RU2281578C2 - Disconnecting switch - Google Patents

Abstract

FIELD: electrical engineering; circuit-opening devices.

SUBSTANCE: proposed disconnecting switch designed for switching electric circuits under no-current conditions and for producing visible open circuit through air gap has one or more poles, current-conducting buses, current-conducting connecting strips coupled with their operating mechanism, and insulating blocks that function to isolate and carry mentioned conducting buses and connecting strips; conducting buses are provided with fixed contacts installed at their adjacent ends and secured on intermediate insulating block whose walls and stiffening ribs, as well as stiffening ribs and base of bottom insulating block form compartment accommodating reversing motor and motor control gear; this motor functions to set in motion connecting strips held within upper insulating block which mount cluster contacts at their ends.

EFFECT: enlarged functional capabilities, enhanced safety, and reduced overall and installation dimensions of disconnecting switch.

8 cl, 2 dwg

Description

The claimed technical solution relates to electrical engineering (high-voltage electrical apparatus), designed to switch electrical circuits without current and to create a visible gap through the air gap.

Known disconnectors (1), consisting of one or three poles, containing a frame, fixed on the support insulators contact leads with fixed L-shaped contacts, interconnected in pairs with knives, which are conductors from two strips of rectangular cross section, fixed at one end with axis relative to one of the L-shaped fixed contacts of the pole connected by them.

Knives of the poles are connected by means of porcelain rods with a shaft, during rotation of which they rotate in the same plane with the axes of the supporting insulators of the corresponding poles, breaking or closing the electrical circuit.

To give the shaft a rotational movement, a manual drive is provided, which is a system of levers and rods and having a device for blocking from erroneous actions by a disconnector.

With obvious simplicity, the considered disconnector has significant drawbacks, one of which is its significant overall installation dimensions, due not only to the dimensions of the disconnector itself, but also to the fact that around this device, due to the fact that the entire current-carrying system is made in an open (uninsulated) form, when it is used in electrical installations, it is necessary to observe the prohibition zone for approaching live parts of other devices and grounded parts of structures.

The second drawback that limits the functionality of this and other similar (2 ÷ 4) disconnectors similar to it is the lack of the ability to remotely control them.

Closest to the proposed disconnector is a high-frequency switch of high power (5), which according to its characteristics (turning on and off the electric circuit without current) corresponds to the name - disconnector (hereinafter disconnector), adopted as a prototype.

This device contains conductive buses located in the same plane with a gap relative to each other, one of which is the input bus, the other is the output bus, and a connecting plate connected to the drive of its movement, which in the on position of the circuit breaker with its ends overlaps the opposing (adjacent) ends of these conductive tires, and the connecting plate is installed with the possibility of its movement in a plane parallel to the plane of the conductive busbars. The circuit breaker is equipped with an intermediate insulating unit, which serves to secure and separate the conductive busbars, and extreme insulating blocks, by means of which the ends of the connecting plate are pressed against the ends of the conductive tires with great force using an electric motor with a large starting torque and a lead screw.

The switch also contains a second electromagnetic drive for moving the connecting plate relative to the ends of the conductive busbars that it closes in a plane perpendicular to the direction of compression of the lead screw.

This switch (disconnector) has several disadvantages:

- the control system for the movement of the connecting plate is complex and not technologically advanced, requires high precision manufacturing and assembly, involves the use of a high-power electric motor capable of providing high pressing forces to create a reliable planar electrical contact;

- the design does not provide a visible gap in the off state of the apparatus;

- due to the fact that the lead screw works on a “stop”, the bevel gear should be made with a large margin of safety;

- due to the complex design using several drives, the device according to the proposed technical solution has overall dimensions that exceed the dimensions of the known (1-4) analogues with the same electrical parameters;

- from the claims and the description of the essence of the technical solution of the prototype does not show the possibility of releasing the ends of the tires clamped by a large force (pressure 2 × 10 ⁶ Pa) if it is necessary to urgently open the circuit breaker in cases of electric motor failure or power supply failure;

- the known solution does not contain blocking devices required for disconnectors from erroneous actions of personnel and a blocking device from opening the circuit breaker during passage of high voltage currents through the device.

The objective of the proposed technical solution is to expand the functionality, increase security and reduce the overall and installation dimensions of the disconnector.

The problem is solved due to the fact that in the disconnector, consisting of one or more poles, containing conductive busbars, conductive connecting plates associated with the drive of their movement, and insulating blocks separating and carrying these conductive busbars and connecting plates, conductive buses are provided with fixed contacts mounted on their adjacent ends and mounted on an intermediate insulating block, the walls and stiffeners of which together with the stiffeners and the base of the lower of the insulating block, a compartment is formed in which the reversible electric motor and control equipment of this electric motor are located, which drive by means of kinematic connection the connecting plates fixed to the upper insulating block with socket contacts installed at their ends, and the kinematic connection between the reversing electric motor and the upper insulating block is made with using a bevel gear, spindle and nut, the spindle nut being installed in the center of gravity the upper insulating block, while the lead screw at one end is installed in the center of symmetry of the base of the lower insulating block and is limited from axial and radial movements by means of a thrust ridge and a clamping ring, it also has an additional kinematic connection with a removable handle for the manual drive of the disconnector, and the hole in the lower insulating block for installing the removable handle of the actuator is equipped with a shutter locked by an electromagnetic lock; Eve switch, and the intermediate insulating unit cover is formed of a transparent insulating material, a ceiling part which radially fixed second end of the lead screw. The conductive connecting plates are mounted symmetrically with respect to the center of gravity of the upper insulating block on one plane parallel to the plane of the conductive busbars mounted on the intermediate insulating block, the contact surfaces of the movable and fixed contacts being made of anti-friction wear-resistant conductive material.

The essence of the proposed technical solution is explained in more detail by the drawings, where:

figure 1 shows a cross section of a three-pole disconnector by a plane passing through the middle pole,

figure 2 is a side view of the disconnector with a breakout of the side walls and stiffeners of the lower and intermediate insulating blocks and with access to the low-voltage compartment.

The disconnector comprises an intermediate unit 1 of a strong insulating material, on which conductive busbars of the input 2 and output 3 contact terminals with fixed contacts 4 at adjacent ends are fixed symmetrically with respect to the longitudinal axis. The intermediate block is mounted on the lower insulating block 5 in such a way that the stiffening ribs 6 and the base of the lower insulating block create, together with the stiffening ribs 7 of the intermediate block and its walls, a low-voltage compartment 8, insulated on all sides by solid insulating partitions and labyrinths as from high-voltage circuits the disconnector itself, and neighboring devices.

In the low-voltage compartment, thus separated within the internal volumes of the disconnector, an asynchronous reversible microelectric motor 9 is placed, connected by any suitable kinematic coupling 10 (a bevel gear transmission is shown in Fig. 1) with a lead screw 11 made of durable electrically insulating material with good antifriction properties.

The lead screw is installed at its one end in the center of symmetry of the plane of the bottom of the base of the lower insulating block 5 and is limited from axial and radial movements by means of a thrust ridge 12 and a clamping ring 27, acting as a radially thrust bearing. A nut 13 interacts with a lead screw, which is firmly fixed at the center of gravity of the plane of the upper insulating block 14. When the lead screw 11 rotates, the nut 13 moves in vertical directions, together with the insulating block 14, with the conductive connecting plates 15 fixed in it and with the moving contacts 16 . In the lower position of the insulating unit 14, the fixed contacts 16 enter the joint with the fixed contacts 4, forming a reliable electrical contact of the pole circuit: conductive busbars and 2 - a fixed contact 4 - left movable contact 16 - the connecting conductor plate 15 - right movable contact 16 - right stationary contact 4 - busbar contact terminal 3. Moving the insulating unit from the upper position to the lower occurs in 2-5 seconds. To turn off the reversing motor 9 in the extreme positions of the upper insulating block 14, conventional trip microswitches are installed in the low-voltage compartment (not shown).

For manual control of the disconnector, it is possible to expose the leadscrew to the removable handle 17 (Fig. 2) through a kinematic connection (the figure shows a bevel gear with gear 18) installed in the low-voltage compartment and having a device 19 for coupling with the end of the removable handle. To insert the handle 17 into the joint with the bevel gear, on the front wall of the lower insulating block 5 there is an opening 24 with a shutter 20, the closed position of which is fixed by an electromagnetic lock 26, and a directional switch is provided for diagnosing the opening of the shutter (not shown in Figs. 1 and 2). These locking devices together with current sensors that are not related to the features of this technical solution, provide the ability to perform the following locks from erroneous actions of personnel with both remote and manual control of the disconnector:

1. Blocking the opening of the electromagnetic lock of the shutter (prohibition of manual control of the actuator) when:

- the presence of current through the poles of the disconnector;

- remote control of the disconnector;

- the on position of the switch (s) from the source (s) of power.

2. Blocking the possibility of remote control of the disconnector, if:

- the shutter is removed from the hole;

- switch (s) on the side of the power source (s) in the on state.

A cover 21 made of transparent electrically insulating material is provided for the electrical isolation of the current-carrying system of the disconnector, including its fixed and movable contacts, from the surrounding structures and current-carrying parts of neighboring devices in the switchgear, as well as for radial fixing of the upper end of the shaft of the screw screw 11 and for visual observation of the quality of the open state disconnector contacts.

To avoid distortions of the upper insulating block 14 during its movement relative to the lead screw 11, guide rods 22 of antifriction material are provided, fixed at their ends between the cover 21 and the intermediate block 1, along which, when the insulating block 14 is moved, bushings 23, also made associated with the block 14, are also made of antifriction material, providing, together with the lead screw 11, the stability of the upper insulating block 14. The lower insulating block 5, the intermediate block 1 and the cover 21 are connected I with each other with the help of flanges 25, forming inside myself a volume protected from the possibility of a dangerous approach, where the entire current-carrying system of the disconnector is located. Outside the disconnector, only the contact terminals for connecting the disconnector using buses or cables to other elements of the power supply system go beyond. The isolation of the protruding contact terminals with the heat-shrinkable tubes connected to them by the cores of the high-voltage cables will make it possible to ensure continuous insulation of all current-carrying parts adjacent to the disconnector, which will significantly increase the reliability and safety of switchgear maintenance.

To reduce sliding friction during movement of the socket contacts 6 relative to the fixed contacts 4 at the moments of switching on and off the disconnector, the lamellas of the socket contacts and the contact surfaces of the fixed contacts are made of antifriction material with good conductivity, for example, cadmium, zirconium or chrome bronze, which makes it possible to use the drive mechanism substantially low power.

Other modifications of the design of the disconnector are possible within the scope of the attached formula of the claimed technical solution. The pilot tests of the inventive disconnector, the use of which is planned in the third quarter of 2004, have been completed.

Information sources

1. Handbook of high-voltage electrical apparatus edited by VV Afanasyev. L., Energoatomizdat, 1987, pp. 203-206, 211-214.

2. RF patent No. RU 2072109 C1, cl. H 01 H 31/24.

3. RF patent No. RU 2134463 C1, cl. H 01 H 31/00.

4. RF patent No. RU 96123327 A, cl. H 01 H 31/20.

5. RF patent No. RU 2137239 C1, cl. H 01 H 31/02.

Claims (8)

1. The disconnector, consisting of one or more poles, containing conductive busbars, conductive connecting plates associated with the drive of their movement, and insulating blocks, separating and supporting these conductive busbars and connecting plates, characterized in that the conductive busbars are equipped with fixed contacts installed at their adjacent ends, and mounted on an intermediate insulating block, the walls and stiffeners of which together with the stiffening ribs and the base of the lower insulating block are azovan compartment, wherein the motor is reversible and that the motor control apparatus, by driving the drive connection fixed in the upper insulating block connecting plates mounted with their ends rosette contacts. 2. The disconnector according to claim 1, characterized in that the kinematic connection between the reversible electric motor and the upper insulating block is made using a bevel gear, spindle and nut, and the spindle nut is installed in the center of gravity of the upper insulating block. 3. The disconnector according to claim 1 or 2, characterized in that the lead screw at one end is installed in the center of symmetry of the base of the lower insulating block and is limited from axial and radial movements by means of a thrust ridge and pressure ring. 4. The disconnector according to claim 3, characterized in that an additional kinematic connection is mounted on the lead screw with a removable handle of the manual actuator of the disconnector. 5. The disconnector according to claim 1, characterized in that the hole in the lower insulating unit for installing the removable handle of the actuator is equipped with a shutter that is locked by an electromagnetic lock, and a directional switch is provided for monitoring the position of the shutter. 6. The disconnector according to claim 1, characterized in that on the intermediate insulating block a cover is made of transparent insulating material, in the ceiling part of which the lead screw is radially fixed by the second end. 7. The disconnector according to claim 1, characterized in that the conductive connecting plates are installed symmetrically with respect to the center of gravity of the upper insulating block on one plane parallel to the plane of the conductive busbars mounted on the intermediate insulating block. 8. The disconnector according to claim 1, characterized in that the contacting surfaces of the movable and fixed contacts are made of anti-friction wear-resistant conductive material.

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