SF6-free gas-insulated disconnector with totally enclosed arc chamber actuated by rod mechanism

Abstract

The invention relates to an SF6-free gas-insulated disconnector with a totally enclosed arc chamber actuated by a rod mechanism, in particular to a disconnector for a GIS, comprising, in the gas chamber and along an axis:-a pair of permanent contacts, both fixed; -an electrically conductive tube movable along said axis (AA '), the tube moving from a position in which the two permanent contacts are in electrical contact to a position in which the two main contacts are electrically separated; -a pair of arc contacts, one being fixed and the other being movable with the conductive tube; -a pair of rear contacts, one of which is in electrical contact with the movable arc contact; means for moving the conductive tube and the movable arcing contact along the axis, thereby opening the disconnector, and for separating the rear contacts from each other before the arcing contacts are separated.

Description

TECHNICAL FIELD

[0001] The present invention relates to a gas-insulated electrical substation, commonly known as a gas-insulated substation (GIS). This type of substation comprises a disconnector, a circuit breaker or a grounding switch. The switchgear components are generally metal tanks filled with pressurized SF6 (sulfur hexafluoride). BACKGROUND

[0002] Sulfur hexafluoride (SF6) causes a greenhouse effect, which has recently been replaced by another gas, the so-called "g3" gas, which comprises heptafluoroisobutyl nitrile mixed with a diluent gas comprising carbon dioxide and oxygen, for replacing SF6, thus opening the way to a new generation of high-voltage (HV) power transmission equipment. This g3 gas has a significantly reduced impact on the environment (more than 98% reduction in global warming potential (GWP)).

[0003] It has however been noted that the disconnector of a GIS implementing said gas generates a powder during disconnection. This powder, resulting from the decomposition of the g3 gas used to replace SF6, is harmful to the dielectric strength. Indeed, the g3 decomposition products combine with the molten metal to form metal oxide particles which diffuse to the corona shield surface, thus causing a peak effect.

[0004] There is therefore a problem of limiting the production of this powder and / or of partially or totally limiting it. SUMMARY

[0005] To solve the above-mentioned problems, the inventors have found a solution to limit the arc produced during the switching of a disconnector.

[0006] The invention first relates to a disconnector for a GIS, comprising:

[0007] - a pair of permanent contacts, one fixed and the other mobile, or both fixed relative to each other; said permanent contacts being for example spring contacts;

[0008] - a pair of arc contacts, one fixed and the other mobile;

[0009] - a pair of back contacts, one of which is in electrical contact with the mobile arc contact;

[0010] - means for separating said back contacts from each other before the separation of the arc contacts.

[0011] Preferably, an electrically conductive tube is mobile along said axis (AA'), this tube being mobile from a position in which the two permanent contacts are in electrical contact with each other to a position in which the two main contacts are electrically separated from each other. The mobile arc contact can be fixed relative to said electrically conductive tube.

[0012] In an embodiment, the means for separating the back contacts from each other comprise a lever, for example a double-armed lever, one of the back contacts being fixed to an end of the lever, the lever being rotatable about an axis, for example fixed with respect to the movable permanent contact.

[0013] Each of the pair of back contacts can for example comprise at least one blade, the back contacts sliding against each other when they are separated. In a more particular embodiment, each of the pair of back contacts comprises two blades parallel to each other.

[0014] Preferably, at least one of the back contacts in electrical contact with the movable arc contact is also in electrical contact with the movable main contact.

[0015] In a particular embodiment, at least one of the pair of back contacts is movable in a plane which can comprise the axis along which the movable main contact and the arc contact are movable, for example along an axis which is preferably perpendicular to the axis along which the movable main contact and the arc contact are movable.

[0016] The application also relates to a GIS comprising:

[0017] - a metal tank filled with a gas;

[0018] - a disconnector according to the application, as disclosed above or in the application.

[0019] The application also relates to a method for opening a disconnector of a GIS according to the application, comprising:

[0020] - moving the movable arc contact and the movable main contact with respect to the fixed arc contact and the fixed main contact, thereby closing the pair of arc contacts and separating the pair of permanent contacts from each other;

[0021] - then separating the pair of back contacts from each other before the arc contacts are separated, thereby triggering an arc between the back contacts;

[0022] - then separating the movable arc contact with respect to the fixed arc contact.

[0023] The application also relates to a method for closing a disconnector of a GIS according to the application, comprising:

[0024] - closing the pair of back contacts before the arc contacts are closed;

[0025] - moving the movable arc contact and the tube with respect to the fixed arc contact and the main contact, thereby closing the pair of arc contacts;

[0026] - closing the main contact;

[0027] - opening the arc contacts.

[0028] Technical solution 1. A disconnector (100) for a GIS, comprising, in a gas chamber and along an axis (AA’):

[0029] - a pair of permanent contacts (24, 41), both fixed;

[0030] - an electrically conductive tube (30) movable along the axis (AA’), the tube (30) moving from a position in which the two permanent contacts are electrically contacted to a position in which the two main contacts are electrically separated;

[0031] - a pair of arc contacts (22, 42), one (22) fixed and the other (42) movable together with the electrically conductive tube (30);

[0032] - a pair of back contacts (521, 522), one of the back contacts (522) being in electrical contact with the movable arc contact (42);

[0033] - means (6) for moving the electrically conductive tube (30) and the movable arc contact (22, 42) along the axis (AA’) so as to open the disconnector (100), and for separating the back contacts (521, 522) from each other before the arc contacts (22, 42) are separated.

[0034] Technical solution 2. The disconnector according to technical solution 1, wherein the means (6) for separating the back contacts (521, 522) from each other comprise a single- or double-armed lever, one of the back contacts being fixed to an end (52) of the lever, the lever rotating about an axis (16) fixed with respect to the movable permanent contact (41).

[0035] Technical solution 3. The disconnector according to any one of technical solutions 1 or 2, wherein a wall (46) divides the gas chamber into a back gas chamber (302) and a front gas chamber (301), the back gas chamber (302) housing the back contacts (521, 522), the front gas chamber (301) housing the arc contacts when the arc contacts are closed.

[0036] Technical solution 4. The disconnector according to any one of technical solutions 1 to 3, wherein one of the back contacts (521, 522) is electrically linked and fixed with respect to the movable electrically conductive tube (30).

[0037] Technical solution 5. The disconnector according to any one of technical solutions 1 to 4, wherein each of the pair of back contacts (521, 522) comprises at least one blade, the back contacts sliding against each other when they are separated.

[0038] Solution 6. The disconnector according to solution 5, wherein each contact of the pair of back contacts (521, 522) comprises two blades (522, 522') parallel to each other.

[0039] Solution 7. The disconnector according to any one of solutions 1 to 6, wherein at least one of the pair of back contacts (521, 522) is movable in a plane (XZ) comprising the axis (AA') along which the movable arc contact is movable.

[0040] Solution 8. The disconnector according to solution 7, wherein at least one of the pair of back contacts (521, 522) is movable along an axis perpendicular to the axis (AA').

[0041] Solution 9. The disconnector according to any one of solutions 1 to 8, wherein the back contacts (521, 522) are located in a portion of the disconnector (100) distal from the arc contacts (22, 42).

[0042] Solution 10. A GIS comprising:

[0043] - a metal tank (1) filled with a gas;

[0044] - a disconnector (100) according to any one of solutions 1 to 9.

[0045] Solution 11. The GIS according to solution 10, the gas comprising:

[0046] - heptafluoroisobutyl nitrile and / or heptafluoroisopropyl trifluoromethyl ketone (also known as 2-butanone, 1,1,1,3,4,4,4-heptafluoro-3-(trifluoromethyl)- (CAS No 756-12-7), possibly mixed with a gas or diluent gas comprising at least CO2 and / or O2 and / or N2 and / or oxygenated compounds;

[0047] - or at least CO2 and / O2 and / or N2 and / or oxygenated compounds and / or water vapor.

[0048] Solution 12. The GIS according to solution 10 or 11, wherein the metal tank is surrounded by, or is intended to be surrounded by, an atmosphere comprising some water and / or water vapor.

[0049] Solution 13. A method for opening the disconnector of a GIS according to solutions 10 to 12, comprising:

[0050] - moving the movable arcing contact (42) and the tube (30) relative to the fixed arcing contact (22) and the main contacts, thereby closing the pair of arcing contacts and separating the pair of permanent contacts (24, 41);

[0051] - separating the pair of back contacts (521, 522) from each other prior to the separation of the arcing contacts (22, 42), thereby triggering an arc (53) between the back contacts;

[0052] - separating the movable arcing contact (42) relative to the fixed arcing contact (22).

[0053] Technical solution 14. A method for closing a disconnector of a GIS according to technical solutions 10 to 12, comprising:

[0054] - closing the pair of back contacts (521, 522) prior to the closing of the arcing contacts (22, 42);

[0055] - moving the movable arcing contact (42) and tube (30) relative to the fixed arcing contact (22) and the main contacts (24, 41), thereby closing the pair of arcing contacts;

[0056] - closing the main contacts (24, 41);

[0057] - opening the arcing contacts (22, 42). BRIEF DESCRIPTION OF DRAWINGS

[0058] - Figure 1 An example of a gas insulated substation is shown;

[0059] - Figures 2A-2D An example of a disconnector according to the present application is shown;

[0060] - Figure 3 An enlarged view of a back or back arcing contact according to the present application is shown;

[0061] - Figure 4 An embodiment of a back or back arcing contact according to the present application is shown;

[0062] - Figures 5A-5B An embodiment of a disconnector according to the present application is shown in a side view Figure 5A ) and a top view Figure 5B ) and its actuation mechanism. DETAILED DESCRIPTION

[0063] Figure 1An example of a metal tank 1 or arc chamber comprising a disconnector is shown above. The metal tank 1 is filled with a gas, for example a "g3" gas, comprising heptafluoroisobutyl nitrite mixed with a diluting gas comprising carbon dioxide and oxygen.

[0064] For example, the gas can comprise:

[0065] - heptafluoroisobutyl nitrite and / or heptafluoroisopropyl trifluoromethyl ketone (also known as 2-butanone, 1,1,1,3,4,4,4-heptafluoro-3- (trifluoromethyl)- (CAS No 756-12-7)), possibly mixed with a gas or diluting gas comprising at least CO2and / or O2and / or N2and / or oxygenated compounds;

[0066] - or at least CO2and / or O2and / or N2and / or oxygenated compounds and / or water vapour.

[0067] The metal tank can be surrounded by, or can be intended to be surrounded by, an atmosphere comprising some water and / or water vapour.

[0068] The disconnector extends along an axis AA' (parallel to the axis X) and comprises a pair of electrodes (corona shields) 2, 4 mounted in contact with each other along said axis AA' by means of an actuation system 6, 8 for moving a conductive tube 30 (see Figure 1 and Figure 2A ) along said axis AA'. This tube 30 is movable along said axis AA' from a closed position in which a current can flow through the contacts to an open position in which the current is interrupted, and vice versa.

[0069] By convention, the term "main contact" is used to designate the electrical contact through which the nominal current passes; this main contact is associated with an "arc contact" which performs the function of correct disconnection and establishment of contact. The term "movable contact" is used to designate the movable arc contact and the tube, both connected to the actuation system 6, 8.

[0070] The disconnector comprises:

[0071] - a first movable contact 4 consisting of an arc contact 42, for example in the form of a plurality of fingers, and a main contact 30, 41 (the arc contact 42 being movable with respect to the contact 41, the tube 30 moving from a position in which the two main contacts are in contact to a position in which the two main contacts are separated);

[0072] - and a second contact 2, which in this example is fixed, consisting of an arc contact 22 and a main contact 24.

[0073] The main contacts 24, 41 can be fixed with respect to each other, the tube 30 moving from a closed position in which the main contacts 24, 41 are in electrical contact with each other to a position in which the main contacts 24, 41 are not in electrical contact.

[0074] These two elements cooperate between a disconnection position, in which the two electrodes 2, 4 are separated from each other, and a closed position, in which they allow the passage of current between them (due to the translation of the tube 30). Figure 1

[0075] During the disconnection process, the two main contacts 30, 24 are separated and the arc contacts 42, 22 then take over. Figure 2B and 2C .

[0076] The actuation system 6, 8, which forms the means for disconnecting the disconnector, comprises for example a lever 6, which is actuated at one of its ends 62 by a lever 8 (see Figure 1 , 5A , 5B), which is mounted to pivot about an axis 14 (perpendicular to the axis AA' of the disconnector). The lever 6 is also mounted to rotate about an axis 16 (in the XZ plane, see Figure 1 , 5A , 5B) so as to move the cylinder 30 along the axis AA'. In other words, the actuation system converts the rotation of the axis 14 (driven by a mechanism not explained in detail) into the translation of the cylinder along the axis AA'. As explained below, the lever 6 extends through a sliding contact inside the arc chamber which is completely closed. In one embodiment, the lever 6 forms a double-armed lever, one arm extending between the end 62 and the axis 16, and the other arm extending between said axis 16 and the other end of the lever 52, which carries at least one electrical contact. In a variant, the means 6 for separating the back contacts (521, 522) from each other can comprise a single-armed lever, instead of a double-armed lever.

[0077] Figures 2A-2D and 3 more precisely show an example of a disconnector according to the application. It extends along a longitudinal axis AA'.

[0078] The movable electrode 4 comprises a main contact 41 (for example an immobile spring contact), a movable tube 30 and an arc contact 42.

[0079] With the help of the actuation system 6, 8, the movable tube 30 can be moved along the axis AA' between a closed position Figure 2A and a disconnection position Figure 2D .

[0080] The movable arc contact 42 is formed at the end of a rod or tube 44 made of an electrically conductive material, preferably identical to the contact 42.

[0081] ​The arc contact 42 is, for example, in the form of a light bulb, having an outer diameter larger than the outer diameter of the rod or tube 44 and slightly larger than the inner diameter of the fixed arc contact 22. The end 42 includes, for example, at least two fingers 421, 422, which are elastic enough to press against the fixed arc contact 22; the fingers 421, 422 are separated by a central tube 43, which gives the fingers a certain degree of freedom so that they can be pressed in the direction of the axis AA', especially when the arc contact 42 enters the fixed arc contact 22.

[0082] Wall 46 divides the gas chamber into two parts: the rear gas chamber 302 and the overall gas volume 301 (which includes the entire cut-off gas chamber). Wall 46 carries the movable arc contact 42 and is also electrically insulated so as to electrically isolate the arc contact 42 from the conductive tube 30.

[0083] On the side of the rear chamber 302, the metal contact 521 is electrically connected to the tube 30 and fixed relative to the tube 30.

[0084] The actuating rod 6 extends beyond the pivot axis 16 via a metal contact 522, which is designed to contact the rear contact 521 (electrically linked and fixed to the tube 30) within the position range of the actuating rod. The metal contact 522 is always electrically contacted by sliding on the movable arc contact 42 (note that components 48, 44, and 42 can be combined into a single machined component). An additional contact may also be included to prevent floating potentials on the arc contact.

[0085] The rear contacts 522 (which maintain electrical contact with the movable arcing contact 42) and 521 are slightly disconnected after the main contact 24 separates from the tube 30, but the arcing contacts 42 and 22 remain in contact during this period. Therefore, the arc 53 is formed between the rear contacts 521 and 522, rather than between the arcing contacts 42 and 22 (as shown in the image). Figure 3 (As shown above). Starting from the position where two of the rear contacts are in contact with each other, when the second rear contact 522 is at the end of the rod 6 in the XZ plane (see... Figure 5A When driven internally, the rear contact 522 can slide against the rear contact 521, and the rod 6 rotates in the XZ plane, thereby separating the rear contact.

[0086] Therefore, the cutter according to the invention may include a device 6 for disconnecting the cutter and for disconnecting the rear contacts or rear contacts 521, 522 before the arc contacts 22, 42 separate.

[0087] In an exemplary embodiment, each of the rear contacts includes at least one blade or a spring blade, and the blades are slidable against each other in the XZ plane, preferably sliding substantially along an axis perpendicular to the AA' axis; Figure 4and Figure 5A In the embodiment shown above, each back contact comprises two parallel blades (see for example Figure 4 and Figure 5B the blades 522, 52'2) on the back.

[0088] Figures 2A-2D Different steps of the opening phase of the disconnector according to the application are shown. It is controlled by a mechanism that drives the translation of the insulating stem 6 and the rotation around the rotation axis 16.

[0089] Figure 2A The first position is shown above, in which the electrodes 2 and 4 are both contacted by the main contacts 24, 41 (spring contacts in this example) and the tube 30 and the back contacts 521 and 522.

[0090] After the opening phase has started, the tube slides against the main contacts 24 until they are separated Figure 2B , the arc contact 22 slides against the arc contact 42. The current flows through the arc contacts 42, 22, the tube 44, the back contacts 521 and 522 (which are still connected together) and the cylinder 30.

[0091] After a certain time, the back contacts 521 and 522 are separated Figure 2C ; this triggers an arc 53 between the two contacts 521 and 522 in the back chamber 302 (as shown in Figure 3 above), the decomposition of the gas at the back chamber 302 is harmless.

[0092] Since the arc 53 is created between the back arc contacts 521 and 522, the decomposition of the gas occurs in the back chamber 302, avoiding the decomposition in the front chamber 301. Since the arc is created inside the back chamber 302, the decomposition of the gas will only occur in this back chamber and will not contaminate the front chamber 301 (the front chamber 301 comprises the whole disconnector gas chamber, where the dielectric strength is critical).

[0093] Subsequently, the arc contacts 22, 42 are separated Figure 2D . Since the current has been cut by the back contacts 521 and 522, no arc is created when the arc contacts 22, 42 are separated.

[0094] The opening of the disconnector thus comprises the following steps:

[0095] - a step of closing the arc contacts 22, 42;

[0096] - a step of opening the main contacts 24, 41;

[0097] - a step of opening the back contacts away from said arc contacts 22, 42, which triggers an arc 53 between said back contacts;

[0098] - a step of opening the arc contacts 22, 42;

[0099] - a step of closing the back contacts so that there is no floating potential after the opening sequence Figure 2D ).

[0100] Thus, the back contacts 521, 522 are separated before the arc contacts 22, 42 are separated.

[0101] The length from the contact 522 to the lever 6 and the size of the back contacts 521, 522 can be set as desired, in particular the expected time of the arc.

[0102] The closing of the circuit breaker can comprise the following steps:

[0103] - a step of closing the back contacts 521, 522;

[0104] - a step of closing the arc contacts 22, 42;

[0105] - a step of closing the main contacts 24, 41;

[0106] - a step of opening the arc contacts 22, 42.

[0107] The application applies to a GIS operating at a rather low voltage (for example 27 V, more generally between 10 V and 500 V) and at a rather low current (for example 3000 A, more generally between 1000 A and 6300 A) between the back contacts.

Claims

1. A cutter (100) for GIS, comprising, within a gas chamber and along an axis (AA'): - A pair of permanent contacts (24, 41), both of which are fixed; - A conductive tube (30) movable along the axis (AA'), the tube (30) moving from a position where two of the permanent contacts are in electrical contact to a position where two of the main contacts are in electrical separation; - A pair of arc contacts (22, 42), one (22) is fixed and the other (42) is movable together with the conductive tube (30); - A pair of rear contacts (521, 522), one of which (522) is in electrical contact with the movable arc contact (42); - Device (6) for moving the conductive tube (30) and the movable arc contacts (22, 42) along the axis (AA') to disconnect the cutter (100), and for separating the rear contacts (521, 522) from each other before the arc contacts (22, 42) separate.

2. The cutter according to claim 1, wherein, The device (6) for separating the rear contacts (521, 522) from each other includes a single-arm lever or a double-arm lever, one of the rear contacts being fixed to an end (52) of the lever, the lever being rotatable about an axis (16) fixed relative to the movable permanent contact (41).

3. The cutter according to any one of claims 1 or 2, wherein, The wall (46) divides the gas chamber into a rear gas chamber (302) and a front gas chamber (301), the rear gas chamber (302) accommodating the rear contacts (521, 522), and the front gas chamber (301) accommodating the arc contacts when the arc contacts are closed.

4. The cutter according to any one of claims 1 to 3, wherein, One of the rear contacts (521, 522) is electrically connected to and fixed relative to the movable conductive tube (30).

5. The cutter according to any one of claims 1 to 4, wherein, Each of the pair of rear contacts (521, 522) includes at least one blade, and the rear contacts slide against each other when they are separated.

6. The cutter according to claim 5, wherein, Each of the two rear contacts (521, 522) comprises two blades (522, 52'2) that are parallel to each other.

7. The cutter according to any one of claims 1 to 6, wherein, At least one of the pair of rear contacts (521, 522) is movable in a plane (XZ) that includes the movable arc contact along its movable axis (AA').

8. The cutter according to claim 7, wherein, At least one of the pair of rear contacts (521, 522) is movable along an axis perpendicular to the axis (AA').

9. The cutter according to any one of claims 1 to 8, wherein, The rear contacts (521, 522) are located in the portion of the cutter (100) away from the arc contacts (22, 42).

10. A GIS, comprising: - A metal can filled with gas (1); - The cutter (100) according to any one of claims 1 to 9.

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