DE1075722B - Magnetic arc blower device in DC high-speed switches - Google Patents

Description

GERMAN

The invention relates to a magnetic arc blowing device for DC high-speed switches in rectifier systems with step chokes.

DC high-speed circuit breakers are equipped with a current-dependent magnetic blowout, which causes the arc formed after the contact has been opened into the quenching chamber of the switch is driven.

Here, the magnetic field acts on the moving charge carriers kn arc plasma in such a way that the voltage gradient necessary to extinguish the arc through elongation and cooling of the arch is reached.

The known high-speed switches are not only used to protect against overcurrent, but are also used as reverse current circuit breakers in rectifier units working in parallel. Large electrolysis plants with contact converters need a protective element for the DC circuit, e.g. B. a switch with extremely fast response times works and a reverse current in the event of failure of a converter unit to a minimum value limited.

In order to delay the transition of the current from forward to reverse current as much as possible, so-called step chokes 6 (Fig. 4) are housed on the secondary side of a contact converter system. The chokes, which are made of transformer sheet metal, are located in one pole of the direct current supply line II (Fig. 4) and are magnetically saturated at full rated current. Only when there are strong changes in current, If the current falls from the forward to the reverse current, the throttle is in the immediate vicinity the current zero crossing a further change in current with their own magnetic energy.

As a result, depending on the characteristics of the choke iron, a current level occurs in the vicinity of the current zero value, the duration of which also depends on the driving voltage. The stage leads, depending on the quality of the choke iron, a return current of a few 100 amperes (Fig. 2 b and 3 b).

If the contacts of the high-speed switch are opened during the low-current break, then it is safe Quenching the relatively small arc before the step current has completely passed through is crucial Meaning. Shortly after the end of the stage, the return current rises to full strength and would feed into the plasma if the arc was not extinguished.

A magnetic field component K generated by the current itself in connection with the blowing coil and the blowing iron is of little importance at the moment of the tap change and thus for blowing and extinguishing the arc. You Magnetic Lidite Arc Blower
with DC high-speed switches

Applicant:

LICENTIA Patent Administration - G. m. B. H., Frankfurt / M., Theodor-Stern-Kai 1

Heinz Fehling, Neumünster,
has been named as the inventor

In addition, due to strong remanence in the blow iron, the duration of the step can be reversed at the moment Direction act so that the arc is not driven into the quenching chamber, but into the Schialterkontakte (Fig. 1, 2anind 2 b).

If the release winding L _n , which causes the high-speed switch to switch off as a function of the change in current, lies parallel to the blower coil, conditions for the magnetic blowing are particularly unfavorable for a switch-off during the stage duration. When loaded with constant direct current, blower coil L _B and _{release winding L n} are loaded with different current strengths according to the resistances of the parallel branches. The current I _n flows through the release coil and the current I ₃ flows through the blower coil. When a reverse current occurs, the change in current occurs at different speeds in the coils connected in parallel because of the different inductivity, so that the current distribution no longer corresponds to the current distribution in stationary operation.

While the less loaded release winding already carries reverse current due to the lower inductance, the change in current in the blowing winding takes a slower course due to the greater inductivity. The blow coil current I _B remains in the forward current, so to speak, especially during the time of the stage duration. When the contacts of the high -speed switch open in the stage (point α in Fig. 3), a reverse current arc is opposed to a blowing field direction that has not yet been changed. The arc is thereby driven into the main contacts coated with silver, stabilizes its plasma by shortening the arc column and takes over after passing through the

909 730/370

Claims (1)

3 4 Stage a relatively strong reverse current, both to the flow 0 _res when using the additional magnetic destruction of the main contacts and to unclean blowing according to the invention.
Shutdown conditions can lead (Fig. 1). Fig. 3 c shows the course of the pulse current I _Imp , which consists of The magnetic arc blowing device is removed from the stage choke 6, DC high-speed switches in rectifier systems 5 Fig. 4 shows an embodiment of the magnetic with step chokes avoids additional blowing device according to the invention according to the invention these disadvantages in that the magnetic main circuit of the release winding according to FIG. 3 a. blowing device an additional magnetic blowing Fig. 4 shows the arrangement of the additional blowing device is assigned, which is from the stepped choke a high-speed switch, the blower coil 1 with an im is excited her in such a way that she provided tripping coil 2 lying during the period io shunted the low-current stage is on for shutdown. In stationary operation, the flows through this unfavorable blowing field of the main blowing device over current I _n , while the blowing coil current I _B together winds, so that the resulting field corresponds to the light with a fixed number of turns has arc deleting direction. Switch rated _{current to} flow Φ Β to the system. The additional, magnetic blowing device compels 15. The blow core 3 is made of laminated sheet metal from one of the main magnetic circuits. In the immediate vicinity of the magnetic field blower parallel iron circle with point is a shaded pole 4, the outer Additional blow windings, which carries the additional blow windings 8 on a secondary tap leg. The Hufder Bkskern3, an iron-shaped built-up choke, continues to succumb to the high-speed switch. 20 is supplemented by an additional iron circle 5, which is used for For switching off small currents of 3 to 10 cfe magnetic field reversal near the pole is essential. Ampere, e.g. B. is practically unrelated to shutdown. From Fig. 4 it can be seen how stationary loaded railway systems are quick switches, as the current load and thus in the event of a normal magnetic blow at these low currents paint the forward current switching off by the is not sufficient, even with a pneumatic contact 12 that can be closed and the arc horn 9 set blowing has been equipped. When opening the created winding the magnetic flow Contacts is moved a small air flask _a m shaded pole reinforced. a short-term, not very strong air flow. B. by presses between the contact pieces. Fault in a converter unit, changes via the Be used in high-speed switches in electric power plants 30 switches total current / dependent with steps chokes loading _V lie on the circuit constants with varying operating conditions differently. It doesn’t come here at high speed, its direction
disable se, low currents, but with through Sekundärabgriff 13 from the stages 6 throttle help of stages in the case of chokes backflow _w i _r d _o f the Zusatzblasspulen 8, a surge gedie to facilitate disconnection. The output, which, in its height through the series resistor 7 circuit, sets in during the stage duration. Which can be set at the beginning of the level. The parallel stage current is then, for example, 500 Ms 600Ampere, _Z tripping coil arranged around the blowing coil circuit and the main blowing field is still ineffective or changes its current more quickly and is already reversed. At this moment by a current, while the blow coil 1 is still vigorous arc blowing, the arc of the ₄₀ approaching the flux Φ _Β in the blow core 3 is maintained. To remove the main contacts and to drive into the extinguishing The current surge conducted through the coils 8 causes the chamber to drive, the additional magnetic blow is applied according to the invention, a blown in opposite directions conducted through the iron circuit 5. A river Φ _ζ . Thus, at the moment of contact opening there is weak air blowing for currents of 3 to 10 Am- not only the pere would be insufficient for blowing the arc 45 wrongly on the reverse current arc during the stage duration during the stromscfowache break. A repealed, but a smaller for the arc magnetic Lichtbogenblaseinridhtung has counter current necessary Anfangsblasung provided over a pneumatic Zusatzblasung no The Zusatzblasung according to the invention can thus-wearing parts, as linkage Urid piston, the overall _where hl for switches with z> ur Blow coils must be lying in parallel, waited and monitored. 50 of the release coil as well as for switches with a The invention can be found in more detail with reference to the drawing structure according to FIG. 2 a. The explains. It shows written additional blowing can also be used with others Fig. 1 apply the arc formation in the switch under switching devices whose contacts in a time-limited and almost currentless break of the resulting field Φ _Γβ3 according to the invention under the influence of the blown field Φ _{Β and under the influence.} 55 open.
With 14 the main and with 15 the tear-off contacts are designated, 16 represents an arcing horn, claims: Fig. 2a shows a known circuit in which the Aus l. Magnetic arc blowing device with release winding L _Nz and blowing coil L _{B are connected} in series with direct current high-speed switches in rectifiers, 60 layers with stepped chokes, characterized Fig. 2 b the associated current and flux curves that the magnetic main blower a Furthermore, the course of the curve for the resulting additional magnetic blowing device is assigned Flux is 0 _res when using the additional magnetic _ne t, which is excited in this way by the step choke bladder, it will be that during the duration of the current Fig. 3a shows another known circuit, in the 65 weak level a for the disconnection ungündie release winding L _n parallel to the blowing coil L _B stiges blow field of the main blower winds, so that the resulting field a the FIG. 3 b has the curves associated with FIG. 3 a for the arc-extinguishing direction. Blow coil current I _B and the tripping winding current 2. Magnetic arc blowing device according to I _n , the flux of the blowing coil Φ _Β and the resulting 70 claim 1, 'characterized in that the Additional magnetic blowing device is formed by one of the magnetic circuit of the Main blowing device (1 to 4), additional iron circuit (5) connected in parallel to the magnetic Field reversal in the vicinity of the pole, also of additional blow windings (8) in this additional Iron circle, which are located on a secondary tap on the stepped throttle (6). 3. Magnetic arc blowing device according to claim 1 or 2, characterized in that a blow core (3) is split in the immediate vicinity of the magnetic field point and the outer legs of the split poles have an additional Blowing (8) carry a current pulse that generates the flow (Φχ) ^to compensate for the damaging flow. 4. Magnetic arc blowing device according to claim 1 Ms 3, characterized in that the level of the current pulse can be adjusted by means of a series resistor (7). Considered publications:
German Patent No. 718 901;
French Patent No. 1,123,448;
AEG-Mitteilungen, 1954, H. 3/4, P. 127. 1 sheet of drawings © 909 730/370 2.60