RU2352012C1 - Multiphase safety fuse-switch-disconnector (sfsd) for protection against overloads and short circuit (sc) - Google Patents

Abstract

FIELD: electrics.

SUBSTANCE: multiphase safety fuse-switch-disconnector (SFSD) is intended for overload and short circuit protection and includes case with cartridge (7) with n fusible inserts (8), 2n-arc blowout chambers (3), where n is phase number in SFSD, contact system (4, 5, 6). Cartridge (7) features latch (12) and can be removed from case by drive plant (11) with disconnection spring. The cartridge features n ports holding one fusible insert each, so that disconnection spring of drive plant (11) provides sequential effort to fusible inserts (8) through cartridge (7). Contact system includes 2n rupture contacts, 2n current conducting contacts and n heat sensors (10) connected mechanically to the latch.

EFFECT: enhanced life time and reliability of SFSD functioning, combined with protection in the whole overload and short circuit range due to direct course SFSD with momentary disconnection and two ruptures per phase.

18 cl, 3 dwg

Description

Technical field

The present invention relates to the field of power electrical engineering, to control and protection devices .

State of the art

Well-known fuses, circuit breakers, switch disconnectors (TACs), see, for example, OEZ catalog “Safety systems”, 2005, Letohrad Czech Republic; as well as TAC, which is the closest analogue of the claimed invention, see the catalog "Low-voltage distribution and control equipment", Part 1, 2006-2007, OJSC "Korenevsky factory of low-voltage equipment", are usually intended for operation in networks with rated voltage (Un) of approximately 220 ~ 660 V and rated current In of approximately 100-630 A and contain fusible inserts, arcing chambers and a contact system consisting of fixed contacts (sponges) and movable contacts (side surfaces knives fusible inserts).

The indicated traditional high voltage transformers are designed to operate in the following modes: continuous passage of the rated current (In); multiple operational on and off of rated currents (In) and overloads; shutdown of emergency short circuit currents. In this case, quick start and shutdowns of the TACs are performed by a contact-extinguishing system, and large overloads at I> 4-5 In and emergency shutdowns are made by fuses. This is because the fuses known from the prior art, including the analog of the claimed invention, are very unreliable or do not disconnect currents of less than 4-5 In.

The lack of protection in the zone of small overloads (I = 1.1-3 In) is a fundamental drawback of the TACs known from the prior art, which significantly limits the scope of their application, since according to statistical data during industrial operation of TACs, from modes requiring shutdown, at least 90% they make up small overloads and only not more than 10% are large overloads and short circuits. A significant disadvantage of the TAC known from the prior art is the absence of momentary disconnection of contacts when the operator disconnects the TAC, which ultimately leads to increased wear of the contacts.

Thus, the objective of the claimed TAC is to eliminate the drawbacks known from the prior art TAC, and to increase the durability and reliability of the TAC while providing protection over the entire range of overloads and short circuits by providing forward-pass TAC with instantaneous opening and two breaks per phase.

SUMMARY OF THE INVENTION

According to the first aspect of the invention, a multiphase fuse-switch-disconnector (TAC) is developed, comprising: a cassette with n fusible inserts, 2n arcing chambers, where n is the number of phases in the TAC, a contact system, and the cassette is provided with a latch and is configured to extraction from the housing by means of a drive mechanism with a breaking spring, moreover, n windows are made in said cassette for placement in each fusible insert in such a way that a consistent application of force the switching spring of the drive mechanism through the cartridge to the fusible inserts, while the contact system contains 2n breaking contacts and 2n conductive contacts, and n thermal sensors mechanically connected to the latch.

In addition, in said multiphase fuse-switch-disconnector (PVR), said conductive contacts, each, consist of two side surfaces of the fusible knife and jaws, from condition 2 jaws on each fuse-knife, and rupture contacts each consist of a fixed contact, functioning as a sponge, and the movable part of the contact, which is the end surface of each knife fusible insert.

In the TAC according to the first aspect of the invention, a cocking handle is provided mechanically coupled to the drive mechanism.

Moreover, in the cartridge with fusible inserts of the TAC according to the first aspect of the invention, the windows are located at the same distance from each other, but with different heights differing by Δ from the height of the subsequent window, while in the upper part of the cartridge, in the direction of removing the cartridge from the case, the windows are made at one level, so if one window has a height h, the next window will have a height h + Δ, and the next one will have h + 2Δ, and so on, where Δ is approximately 0.5-1.0 mm.

In the claimed according to the first aspect of the invention, multiphase tamper switch, 2n current-carrying terminals are provided for connection to the protected circuit, as well as a tamper disconnect button.

According to a second aspect of the invention, there is provided a multiphase fuse-switch-disconnector (TAC) comprising a cassette with n fusible inserts, 2n arcing chambers located in the housing, where n is the number of phases in the TAC, a contact system, the cassette being provided with a latch and is removable from the housing by means of a drive mechanism with a breaking spring, and in this cassette n windows are made for placement in each fuse-link in such a way that a consistent application of force is provided disconnecting springs of the drive mechanism through the cartridge to the fusible inserts, while the contact system contains 2n conductive contacts, each consisting of two side surfaces of the fusible knife and jaws, from the condition 2 jaws on each fusible knife, and 2n breaking contacts, each consisting of a fixed contact, functioning as a sponge, and the movable part of the contact, which is the end surface of each knife fusible insert, as well as n thermal sensors, mechanically connected to the latch.

In the TAC according to the second aspect of the invention, a cocking handle is provided mechanically coupled to the drive mechanism.

Moreover, in the cartridge with fusible inserts of the TAC according to the second aspect of the invention, the windows are located at the same distance from each other, but with different heights differing by Δ from the height of the subsequent window, while in the upper part of the cartridge, in the direction of removing the cartridge from the case, the windows are made at one level, so if one window has a height h, the next window will have a height h + Δ, and the next one will have h + 2Δ, and so on, where Δ is approximately 0.5-1.0 mm.

According to the first aspect of the invention, 2n current-carrying terminals for connecting to the protected circuit, as well as a button for disconnecting the TAC, are provided in the claimed multiphase STD according to the first aspect of the invention.

Brief Description of the Drawings

The invention is further explained in the description of specific variants of its implementation with reference to the accompanying drawings. Identical elements of the device are denoted by the same positions in all the drawings.

Figure 1 is a General view of a three-phase fuse-switch-disconnector (TAC) in the "on" position according to an embodiment of the invention.

Figure 2 is a General view of a three-phase fuse-switch-disconnector (TAC) in the off position according to an embodiment of the invention.

Figure 3 is a view of the TAC in cross section with a section along the line aa (the drive is not shown).

Description of a preferred embodiment of the invention

A description of a multiphase tamper switch will be presented on the example of a three-phase tamper switch with reference to Figs. 1, 2 and 3, in which under 1 the power current-carrying leads of the TAC are indicated at the rate of two leads for each phase, through which it is connected to the protected circuit; under position 2 denotes a cocking handle (PB) (Fig.1-2 shown in the "on" position); Arcing chambers are indicated under position 3 at the rate of two for each phase, while breaking contacts (not marked), two for each phase consist (each) of a fixed contact (position 4), functioning as a sponge, and the end surface of the “knife” 5 fusible insert, where the end surface of each knife is the movable part of the specified breaking contact. The main conductive contacts, two for each phase (not indicated), each of which consists of two side surfaces of the knife 5 fuse and jaws 6 (at the rate of 2 jaws for each knife fuse); under reference numeral 7 is a cartridge configured to be removed from the TAC casing, in which n windows are provided in which fuse-links 8 are placed (in the three-phase version under consideration, 3 fuse-links, in Fig. 3, positions 8A, 8B, 8C); under position 9 the button of shutdown (KO) is designated; under position 10 - thermal sensor (TD) (based on one per phase); under 11 - a drive mechanism (MP) with a breaking spring, in which, when the cocking handle (PB) (2) is moved, a breaking spring (not indicated) is cocked, under 12 is a latch for holding the cartridge 7 in the “on” position, mechanically connected with heat sensor 10.

The operation of a multi-phase TAC will be disclosed by the example of a three-phase TAC with reference to FIG. 1, 2 and 3.

As indicated above, the advantage of the proposed TAC is the protection at low overloads, in contrast to the TACs known from the prior art, which is achieved as follows. In case of overloads of the protected circuit, which is 1-1.3 In, which cannot be provided by the existing fuses, n thermal sensors 10, one for each phase, detect the overload of the protected circuit and ensure that the latch 12 is disconnected. As a result, even with an overload in one the phase provides the shutdown of the entire TAC the drive mechanism 11 with the help of a breaking spring provides the extension of the cartridge 7 with fusible inserts 8, i.e. the transfer of the cartridge from the “on” position to the “off” position, according to figure 2, due to which there is a momentary opening of the main conductive (5, 6) and breaking contacts (4, 5).

When this happens: 1) an arcless transfer of the overload current from the main conductive contacts (5, 6), which ensures their protection against burning in breaking contacts (4, 5); 2) the formation of an arc in the gap between the breaking contacts (between the end surface of the knife 5 of the fusible insert and the stationary contact of the breaking contact); and 3) the subsequent transition of the arc from the specified gap into the arcing chambers 3, in which it is extinguished. At the same time, due to the forward motion of the contacts (main conductive contacts and breaking contacts) of fuse-link 2, two arcs are formed in series when disconnected, which ensures reliable disconnection of the circuit and allows raising the rated voltage of the protected circuit from 660 to 1000 V. This completes the automatic shutdown of the overload.

In this case, the fusible inserts 8 remain intact, since their melting time during overloads is obviously longer than the response time of the contact system (4, 5, 6) and arc extinction in the arcing chambers 3.

In the event of a short circuit and large overloads> 4-5 In, the fuse links 8 are triggered. In this case, the contact system, consisting of the main conductive and rupture contacts, does not have time to open, since during short-circuit (and, accordingly, large multiples of emergency currents), the speed of the fuse inserts 8 are obviously higher than the speed of the thermal sensor 10. This completes the shutdown of a short circuit or a large overload of the protected circuit.

The replacement of the burnt fusible inserts 8 is done manually by the operator, after he transfers the cartridge and the TAC from the on position (FIG. 1) to the off position of FIG. 2 and removes it from the TAC housing.

Quite often, during operation, in the event of a short circuit, disconnection of strongly inductive loads (modes DS-23V, AC-23V, etc.), “welding” of the main and breaking contacts of the TAC occurs.

In this case, in order to reliably destroy the “welding” spots in multiphase, for example, three-phase TACs, successive application of the force of the breaking spring of the drive mechanism 11 through the cassette 7 to the fusible inserts 8 is carried out, which allows destroying the welding spots of these contacts, respectively, in series.

To this end, in the cassette 7, according to FIG. 3, where an embodiment of the invention is presented, n three windows are made on the example of a three-phase TAC, one for each phase, distributed uniformly along the cassette plane, i.e. at the same distance from each other, in which the fusible inserts 8A, 8B, 8C are placed, while the windows are made with different heights differing by Δ, i.e. when considering a three-phase TAC, if one window has a height h, then the next window will have a height h + Δ, and the next window will have h + 2Δ.

Moreover, the specified value of Δ is approximately 0.5-1.0 mm, which is obtained as a result of experimental studies and provides a consistent application of the force of the breaking spring to the weld points of the contacts and, accordingly, reliable destruction of the weld points.

In addition, in the upper part of the cartridge 7 (in the direction of removing the cartridge), the windows are made at the same level, due to which when switching on the TAC, all phases are switched on simultaneously, and when disconnected, the fuse links are sequentially switched off with the start of the shift of the fuse links by the shift Δ due to the structural the implementation of windows of different heights.

When the TAC apparatus is turned off, the fusible insert located in the minimum height window (phase “A” of Fig. 3) is set in motion, and when it starts to move and moves by “Δ”, the force of the breaking spring will be applied to the fuse of phase “B” ", And then to the fuse insert phase" C ", which creates the desired effect.

When the TAC is operating in the disconnector mode, the cassette 7 with fusible inserts 8 is manually removed by the operator from the TAC casing, and a visible gap is formed in the protected circuit.

When operational shutdowns, at the command of the operator acting either on the shutdown button 9, as well as when the overloads are automatically turned off, the latch 12 and the momentary transfer of the cartridge 7 with fusible inserts 8 from the “on” position (FIG. 1) the “off” position of FIG. 2, with an arcless transfer of the load current from the main contacts to the breaking contacts and subsequent extinction of the arc in the arcing chambers 3.

Turning on the TAC is done manually by the operator, when the handle of the platoon 2 is exposed. At the same time, the disconnecting spring of the drive mechanism 11 is cocked and the cartridge 7 with fusible inserts 8 is turned from the off position (FIG. 2) to the on position (FIG. 1 )

Industrial applicability

The multi-phase TAC according to the invention can be used to protect general technical industrial and domestic installations of medium power and replaces circuit breakers with similar nominal parameters.

Claims (18)

1. A multiphase fuse-switch-disconnector (TAC) comprising a cassette with n fusible inserts located in the housing, 2n arcing chambers, where n is the number of phases in the TAC, a contact system, and the cassette is provided with a latch and is removable from the housing by means of a drive mechanism with a breaking spring, wherein n cassettes are made in said cassette for placement in each fuse-link in such a way that a consistent application of the force of the breaking spring of the drive mechanism through the checkout is ensured to fusible inserts, while the contact system contains 2n breaking contacts and 2n main conductive contacts and n thermal sensors mechanically connected to the latch. 2. The multiphase fuse-switch-disconnector (TAP) according to claim 1, in which each main conductive contact consists of two side surfaces of the fusible knife and jaws, from the condition 2 jaws on each fusible knife. 3. The multiphase fuse-switch-disconnector (TAP) according to claim 2, wherein each breaking contact consists of a fixed contact functioning as a sponge and a movable part of the contact, which is the end surface of each fuse insert knife. 4. The multiphase fuse-switch-disconnector (TAC) according to claim 1, which is further provided with a cocking handle, mechanically connected to the drive mechanism. 5. Multiphase fuse-switch-disconnector (TAC) according to claim 1, in which the windows made in the cassette are placed at the same distance from each other. 6. Multiphase fuse-switch-disconnector (TAC) according to claim 1 or 2, in which n windows are made in a cassette with different heights, different by Δ from the subsequent one, while in the upper part of the cassette, in the direction of removing the cassette from the housing, windows are made on the same level. 7. The multiphase fuse-switch-disconnector according to claim 6, wherein one window has a height h, the next window will have a height h + A, and the next one will have a height h + 2Δ, and so on. 8. The multiphase fuse-switch-disconnector (TAC) according to claim 7, in which the Δ value is about 0.5-1.0 mm 9. The multiphase fuse-switch-disconnector (TAC) according to claim 1, in which 2n current-carrying terminals are provided for connection to the protected circuit. 10. Multiphase fuse-switch-disconnector (TAC) according to claim 1, in which there is a button to turn off the TAC. 11. A multiphase fuse-switch-disconnector (TAC) comprising a cassette with n fusible inserts located in the housing, 2n arcing chambers, where n is the number of phases in the TAC, a contact system, and the cassette is provided with a latch and can be removed from the housing with using a drive mechanism with a tripping spring, and in this cassette n windows are made for placement in each fuse-link in such a way that a consistent application of the force of the tripping spring of the drive mechanism through etu on fusible inserts, while the contact system contains 2n main conductive contacts, each consisting of two side surfaces of the fusible knife and jaws, from the condition two jaws on each fusible knife, and 2n rupture contacts, each consisting of a fixed contact functioning in the quality of the sponge, and the movable part of the contact, which is the end surface of each knife of the fusible insert, as well as n thermal sensors, mechanically connected to the latch. 12. The multiphase fuse-switch-disconnector (TAP) according to claim 11, which is further provided with a cocking handle, mechanically connected to the drive mechanism. 13. The multiphase fuse-switch-disconnector (TAP) according to claim 11, in which the windows made in the cassette are placed at the same distance from each other. 14. The multiphase fuse-switch-disconnector (TAP) according to claim 11, in which n windows are made in the cartridge with different heights, differing by a value Δ from the next, while in the upper part of the cartridge, in the direction of removing the cartridge from the housing, the windows are made on the same level. 15. The multiphase fuse-switch-disconnector according to claim 13, wherein one window has a height h, the next window will have a height h + Δ, and the next one will have a height h + 2Δ, and so on. 16. The multiphase fuse-switch-disconnector (TAC) of claim 15, wherein the Δ value is about 0.5-1.0 mm. 17. The multiphase fuse-switch-disconnector (TAC) according to claim 11, wherein 2n current-carrying terminals are provided for connection to a protected circuit. 18. Multiphase fuse-switch-disconnector (TAC) according to claim 11, in which there is a button to turn off the TAC.

Images