SU1198594A1 - Short-circuiting switch - Google Patents

Description

The invention relates to high-voltage instrumentation, and more specifically to the design of short circuits.

The purpose of this invention is to increase the switching capacity of the shorting device while ensuring the required resistance to the passage of short-circuit currents, simplifying its design, reducing the power of the drive mechanism, reducing shock loads on the insulating column, and improving the reliability of its work as a whole.

FIG. 1 schematically shows a shorting device At the moment of closing when the lamellae of the contact of the grounding knife are located in the lead-in part of the rod; in fig. 2 - the same, top view (dash-dotted lines indicate the position of the grounding blade in the fully engaged position); in fig. 3 - shorting switch in the off position.

The shorting device consists of a movable grounding knife 1 of the cutting type with current-conducting lamellae 2 at its end, equipped with magnetic locks, an insulating support column 3, a fixed contact 4 mounted on an insulation column and including a contact holder 5 with a current-carrying rod 6 fixed on it. On a contact holder 5 rigidly fixed two vertically arranged plates 7, which are made of ferromagnetic material and cover the current-carrying rod 6 with a gap on both sides only in its lead-in (catching) parts. The width of the plates must be equal to the length of the lead-in (catching) part of the current-carrying rod (in Fig. 2).

This condition arises from the fact that, when the width of the ferromagnetic plates 7 is greater than the length of the lead-in (catching) part of the current-carrying rod, their weakening effect already affects. its active part also causes welding or melting of the lamellae. When the width of the plates 7 shorter, an excessive tightening force is applied, which causes the knife to stop in the initial (inactive) part of the current-carrying rod, i.e., the most optimal condition for maximum positive effect occurs when the equality b = 5 is observed, where b is the length of the feed ( catching part of the current-carrying rod; 5 - width of ferromagnetic plates.

The inclusion of the shorting device occurs under the action of the force of the spring mechanism when the actuator triggers from relay protection.

In the open position, the elements of the grounding knife are outside the minimum allowable discharge distance.

When the knife is turned on for a short circuit at the moment of breakdown of the air gap and subsequent contact closure, the short-circuit current flowing through the lamellas of contact 2 of the grounding knife 1 creates a circular electromagnetic field around it, attracting the lamellae to one another with high electrodynamic force. The friction forces arising in this case prevent further rotational movement of the grounding blade. In the presence of plates 7 of ferromagnetic material, which cover the lead-in part of the current-carrying rod 6 of fixed contact 4 with a gap, the electromagnetic field lines are closed through these plates, significantly reducing the force of attraction of the lamellae to one another, including the compression force of the contact springs and thereby reducing the force of friction on the current-carrying rod in the lead-in wedge-shaped catching part, as well as the component forces directed in the direction opposite to the movement of the knife. This allows the grounding ^ knife with a lamella contact to continue the rotational movement under the action of the spring register mechanism, significantly reducing the impact loads on the insulation column of the short circuiter at the moment of its activation. In this case, this effect affects only the initial lead-in (catching) part of the contact. After passing the lead-in part of the lamella leaving from the zone of the “negative” action of the plates 7, falling on the active (straight) part of the current-carrying rod, their influence ceases to affect, and the lines of force of the electromagnetic field begin to compress the lamellae again, creating the necessary contact pressure (i.e., ordinary magnetic lock) and ensuring reliable switching on and the required stability when short circuit currents pass through the short-circuit.

Reducing the force of attraction of the lamellae to one another at the moment of switching on (only in the starting part of the fixed contact) in this shortcap allows you to operate shortclippers with a lower power drive and use less durable insulators in the insulating column. At the same drive power, the switching capacity of the short circuiter increases, the shock loads on the insulating column decrease, and the reliability of its operation as a whole increases.

1198594

Phage. 2

phage. 3

Claims (2)

1. KOROTKOZMIKATEL, containing a movable grounding knife of a chopping type with conductive lamellas located at its end, fitted with magnetic locks, and a fixed contact mounted on an insulating column and including a contact holder with a current-carrying rod attached to it, in order to increase including short circuit short-circuit while ensuring the required resistance to the passage of short-circuit currents, simplifying its design, reducing the power of the drive anizma, reduce shock loads on the insulating column and increase the reliability of its operation as a whole, the fixed contact is provided with two vertically arranged plates made of a ferromagnetic material covering the conductor pins with clearance on both sides only in its collecting part. § 2. Shortcutters on π. 1, characterized in that the width of these plates is equal to the length of the catching part of the current-carrying rod. 3 and η 98594 FIG. 7 one 1198594 2