EA025418B1 - A high-speed dc switch - Google Patents

Abstract

The present invention is related to an electric switch comprising closable/openable electric contacts at least one of which is movable; driving means connected to the movable contact and providing the possibility of closing/opening of the electric contacts; a fixing element able to fix the drive means in a position ensuring an open position of the electric contacts; and release means able to transfer the fixing element to a position ensuring free movement of the drive means. To provide the possibility of quick opening of the contact immediately after closing, the switch in accordance with the present invention further includes a second fixing element that can fix the drive means in a position ensuring an open state of the electric contacts in the case where the main fixing element is in the position ensuring free movement of the drive means.

Description

The present invention relates to electrical engineering, in particular to electrical switches, for example, high-speed DC switches.

State of the art

Known circuit breakers with the design of an electromagnetic drive, in which the movable contacts of the vacuum interrupter chambers are connected to an electromagnetic device containing a control winding and permanent magnets (KN 2020631). When current is supplied to the control winding, the core of the electromagnet is attracted to the magnetic circuit, compressing the power contacts of the arcing chamber through the preload spring. When the control winding is de-energized, the core is held in an attracted position by permanent magnets. When a current is passed through the control winding, the magnetic field created by which compensates for the field of permanent magnets, the core returns under the action of compressed springs and the power contacts of the arcing chamber are disconnected. The disadvantages of this design is the low speed.

Known are high-speed DC switches, which in their composition contain a high-speed drive that provides quick opening of the contacts and a latch that holds the movable contacts of the switch in the open position (V.P. Ivanov, A.I. Budovsky, D.F. Alferov, D. V. Evsin, IP Neugodnikov, AP Teterin Results of the development of a DC vacuum circuit breaker for traction substations, Materials of the international scientific and technical conference SCIENCE, INNOVATION, EDUCATION: ACTIVITY OF THE TRANS DEVELOPMENT PROBLEM ORTNOGO COMPLEX OF RUSSIA, Ekaterinburg, 2006, p. 157).

In existing high-speed circuit breakers, opening of contacts occurs under the influence of an electrodynamic drive for times of a few millisecond scale. The contact closure occurs under the action of the springs when the latch of the open position in the latch is released. The release of the latch latch is carried out by an electromagnet.

The disadvantage of this design is that the time interval of the operation of this mechanism from the beginning of the release of the latch to the restoration of the readiness of the latch to hold the contacts in the open position is several tenths of a second, while the release of the latch after their release occurs in less than one tenth of a second.

In this regard, switches with a fast drive cannot provide a quick disconnection of the circuit immediately after a short circuit, since the latch will not be ready for operation. And this in the case of a short circuit in the load circuit can lead to a rapid increase in currents. It is possible to disconnect (open contacts) only after a few tenths of a second, when the circuit breakers are ready for operation again, which, with low inductance of the circuit, leads to the fact that the currents can exceed several times the permissible operating currents of the circuit breaker.

SUMMARY OF THE INVENTION

An object of the present invention is to enable the power circuit to be switched off by a high-speed circuit breaker immediately after closing its contacts.

The objective of the invention is solved by means of an electric switch, which contains lockable / openable electrical contacts, at least one of which is made movable;

drive means connected to the movable contact and made with the possibility of closing / opening of electrical contacts;

a latch configured to lock the drive means in a position that provides an open state of electrical contacts;

unlocking means configured to translate the latch into a position providing free movement of the drive means; and to ensure quick opening of the contacts immediately after their closure, the switch further comprises a second (additional) lock, made with the possibility of fixing the drive means in a position that provides an open state of the electrical contacts, in the case when the main lock is in a position that allows free movement of the drive means . Unlocking means in an advantageous embodiment is arranged to hold the main latch in a position providing free movement of the actuator (rod).

Each latch preferably comprises a rod with a variable cross section and means for blocking the movement of the rod, configured to block the movement of the rod depending on the cross section of the rod. In addition, in an advantageous embodiment, synchronized movement of the rods is provided, for which the rods can be rigidly connected to each other.

One of the options for implementing the present invention provides that the cross section of one of the rods forms a gap that allows free movement of the rod when the other rod is in a position that allows the triggering means of blocking. Such a gap may have a value of from 0.1 to 5 mm along the axis of the rod, preferably 1.5 mm.

The locking means of one of the rods may include a recess that allows the rod to move freely when the other rod is in a position that allows the locking means to operate.

In a preferred embodiment of the invention, the closable / openable electrical contacts are contacts of a vacuum arcing chamber. The switch may comprise a plurality of vacuum interrupter chambers connected in parallel or in series, and in this case, mainly synchronous movement of the rods of each of the plurality of said chambers is provided. In some cases, a diode or a diode assembly can be connected in parallel with one of the vacuum chambers.

The switch may contain additional unlocking means, configured to translate the additional lock into position, providing free movement of the drive means. Means for blocking the movement of the rod of at least one latch can be a rotary latch with protrusions and can be made in the form of a cover with protrusions, which are made in the form of providing, when interacting with the protrusions of the rotary latches, the release of the rod, the movement of which is blocked by said latches.

The drive means in one of the embodiments include an electric drive, a spring drive and a lever, providing a movable contact with the clamp rods.

The present invention can also be expressed as a method for controlling an electrical connection, which includes the following steps:

open the contacts by means of drive means connected to at least one movable contact;

fix the drive means in a position that provides an open state of electrical contacts;

close the contacts with drive means after moving the latch to a position that provides free movement of the drive means using the release means of the latch; at the same time, to ensure the possibility of quick opening of the contacts immediately after their closure, the drive means are fixed using an additional lock in a position that ensures the open state of the electrical contacts, immediately after the main lock is moved to a position that provides free movement of the drive means, and the additional lock is moved to a position that provides free movement of drive means, after restoring the initial state of the main fixative ora.

Particular embodiments of the circuit breaker in accordance with the present invention, as well as drive means, latches, unlocking means and contacts, are described in the section of the invention.

The technical result of the present invention is to prevent the closure of electrical contacts until that moment, until the latch of the circuit breaker comes into working condition after fixing the contacts in the open position, which will provide the ability to disconnect the power circuit with a high-speed circuit breaker immediately after closing its contacts.

List of drawings

The invention is further described by the example of an electric switch with two blocks of vacuum arcing chambers for switching high-voltage direct current. However, it is obvious to a specialist that the invention is not limited to this type of circuit breakers and can be implemented in the design of high-voltage or low-voltage circuit breakers designed for switching current in other equipment, if during operation of such equipment it is necessary to guarantee the possibility of quick opening of the contacts immediately after their closure.

In FIG. 1 shows the design of the blocks of the vacuum chambers 081 and 082. containing one and two clamps, respectively.

In FIG. 2a and 2b show the construction of a block of vacuum interrupter chambers 082, with FIG. 2a shows a main view, and in FIG. 2b shows a side view of the structure of the block of vacuum chambers 082.

In FIG. 3 and 4 show the joint operation of the clips of the present invention, with FIG. 3, the rod is fixed in the main retainer, and in FIG. 4 rod is fixed in an additional clamp.

In FIG. 1-4 the following notation is used:

- induction-dynamic drives, 2 - frame, 3 - retainer, 4 - shaft, 5 - axis, 6 - additional retainer, 7 - VDK block, 8 - insulator, 9 - case, 10 - roller, 11 - contact attachment, 12 - latch housing, 13 - cover, 14 - lever, 15 - latch, 16 - rod, 17 - coil, 18 - spring, 19 - spring of the latch.

Information confirming the possibility of carrying out the invention

The DC vacuum circuit-breaker consists of two blocks of vacuum interrupter chambers (VDK) 081 and 082. Each switching unit consists of two vacuum chambers connected in parallel. The switching blocks, in turn, are connected in series, and for the current to flow in the circuit, it is necessary to close the VDK contacts of both blocks (081 and 082).

The design of the drive means for block 081 and block 082 is shown in FIG. 1 and 2, respectively.

To open the contacts of the VDK unit, each of the vacuum chambers is equipped with its own induction-dynamic drive (1). The movable rods of each of the drives are rigidly interconnected by a common shaft (4), which ensures synchronous operation of the cameras. The contacts are locked in the open state by a lock (3) in block 081 and two locks (3, 6) in block 082. The stems of the clamps (3, 6) of chamber 082 are rigidly connected to each other and connected to a common shaft (4) using a lever (14). Accordingly, when opening (moving the movable rod of the actuator 1 down), the rods (3, 6) of the latches move upward synchronously, and when closing (moving the movable rod of the actuator 1 up) the rods move synchronously down with the latch.

To close the contacts of each of the cameras, a spring drive is used, which is structurally located in the drive housing. The same spring provides the necessary force to compress the contacts in the closed state.

All main drive units are fixed on the metal frame of the switch.

The locking device is shown in more detail in FIG. 2a, 3 and 4.

The latch structurally consists of a housing (12) and a cover (13) made of ferromagnetic material. The cover in its initial position is held by springs (19). The coil (17), as well as four latches (15), which provide reliable fixation of the rod (16) in the open state of the VDK contacts, are placed in the housing. The latches are pressed to the rod by springs (19).

In this example, the design of the additional latch has a similar design. The difference lies in the shape of the stem, which does not have a tapered part in its lower part.

In the initial position, the contacts of the vacuum chambers are in a closed position and are held by the drive springs. To open the contacts at the command of the control unit, the capacitor is discharged through the drive coil of this unit. Under the influence of an electromagnetic field, the rod connected to the VDK contacts moves downward, ensuring their opening.

The clamp rod (16), rigidly connected to the shaft (4) by means of a lever (14), moves up. This frees up space for rotation (in the plane of the figure) of the latches, since they are next to the part of the rod having a reduced outer diameter.

The rotation of the latches occurs both due to the forces of the springs (19) and the conical part of the rod, which abuts against the latches (15) and rotates them. The latches, turning, limit the movement of the rod and, accordingly, the VDK contacts during the reverse stroke, since the rod stop (20) abuts against the upper plane (21) of the latches, as shown in FIG. 3 on the left. Holding the latches in this position is provided by springs (19).

Under the action of the actuator spring, the actuator rod (1) tends to return to the upper position, and the rod (16) of the lock, respectively, should move down. However, the turned latches do not allow this movement and fix the open position of the VDK contacts.

To carry out the closure of the external power circuit in the circuit breaker, the VDK contacts that are part of block 081 are first closed. The contacts of block 082 are in the open state. After some time, necessary to return the latch cover of the block 081 to its original state, a command is issued to close the contacts of block 082.

To close the VDK contacts from the electromagnet control unit, power is supplied to the latch coil (17). Under the influence of electromagnetic forces, the cover (13) is attracted to the latch housing and, moving downward, acts on the latches (15). The latches rotate, due to which the stop (20) of the rod ceases to contact the upper planes (21) of the latches, and essentially free movement of the rod (16) is ensured. Under the influence of the actuator spring, the rod with the liner in the actuator (1) moves up, and the rod (16) - down. Without the presence of additional fixing means, the VDK contacts in such a situation will immediately close.

If in block 082 there would be one fixing device, then after the circuit is closed, when the device needs to be immediately turned off again, the falling cover of the lock of block 082 would not allow the latches to turn and stop the rod in the open contact position.

In order to avoid such situations, in block 082 there are two latches: the main and additional. When the VDK is turned off, the rods are fixed in the main lock. In this position, there is a gap of about 1.5 mm in the additional lock between the rod stop and the upper planes of the latches. This is shown in FIG. 3: on the left, the stem (16) of the main retainer abuts against the spring latches (19), while on the right, there is a gap between the stop (20) of the additional clamp rod and the upper planes (21) of the latches. It is obvious that it is possible to use essentially the same rods if the delayed actuation of the additional latch is ensured using the shape of the latches (19), for example, by forming deeper recesses.

If necessary, close the power circuit at the same time as applying power to the lock coil of block 081, power is supplied to the coil of the main lock of block 082, in which the cover of the main lock is lowered, spreading the latches to the sides. The main retainer rod is released and continues to move down. The rod of the additional latch, synchronous with the rod of the main one, also moves downward until it abuts against the upper plane of the latches. In other words, in block 081, the VDKs close their contacts immediately, while in block 082, the movement of the rods is fixed by an additional lock, and the contacts of the VDK of block 082 remain open.

- 3 025418

After some time, necessary to return the lock cover of block 081 and the cover of the main lock of block 082 to its initial state, a command is issued to close the contacts of block 082. To do this, power is supplied to the coil of the additional lock, the cover of the assembly is attracted to the body, moving the latches and freeing the rods .

If necessary, an instant repeated disconnection can be carried out, since the fixing of contacts in block 082 will be carried out in the main latch. At this time, the additional lock will not yet be ready for use, since its cover will not have time to occupy its original upper position and will not release the locks.

Claims (15)

CLAIM 1. An electrical switch comprising lockable / openable electrical contacts, at least one of which is movable; drive means connected to the movable contact and made with the possibility of closing / opening of electrical contacts; a latch made with the possibility of fixing the drive means in a position that provides an open state of electrical contacts; and unlocking means configured to translate the latch into a position providing free movement of the drive means, characterized in that it comprises an additional latch configured to fix the drive means in a position that provides an open state of electrical contacts, in the case when the main latch is in position ensuring the free movement of the drive means. 2. The switch according to claim 1, characterized in that each latch includes a rod with a variable cross section and means for blocking the movement of the rod, made with the possibility of blocking the movement of the rod depending on the cross section of the rod. 3. The switch according to claim 2, characterized in that the synchronous movement of the rods. 4. The switch according to claim 3, characterized in that the rods are rigidly connected to each other. 5. The switch according to claim 3 or 4, characterized in that the cross-section of one of the rods forms a gap that allows the rod to move freely when the other rod is in a position that allows the locking means to operate. 6. The switch according to claim 5, characterized in that the gap has a value of from 0.1 to 5 mm along the axis of the rod. 7. The switch according to claim 5, characterized in that the gap has a value of 1.5 mm along the axis of the rod. 8. The switch according to claim 3 or 4, characterized in that the means for blocking one of the rods contains a recess that provides free movement of the rod, in the case when the other rod is in a position that ensures the triggering of the blocking means. 9. The switch according to claim 1, characterized in that the closable / openable electrical contacts are contacts of a vacuum arcing chamber. 10. The switch according to claim 9, characterized in that it comprises a plurality of vacuum interrupter chambers connected in parallel or in series, moreover, the rods of each of the plurality of said chambers are synchronized. 11. The switch of claim 10, characterized in that a diode or diode assembly is connected in parallel to one of the vacuum chambers. 12. The switch according to claim 1, characterized in that it contains additional unlocking means configured to translate the additional latch into a position that provides free movement of the drive means. 13. The switch according to item 12, wherein the means for blocking the movement of the rod of at least one latch are rotary latches with protrusions. 14. The switch according to item 13, wherein the means for unlocking at least one latch are a cover with protrusions that are made in a form that, when interacting with the protrusions of the rotary latches, releases a rod whose movement is blocked by said latches. 15. The switch according to claim 3 or 4, characterized in that the drive means comprise an electric drive, a spring drive and a lever, providing a movable contact with the clamp rods.