EP1480241B1 - Hybrid DC circuit breaker with zero current switching and method of switching - Google Patents

Hybrid DC circuit breaker with zero current switching and method of switching Download PDF

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Publication number
EP1480241B1
EP1480241B1 EP03090155A EP03090155A EP1480241B1 EP 1480241 B1 EP1480241 B1 EP 1480241B1 EP 03090155 A EP03090155 A EP 03090155A EP 03090155 A EP03090155 A EP 03090155A EP 1480241 B1 EP1480241 B1 EP 1480241B1
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EP
European Patent Office
Prior art keywords
current
quenching
switching
time
switching device
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EP03090155A
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German (de)
French (fr)
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EP1480241A1 (en
Inventor
Jürgen Kunhardt von Schmidt
Ulrich Kahnt
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Elpro BahnstromAnlagen GmbH
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Elpro BahnstromAnlagen GmbH
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Priority to DE50302112T priority Critical patent/DE50302112D1/en
Priority to EP03090155A priority patent/EP1480241B1/en
Priority to AT03090155T priority patent/ATE315274T1/en
Publication of EP1480241A1 publication Critical patent/EP1480241A1/en
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    • 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
    • H01H33/02—Details
    • H01H33/59—Circuit arrangements not adapted to a particular application of the switch and not otherwise provided for, e.g. for ensuring operation of the switch at a predetermined point in the ac cycle
    • H01H33/596—Circuit arrangements not adapted to a particular application of the switch and not otherwise provided for, e.g. for ensuring operation of the switch at a predetermined point in the ac cycle for interrupting dc
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
    • H01H9/54—Circuit arrangements not adapted to a particular application of the switching device and for which no provision exists elsewhere
    • H01H9/541—Contacts shunted by semiconductor devices
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
    • H01H9/54—Circuit arrangements not adapted to a particular application of the switching device and for which no provision exists elsewhere
    • H01H9/56—Circuit arrangements not adapted to a particular application of the switching device and for which no provision exists elsewhere for ensuring operation of the switch at a predetermined point in the ac cycle

Definitions

  • the invention relates to a DC rapid switching device for traction power supplies using a vacuum switch and an extinguishing circuit and a method for switching off a direct current in a rectifier substation.
  • a thyristor in the Kommut réelleszweig is ignited at the same time as the opening command for the vacuum switch, so that the current to be switched from the load circuit commutated in the Kommut réelleszweig and is then completely interrupted by deleting the thyristors.
  • the main disadvantages of this device are that only currents can be switched in one direction and that the switching path is formed exclusively by semiconductors.
  • the object is to provide a DC rapid switching device for traction power supplies and a method that ensures a reliable and rapid shutdown of the operating current or short-circuit currents but also reverse currents while galvanic isolation of the distance from the busbar of the rectifier substation, the components are not exposed to high dynamic requirements, so that the device with low-cost components can be realized.
  • the DC rapid switching device for traction power supplies is characterized by the features of claim 1, wherein between the track and the busbar of the rectifier substation, a switching device is arranged. Parallel to this switching device, an erase circuit is arranged, which consists of a Löschkondenstor, which is connected in series with a switching unit consisting of two antiparallel arranged thyristors. To the switching device also a test branch is arranged in parallel. The test branch consists of a series connection of a test thyristor, a current measuring element and a test resistor.
  • the DC rapid switching device also has a freewheeling circuit, each having a branch for each current direction, from the busbar to the return conductor or from the line to the return conductor, in each of which two freewheeling diodes, which are connected in series, are arranged.
  • a freewheeling diode in each branch of the freewheeling circuit is arranged in parallel a fuse with message.
  • the Dimensioning of the freewheeling diode and the fuse is chosen so that only a small portion of the freewheeling current flows through the respective fuse, while most of the freewheeling current flows through the freewheeling diode arranged in parallel to the fuse.
  • a control module which is known per se but is specially programmed in accordance with the method steps is provided.
  • the acquired measured values are processed by a conventional control module which outputs the corresponding control commands to the switching device and the quenching thyristors on this basis.
  • the opening process of the switching device is initiated automatically depending on the set limits and taking into account the dimensioning of the cancellation circuit, in particular the capacity of the quenching capacitor, the time-optimized control of the quenching thyristors.
  • the route test is also carried out by the control module, by calculating the current output voltage of the track resistance and the connection of the track is only possible with sufficiently large line resistance.
  • the fuse monitoring of the fuses of the freewheeling circuit is carried out by the control module, which also monitors other safety-related variables, such as the charging voltage of the quenching capacitor.
  • the quick-switching device has the advantage that it can be realized with inexpensive components, in particular thyristors and capacitors, since no high demands are placed on the switching speed and the dynamic properties. Another advantage is that with this quick-switching device, the galvanic isolation path is not bridged by semiconductor devices which could take over an unintentional power supply as a result of lightning surges. Thus, this arrangement always ensures plant safety. Since an arc is formed at the beginning of the switch-off between the switching contacts of the switching device, the switching resistance of the vacuum interrupter chamber is constantly regenerated. The freewheeling circuit designed according to the invention always ensures that the freewheeling function is maintained even if the freewheeling diode fails due to high voltage load (eg lightning strike) and at the same time the defect is displayed.
  • high voltage load eg lightning strike
  • the shutdown is initiated by a switching command to open the metallic contact of the switching device, which is preferably a vacuum switch. This forms an arc in the vacuum interrupter chamber over the contact gap.
  • An extinguishing capacitor arranged parallel to the switching path is constantly charged between the discharging processes in order to ensure that the quick-switching device is ready for operation.
  • the discharge unit of the quenching capacitor is initiated by the switching unit, whereby the quenching capacitor discharges via the switching path of the switching device.
  • the discharge capacitor is discharged in the form of a "swinging" alternating current / oscillating process, this current being superimposed on the direct current flowing over the switching path.
  • the quenching / Umschwingstrom will have such a profile and a size that by the superimposition of the operating current (from the busbar) and the quenching / Umschwingstromes (from the capacitor), the resulting Current, the switch current flowing through the switching path, reaches the value "zero" at a certain time.
  • the defined time at which the first quenching thyristor is ignited taking into account the mechanical switching times of the switching device and depending on the current to be switched so chosen that the "zero value" of the resulting switch current occurs at a time at which the dielectric strength of the switching path in Switching device is guaranteed. So that the system load is kept as low as possible, the "zero value" of the resulting current but should occur at the earliest possible time, ie immediately or as soon as possible after the switching path has reached the dielectric strength.
  • the quenching capacitor is charged before each discharging so that with ignition of the first quenching thyristor, the quenching current of the quenching capacitor flows against the preferred direction of the operating current over the switching path during the first swing, so that when switching forward currents already at the first Umschwingvorgang a "zero value" of the resulting switch current over the switching path occurs.
  • the ignition pulse for the first quenching thyristor is in each case offset in time, depending on the time course of Umschwingvorganges the extinguishing current before the extinguishing current reaches the value of "zero" at the end of the first charge, the ignition pulse for the second quenching thyristor.
  • the second charge transfer of the quenching capacitor, now reversed current direction, initiated, if at this time not already switching the operating current is switched off.
  • the shutdown is triggered automatically when reaching a set limit of the operating current.
  • Fig. 1 shows the basic circuit arrangement for the quick-switching device, being used as a switching device, a vacuum switch VS.
  • the quick-switching device is connected via a two-pole circuit breaker SBT on the one hand to the busbar SS of the traction power supply and on the other hand to the line ST .
  • the track is galvanically isolated from the busbar by means of the two-pole SBT disconnector.
  • the vacuum switch VS is arranged between the busbar SS of the traction power supply and the line ST and serves, on the one hand, to carry operating currents, load or short-circuit currents in both current directions and, on the other hand, to rapidly produce a galvanic isolating path.
  • the drive of the vacuum switch VS takes place by means of an electromagnetic drive:
  • a current detection element T is arranged, which detects the operating and fault currents.
  • This erase circuit consists of an erase capacitor LK, two with this in series antiparallel arranged quenching thyristors LT1, LT2 and a series-connected inductance L.
  • a test circuit is also arranged in parallel to the vacuum switch VS , which checks before the reconnection of the route this to its current state.
  • the test circuit consists of a series connection of a test thyristor Vp, a current measuring element Tp and a test resistor PW. For testing the test thyristor Vp is ignited and detected with the current measuring element Tp of the current flowing through the test resistor PW current.
  • the quick-switching device is completed by a freewheeling circuit FK, which has two branches, one of which is arranged between the busbar SS of the traction power supply and the return conductor RL and the other between the route ST and the return conductor RL .
  • the freewheeling circuit FK ensures that after the production of the galvanic isolating distance in the vacuum switch VS, the energy present in the inductances of the line is quickly reduced by freewheeling currents I F.
  • This freewheeling circuit FK is constructed in such a way that two freewheeling diodes FD1, FD2 and FD3, FD4 connected in series are arranged for each branch, from the busbar SS to the return conductor RL or from the line ST to the return conductor RL .
  • a fuse Si1, Si2 with a message is arranged.
  • the fuse Si1, Si2 is dimensioned so that the voltage drop across the parallel freewheeling diode FD1, FD4 even at maximum freewheeling current I F does not exceed the voltage drop of the fuse at twice the rated current. This ensures that normally only about 0.1% to 1% of the freewheeling current I F flows via the respective fuse Si1 or Si2 . Most of the freewheeling current I F always flows through the freewheeling diode FD1 or FD4.
  • the control module SG processes the detected measured values and outputs the corresponding control commands to the vacuum switch VS and the quenching thyristors LT1, LT2 .
  • the opening process of the vacuum switch VS is automatically initiated in accordance with the set limit values.
  • the dimensioning of the extinguishing circuit in particular the capacity of the extinguishing capacitor LK. and the inductance L, there is the time-optimized control of the quenching thyristors LT1, LT2.
  • the control module SG also carries out the route check, in which the travel resistance is calculated taking into account the current outgoing voltage.
  • a connection of the route ST is only possible if the track resistance determined during the route test is greater than the specified limit value.
  • the fuse monitoring of the fuses Si1, Si2 of the freewheeling circuit FK is also performed by the control module SG, which also monitors other safety-related variables, such as the charging voltage of the quenching capacitor LK .
  • Fig. 1 will be described closer to three typical / critical operating conditions.
  • the current curves are gem. of Fig. 2 to Fig. 4 used.
  • a first example is selected in which a occurring short-circuit current I K is to be switched off in the preferred direction, ie a short circuit on the line ST is fed by the traction power supply via the busbar SS .
  • the rising short-circuit current I K is detected by the current detection element T in the current path of the vacuum switch VS.
  • the switch-off command for the vacuum switch VS is given at time t 1 and the drive begins to open the contacts of the vacuum switch VS after about 0.3 ms at time t 2 .
  • the contact opening runs evenly over the contact path KW , the maximum contact distance is 2 mm.
  • the short-circuit current I K continues to flow via the switching arc that forms when the contact is lifted within the vacuum chamber.
  • the flowing current has to assume the value "zero", since the vacuum switch used is not able to switch off a flowing short-circuit current.
  • the control command for igniting the quenching thyristor LT1 added. This stored in the turn-off capacitor LK energy is released, it flows erase current I L from the quenching capacitor LK via the switching path of the vacuum switch VS counter to the current direction of the short-circuit current I K.
  • the extinguishing current I L in the form of a swinging alternating current. Due to the selected scale, not the entire course of the extinguishing current I L is shown in FIG. 2, but only the detail which is relevant for extinguishing the arc.
  • the two currents, the short-circuit current I K and the extinguishing current I L are superimposed in the current path of the vacuum switch VS and thus over the switching path to the resulting switch current I S.
  • the two currents, the short-circuit current I K and the extinguishing current I L each have such a value, so that the resulting switch current I S reaches the value "zero".
  • the erasing current I L from the quenching capacitor LK also continues to flow via the switching path of the vacuum switch VS counter to the current direction of the short-circuit current I K. Since the erasing current I L corresponds to a sine half-wave, the resulting switch current I S at time t 5 for the second time the value "zero". At this point, the arc over the contact gap of the vacuum switch VS extinguishes (the contact distance is now approx. 1 mm), since the required dielectric strength now exists, no arc can be re-ignited. Thus, the short-circuit current I K is finally turned off. The energy still present in the route network is reduced by a flowing freewheeling current I F via the corresponding branch of the freewheeling circuit FK, the freewheeling diodes FD3, FD4 in the direction of the return conductor RL .
  • the extinguishing current I L and thus also the resulting switch current I S can be determined as a function of the ignition time t 3 of the extinguishing capacitor LK for each short-circuit current I K to be switched.
  • the defined time t 3 for firing the quenching thyristor LT1 is selected so that the maximum of the oscillating quenching current I L in each case is greater than the current flowing at this time short-circuit current I K. This ensures that the resulting switch current I S has twice the value "zero".
  • the switching path has the required dielectric strength. Since the two "zero values" of the switch current I S at t 4 and t 5 have a time interval of a maximum of 0.6 ms, the system load by switching off the short-circuit current I K is certainly responsible for the second "zero value".
  • a small operating current I B is to be switched off.
  • I B When shutting off small currents, there is the possibility that the arc in the opening contact tears off automatically before the initiation of the deletion process. This could lead to a high voltage load of the system by the inductors located in the circuit, in addition then would be pending with ignition of the quenching thyristor LT1 on the separation line, the capacitor voltage. This would be applied over the distance to the transfer of the quenching capacitor LK over the line ST in the amount of addition of busbar voltage and capacitor voltage corresponding voltage.
  • the ignition pulse for igniting the quenching thyristor LT1 at time t 3 is given before the time t 2 , the beginning of the contact opening, so that no galvanic isolation gap in the vacuum switch VS can arise.
  • a defined transhipment of the quenching capacitor LK on the still closed contact path or the forming arc between the contacts of the vacuum switch VS and the overvoltage is avoided.
  • the switch-off command for the vacuum switch VS is given at time t 1 and the drive begins to open the contacts of the vacuum switch VS at time t 2 , wherein the extinguishing current I L from the quenching capacitor LK already flows.
  • the extinguishing current I L from the quenching capacitor LK also flows in the opposite direction to the operating current I B through the switching path of the vacuum switch VS.
  • the switching path is still conductive. It follows that the arc only at time t 5 , the dielectric strength of the switching path is now guaranteed, extinguished on reaching the second "zero value" of the switch current I S and the operating current I B is turned off. Now the freewheeling current I F starts to flow.
  • a reverse current I R flowing from the route ST to the busbar SS is to be switched off. Since in this case a current is to be switched off, which flows contrary to the "preferred direction", in this case the quenching thyristor LT1 is again ignited at a different time, whereby a "zero value" of the switch current I S at the earliest possible time to pass the dielectric strength of the switching path is achieved.
  • the ignition pulse at the time t 3 for the quenching thyristor LT1 immediately after the time t 1 the switch-off command for the vacuum switch VS is given. This results in a defined transfer of the quenching capacitor LK on the closed contact of the vacuum switch VS.
  • the extinguishing current I L of the quenching capacitor LK and the return current I R have in the vacuum switch VS for the period between the times t 3 and t 7 , the duration of the first Umschwingvorganges, the same direction of current and add up. Characterized the erasing current I L obtained in the first current rise no "zero" value of the resulting switch current I S.
  • the ignition pulse for the second quenching thyristor LT2 is given, whereby at time t 7, the second charge reversal of the quenching capacitor LK is initiated.
  • the two currents, the extinguishing current I L and the return current I R different current directions, whereby the switch current I S at time t 4 reaches the value "zero".
  • the switching distance of the vacuum switch VS has the required dielectric strength, so that the standing between the contacts of the vacuum switch VS arc is extinguished and the return current is turned off.
  • the freewheeling current I F begins to flow.
  • the three examples described above correspond to typical / critical operating currents that are to be turned off by the DC quick-connect device. According to the dimensioning in particular of the cancellation circuit and the vacuum switch VS used , the times t 1 to t 7 can be predefined in the control unit SG .
  • the freewheeling circuit FK ensures that, after the production of the galvanic isolating path, the energy present in the inductances of the line ST is dissipated by the flowing freewheeling currents I F in one or the other direction.
  • This freewheeling circuit FK is constructed such that it has a branch for each current direction, from the busbar SS to the return conductor RL or from the line ST to the return conductor RL . In each branch, two freewheeling diodes FD1, FD2 and FD3, FD4 are connected in series.
  • a freewheeling diode FD1, FD4 a fuse Si1, Si2 is connected in parallel with message, wherein the largest part of the freewheeling current I F always flows through the freewheeling diode FD1 and FD4 .
  • very high voltage loads such as lightning overvoltages
  • Freewheeling diodes FD2, FD3 claimed.
  • they can lose their blocking ability. Since the two other freewheeling diodes FD1, FD4 are virtually short-circuited by the respective fuse Si1, Si2 , they are not stressed by the overvoltage and remain functional.
  • the failure of the freewheeling diode FD2 or FD3 has a short-circuit current through the fuse Si1 or Si2 result, causing it responds and shuts off this short-circuit current.
  • the freewheeling circuit FK is because of the functional residual freewheeling diodes FD1, FD4 voltage resistant again.
  • the respective fuse Si1 , Si2 reports this state to the control module SG .
  • the freewheeling circuit FK always remains functional.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)
  • Rectifiers (AREA)
  • Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The method involves using a DC rapid switching device with a switching unit (VS) and a quenching circuit parallel to the shaft section of the switching unit, consisting of a quenching capacitor (LK) connected in series with two antiparallel quenching thyristors (LT1,LT2) and an inductance (L). The switching process is initiated by a control command to open the metal contact of the switching unit at a certain time point. The first thyristor is fired at a defined time point dependent on the level and direction of the operating current. The second thyristor is fired at a time dependent on the quenching current's time profile. An independent claim is also included for rapid switching devices for quenching a DC current in a rectifier sub-mechanism for a railway current supply.

Description

Die Erfindung betrifft eine Gleichstrom-Schnellschalteinrichtung für Bahnstromversorgungen unter Verwendung eines Vakuumschalters und eines Löschkreises sowie ein Verfahren zur Abschaltung eines Gleichstromes in einem Gleichrichter-Unterwerk.The invention relates to a DC rapid switching device for traction power supplies using a vacuum switch and an extinguishing circuit and a method for switching off a direct current in a rectifier substation.

Zur Gewährleistung eines störungsfreien und sicheren Betriebs elektrischer Bahnen ist es erforderlich, dass bei ungewollten Betriebszuständen bzw. Havarien die Stromversorgung des gestörten Abgangs schnell und zuverlässig vom Gleichstromnetz getrennt wird. Da ein Gleichstrom durch herkömmliche Schaltgeräte mit metallischen Schaltkontakten schwer abgeschaltet werden kann, wurden in der Vergangenheit verschiedene Lösungen, die eine Kombination aus einer metallischen Schaltstrecke und einer Halbleiter-Schaltstrecke darstellen, sogenannte Hybridschalter, vorgeschlagen und eingesetzt. Hierbei wird grundsätzlich parallel zur metallischen Schaltstrecke, die vorzugsweise durch einen Vakuumschalter realisiert wurde, eine Kommutierungsstrecke mit Thyristoren angeordnet. Bei diesen Schalteinrichtungen wird zeitgleich mit dem Öffnungsbefehl für den Vakuumschalter ein Thyristor im Kommutierungszweig gezündet, so dass der zu schaltende Strom aus dem Lastkreis in den Kommutierungszweig kommutiert und danach durch Löschen der Thyristoren vollständig unterbrochen wird.In order to ensure a trouble-free and safe operation of electric railways, it is necessary that the power supply of the faulty outgoings be quickly and reliably disconnected from the DC power supply in the event of unwanted operating conditions or accidents. Since a DC current can be switched off by conventional switching devices with metallic switching contacts difficult, various solutions that represent a combination of a metallic switching path and a semiconductor switching path, so-called hybrid switch, have been proposed and used in the past. Here, in principle, a commutation path with thyristors is arranged parallel to the metallic switching path, which was preferably realized by a vacuum switch. In these switching devices, a thyristor in the Kommutierungszweig is ignited at the same time as the opening command for the vacuum switch, so that the current to be switched from the load circuit commutated in the Kommutierungszweig and is then completely interrupted by deleting the thyristors.

Der Nachteil der bekannten Hybridschalter, wie sie in der DE 37 35 009 A1 bzw. in der EP 0 184 566 beschrieben sind, besteht darin, dass der eingesetzte Kondensator zeitgleich, in einem Schaltzustand, sowohl Antriebsals auch Löschkondensator ist und zudem die Kapazität durch die Brückenschaltung (beide Stromrichtungen für den metallischen Kontakt) kurzgeschlossen ist.The disadvantage of the known hybrid switch, as described in DE 37 35 009 A1 or in EP 0184 566, is that the capacitor used at the same time, in a switching state, both drive and quenching capacitor and also the capacity of the Bridge circuit (both current directions for the metallic contact) is short-circuited.

In der DE 44 47 439 ist ein Verfahren und eine Schaltungsanordnung für eine Kommutierungs- und Löscheinrichtung eines Schnellunterbrechers beschrieben, bei der zeitgleich mit dem Schaltbefehl für den Schnellunterbrecher Zündimpulse für zwei Schaltthyristoren im Kommutierungszweig ausgelöst werden, wodurch sich der Kondensator über die Antriebsspulen des Schnellunterbrechers entlädt und die Kontaktöffnung bewirkt. Gleichzeitig kommutiert der Strom in den Kommutierungszweig. Zu einem späteren Zeitpunkt werden zwei Ladethyristoren gezündet, wodurch der Kondensator umgeladen wird und die volle Kondensatorspannung die beiden Schaltthyristoren im Kommutierungszweig löscht.
Der Nachteil dieser Einrichtung besteht insbesondere darin, dass eine Vielzahl von schnellen und hochbelastbaren Bauelementen, insbesondere Thyristoren erforderlich ist, wodurch diese Einrichtung sehr teuer ist.
Ein weiterer Nachteil besteht darin, dass bei diesen Einrichtungen zu einer von den Anwendern geforderten galvanischen Trennung der Strecke von der Sammelschiene eine zusätzliche Trennstelle vorgesehen werden musste.In DE 44 47 439 a method and a circuit arrangement for a Kommutierungs- and quenching device of a quick breaker is described, are triggered at the same time with the switching command for the quick breaker firing pulses for two switching thyristors in Kommutierungszweig, causing the capacitor discharges through the drive coils of the quick breaker and the contact opening causes. At the same time the current commutes in the Kommutierungszweig. At a later time, two charging thyristors are ignited, whereby the capacitor is reloaded and the full capacitor voltage deletes the two switching thyristors in Kommutierungszweig.
The disadvantage of this device is in particular that a large number of fast and highly loadable components, in particular thyristors is required, whereby this device is very expensive.
A further disadvantage is that in these devices an additional separation point had to be provided for a galvanic separation of the path from the busbar required by the users.

Von P.M. McEwan, S.B. Tennakoon wird in "A Two Stage DC Thyristor Circuit Breaker", IEEE Transactions on Power Electronics, Vol. 12, no. 4, July 1997 eine zweistufige elektronische Gleichstromschalteinrichtung beschrieben, bei der über zwei unterschiedliche Kommutierungszweige der Kommutierungskondensator zweimal nacheinander in unterschiedlichen Richtungen auf- und umgeladen wird, wodurch die entstehenden Schaltüberspannungen wesentlich verringert werden können.PM McEwan, SB Tennakoon describes in a "Two Stage DC Thyristor Circuit Breaker", IEEE Transactions on Power Electronics, Vol. 12, no. 4, July 1997, a two-stage electronic DC switching device in which the commutating capacitor is passed through two different commutation branches twice in succession is loaded and reloaded in different directions, whereby the resulting switching overvoltages can be significantly reduced.

Die wesentlichen Nachteile dieser Einrichtung bestehen darin, dass nur Ströme in einer Richtung geschaltet werden können und dass die Schaltstrecke ausschließlich durch Halbleiter gebildet wird.The main disadvantages of this device are that only currents can be switched in one direction and that the switching path is formed exclusively by semiconductors.

Die Aufgabe besteht darin, eine Gleichstrom-Schnellschalteinrichtung für Bahnstromversorgungen und ein Verfahren anzugeben, die eine zuverlässige und schnelle Abschaltung des Betriebsstromes bzw. von Kurzschlußströmen aber auch von Rückwärtsströmen bei gleichzeitiger galvanischer Trennung der Strecke von der Sammelschiene des Gleichrichter-Unterwerks gewährleistet, wobei die Bauelemente keinen hohen dynamischen Anforderungen ausgesetzt sind, so dass die Einrichtung mit preiswerten Bauelementen realisierbar ist.The object is to provide a DC rapid switching device for traction power supplies and a method that ensures a reliable and rapid shutdown of the operating current or short-circuit currents but also reverse currents while galvanic isolation of the distance from the busbar of the rectifier substation, the components are not exposed to high dynamic requirements, so that the device with low-cost components can be realized.

Erfindungsgemäß wird diese Aufgabe durch eine Gleichstrom-Schnellschalteinrichtung und ein Verfahren mit den Merkmalen der Patentansprüche 1 und 3 gelöst.According to the invention this object is achieved by a DC rapid switching device and a method having the features of claims 1 and 3.

Die Gleichstrom-Schnellschalteinrichtung für Bahnstromversorgungen wird charakterisiert durch die Merkmale des Patentanspruchs 1, wobei zwischen der Strecke und der Sammelschiene des Gleichrichter-Unterwerks ein Schaltgerät angeordnet ist. Parallel zu diesem Schaltgerät ist ein Löschkreis angeordnet, der aus einem Löschkondenstor besteht, der mit einer Schalteinheit, bestehend aus zwei antiparallel angeordneten Löschthyristoren, in Reihe geschaltet ist. Zu dem Schaltgerät ist außerdem ein Prüfzweig parallel angeordnet. Der Prüfzweig besteht aus einer Reihenschaltung von einem Prüfthyristor, einem Strommessglied und einem Prüfwiderstand. Die Gleichstrom-Schnellschalteinrichtung weist außerdem einen Freilaufkreis auf, der für jede Stromrichtung jeweils einen Zweig aufweist, von der Sammelschiene zum Rückleiter bzw. von der Strecke zum Rückleiter, in denen jeweils zwei Freilaufdioden, die in Reihe geschaltet sind, angeordnet sind. Jeweils einer Freilaufdiode in jedem Zweig des Freilaufkreises ist parallel eine Sicherung mit Meldung angeordnet. Die Dimensionierung der Freilaufdiode und der Sicherung ist dabei so gewählt, dass jeweils nur ein geringer Teil des Freilaufstromes über die jeweilige Sicherung fließt, während der größte Teil des Freilaufstromes über die zur Sicherung parallel angeordnete Freilaufdiode fließt.The DC rapid switching device for traction power supplies is characterized by the features of claim 1, wherein between the track and the busbar of the rectifier substation, a switching device is arranged. Parallel to this switching device, an erase circuit is arranged, which consists of a Löschkondenstor, which is connected in series with a switching unit consisting of two antiparallel arranged thyristors. To the switching device also a test branch is arranged in parallel. The test branch consists of a series connection of a test thyristor, a current measuring element and a test resistor. The DC rapid switching device also has a freewheeling circuit, each having a branch for each current direction, from the busbar to the return conductor or from the line to the return conductor, in each of which two freewheeling diodes, which are connected in series, are arranged. In each case a freewheeling diode in each branch of the freewheeling circuit is arranged in parallel a fuse with message. The Dimensioning of the freewheeling diode and the fuse is chosen so that only a small portion of the freewheeling current flows through the respective fuse, while most of the freewheeling current flows through the freewheeling diode arranged in parallel to the fuse.

Zur Verarbeitung der ermittelten Betriebswerte und Ausgabe der Steuerbefehle ist eine an sich bekannte aber entsprechend der Verfahrensschritte speziell programmierte Steuerbaugruppe vorgesehen. Die erfassten Messwerte werden durch eine herkömmliche Steuerbaugruppe verarbeitet die auf dieser Grundlage die entsprechenden Steuerbefehle an das Schaltgerät sowie die Löschthyristoren ausgibt. Durch die Auswertung der Größe des Stroms und der Stromanstiegsgeschwindigkeit wird in Abhängigkeit der eingestellten Grenzwerte der Öffnungsvorgang des Schaltgeräts selbsttätig eingeleitet und unter Berücksichtigung der Dimensionierung des Löschkreises, insbesondere der Kapazität des Löschkondensators erfolgt die zeitoptimierte Ansteuerung der Löschthyristoren. Die Streckenprüfung wird ebenfalls durch die Steuerbaugruppe durchgeführt, indem unter Einbeziehung der aktuellen Abgangsspannung der Streckenwiderstandes berechnet wird und die Zuschaltung der Strecke nur bei ausreichend großem Streckenwiderstand möglich ist.
Auch die Sicherungsüberwachung der Sicherungen des Freilaufkreises erfolgt durch die Steuerbaugruppe, die auch weitere sicherheitsrelevante Größen, wie beispielsweise die Ladespannung des Löschkondensators überwacht.For processing the determined operating values and output of the control commands, a control module which is known per se but is specially programmed in accordance with the method steps is provided. The acquired measured values are processed by a conventional control module which outputs the corresponding control commands to the switching device and the quenching thyristors on this basis. By evaluating the size of the current and the rate of increase in current, the opening process of the switching device is initiated automatically depending on the set limits and taking into account the dimensioning of the cancellation circuit, in particular the capacity of the quenching capacitor, the time-optimized control of the quenching thyristors. The route test is also carried out by the control module, by calculating the current output voltage of the track resistance and the connection of the track is only possible with sufficiently large line resistance.
The fuse monitoring of the fuses of the freewheeling circuit is carried out by the control module, which also monitors other safety-related variables, such as the charging voltage of the quenching capacitor.

Die erfindungsgemäße Schnellschalteinrichtung hat den Vorteil, dass sie mit preiswerten Bauelementen, insbesondere Thyristoren und Kondensatoren realisiert werden kann, da keine hohen Anforderungen an die Schaltgeschwindigkeit und die dynamischen Eigenschaften gestellt werden. Ein weiterer Vorteil besteht darin, dass mit dieser Schnellschalteinrichtung die galvanische Trennstrecke nicht durch Halbleiterbauelemente überbrückt wird, die infolge von Blitzüberspannungen eine unbeabsichtigte Stromführung übernehmen könnten. Somit gewährleistet diese Anordnung stets die Anlagensicherheit.
Da bei Beginn des Abschaltvorgangs zwischen den Schaltkontakten des Schaltgerätes ein Lichtbogen ausgebildet wird, wird ständig die Schaltfestigkeit der Vakuumschaltkammer regeneriert.
Durch den erfindungsgemäß ausgeführten Freilaufkreis ist stets gewährleistet, dass auch bei einer durch hohe Spannungsbelastung (z. B. Blitzschlag) ausgefallenen Freilaufdiode die Freilauffunktion erhalten bleibt und gleichzeitig der Defekt angezeigt wird.The quick-switching device according to the invention has the advantage that it can be realized with inexpensive components, in particular thyristors and capacitors, since no high demands are placed on the switching speed and the dynamic properties. Another advantage is that with this quick-switching device, the galvanic isolation path is not bridged by semiconductor devices which could take over an unintentional power supply as a result of lightning surges. Thus, this arrangement always ensures plant safety.
Since an arc is formed at the beginning of the switch-off between the switching contacts of the switching device, the switching resistance of the vacuum interrupter chamber is constantly regenerated.
The freewheeling circuit designed according to the invention always ensures that the freewheeling function is maintained even if the freewheeling diode fails due to high voltage load (eg lightning strike) and at the same time the defect is displayed.

Nach dem erfindungsgemäßen Verfahren zur Abschaltung eines Gleichstromes, bei dem eine Einrichtung mit den Merkmalen des Patentanspruchs 1 verwendet wird, wird der Abschaltvorgang durch einen Schaltbefehl zum Öffnen des metallischen Kontakts des Schaltgerätes, das vorzugsweise ein Vakuumschalter ist, eingeleitet. Dabei bildet sich in der Vakuumschaltkammer über der Schaltstrecke ein Lichtbogen aus. Ein parallel zur Schaltstrecke angeordneter Löschkondensator wird zur Gewährleistung der Betriebsbereitschaft der Schnellschalteinrichtung zwischen den Entladevorgängen ständig aufgeladen. Zu einem definierten Zeitpunkt, der zeitlich nach dem Schaltbefehl zum Öffnen des metallischen Kontakts des Schaltgerätes liegt, wird durch die Schalteinheit die Entladung des Löschkondensators eingeleitet, wodurch sich der Löschkondensator über die Schaltstrecke des Schaltgerätes entlädt. Durch die im Löschkreis vorhandenen Induktivitäten erfolgt die Entladung des Löschkondensators in Form eines "schwingenden" Wechselstroms / Umschwingvorganges, wobei sich dieser Strom dem über der Schaltstrecke fließenden Gleichstrom überlagert. Bei einer entsprechenden Dimensionierung des Löschkreises, insbesondere des Löschkondensators, wird der Löschstrom/ Umschwingstrom einen derartigen Verlauf und eine Größe aufweisen, dass durch die Überlagerung des Betriebsstromes (von der Sammelschiene) und des Löschstromes/ Umschwingstromes (vom Kondensator), der resultierende Strom, der über die Schaltstrecke fließende Schalterstrom, zu einem bestimmten Zeitpunkt den Wert "Null" erreicht.According to the inventive method for switching off a direct current, in which a device having the features of claim 1 is used, the shutdown is initiated by a switching command to open the metallic contact of the switching device, which is preferably a vacuum switch. This forms an arc in the vacuum interrupter chamber over the contact gap. An extinguishing capacitor arranged parallel to the switching path is constantly charged between the discharging processes in order to ensure that the quick-switching device is ready for operation. At a defined time, which is after the switching command to open the metallic contact of the switching device, the discharge unit of the quenching capacitor is initiated by the switching unit, whereby the quenching capacitor discharges via the switching path of the switching device. As a result of the inductances present in the extinguishing circuit, the discharge capacitor is discharged in the form of a "swinging" alternating current / oscillating process, this current being superimposed on the direct current flowing over the switching path. With a corresponding dimensioning of the quenching circuit, in particular the quenching capacitor, the quenching / Umschwingstrom will have such a profile and a size that by the superimposition of the operating current (from the busbar) and the quenching / Umschwingstromes (from the capacitor), the resulting Current, the switch current flowing through the switching path, reaches the value "zero" at a certain time.

Der definierte Zeitpunkt, zu dem der erste Löschthyristor gezündet wird, wird unter Berücksichtigung der mechanischen Schaltzeiten des Schaltgerätes und in Abhängigkeit des zu schaltenden Stromes so gewählt, dass der "Nullwert" des resultierenden Schalterstromes zu einem Zeitpunkt erfolgt, zu dem die Durchschlagsfestigkeit der Schaltstrecke im Schaltgerät gewährleistet ist. Damit die Anlagenbelastung möglichst gering gehalten wird, soll der "Nullwert" des resultierenden Stromes aber zu einem möglichst frühen Zeitpunkt auftreten, also unmittelbar bzw. möglichst frühzeitig nachdem die Schaltstrecke die Durchschlagsfestigkeit erreicht hat. Bei Einhaltung der Voraussetzung, dass der "Nullwert" des resultierenden Stromes zu einem Zeitpunkt auftritt, wenn die Kontakte des Schaltgerätes bereits einen entsprechenden Abstand voneinander haben, dass die nun vorhandene Durchschlagsfestigkeit der Schaltstrecke ein Wiederzünden des Lichtbogens bei der anliegenden Schalterspannung verhindert, ist der Gleichstrom abgeschaltet.The defined time at which the first quenching thyristor is ignited, taking into account the mechanical switching times of the switching device and depending on the current to be switched so chosen that the "zero value" of the resulting switch current occurs at a time at which the dielectric strength of the switching path in Switching device is guaranteed. So that the system load is kept as low as possible, the "zero value" of the resulting current but should occur at the earliest possible time, ie immediately or as soon as possible after the switching path has reached the dielectric strength. In compliance with the requirement that the "zero value" of the resulting current occurs at a time when the contacts of the switching device already have a corresponding distance from each other that the now existing dielectric strength of the switching path prevents re-ignition of the arc at the applied switch voltage, is the DC off.

Der Löschkondensator wird vor jedem Entladevorgang so aufgeladen, dass mit Zünden des ersten Löschthyristors der Löschstrom des Löschkondensator beim ersten Umschwingen entgegen der Vorzugsrichtung des Betriebsstromes über die Schaltstrecke fließt, so dass beim Schalten von Vorwärtsströmen bereits beim ersten Umschwingvorgang ein "Nullwert" des resultierenden Schalterstromes über der Schaltstrecke auftritt.The quenching capacitor is charged before each discharging so that with ignition of the first quenching thyristor, the quenching current of the quenching capacitor flows against the preferred direction of the operating current over the switching path during the first swing, so that when switching forward currents already at the first Umschwingvorgang a "zero value" of the resulting switch current over the switching path occurs.

Nach dem Zündimpuls für den ersten Löschthyristor wird in jedem Fall zeitlich versetzt, in Abhängigkeit vom zeitlichen Verlauf des Umschwingvorganges des Löschstromes, bevor der Löschstrom am Ende des ersten Umladevorganges den Wert "Null" erreicht, der Zündimpuls für den zweiten Löschthyristor gegeben. Dadurch wird der zweite Umladevorgang des Löschkondensators, jetzt mit umgekehrter Stromrichtung, eingeleitet, sofern zu diesem Zeitpunkt nicht bereits der zu schaltende Betriebsstrom abgeschaltet ist.After the ignition pulse for the first quenching thyristor is in each case offset in time, depending on the time course of Umschwingvorganges the extinguishing current before the extinguishing current reaches the value of "zero" at the end of the first charge, the ignition pulse for the second quenching thyristor. As a result, the second charge transfer of the quenching capacitor, now reversed current direction, initiated, if at this time not already switching the operating current is switched off.

Durch das Steuergerät wird der Abschaltvorgang bei Erreichen eines eingestellten Grenzwertes des Betriebsstromes selbsttätig ausgelöst.By the controller, the shutdown is triggered automatically when reaching a set limit of the operating current.

Weitere vorzugsweise Ausgestaltungen des Verfahrens können den Unteransprüchen 4 bis 10 entnommen werden.Further preferred embodiments of the method can be taken from the subclaims 4 to 10.

Die Erfindung wird nachstehend an Hand eines Ausführungsbeispiels näher erläutert. Die zugehörigen Zeichnungen stellen dar:

Fig. 1:
Prinzipschaltung der Schnellschalteinrichtung
Fig. 2:
Stromverläufe und Zeitpunkte für Öffnung des Schaltgerätes und Zündung des Löschthyristors für große Ströme
Fig. 3:
Stromverläufe und Zeitpunkte für Öffnung des Schaltgerätes und Zündung des Löschthyristors für kleine Ströme
Fig. 4:
Stromverläufe und Zeitpunkte für Öffnung des Schaltgerätes und Zündung des Löschthyristors für Rückströme
The invention will be explained in more detail below with reference to an embodiment. The accompanying drawings show:
Fig. 1:
Basic circuit of the quick-switching device
Fig. 2:
Current curves and times for opening of the switching device and ignition of the quenching thyristor for large currents
3:
Current curves and times for opening of the switching device and ignition of the quenching thyristor for small currents
4:
Current characteristics and times for opening of the switching device and ignition of the quenching thyristor for return currents

Die Fig. 1 zeigt die prinzipielle Schaltungsanordnung für die Schnellschalteinrichtung, wobei als Schaltgerät ein Vakuumschalter VS eingesetzt ist. Die Schnellschalteinrichtung ist über einen zweipoligen Trennschalter SBT einerseits mit der Sammelschiene SS der Bahnstromversorgung und andererseits mit der Strecke ST verbunden. Im abgeschalteten Zustand wird die Strecke mittels des zweipoligen Trennschalters SBT galvanisch von der Sammelschiene getrennt.Fig. 1 shows the basic circuit arrangement for the quick-switching device, being used as a switching device, a vacuum switch VS. The quick-switching device is connected via a two-pole circuit breaker SBT on the one hand to the busbar SS of the traction power supply and on the other hand to the line ST . When switched off, the track is galvanically isolated from the busbar by means of the two-pole SBT disconnector.

Der Vakuumschalter VS ist zwischen Sammelschiene SS der Bahnstromversorgung und der Strecke ST angeordnet und dient einerseits dem Führen von Betriebsströmen, Last- oder Kurzschlussströmen in beiden Stromrichtungen und andererseits zur schnellen Herstellung einer galvanischen Trennstrecke. Der Antrieb des Vakuumschalters VS erfolgt mittels eines elektromagnetischen Antriebes:The vacuum switch VS is arranged between the busbar SS of the traction power supply and the line ST and serves, on the one hand, to carry operating currents, load or short-circuit currents in both current directions and, on the other hand, to rapidly produce a galvanic isolating path. The drive of the vacuum switch VS takes place by means of an electromagnetic drive:

Im Strompfad des Vakuumschalters ist ein Stromerfassungsglied T angeordnet, welches die Betriebs- und Fehlerströme erfasst.In the current path of the vacuum switch, a current detection element T is arranged, which detects the operating and fault currents.

Parallel zum Vakuumschalter VS ist ein Löschkreis zwischen Sammelschiene SS der Bahnstromversorgung und der Strecke ST angeordnet. Dieser Löschkreis besteht aus einem Löschkondensator LK, zwei mit diesem in Reihe liegenden antiparallel angeordnete Löschthyristoren LT1, LT2 und einer in Reihe geschalteten Induktivität L. Parallel to the vacuum switch VS an erase circuit between the busbar SS of the traction power supply and the line ST is arranged. This erase circuit consists of an erase capacitor LK, two with this in series antiparallel arranged quenching thyristors LT1, LT2 and a series-connected inductance L.

Ein Prüfkreis ist ebenfalls parallel zum Vakuumschalter VS angeordnet, der vor der Wiederzuschaltung der Strecke diese auf ihren aktuellen Zustand überprüft. Der Prüfkreis besteht aus einer Reihenschaltung von einem Prüfthyristor Vp, einem Strommessglied Tp und einem Prüfwiderstand PW. Zur Streckenprüfung wird der Prüfthyristor Vp gezündet und mit dem Strommessglied Tp der durch den Prüfwiderstand PW fließende Strom erfasst.A test circuit is also arranged in parallel to the vacuum switch VS , which checks before the reconnection of the route this to its current state. The test circuit consists of a series connection of a test thyristor Vp, a current measuring element Tp and a test resistor PW. For testing the test thyristor Vp is ignited and detected with the current measuring element Tp of the current flowing through the test resistor PW current.

Vervollständigt wird die Schnellschalteinrichtung durch einen Freilaufkreis FK, der zwei Zweige aufweist, von denen einer zwischen der Sammelschiene SS der Bahnstromversorgung und dem Rückleiter RL und der andere zwischen der Strecke ST und dem Rückleiter RL angeordnet ist. Der Freilaufkreis FK gewährleistet, dass nach der Herstellung der galvanischen Trennstrecke im Vakuumschalter VS die in den Induktivitäten der Strecke vorhandene Energie durch Freilaufströme I F schnell abgebaut wird. Dieser Freilaufkreis FK ist derart aufgebaut, dass für jeden Zweig, von der Sammelschiene SS zum Rückleiter RL bzw. von der Strecke ST zum Rückleiter RL, jeweils zwei in Reihe geschaltete Freilaufdioden FD1, FD2 bzw. FD3, FD4 angeordnet sind. Parallel zur jeweiligen mit der Sammelschiene SS bzw. bzw. mit der Strecke ST verbundenen Freilaufdiode FD1, FD4, ist jeweils eine Sicherung Si1, Si2 mit Meldung angeordnet. Die Sicherung Si1, Si2 ist so dimensioniert, dass der Spannungsabfall über der parallelen Freilaufdiode FD1, FD4 auch bei maximalem Freilaufstrom IF den Spannungsabfall der Sicherung bei doppeltem Nennstrom nicht überschreitet. Dadurch wird gewährleistet, dass normalerweise nur ca. 0,1 % bis 1 % des Freilaufstromes I F über die jeweilige Sicherung Si1 bzw. Si2 fließt. Der größte Teil des Freilaufstromes I F fließt stets über die Freilaufdiode FD1 bzw. FD4. The quick-switching device is completed by a freewheeling circuit FK, which has two branches, one of which is arranged between the busbar SS of the traction power supply and the return conductor RL and the other between the route ST and the return conductor RL . The freewheeling circuit FK ensures that after the production of the galvanic isolating distance in the vacuum switch VS, the energy present in the inductances of the line is quickly reduced by freewheeling currents I F. This freewheeling circuit FK is constructed in such a way that two freewheeling diodes FD1, FD2 and FD3, FD4 connected in series are arranged for each branch, from the busbar SS to the return conductor RL or from the line ST to the return conductor RL . Parallel to the respective freewheeling diode FD1, FD4 connected to the busbar SS or to the line ST , respectively, a fuse Si1, Si2 with a message is arranged. The fuse Si1, Si2 is dimensioned so that the voltage drop across the parallel freewheeling diode FD1, FD4 even at maximum freewheeling current I F does not exceed the voltage drop of the fuse at twice the rated current. This ensures that normally only about 0.1% to 1% of the freewheeling current I F flows via the respective fuse Si1 or Si2 . Most of the freewheeling current I F always flows through the freewheeling diode FD1 or FD4.

Die Steuerbaugruppe SG verarbeitet die erfassten Messwerte und gibt die entsprechenden Steuerbefehle an den Vakuumschalter VS sowie die Löschthyristoren LT1, LT2 aus. Durch die Auswertung des Stromsignals vom Stromerfassungsglied T und der Stromanstiegsgeschwindigkeit wird entsprechend der eingestellten Grenzwerte der Öffnungsvorgang des Vakuumschalters VS selbsttätig eingeleitet. In Abhängigkeit vom zu schaltenden Betriebsstrom I B , der Dimensionierung des Löschkreises, insbesondere der Kapazität des Löschkondensators LK. und der Induktivität L, erfolgt die zeitoptimierte Ansteuerung der Löschthyristoren LT1, LT2. Durch die Steuerbaugruppe SG wird auch die Streckenprüfung durchgeführt, bei der unter Einbeziehung der aktuellen Abgangsspannung die Berechnung des Streckenwiderstandes erfolgt. Eine Zuschaltung der Strecke ST ist nur möglich, wenn der bei der Streckenprüfung ermittelte Streckenwiderstand größer als der vorgegebene Grenzwert ist.
Die Sicherungsüberwachung der Sicherungen Si1, Si2 des Freilaufkreises FK erfolgt auch durch die Steuerbaugruppe SG, die auch weitere sicherheitsrelevante Größen, wie beispielsweise die Ladespannung des Löschkondensators LK überwacht.The control module SG processes the detected measured values and outputs the corresponding control commands to the vacuum switch VS and the quenching thyristors LT1, LT2 . By evaluating the current signal from the current detection element T and the current increase speed, the opening process of the vacuum switch VS is automatically initiated in accordance with the set limit values. Depending on the operating current I B to be switched , the dimensioning of the extinguishing circuit, in particular the capacity of the extinguishing capacitor LK. and the inductance L, there is the time-optimized control of the quenching thyristors LT1, LT2. The control module SG also carries out the route check, in which the travel resistance is calculated taking into account the current outgoing voltage. A connection of the route ST is only possible if the track resistance determined during the route test is greater than the specified limit value.
The fuse monitoring of the fuses Si1, Si2 of the freewheeling circuit FK is also performed by the control module SG, which also monitors other safety-related variables, such as the charging voltage of the quenching capacitor LK .

Nachfolgend soll das erfindungsgemäße Verfahren zur Abschaltung von Betriebs- oder Fehlerströmen mit der zuvor beschriebenen Einrichtung gem. Fig. 1 näher an Hand von drei typischen / kritischen Betriebszuständen beschrieben werden. Dazu werden auch die Stromverläufe gem. der Fig. 2 bis Fig. 4 herangezogen.Below is the inventive method for switching off operating or fault currents with the device described above gem. Fig. 1 will be described closer to three typical / critical operating conditions. For this purpose, the current curves are gem. of Fig. 2 to Fig. 4 used.

In Fig. 2 ist ein erstes Beispiel gewählt, bei dem ein auftretender Kurzschlussstrom I K in Vorzugsrichtung abgeschaltet werden soll, d. h. ein Kurzschluss auf der Strecke ST wird durch die Bahnstromversorgung über die Sammelschiene SS gespeist. Der ansteigende Kurzschlussstrom I K wird durch das Stromerfassungsglied T im Strompfad des Vakuumschalters VS erfasst. Bei Erreichen eines einstellbaren Betriebsstromes von beispielsweise 4 kA wird zum Zeitpunkt t 1 der Ausschaltbefehl für den Vakuumschalter VS gegeben und der Antrieb beginnt die Kontakte des Vakuumschalters VS nach ca. 0,3 ms zum Zeitpunkt t 2 zu öffnen. Die Kontaktöffnung verläuft über den Kontaktweg KW gleichmäßig, der maximale Kontaktabstand beträgt 2 mm. Der Kurzschlussstrom I K fließt über den sich beim Abheben des Kontaktes innerhalb der Vakuumkammer ausbildenden Schaltlichtbogen weiter. Um den Schaltlichtbogen zwischen den Kontakten des Vakuumschalters VS zu löschen, muss der fließende Strom den Wert "Null" annehmen, da der verwendete Vakuumschalter nicht in der Lage ist, einen fließenden Kurzschlussstrom abzuschalten. Um dies zu erreichen wird zum Zeitpunkt t 3 der Steuerbefehl zum Zünden des Löschthyristors LT1 gegeben. Dadurch wird die im Löschkondensator LK gespeicherte Energie freigegeben, es fließt ein Löschstrom I L vom Löschkondensator LK über die Schaltstrecke des Vakuumschalters VS entgegen der Stromrichtung des Kurzschlussstromes I K . Da sich in diesem Löschkreis Induktivitäten befinden, weist der Löschstrom I L die Form eines schwingenden Wechselstromes auf. Auf Grund des gewählten Maßstabes ist in der Fig. 2 nicht der gesamte Verlauf des Löschstromes I L dargestellt, sondern lediglich der Ausschnitt, der für die Löschung des Lichtbogens relevant ist. Die beiden Ströme, der Kurzschlussstrom I K und der Löschstrom I L überlagern sich im Strompfad des Vakuumschalters VS und damit über der Schaltstrecke zum resultierenden Schalterstrom I S . Zum Zeitpunkt t 4 weisen die beiden Ströme, der Kurzschlussstrom I K und der Löschstrom I L jeweils einen solchen Wert auf, so dass der resultierende Schalterstrom I S den Wert "Null" erreicht. Zu diesem Zeitpunkt t 4 erlischt somit auch der Schaltlichtbogen zwischen den Kontakten des Vakuumschalters VS. Mit dem Erlöschen des Schaltlichtbogens steht über der Schaltstrecke die momentan vorhandene Spannung des Löschkondensators LK an. Übersteigt diese Spannung die zu diesem Zeitpunkt t 4 bestehende Durchschlagsfestigkeit der Schaltstrecke nicht, zündet der Lichtbogen nicht wieder und der Kurzschlussstrom I K ist abgeschaltet. Ist dagegen zu diesem Zeitpunkt t 4 , wie im gewählten Beispiel (der Kontaktabstand beträgt ca. 0,2 mm) die Durchschlagsfestigkeit der Schaltstrecke des Vakuumschalters VS noch nicht gegeben, kommt es zu einer Wiederzündung des Lichtbogens und der Kurzschlussstrom I K fließt weiter über die Schaltstrecke. Der Löschstrom I L vom Löschkondensator LK fließt ebenfalls weiter über die Schaltstrecke des Vakuumschalters VS entgegen der Stromrichtung des Kurzschlussstromes I K . Da der Löschstrom I L einer Sinushalbwelle entspricht, weist der resultierende Schalterstrom I S zum Zeitpunkt t 5 zum zweiten Mal den Wert "Null" auf. Zu diesem Zeitpunkt erlischt der Lichtbogen über der Schaltstrecke des Vakuumschalters VS (der Kontaktabstand beträgt nun ca. 1 mm), da jetzt die die erforderliche Durchschlagsfestigkeit besteht, kann kein Lichtbogen wieder gezündet werden. Somit ist der Kurzschlussstrom I K endgültig abgeschaltet. Die noch im Streckennetz vorhandene Energie wird durch einen fließenden Freilaufstrom I F über den entsprechenden Zweig des Freilaufkreises FK, die Freilaufdioden FD3, FD4 in Richtung auf den Rückleiter RL abgebaut.2, a first example is selected in which a occurring short-circuit current I K is to be switched off in the preferred direction, ie a short circuit on the line ST is fed by the traction power supply via the busbar SS . The rising short-circuit current I K is detected by the current detection element T in the current path of the vacuum switch VS. Upon reaching an adjustable operating current of, for example, 4 kA, the switch-off command for the vacuum switch VS is given at time t 1 and the drive begins to open the contacts of the vacuum switch VS after about 0.3 ms at time t 2 . The contact opening runs evenly over the contact path KW , the maximum contact distance is 2 mm. The short-circuit current I K continues to flow via the switching arc that forms when the contact is lifted within the vacuum chamber. In order to clear the switching arc between the contacts of the vacuum switch VS , the flowing current has to assume the value "zero", since the vacuum switch used is not able to switch off a flowing short-circuit current. To achieve this, at time t 3, the control command for igniting the quenching thyristor LT1 added. This stored in the turn-off capacitor LK energy is released, it flows erase current I L from the quenching capacitor LK via the switching path of the vacuum switch VS counter to the current direction of the short-circuit current I K. Since there are inductances in this quenching circuit, the extinguishing current I L in the form of a swinging alternating current. Due to the selected scale, not the entire course of the extinguishing current I L is shown in FIG. 2, but only the detail which is relevant for extinguishing the arc. The two currents, the short-circuit current I K and the extinguishing current I L are superimposed in the current path of the vacuum switch VS and thus over the switching path to the resulting switch current I S. At time t 4 , the two currents, the short-circuit current I K and the extinguishing current I L each have such a value, so that the resulting switch current I S reaches the value "zero". At this point in time t 4 , the switching arc between the contacts of the Vacuum switch VS. When the switching arc goes out, the current voltage of the quenching capacitor LK is present across the contact gap. If this voltage does not exceed the dielectric strength of the contact gap existing at this point in time t 4 , the arc does not re-ignite and the short-circuit current I K is switched off. However, if at this time t 4 , as in the example chosen (the contact distance is about 0.2 mm), the dielectric strength of the switching path of the vacuum switch VS is not yet given, there is a re-ignition of the arc and the short-circuit current I K continues to flow over the switching path. The erasing current I L from the quenching capacitor LK also continues to flow via the switching path of the vacuum switch VS counter to the current direction of the short-circuit current I K. Since the erasing current I L corresponds to a sine half-wave, the resulting switch current I S at time t 5 for the second time the value "zero". At this point, the arc over the contact gap of the vacuum switch VS extinguishes (the contact distance is now approx. 1 mm), since the required dielectric strength now exists, no arc can be re-ignited. Thus, the short-circuit current I K is finally turned off. The energy still present in the route network is reduced by a flowing freewheeling current I F via the corresponding branch of the freewheeling circuit FK, the freewheeling diodes FD3, FD4 in the direction of the return conductor RL .

Da die Dimensionierung des Löschkreises bekannt ist, kann auch für jeden zu schaltenden Kurzschlussstrom I K der Löschstrom I L und somit auch der resultierende Schalterstrom I S in Abhängigkeit vom Zündzeitpunkt t 3 des Löschkondensators LK ermittelt werden. Der definierte Zeitpunkt t 3 zum Zünden des Löschthyristors LT1 ist so gewählt, dass das Maximum des schwingenden Löschstromes I L in jedem Falle größer ist als der zu diesem Zeitpunkt fließende Kurzschlussstrom I K . Dadurch wird gewährleistet, dass der resultierende Schalterstrom I S zweimal den Wert "Null" aufweist. Spätestens zum Zeitpunkt t 5 , wenn der resultierende Schalterstrom I S zum zweiten Mal den Wert "Null" aufweist, hat die Schaltstrecke die erforderliche Durchschlagsfestigkeit. Da die beiden "Nullwerte" des Schalterstromes I S bei t 4 und t 5 einen zeitlichen Abstand von maximal 0,6 ms aufweisen, ist die Anlagenbelastung durch ein Abschalten des Kurzschlussstromes I K erst beim zweiten "Nullwert" durchaus zu vertreten.Since the dimensioning of the extinguishing circuit is known, the extinguishing current I L and thus also the resulting switch current I S can be determined as a function of the ignition time t 3 of the extinguishing capacitor LK for each short-circuit current I K to be switched. The defined time t 3 for firing the quenching thyristor LT1 is selected so that the maximum of the oscillating quenching current I L in each case is greater than the current flowing at this time short-circuit current I K. This ensures that the resulting switch current I S has twice the value "zero". At the latest at time t 5 , when the resulting switch current I S for second time the value "zero", the switching path has the required dielectric strength. Since the two "zero values" of the switch current I S at t 4 and t 5 have a time interval of a maximum of 0.6 ms, the system load by switching off the short-circuit current I K is certainly responsible for the second "zero value".

In einem weiteren Beispiel gem. Fig. 3 soll ein kleiner Betriebsstrom I B abgeschaltet werden. Beim Abschalten kleiner Ströme besteht die Möglichkeit, dass der Lichtbogen im sich öffnenden Kontakt selbsttätig vor der Einleitung des Löschvorganges abreißt. Dies könnte durch die im Kreis befindlichen Induktivitäten zu einer hohen Spannungsbelastung der Anlage führen, darüber hinaus würde dann mit Zünden des Löschthyristors LT1 über der Trennstrecke zusätzlich die Kondensatorspannung anstehen. Damit würde über der Trennstrecke bis zum Umladen des Löschkondensators LK über die Strecke ST eine im Betrag der Addition von Sammelschienenspannung und Kondensatorspannung entsprechende Spannung anliegen. Um dies zu verhindern wird der Zündimpuls zum Zünden des Löschthyristors LT1 im Zeitpunkt t 3 bereits vor dem Zeitpunkt t 2 , dem Beginn der Kontaktöffnung gegeben, so dass keine galvanische Trennstrecke im Vakuumschalter VS entstehen kann. Somit erfolgt eine definierte Umladung des Löschkondensators LK über die noch geschlossene Kontaktstrecke bzw. den sich ausbildenden Lichtbogen zwischen den Kontakten des Vakuumschalters VS und die Überspannung wird vermieden. Zum Abschalten eines kleinen Betriebsstromes wird zum Zeitpunkt t 1 der Ausschaltbefehl für den Vakuumschalter VS gegeben und der Antrieb beginnt die Kontakte des Vakuumschalters VS zum Zeitpunkt t 2 zu öffnen, wobei der Löschstrom I L vom Löschkondensator LK bereits fließt. Analog zum vorigen Beispiel fließt der Löschstrom I L vom Löschkondensator LK ebenfalls in entgegengesetzter Richtung zum Betriebsstrom I B durch die Schaltstrecke des Vakuumschalters VS. Da in diesem Fall der erste "Nullwert" zum Zeitpunkt t 4 erreicht wird, der vor dem Zeitpunkt t 2 liegt, d. h. die Kontaktöffnung hat noch nicht begonnen, ist die Schaltstrecke noch leitend. Daraus folgt, dass der Lichtbogen erst zum Zeitpunkt t 5 , die Durchschlagsfestigkeit der Schaltstrecke ist jetzt auch gewährleistet, beim Erreichen des zweiten "Nullwertes" des Schalterstromes I S erlischt und der Betriebsstrom I B abgeschaltet ist. Jetzt beginnt der Freilaufstrom I F zu fließen.In another example gem. 3, a small operating current I B is to be switched off. When shutting off small currents, there is the possibility that the arc in the opening contact tears off automatically before the initiation of the deletion process. This could lead to a high voltage load of the system by the inductors located in the circuit, in addition then would be pending with ignition of the quenching thyristor LT1 on the separation line, the capacitor voltage. This would be applied over the distance to the transfer of the quenching capacitor LK over the line ST in the amount of addition of busbar voltage and capacitor voltage corresponding voltage. To prevent this, the ignition pulse for igniting the quenching thyristor LT1 at time t 3 is given before the time t 2 , the beginning of the contact opening, so that no galvanic isolation gap in the vacuum switch VS can arise. Thus, a defined transhipment of the quenching capacitor LK on the still closed contact path or the forming arc between the contacts of the vacuum switch VS and the overvoltage is avoided. To switch off a small operating current, the switch-off command for the vacuum switch VS is given at time t 1 and the drive begins to open the contacts of the vacuum switch VS at time t 2 , wherein the extinguishing current I L from the quenching capacitor LK already flows. Analogous to the previous example, the extinguishing current I L from the quenching capacitor LK also flows in the opposite direction to the operating current I B through the switching path of the vacuum switch VS. In this case, since the first "zero value" is reached at the time t 4 , which is before the time t 2 , ie Contact opening has not yet started, the switching path is still conductive. It follows that the arc only at time t 5 , the dielectric strength of the switching path is now guaranteed, extinguished on reaching the second "zero value" of the switch current I S and the operating current I B is turned off. Now the freewheeling current I F starts to flow.

In einem dritten Beispiel gem. Fig. 4 soll ein Rückstrom I R , der von der Strecke ST zur Sammelschiene SS fließt, abgeschaltet werden. Da in diesem Fall ein Strom abgeschaltet werden soll, der entgegen der "Vorzugsrichtung" fließt, wird auch in diesem Fall der Löschthyristor LT1, wiederum zu einem anderen Zeitpunkt gezündet, wodurch ein "Nullwert" des Schalterstromes I S zu einem möglichst frühen Zeitpunkt nach Bestehen der Durchschlagsfestigkeit der Schaltstrecke erreicht wird.
In diesem Fall wird der Zündimpuls im Zeitpunkt t 3 für den Löschthyristor LT1 sofort nach dem Zeitpunkt t 1 , dem Ausschaltbefehl für den Vakuumschalter VS gegeben. Damit erfolgt ein definiertes Umladen des Löschkondensators LK über den geschlossenen Kontakt des Vakuumschalters VS. Der Löschstrom I L des Löschkondensators LK und der Rückstrom I R haben im Vakuumschalter VS für den Zeitraum zwischen den Zeitpunkten t 3 und t 7 , der Zeitdauer des ersten Umschwingvorganges, die gleiche Stromrichtung und addieren sich. Dadurch ergibt sich beim ersten Stromanstieg des Löschstromes I L kein "Nullwert" des resultierenden Schalterstromes I S .
Zum Zeitpunkt t 6 wird der Zündimpuls für den zweiten Löschthyristor LT2 gegeben, wodurch zum Zeitpunkt t 7 der zweite Umladevorgang des Löschkondensators LK eingeleitet wird. Nun weisen die beiden Ströme, der Löschstrom I L und der Rückstrom I R unterschiedliche Stromrichtungen auf, wodurch der Schalterstrom I S zum Zeitpunkt t 4 den Wert "Null" erreicht. Zu diesem Zeitpunkt weist die Schaltstrecke des Vakuumschalters VS die erforderliche Durchschlagsfestigkeit auf, so dass der zwischen den Kontakten des Vakuumschalters VS stehende Lichtbogen gelöscht wird und der Rückstrom ist abgeschaltet. Der Freilaufstrom I F beginnt zu fließen.In a third example acc. 4, a reverse current I R flowing from the route ST to the busbar SS is to be switched off. Since in this case a current is to be switched off, which flows contrary to the "preferred direction", in this case the quenching thyristor LT1 is again ignited at a different time, whereby a "zero value" of the switch current I S at the earliest possible time to pass the dielectric strength of the switching path is achieved.
In this case, the ignition pulse at the time t 3 for the quenching thyristor LT1 immediately after the time t 1 , the switch-off command for the vacuum switch VS is given. This results in a defined transfer of the quenching capacitor LK on the closed contact of the vacuum switch VS. The extinguishing current I L of the quenching capacitor LK and the return current I R have in the vacuum switch VS for the period between the times t 3 and t 7 , the duration of the first Umschwingvorganges, the same direction of current and add up. Characterized the erasing current I L obtained in the first current rise no "zero" value of the resulting switch current I S.
At time t 6 , the ignition pulse for the second quenching thyristor LT2 is given, whereby at time t 7, the second charge reversal of the quenching capacitor LK is initiated. Now, the two currents, the extinguishing current I L and the return current I R different current directions, whereby the switch current I S at time t 4 reaches the value "zero". At this time, the switching distance of the vacuum switch VS has the required dielectric strength, so that the standing between the contacts of the vacuum switch VS arc is extinguished and the return current is turned off. The freewheeling current I F begins to flow.

Die drei zuvor beschriebenen Beispiele entsprechen typischen / kritischen Betriebsströmen, die durch die Gleichstrom-Schnellschalteinrichtung abgeschaltet werden sollen. Entsprechend der Dimensionierung insbesondere des Löschkreises und des verwendeten Vakuumschalters VS können die Zeitpunkte t 1 bis t 7 in der Steuerbaugruppe SG vordefiniert werden.The three examples described above correspond to typical / critical operating currents that are to be turned off by the DC quick-connect device. According to the dimensioning in particular of the cancellation circuit and the vacuum switch VS used , the times t 1 to t 7 can be predefined in the control unit SG .

Damit auch in außergewöhnlichen Situationen ein fließender Gleichstrom sicher und zuverlässig abgeschaltet wird, kann vorgesehen werden, dass die Löschthyristoren LT1, LT2 wiederholt gezündet werden, so dass die Entladung des Löschkondensators LK analog der zuvor beschriebenen Verfahrensschritte wiederholt wird. Da spätestens bei Erreichen eines dritten "Nullwertes" des Schalterstromes I S die Durchschlagsfetigkeit gewährleistet ist, kommt es dann nicht zum Wiederzünden eines Lichtbogens über der Schaltstrecke und der zu schaltende Betriebsstrom ist auch spätestens zu diesem Zeitpunkt abgeschaltet.So that even in exceptional situations, a flowing direct current is switched off safely and reliably, it can be provided that the quenching thyristors LT1, LT2 are repeatedly ignited, so that the discharge of the quenching capacitor LK is repeated analogously to the method steps described above. Since the Durchschlagfetigkeit is guaranteed at the latest when reaching a third "zero value" of the switch current I S , it does not then re-ignite an arc over the switching path and the operating current to be switched is switched off at the latest at this time.

Abschließend soll die Wirkungsweise des erfindungsgemäßen Freilaufkreises näher erläutert werden. Der Freilaufkreis FK gewährleistet, dass nach der Herstellung der galvanischen Trennstrecke die in den Induktivitäten der Strecke ST vorhandene Energie, durch die fließenden Freilaufströme I F in der einen oder der anderen Richtung, abgebaut wird. Dieser Freilaufkreis FK ist derart aufgebaut, dass er für jede Stromrichtung einen Zweig, von der Sammelschiene SS zum Rückleiter RL bzw. von der Strecke ST zum Rückleiter RL aufweist. In jedem Zweig sind zwei Freilaufdioden FD1, FD2 bzw. FD3, FD4 in Reihe geschaltet. Jeweils einer Freilaufdiode FD1, FD4, ist eine Sicherung Si1, Si2 mit Meldung parallel geschaltet, wobei der größte Teil des Freilaufstromes I F stets über die Freilaufdiode FD1 bzw. FD4 fließt. Durch auftretende sehr hohe Spannungsbelastungen, wie beispielsweise Blitzüberspannungen, werden nur die jeweils nicht beschalteten Freilaufdioden FD2, FD3 beansprucht. Dadurch können sie ihre Sperrfähigkeit verlieren. Da die beiden anderen Freilaufdioden FD1, FD4 durch die jeweilige Sicherung Si1, Si2 quasi kurzgeschlossen sind, werden sie durch die Überspannung nicht beansprucht und bleiben funktionsfähig. Der Ausfall der Freilaufdiode FD2 bzw. FD3 hat einen Kurzschlussstrom über die Sicherung Si1 bzw. Si2 zur Folge, wodurch diese anspricht und diesen Kurzschlussstrom abschaltet. Nach dem Ansprechen der Sicherung Si1 bzw. Si2 ist der Freilaufkreis FK wegen der funktionsfähig gebliebenen Freilaufdioden FD1, FD4 wieder spannungsfest. Die jeweilige Sicherung Si1, Si2 meldet diesen Zustand an die Steuerbaugruppe SG. Somit bleibt der Freilaufkreis FK stets funktionstüchtig.Finally, the operation of the freewheeling circuit according to the invention will be explained in more detail. The freewheeling circuit FK ensures that, after the production of the galvanic isolating path, the energy present in the inductances of the line ST is dissipated by the flowing freewheeling currents I F in one or the other direction. This freewheeling circuit FK is constructed such that it has a branch for each current direction, from the busbar SS to the return conductor RL or from the line ST to the return conductor RL . In each branch, two freewheeling diodes FD1, FD2 and FD3, FD4 are connected in series. In each case a freewheeling diode FD1, FD4 , a fuse Si1, Si2 is connected in parallel with message, wherein the largest part of the freewheeling current I F always flows through the freewheeling diode FD1 and FD4 . By occurring very high voltage loads, such as lightning overvoltages, only the respectively unconnected Freewheeling diodes FD2, FD3 claimed. As a result, they can lose their blocking ability. Since the two other freewheeling diodes FD1, FD4 are virtually short-circuited by the respective fuse Si1, Si2 , they are not stressed by the overvoltage and remain functional. The failure of the freewheeling diode FD2 or FD3 has a short-circuit current through the fuse Si1 or Si2 result, causing it responds and shuts off this short-circuit current. After the response of the fuse Si1 and Si2 the freewheeling circuit FK is because of the functional residual freewheeling diodes FD1, FD4 voltage resistant again. The respective fuse Si1 , Si2 reports this state to the control module SG . Thus, the freewheeling circuit FK always remains functional.

Claims (10)

  1. A direct current rapid-switching device for quenching a direct current in a rectifier substation for a direct current traction power supply, wherein a switching device (VS), which is connected in series to a current detecting element (T), is situated between the path (ST) and the bus bar (SS) of the rectifier substation, also a quenching circuit including a quenching capacitor (LK), an inductance (L), and a switching unit is connected in parallel therewith, and further a freewheeling circuit (FK) is positioned parallel to the switching device (VS),
    characterised in that
    the switching unit includes two quenching thyristors (LT1, LT2) arranged antiparallel, and a test branch that is made up of a test thyristor (Vp) in series connection, a current-measuring element (Tp), and a test resistor (PW) is also arranged in parallel to the switching device (VS), and further that the freewheeling circuit (FK) is made up of two branches, one of which is positioned between the bus bar (SS) and the return conductor (RL) and the other is positioned between the path (ST) and the return conductor (RL), each branch having two series-connected freewheeling diodes (FD1, FD2 and FD3, FD4, respectively), and a fuse (Si1, Si2) having a signal is situated in parallel with the freewheeling diode (FD1, FD4) connected to the bus bar (SS) and the path (ST) respectively.
  2. The direct current rapid-switching device as cited in claim 1,
    characterised in that
    the dimensioning of the freewheeling diode (FD1, FD4) and the fuse (Si1, Si2) arranged in parallel therewith is selected such that in each case only a small part of the freewheeling current (IF) flows over the associated fuse (Si1, Si2), while the majority of the freewheeling current (IF) flows over the freewheeling diode (FD1, FD4) arranged in parallel with this fuse (Si1, Si2).
  3. A method for switching off direct currents in a rectifier substation for traction power supplies using a direct current rapid-switching device according to claim 1, wherein the switching off procedure is initiated by a switching command for opening the metallic contact of the switching device (VS) when a settable current value is reached at time (t1) and discharging of the quenching capacitor (LK) is subsequently initiated by the switching unit at a defined time (t3), resulting in the quenching capacitor (LK) discharging along the switching path of the switching device (VS), wherein given corresponding dimensioning of the quenching circuit the switch current (IS) assumes the value "zero" at least once due to the superimposition of the operating current (IB) from the bus bar (SS) and the quenching current (IL) from the quenching capacitor (LK) to form the resulting switch current (IS) over the switching path,
    characterised in that
    the time (t3) at which the first quenching thyristor (LT1) is ignited is determined as a function of the size and direction of the operating current (IB) to be switched, and the second quenching thyristor (LT2) is ignited in delayed manner at time (t6) depending on the temporal progress of the quenching current (IL) of the quenching capacitor (LK), and the defined time (t3) for igniting the quenching thyristor (LT1) is selected such that a "zero value" of the switch current (IS) is reached at a time (t4, t5) at which the dielectric strength of the switching path in the switching device (VS) is ensured.
  4. The method as cited in claim 3,
    characterised in that
    the switch off command for the switching device (VS) to switch off a large operating current (IB) flowing in the predominant direction, in particular a short-circuit current (IK), is given at time (t1) when a settable limit value is reached, and the control command for igniting the quenching thyristor (LT1) is present at time (t3) following the start of the contact opening at time (t2), causing the quenching current (IL) to flow over the switching path of the switching device (VS) against the direction of flow of short-circuit current (IK), and the switch current (IS) reaches the value "zero" in each case at times (t4, t5), and the operating current (IB) or short-circuit current (IK) is switched off at this time given the presence of the dielectric strength of the switching path at one of the two times (t4, t5).
  5. The method as cited in claim 3,
    characterised in that
    the switch off command for the switching device (VS) to switch off a small operating current (IB) flowing in the predominant direction, is given at time (t1) and the ignition pulse to ignite the quenching thyristor (LT1) is given at time (t3) prior to time (t2), the start of the contact opening, so that a defined change in charge of the quenching capacitor (LK) takes place over the still closed contact path or the electric arc forming between the contacts of the switching device (VS), wherein the quenching current (IL) from the quenching capacitor (LK) flow against the direction of the operating current (IB) over the switching path of the switching device (VS), and the switching current (IS) reaches the value "zero" for the first time at time (t4), when the switching path is still conductive, and the switching current (IS) reaches the value "zero" for the second time at time (t5) and the operating current (IB) is now switched off since the dielectric strength of the switching path is assured.
  6. The method as cited in claim 3,
    characterised in that
    the ignition impulse for quenching thyristor (LT1) to switch off a reflux current (IR) flowing against the predominant direction is given at time (t3), immediately following time (t1) at which the switch off command is given for the switching device (VS), so that a defined change in charge of the quenching capacitor (LK) takes place over the still closed contact of the switching device (VS), and the amounts of quenching current (IL) and of back current (IR) are added together since they have the same flow direction, and the ignition pulse for the second quenching thyristor (LT2) is given at time (t6), causing the second charge changing procedure of the quenching capacitor (LK) to be initiated with the reverse flow direction, so that the quenching current (IL) now flows in the opposite direction of the reflux current (IR) over the switching path of the switching device (VS) and the switch current (IS) thus assumes the value "zero" at time (t4), at which the switching path of the switching device (VS) has the necessary dielectric strength so that the reflux current (IR) is switched off.
  7. The method as cited in claim 3,
    characterised in that
    the quenching capacitor (LK) is always precharged such that when the first quenching thyristor (LT1) is ignited, the quenching current (IL) of the quenching capacitor (LK) flows against the preferred direction of the operating current (IB) upon the first oscillation reversal.
  8. The method as cited in claim 3,
    characterised in that
    the ignition pulse for the second quenching thyristor (LT2) is given in all cases at time (t6), which is determined as a function of the temporal progression of the oscillation reversal, thus causing the second charge changing operation of the quenching capacitor (LK) to be initiated with a reverse current direction, so that the quenching current (IL) now flows in the predominant direction of the operating current (IB) over the switching path of the switching device (VS), if the operating current (IB) to be switched is not already switched off at this time.
  9. The method as cited in claim 3,
    characterised in that
    the switch off procedure is triggered automatically via the control device (SG) when set threshold values of the operating current (IB) are reached.
  10. The method as cited in claim 3,
    characterised in that
    under extreme conditions the quenching thyristors (LT1, LT2) are repeatedly ignited alternatingly to switch off an operating current (IB) so that the quenching capacitor (LK) discharges multiple times consecutively over the switching path of the switching device (VS) until the requisite dielectric strength of the switching path is assured when a "zero value" of the switch current (IS) reached and the operating current (IB) is definitively switched off.
EP03090155A 2003-05-23 2003-05-23 Hybrid DC circuit breaker with zero current switching and method of switching Expired - Lifetime EP1480241B1 (en)

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DE50302112T DE50302112D1 (en) 2003-05-23 2003-05-23 Method for disconnecting direct currents and DC rapid switching device for traction power supplies
EP03090155A EP1480241B1 (en) 2003-05-23 2003-05-23 Hybrid DC circuit breaker with zero current switching and method of switching
AT03090155T ATE315274T1 (en) 2003-05-23 2003-05-23 METHOD FOR TURNING DIRECT CURRENT OFF AND DIRECT CURRENT FAST SWITCHING DEVICE FOR TRACK POWER SUPPLIES

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US8174801B2 (en) 2009-04-01 2012-05-08 Honeywell International, Inc. Controlling arc energy in a hybrid high voltage DC contactor
US9742185B2 (en) 2015-04-28 2017-08-22 General Electric Company DC circuit breaker and method of use

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Publication number Priority date Publication date Assignee Title
DE102011082568A1 (en) 2011-09-13 2013-03-14 Siemens Aktiengesellschaft DC circuit breaker
DE102012008614A1 (en) 2012-04-27 2013-10-31 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Electrical plug connector for disconnecting electric current, has controller to control semiconductor electronics such that arc is prevented or reduced when disconnecting connector regardless of direction of flow of electric current
US9054530B2 (en) 2013-04-25 2015-06-09 General Atomics Pulsed interrupter and method of operation
KR20150078491A (en) * 2013-12-30 2015-07-08 주식회사 효성 High-voltage DC circuit breaker

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8174801B2 (en) 2009-04-01 2012-05-08 Honeywell International, Inc. Controlling arc energy in a hybrid high voltage DC contactor
US9742185B2 (en) 2015-04-28 2017-08-22 General Electric Company DC circuit breaker and method of use

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DE50302112D1 (en) 2006-03-30
EP1480241A1 (en) 2004-11-24
ATE315274T1 (en) 2006-02-15

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