EP0002985A1 - Hydraulic operating system for electric circuit breakers - Google Patents

Abstract

Remote control system in which the circuit breaker switch-on or trip-out orders are transmitted from the control cabinet to the circuit-breaker by a hydraulic pressure drop signal. The pilot valves for switching on (24) and tripping (26) of the control unit (12) of the circuit breaker (2-4-6) are actuated by a hydraulic device (28-30) controlled by a drop in pressure appearing in the pipes (44-44 ') in response to the fugitive opening of a purge solenoid valve (52-52') located in the control cabinet (46). Application in particular to the centralized control of several circuit breakers or circuit breaker modules.

Description

The present invention relates to a hydraulic control system, for an electric circuit breaker, which can be operated remotely from an order transmitter.

A hydraulic control for a circuit breaker essentially comprises, in a known manner: an actuator for operating the movable contact of the circuit breaker; a source of pressurized hydraulic fluid; and a set of hydraulic switching members, which will be designated in the following under the term of "control block" and which comprises at least one supply-bleed valve for the operating cylinder, this valve being controlled towards the either of its positions by two pilot valves, called interlock valves and tripping valves, which are actuated fleetingly to cause the interlocking operation or the tripping operation of the circuit breaker.

In modern installations, the control unit is mounted in the immediate vicinity of the cylinder, to which it is often even attached to reduce operating times and avoid losses of hydraulic loads.

In all these installations, the interlocking and tripping valves must be able to be controlled remotely from the circuit breaker, either for safety reasons or, above all, because from a single interlocking or tripping order several circuit breakers (for example the three circuit breakers mounted on the three phases of a network), or several circuit breaker modules (elementary circuit breakers mounted in series on the same phase of a network) must be tripped or tripped simultaneously. This is why, until now, only solenoid valves have been used as pilot valves for switching on and off, these solenoid valves being excited from an order transmitter located at a suitable distance from the point or points. circuit breakers.

Circuit breaker commands of the aforementioned type are well known and have been described for example in French patent No. 1,098,565 and its addition No. 67,250 respectively filed on January 15, 1954 and December 28, 1954, as well as in French patent No. 1,355,701 deposited on February 6, 1963, all these patents having been deposited in the name of Jean Louis Gratzmuller.

It can be seen from the above that the known control blocks not only included hydraulic equipment, but also electrical equipment, which generally required the installation, in the immediate vicinity of each circuit breaker or module, of a cabinet containing these equipment , another cabinet known as a "control cabinet" being of course provided to house the hydraulic and electrical safety, control equipment open or closed position of the circuit breaker (s) and transmission, after checking the possibilities of execution, of orders from the order issuer. Finally, hydraulic connections, some of which have a large section, and electrical connections were to unite the control cabinet with the control block of each circuit breaker.

The present invention makes it possible to greatly simplify installations of this kind by virtue of the fact that each control unit can comprise only hydraulic equipment, the pilot valves being controlled by hydraulic signals, so that all electrical system is eliminated on the modules. . This also has the advantage that the connections between each control unit and the control cabinet can be uniquely hydraulic connections produced in small section pipes. Finally, each control unit being a purely hydraulic device, it can be produced in the form of a sealed unit which does not require the installation of an individual cabinet for each circuit breaker or each circuit breaker module.

The subject of the invention is a hydraulic control system of the aforementioned type in which: each of the pilot valves is controlled by a hydraulic device attached to the pilot valve, said device being sensitive to a drop in pressure appearing in a control pipe at low flow and bringing the corresponding pilot valve into its active position in response to such a pressure drop; said control lines terminate in the control cabinet aforementioned trole; each of said pipes is provided, in the control cabinet, with a fugitively actuated purge valve and constituting respectively the latching control member and the tripping control member; and means are provided for permanently replenishing at low flow rate and for normally maintaining said high-pressure pipes and hydraulic devices under high pressure outside the transient periods of venting said purge valves.

As will be seen below, the pilot valves being controlled by a pressure drop signal transmitted by the control pipes, the response times between sending the order from the control cabinet and executing (switching on or off) of the order are very brief, since there is no need for said pipes to be purged up to atmospheric pressure.

The invention is particularly applicable to the control of circuit breakers of the elastic return type towards the tripped position and maintained in the latched position after disappearance of the fugitive latching signal, by a hydraulic self-holding circuit forming part of the block. control. Such hydraulic controls have been described in the aforementioned French patents.

In this case, according to the invention, the pilot trigger valve, which is controlled by a drop in pressure in the corresponding control pipe, is a purge valve of the self-maintaining hydraulic circuit provided in the block of ordered.

_E z ^t in, the invention finds a particularly advantageous application for controlling a plurality of circuit breakers, or circuit breaker modules, from a single central control cabinet. In this case, according to the invention, all of the aforementioned control pipes, leading to the hydraulic devices of the release valves of all the circuit breakers, are connected together, to the central cabinet, to a single purge valve, constituting a single trip, momentarily actuated, for the plurality of circuit breakers. Likewise, all of the aforementioned control lines leading to the hydraulic devices of the interlocking valves of all the circuit breakers are connected together in the central control cabinet, to a single purge valve constituting a single interlocking member for the plurality of circuit breakers. .

• la figure 1 est une représentation schématique du système suivant l'invention appliqué à la commande d'un seul disjoncteur ;
• la figure 2 est une vue en coupe des dispositifs hydrauliques de commande des valves pilotes d'enclenchement et de déclenchement ;
• la figure 3 est une représentation schématique du système suivant l'invention appliqué à la commande centralisée d'une pluralité de disjoncteurs ou de modules de disjoncteurs ;
• la figure 4 est un schéma d'une installation suivant l'invention pourvue de moyens d'enclenchement et de déclenchement supplémentaires.

The invention will be better understood on reading the detailed description which follows and on examining the appended drawings which represent, by way of nonlimiting examples, various embodiments of the invention. In these drawings:

• Figure 1 is a schematic representation of the system according to the invention applied to the control of a single circuit breaker;
• Figure 2 is a sectional view of the hydraulic devices for controlling the pilot interlocking and tripping valves;
• Figure 3 is a schematic representation of the system according to the invention applied to centralized control of a plurality of circuit breakers or circuit breaker modules;
• Figure 4 is a diagram of an installation according to the invention provided with additional engagement and trigger means.

There is shown in Figure 1 an electrical circuit breaker shown schematically by its movable contact 2 and its two fixed contacts 4 and 6, the movable contact being actuated by the rod 8 of a hydraulic cylinder 10. The circuit breaker shown is of the elastic return type permanent to the open position. In the figure, the elastic return means are constituted by a spring 11, but they could be constituted by a fluid under pressure. The control unit 12 essentially comprises a supply-purge valve 14 suitable for establishing either the communication (connection 16) between the jack 10 and a source of pressurized liquid such as a hydropneumatic accumulator 18 (circuit breaker engagement and maintenance engaged. ), or the communication (connection 20) between the jack 10 and a low pressure tank 22 (tripping of the circuit breaker).

The valve 14, which is a high flow valve, for rapidly supplying and purging the jack 10, is controlled to one or other of its positions (16 or 20) by pilot valves: engagement valve 24, trigger valve 26, which are fleetingly actuated. Hydraulic control blocks of this kind are well known and have been described in the aforementioned patents. Until now, electro-valves have been used as pilot valves 24-26, the electromagnet of which could be excited remotely from an order transmitter.

According to the present invention, the pilot valves 24-26 are actuated, no longer directly by an electrical signal, but by a hydraulic signal of pressure drop.

For this purpose, the pilot valves 24-26 are respectively actuated by hydraulic manostatic devices 28-30, which are attached to the corresponding pilot valve and an embodiment of which has been shown in more detail in FIG. 2.

Each hydraulic device 28-30 comprises a separate cylinder, by a piston 32-32 ', in two chambers 34-36 and 34'-36'. The rods 38-38 'of the pistons act on the valves 40-40' of the pilot valves 24-26 of the control unit, said valves having been shown in FIG. 2 in their normal rest position.

The chambers 36-36 'have an inlet 37-37' and are permanently in communication, via pipes 42, with the pressure of the accumulator 18, while the chambers 34-34 'have an inlet 35-35' and are connected to hydraulic lines 44-44 ', called "control lines", in which the pressure can be lowered from a control cabinet 46 (FIG. 1), by means which will be described in what follows, the control cabinet 46 can be located several meters from the circuit breaker to be controlled.

The control lines 44-44 'which terminate in the control cabinet 46 are permanently supplied with pressurized hydraulic fluid by connection, by means of lines 48, with the accumulator 18, or alternatively, with an 18 'accumulator which can be provided in or in the vicinity of the control cabinet.

In the position shown in FIG. 2, the pressure exerted on the pistons 32-32 'in the chambers 36-36' is balanced by the pressure exerted on the opposite faces of the pistons by the pressurized liquid contained in the chambers 34-34 'and by the force of the springs 50-50' which compensate for the difference in active surface of the two faces of the piston due to the presence of the rods 38-38 '.

In this rest position of the pilot valves 24-26, the valves 40-40 'of these valves are closed.

We will now describe the means for remotely controlling, from the control cabinet, the fugitive opening of the pilot valves 24-26, opening which respectively causes the switching on or off of the circuit breaker.

On the line 44 is interposed, in the control cabinet 46, a purge valve 52, which, in the normal closed position, places the line 44 in communication with the line 54 connecting with the accumulator 18 (or 18 ′). In the open position of the valve 52, the pipe 44 is placed in communication with a low-pressure tank 56. In the preferred embodiment of the invention, a simple, two-way purge valve is used, so that in open position of the valve 52, both the pipes 44 and 54 are vented but a nozzle 58 of small cross section relative to the opening section of the purge valve is interposed on the pipe 54.

The purge valve 52 is preferably a solenoid valve which can be operated fleetingly by means of a ultra-fast electromagnet 60 of a type well known in circuit breaker control.

The control line 44 'of the trigger pilot valve 26 is equipped in the same way with a purge solenoid valve 52' connected in an identical manner to what has just been described.

The operation of the installation is as follows, for the engagement command: in the position shown, the pipes 54-44 and the chamber 34 of the hydraulic device 28 are filled with liquid at the pressure P of the accumulator 18 (or 18 '). Lines 48-42 and chamber 36 are filled with liquid at the same pressure P.

If the electro-valve 52 is fleetingly excited, by means of the command transmitter located in the control room of the electrical station, the pipe 44 decompresses and its pressure decreases by an amount at P, likewise than in chamber 34. The pressure P which continues to prevail in chamber 36 exceeds the sum of the pressure P-AP in chamber 34 and the force of the spring 50, so that the piston 32 is pushed back down ( Figure 2) and opens the valve of the pilot pilot valve 24.

This pilot valve is for example of a type well known in circuit breaker control blocks and it establishes, in the open position, communication between a line 62 connected to the accumulator 18 and another line 64 connected to the pilot cylinder (not shown) of the main supply-purge valve, to bring the latter valve to position 16 (supply) indicated in FIG. 1. After disappearance of the fugitive signal from latching, the valve is maintained in the supply position by the self-maintaining hydraulic circuit described in the aforementioned patents. A non-return valve 66 is interposed in a known manner on the pipe 64.

After disappearance of the fugitive engagement signal emitted by the purge solenoid valve 52, the latter closes again and the pipe 44 is again supplied with low flow through the pipe 54, through the nozzle 58. The pressure in the chamber 34 is thus reduced to the same value as in the chamber 36, this pressure P ′ being lower than the initial pressure P, owing to the fact that the accumulator 18 has delivered the quantity of oil necessary for supplying the jack 10 of the circuit breaker to bring the latter into the engaged position. The hydraulic pressures between the two chambers 34 and 36 being identical, the piston 32 rises and the valve 40, assisted by its spring 68 closes. The hydraulic devices 28 therefore resume the rest position shown in FIG. 2.

If the new pressure P ′ is lower than the restarting pressure of the pump 70 for recharging the accumulators, the pump recharges the accumulator 18 via the small section pipe 48 to the pressure P chosen, the pressures in the chambers 34 and 36 therefore always remaining equal and the pilot valve 24 therefore remaining closed.

The control of the pilot trigger valve 26 by the purge solenoid valve 52 'is identical to what has just been described with regard to the control of the pilot pilot valve 24. It may simply be noted (FIG. 2 ) that the pilot valve 26, when open, puts in communication a pipe 72 connected to the hydraulic self-holding circuit (not shown) of the control unit 14 with a low pressure tank 74.

It is clear from the above that the invention makes it possible to ensure remote control of a circuit breaker, from a control cabinet, by means of only hydraulic connections with a small section (pipes 44, 44 ', 48 ), for example tubes with an inside diameter of 3 mm, which are easy to install because they are unrollable and not rigid.

On the other hand, it appears that the valves 24 and 26 are actuated simply by a pressure drop signal in the control lines 44-44 'without these lines needing to be purged to atmospheric pressure. A very rapid response is therefore obtained, since the only decompression of the oil in the lines 44-44 'is sufficient to actuate the hydraulic devices and the decompression wave propagates at the speed of sound in the oil. This speed of response is particularly valuable for tripping the circuit breaker which is a safety operation.

Finally, it should be noted that the absolute value P or P 'of the oil pressure in the control system has no influence on the reliability of the system according to the invention, the hydraulic signal consisting only of a relative drop in pressure .

FIG. 1 shows a circuit breaker with elastic return to the spring-triggered position, but it is understood that the invention tion also applies to circuit breakers actuated by a double-acting cylinder or by a differential cylinder with hydropneumatic return.

The invention is of particular interest when it is intended for the simultaneous control of several circuit breakers or of several circuit breaker modules from a central control cabinet. FIG. 3 shows the case of two modules which are each controlled by a control block 12 or 112, identical to the control block 12 described in connection with FIG. 1 and which are located at a certain distance one of the other. In this case, the two interlocking control lines 44 and 144 are connected at a common point 76 to the control cabinet 146 and a single purge solenoid valve 52 allows, when it is energized, to lower the pressure. both in the two pipes 44 and 144, that is to say simultaneously transmitting to the two control blocks 12 and 112 the hydraulic engagement signal.

It is the same for the two trip control lines 44 'and 144' which are joined at a common point 76 'to the control cabinet and whose pressure can be reduced simultaneously by means of the solenoid valve single purge valve 52 'for transmitting the tripping order to the two blocks 12-112.

Manual control of switching on or off of all the circuit breakers can be obtained by manually actuating the solenoid valves 52 and 52 'respectively.

As in the case of FIG. 1, the control lines 44-144-44'-144 'are made ment in liquid under pressure through nozzles 58-58 'having a much lower flow rate than the purge valves 52-52' in the open position.

As in the case of FIG. 1, it is possible to provide only a local hydropneumatic accumulator 18 near each module, that is to say in each of the control blocks 12 and 112, these accumulators being recharged, through pipes. equivalent to the pipe 48 (FIG. 1), by the pump 70 provided in the control cabinet 146. As a variant, an additional central accumulator 18 ′ can also be provided.

In certain installations, the user requires, for safety reasons, to be able to have several locking and especially triggering control members.

The present invention lends itself well to the installation of such additional members since it suffices to have, at any point of the control lines 44-44'-144-144 ', an additional purge valve, in addition to the main valve. 52 or 52 'provided in the central control cabinet.

Thus in the embodiment of Figure 4 which, like that of Figure 3, relates to the simultaneous control of two circuit breakers or circuit breaker modules 10 and 110, was mounted on the trip control line 44 ' , near or in the control unit 12, an additional tripping electro-valve 78. Similarly, an additional tripping electro-valve 78 'is mounted on the control line 144' in the control block 112 of the second module. Of course, the fleeting excitation of one or the other of these electro-valves causes the triggering of the two modules (or of all the modules) since the pipes 44 'and 144' are in communication.

Finally, FIG. 4 shows the application to an installation according to the invention of the security system against "discrepancies" which has been described in French patent application number 77 36277 filed on December 2, 1977 in the name of the same inventor.

It suffices to recall that this system prevents the complete execution of a maneuvering order, in particular a closing order, if the simultaneity of the maneuvering of all the modules is not respected. The system essentially comprises a "discrepancy" detector constituted by a differential pressure detector 80 comprising a cylinder in which a free piston 82 determines two chambers 84-84 'maintained in permanent communication, by lines 86-86' with the chambers cylinders 10-110.

In the event of a pressure difference, the piston 82 moves and actuates a control device 88 causing the tripping of all the circuit breakers, which avoids dangerous non-simultaneous engagement.

According to the present invention, the device 88 controls the opening of an additional purge valve 90 disposed on the trigger control pipe 44 '(or 144'). The opening of the valve 90 lowers the pressure in both the lines 44 'and 144' and therefore interrupts the switching operation of all modules in the event of a discrepancy, since a general priority trip order is given. The control link 92 between the device 88 and the purge valve 90 can be an electrical connection or, preferably, a mechanical connection, as described in the aforementioned patent.

It should also be noted that in all of the embodiments of the present invention which have been described, there is no hydraulic connection with a large section and at high flow rate between the control blocks 12-112 and the control cabinet 46 or 146, but only small section pipes such as 44-44 '- 144-144' - 48-86-86 'which can be non-rigid unrollable pipes.

This has the great advantage that no shock or dynamic force is transmitted from the circuit breakers to the control cabinet. In fact, circuit breakers are devices that operate brutally and control cabinets often contain relatively fragile accessories such as recorders, relays, etc. which are often disturbed by the shocks transmitted by large section pipes.

Among these sensitive accessories, it should be noted, in control cabinets, electro-valves which, to provide the extremely short response times required on modern circuit breakers, are very short stroke valves. As a result, the hydraulic shocks transmitted to the cabinet by large section pipes with high flow rate could cause untimely switching of these valves and, consequently, maneuvers. nuisance circuit breakers. These various drawbacks are therefore eliminated thanks to the invention.

Claims (12)

1. Hydraulic control system for circuit breaker or circuit breaker module that can be operated remotely from a control cabinet; said system being of the known type comprising: a pressure source; a low pressure receptacle; a permanent elastic return device of the circuit breaker towards the open position; a hydraulic cylinder engaging the circuit breaker against said elastic means and keeping it in the closed position when it is supplied under pressure; in the immediate vicinity of said cylinder, a control unit comprising, on the one hand, at least one supply-purge valve of the cylinder and, on the other hand, two pilot valves, called interlock valves and tripping valve, having a rest position and an active position in which they are actuated fleetingly, the two said valves controlling the switching of said supply-purge valve respectively to the supply positions and to the purge position, said system being characterized in that each of said pilot valves is controlled by a hydraulic device, having on the one hand a first inlet connected to said pressure source and on the other hand a second inlet connected to a control pipe, bringing said pilot valve in the active position when the pressure in the control line is lower than the pressure of the source; in that each of said control pipes ends at the control cabinet and is provided, in the control cabinet, with a fugitively actuable purge valve constituting respectively the engagement control member and the member circuit breaker trip control; and in that a permanent communication, provided with flow restriction devices is established between said pressure source and each of said control lines. 2. System according to claim 1, characterized in that the supply-purge valve of the jack is provided with a hydraulic self-maintenance circuit in the supply position and in that the pilot trigger valve is a purge valve of said circuit self-sustaining. 3. System according to one of claims 1 or 2, characterized in that each aforementioned hydraulic device is a device operating by differential pressure which has a capacity separated into two chambers by a movable partition, the two of said chambers being respectively supplied by said first and second inlets, and in that said movable partition actuates the valve corresponding pilot. 4. System according to any one of claims 1, 2 or 3 for the control of a plurality of circuit breakers, from a single central control cabinet, characterized in that all of the aforementioned control pipes, leading to the devices hydraulic tripping valves of all circuit breakers, are connected together in the central cabinet to a single purge valve constituting a single tripping member, actuated fleetingly, for the plurality of circuit breakers and in the same way for all the aforementioned control lines leading to the hydraulic devices of the interlocking valves of all the circuit breakers. 5. System according to any one of claims 1 to 4, characterized in that the aforementioned control block, for each circuit breaker or circuit breaker module, comprises only hydraulic members and in that said blocks are connected to the cabinet control only by hydraulic link pipes of small cross section at low flow. 6. System according to any one of the preceding claims, characterized in that at least one of the control lines pre cited, in particular the control pipe leading to the hydraulic devices for triggering valves, is provided with at least one additional purge valve disposed at a chosen point of said pipe, whereby the actuation of a single purge valve on said pipe causes the operation, in particular the tripping operation, of the circuit breaker. 7. System according to claim 6, characterized in that at least some of the aforementioned additional purge valves are electro-valves. 8. System according to one of claims 6 or 7, for a simultaneous hydraulic control installation of several circuit breakers or mobile circuit breakers comprising a safety system against "discrepancies" which essentially comprises a discrepancy detector constituted by a pressure detector differential which is formed by a separate cylinder, by a free piston, which determines two chambers maintained permanently in communication with the chambers of the operating cylinders of the circuit breakers, the movement of said free piston controlling the tripping of all the circuit breakers, said system being characterized in that at least one of the additional purge valves shutdown is controlled by said differential pressure detector. 9. System according to any one of the preceding claims, characterized in that each of the aforementioned control blocks is provided with a local hydropneumatic accumulator, said accumulator constituting the energy source actuating the actuator of the circuit breaker associated with the block of control considered and forming part of the means for permanently supplying the aforementioned control pipes and hydraulic devices at low flow rate. 10. System according to claims 1 and 9, characterized in that the means for permanently replenishing the control pipes and the hydraulic devices at low flow rate comprise throttles arranged on the connecting pipes between the aforementioned accumulator and said pipes. 11. System according to claim 9, characterized in that it comprises, in the control cabinet, a pump for recharging the local accumulators of the control blocks. 12. System according to any one of the preceding claims, characterized in that the aforementioned control lines are small section, unrollable, non-rigid pipes.

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