SU433556A1 - SWITCH - Google Patents

Description

one

The invention relates to electrical equipment and can be used in switches having electric parallel arcing breaks (chambers).

The use of parallel arc-suppressing discontinuities to increase the tripping current of the breakers becomes necessary if the current to 3. is so large that it cannot be disconnected by a single break.

Parallel chambers in high-power low-voltage circuit breakers are known, however, this only achieves an increase in the rated current and the service life of the switch, and the cut-off current is almost NS.

Studies have shown that the presence of parallel arcing breaks increases the switch-off current only under the condition of parallel arc suppression, i.e., if electric arcs are lit at all parallel discontinuities (with some unavoidable non-simultaneity of the arc of parallel arc extinguishing contacts); unstable, fairly uniform distribution of disconnected current in parallel arcs during the current half-period; at zero current values, either quenching of all arcs, or, if at least one of them does not go out, re-ignites them all, so that the current is turned off after a half-period.

Studies have shown the same. That parallel arc suppression is more difficult to ensure, because less switching current is less.

Practically in a switch with parallel arc-breaks (chambers) parallel arc suppression must be ensured at currents starting from the specified minimum. Obviously, the minimum current does not exceed the limit current of a single camera.

The purpose of the proposed 11th acquisition is an ul-parallel parallel arc arc welding.

For this, the switch is equipped with a reactor with two windings connected in different arcing circuits so that the magnetic fields of the windings in the reactor are directed oppositely.

The inductance of one winding of the reactor (when it is de-energized) BTOpoii winding) must exceed the inductance of the phase of the circuit-breaker to be disconnected at a given minimum parallel arc current.

The reactor may have a closed ferromagnetic magnetic core.

As is well known, in such cases the concept of inductance becomes vague, since the static, dynamic and energy inductance will be unequal and depend on the magnitude of the current.

Therefore, in the case of a reactor with a ferromagnetic magnetic core, the inductance of the reactor winding should be understood to mean the dynamic inductance of the winding at zero values of the alternating current in it.

If parallel arc circuits contain two or more series of arc suppressor breaks, then the reactor winding should be placed between two successive breaks. The drawing shows an electrical circuit of the arc-suppressing circuits of the proposed switch.

Each of the two parallel arcing circuits of the generator switch 1 contains two arcing trips connected in series, for example, 2 and 3.

The switch is equipped with a reactor 4 with two identical windings 5 and 6, which are included in different arcing circuits (not in one), and the magnetic fields of the windings in the reactor are directed oppositely.

The inductance of each winding of the reactor exceeds the inductance of the phase of the circuit to be disconnected at a predetermined minimum parallel arc current, i.e., it exceeds the sum of inductances 7 and 8, and inductance 7 is the phase inductance of the generator 9 and conductor section from the generator to the switch 1, from switch 1 to the point of short circuit 10, in which the short circuit current is equal to the specified minimum. current. of parallel arc arc.

So, if this current is equal to 100 ka, and the line voltage of the switch is 24 kV, then the inductance of the windings 5 and 6 must exceed the value l /) 1

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If reactor 4 has a closed ferromagnetic magnetic core, then the dynamic inductance of the winding at zero values of alternating current in it should exceed 440 µH.

Note that the inductance of the switch 1 is generally small compared to the inductance of one winding, since the magnetic fields of the windings are directed oppositely.

When switching off the short circuit current switch 1 in arcing breaks, the arcs are hot.

Reactor 4 with the corresponding parameters of their windings provides parallel arc suppression.

As a result, the switchable power is fairly evenly distributed across all arcing breaks (for currents exceeding the specified minimum) and the breaker trip current increases approximately in proportion to the number of parallel arcing circuits.

Subject invention

Claims (3)

1. A switch for super-large tripping currents with electrically parallel arcing circuits containing arcing triggers formed by opening arcing voltages, characterized in that, in order to improve the parallel arcing, it is equipped with a reactor with two windings connected in series with the ruptures in different arcing chains so that the magnetic fields of the windings in the reactor are directed oppositely. 2. The switch according to claim 1, in accordance with Clause 1, and in order to improve parallel arc suppression at currents exceeding a predetermined minimum, the reactor winding is made with an inductance exceeding the inductance of the phase of the circuit to be disconnected for a given minimum current. 3. The switch according to claim 1, characterized in that, in order to improve parallel arc extinguishing at currents exceeding a predetermined mission. Maximum, the reactor winding is made with a ferromagnetic magnet conductor with a dynamic inductance} at zero values of alternating current exceeding the phase inductance of the disconnected circuit for a given minimum current.