CS270466B1 - High voltage section switch contact system - Google Patents

Abstract

A contact system, the movable U-shaped contact tongue (1) of which has a longitudinal recess (2) in the center of both arms, which rests on the contact projections (14) formed on both end faces (12) by a longitudinal groove (9) of the contact blade (8). The contact system is preferably provided with a protective cover (11;).

Description

The invention relates to a contact system for high-voltage circuit-breakers, in particular circuit-breakers for outdoor designs.

Previously known contact systems of section switches for converting rated short-term and dynamic currents consist essentially of contact vapors and contact knives. In some embodiments, the movable contact pens and the stationary contact knives are movable, while in other embodiments, the contact knives and the contact pens are stationary. The contact pens are formed into various shapes in connection with the vertical or horizontal arrangement of the contact knives and according to the direction of insertion of the knives into the contact pens or vice versa. In the case of compressive contact forces, different types of springs are exerted. However, the operation of contact systems is less reliable after a certain period of operation at large pole spacings and a large disconnection path. Due to manufacturing and assembly tolerances, the mechanical resistances often change considerably during switching, which increases the demands on the driving forces induced by the motion mechanisms. The required control force for work on annual drives is considerably large. Therefore, sometimes there is a permanent deformation of the movement mechanism and the contact system. In the contact system, even with a relatively small misalignment of the fixed and movable parts of the switch, deteriorated, practically only two-point contact contact occurs in each phase. This is also related to higher voltage drops, higher contact warming and increased energy losses in transmission networks. Structurally, these systems are more complex and demanding on the consumption of non-ferrous metals.

These disadvantages are eliminated by the contact system of the electrical switch according to the invention, the essence of which consists in that the movable U-shaped contact tongue has a longitudinal recess in the middle of both arms and that the fixed contact knife has a longitudinal groove on both front contact surfaces.

The advantages of the contact system according to the invention lie in the design simplicity, in the reduction of labor during assembly and adjustment, in the reduction of the human actuating force and in the improved ability to switch off under difficult conditions, e.g. during icing.

An exemplary embodiment of the invention is shown in the drawings, in which FIG. 1 is a front view of the contact system of the circuit-breaker in the switched-on state in partial section, FIG. 2 is a side view thereof, FIG. 3 is a plan view thereof. Fig. 4 shows this contact system with a fitting on top of both the fixed and the movable system, the whole system being supplemented by a protective cover.

The contact system of the section switch according to the invention consists of a U-shaped contact tongue 6, which has a longitudinal flange 2 formed in the center of both arms. A bolt 2 with a spacer 6 and two springs 7 passes through the upper part of the contact tongue 2. The contact system has a contact knife 2 ^with two grooves 2, which is firmly connected in the middle part to the fixed part 10 of the circuit breaker, its other end serving as a connecting flag. 12 · The grooves 2 ^{in the} front surfaces 12 of the contact knife 8 form four contact projections 14. In the exemplary embodiment, an additional cover 11 of the switch contact system is indicated, fastened by a screw 15 on the connecting flag 2 ·

The function of the contact system is as follows! in the on position of the section switch (Fig. 1), the current from the connecting flag 13 passes through the stationary contact knife 2 into its contact protrusions 14, abutting on the longitudinal recesses 2 of the contact pen 6. Four point contact transitions are formed at the point of abutment of the contact projections 14 on the longitudinal recesses 2 ^{tal <.} The current passes through the longitudinal slots 2 of the contact pen 6 to the connecting flag 2. The distribution and direction of the electric current flow is indicated in FIG. 1 by thick lines and arrows. The contact projections 14 of the two arms of the contact tongue £ are pressed by compression springs 2 against the longitudinal recesses £ of the contact spring £. By setting the pressing force of the springs 2, it is possible to spread

CS 270466 B1 to obtain the required value required to slide the contact pen 1. out of the contact knife B within small tolerances. Longitudinal recesses 2 of the contact pen _! (Fig. 3) further allow to compensate for mutual tolerances of position deviations of the movable and stationary contact parts, which allows stabilization.

Functional significance of the cover 11, mounted on the connecting flag 2, which covers the contact pen! and in the switched-on state also the functional part of the contact knife 8, consists in the fact that during the formation of icing in the form of hoarfrost or in freezing rain (iceberg) the formation of icing at the contact transitions prevents the movable and immovable part of the switch.

Claims (2)

OBJECT OF THE INVENTION Contact system for high-voltage section switches, in particular switches in the outdoor version, characterized in that its movable U-shaped contact tongue (1) has a longitudinal recess (2) in the middle of both arms and that its fixed contact knife (B) has a longitudinal groove (9) on both front surfaces (12), forming contact protrusions (14). 2. A contact system of section switches according to claim 1, characterized in that the movable contact tongue (1) is provided with a protective cover (11).