SU429382A1 - DEVICE FOR TESTING THE HIGH-VOLTAGE SWITCH-OFF SWITCHING CAPACITY - Google Patents

Description

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Devices for testing high-voltage circuit-breakers for switching capacity are known, including an oscillating circuit, an auxiliary source of alternating current, and two transformers.

In the known device for testing switches with the attenuation of the discharge current of the capacitor battery of the oscillating circuit, the operation mode M1 is set at the instant of closing the circuit, which is chosen so that the current in the circuit does not exceed the nominal operating circuit of the capacitor battery.

Adherence to this mode does not fully compensate for the attenuation of the switched-off current when testing switches with arc duration of several half periods.

It is especially difficult to ensure that the current remains unchanged when tested in synthetic circuits, where the lower voltage of the switchable current source is applied, as a result of which its change in this circuit is highly dependent on the voltage across the arc.

In order to obtain a continuous switching-off current during the entire shutdown process, ensure stable reliable operation of the circuit and better utilize the installed power, the current attenuation of the discharge of the capacitor battery of the circuit can be dried before the arc occurs.

source of alternating current (IPT), connected in series with the oscillatory circuit, and after ignition of the arc at the contacts of the test switch, both due to the series-connected IPT and the same IPT, but connected in parallel and .-; circuit duplicity.

The drawing shows the proposed device and schedule. The device consists of a pre-charged capacitor bank /, inductance 2, a source of alternating current 3 7, test transformers 4 and 5, controlled switching arresters 6 and 7, safety switches 8-

10 and the subject //.

Current 1 | enters through the switches 9 11 before switching on the detector 7 (switchable current on the interval); i2 is the current that would flow through the closed contacts of switches 9 and //, i.e., in the absence of an arc, after being connected (by means of the IPT 3 distributor 7 through the transistor jmator 5 parallel to the inductance 2. The graph shows the following

GZ - switchable current. Of. - arc voltage, t - moment of switching on the G, t-i-moment of opening the contacts of the switch 9 or 11, 3 - moment of connecting the IPT 3 through the transformer 5 parallel to the inductance 2 of the circuit.

The device works as follows. After charging a capacitor battery / up to a predetermined voltage with the help of switching on voltage 6, the circuit closes into a strictly predetermined voltage phase of the IPT 3 connected in series with the oscillatory circuit through the transformer 4. Voltage phase at the instant of closing the test circuit and polarity of the charging voltage Yes, the capacitor battery 1 is selected so that in the executive circuit immediately get a settling mode.

The power of the IPT 3 and its voltage value is chosen so that the value of the forced component of the current flowing in the test circuit after turning on the discharge capacitor 6 does not exceed the value of the nominal operating capacitor.

After the test circuit is closed, the continuous current of the industrial frequency (current tl, interval ti- / 3) will flow through switches 9 and 11 — At the time of the arc (fz) in you; switch 9 or L or a little later (moment 4) parallel to the inductance an oscillating circuit 2 is connected to the IPT 5 through a transformer 5 by means of a surge 7.

Then, parallel to inductance 2, due to a change in the frequency of free oscillations, the shear angle between the voltage of the IPT 3 and the induced component of the current, phase and magnitude of the effective voltage, a transient occurs in the test circuit. The frequency of free oscillations, which before connecting IPT 3 through transformer 5 parallel to inductance 2 was lower than industrial one, will become equal to or higher than industrial one after connecting, and the angle between current and voltage can change sign.

The magnitude of the equivalent voltage acting in the test circuit after connecting the IPT 3 through the transformer 5 parallel to the inductance 2, and the phase of this voltage can be easily adjusted to

wide limits due to the connection of the transformer 5 to the same phases to which the transformer 4 is connected, and to the free third phase.

By connecting the transformer 5 to the same phases to which the transformer 4 is connected, the magnitude of the equivalent voltage acting in the test circuit can be significantly increased without changing

its phases.

When using the free third phase (phase B), the phase of the equivalent voltage acting in the test circuit with a slight change in its value can be adjusted within wide limits.

Thus, the connection of the IPT 3 through the transformer 5 parallel to the inductance 2 will allow, in addition to changing the operating mode, to regulate the forced and free components. Harvesting harmonic vibrations with close frequencies (forced and free components) results in a beat chain in the test circuit (curve y), thereby compensating for the attenuation of switched off current (curve gz).

Claims (2)

1. A device for testing high-voltage switches for switching capacity, comprising an oscillating circuit, an auxiliary source of alternating current and two transformers, characterized in that, in order to obtain a continuous switching-off current with the switch contacts closed and during the arc burning at its contacts, one transformer is connected in series with the oscillating circuit, and the other is parallel to the inductance of the oscillating circuit. 2. The device according to claim 1, characterized in that, in order to enable the control of the tripping current, the transformers are connected to the opposite phases of the non-random current source. Hh