citations (1)

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