FR2674678A1 - HIGH-VOLTAGE DISCONNECTABLE DEVICE FOR ESTABLISHING AND CUTTING BAR TRANSFER CURRENTS IN A LOOP CIRCUIT. - Google Patents

Abstract

High-voltage disconnector designed to establish and cut, without creating sparks at the main contact (2, 3), the bus transfer currents in a loop circuit. Means (4 to 7) are provided for, on closing, first of all immobilizing the male part (1) of the contact and providing an auxiliary contact (7, 15) of the spark arrester type, and only then closing the part. female (2, 3) of the contact on its male part (1), and vice versa when opening.

Description

HIGH-VOLTAGE DISCONNECT TO SET AND CUT THE

  CURRENT TRANSFERRING BARS IN A LOOP CIRCUIT

  the present invention relates to a disconnector for a high-voltage power supply network, this disconnector being able to establish and cut the transfer currents of bars in a high-voltage supply circuit called "loop" . It is well known to use, for a conventional high-voltage ac power supply network, a so-called "loop-shaped" supply circuit. The supply of the users S 'is then carried out by a first set of bars, and there is further provided a second busbar replacement, which is generally identical to the first and which is connected in parallel thereto This second busbar is in normal operation not traversed by the supply current, a The disconnector placed on this busbar then being in the open position It is however intended to supply it to replace the first set when it is desired to isolate the latter, for example to carry out repair work or even simply maintenance. It is then necessary to carry out a so-called bar transfer operation, from the first game to the second game, which is performed conventionally, without interrupting the supply of electrical energy to users, as follows: first the disconnector which is placed on the second busbar The voltage across this disconnector, which is before closing equal to the ohmic drop d V in the first busbar, then changes from this value d V to the value zero, 3 O while almost simultaneously the intensity of the current in this disconnector changes from the value zero to a value that is approximately equal to half the line current that crossed the first busbar before closing this disconnector To fix the ideas by a plausible numerical example, the ohmic drop of V is about 200 volts for a line length of a few hundred kilometers and a line current of 1300 amperes, so that this disconnector must establish a current of about 650 Amps, with a voltage

  at its 200 Volts terminals before closing.

  The disconnector which is placed on the first busbar is then opened. In the numerical example considered, the intensity of the current in this other disconnector then changes from the value 650 Amperes to the value zero, while the voltage at its terminals passes. from zero to the approximate value of 200 volts above. It is obvious that, at least for sufficiently high drop values in line d V, which is the case for the numerical example considered, this closing of the disconnector of the second busbar as well as this opening of the disconnector of the first The game does not occur without creating sparks in these disconnectors, which is very damaging, not only because these sparks reduce the life of these disconnectors, but also and especially because there is a risk of serious accident that may be caused by a thermal runaway phenomenon. Various devices have recently been put on the market, these devices providing, in a more or less conventional manner, the installation of a "spark arrester" on each disconnector used during the transfer of bars. In reality, this problem does not exist. It has not been possible to solve in a sufficiently simple and reliable way in view of the stresses due to bad weather to which the gripping bars are in particular subject, so that the various solutions retained so far are really satisfactory both from the point of view of technical view that from the point

  from the point of view of the cost price and the cost of exploitation.

  The object of the invention is to remedy this drawback. It relates, for this purpose, to a high-voltage disconnector adapted to establish and cut the transfer currents of bars in a "loop" supply circuit, this disconnector comprising generally means for opening or closing a female contact 3 5 on a male contact by disconnecting or connecting two terminals of the same line bar which are connected to this male contact and the other connected to this contact female, other means being provided on this disconnector to, at closure, first immobilize this male contact between at least two jaws and, according to the general principle of the spark arrester, establish a preliminary electrical connection, by an organ separated conductor, between this male contact and said other terminal, and then only to make the actual direct electrical connection between the female contact and the male contact, and

  vice versa for the opening operation of this disconnector.

  In any case, the invention will be well understood, and its advantages and other characteristics will emerge, when

  following description of a non-limiting embodiment of

  this isolator, with reference to the attached schematic drawing in which: FIGS. 1 to 3 illustrate the general principle of operation of

this isolator.

  Figures 4 and 5 show the two extreme positions of the semi-

  pantograph which, in this particular embodiment,

operates this isolator.

  2 O Figure 6 shows, in perspective, this disconnector totally

  open, the semi-pantograph being in the low position.

  Figure 7 similarly shows this disconnector completely closed on its gripping bar, this same semi-pantograph being in

high position.

  Figure 8 is a simplified top view of the disconnect switch in

its position according to Figure 7.

  Referring firstly to FIGS. 1 to 3, reference numeral 1 denotes the male contact which, for example, conventionally constitutes the silver-plated copper gripping bar which is traditionally suspended elastically at the line bar by

  through a "trapeze" (not shown here).

  The female contact is, always very classically, consisting of two sets of contact blades 2.3 facing each other, and

  made for example them also in silver-plated copper.

  These two sets of blades 2,3 are movable relative to each other, and they are mounted on the disconnector so that, as in Figure 1, be separated from the bar 1 before the production of the male-female electrical contact assembly, and conversely, as in FIG. 3, grip the bar very tightly when

  this assembly, and therefore the electrical connection, is achieved.

  Of course, the operating device of the disconnector is such that, when the disconnector is in the fully open position, the contact blades 2, 3 are respectively remote from the bar 1 of the regulatory distance which guarantees the cutting of the line, this distance can be of several

1 0 meters.

  According to the invention, it is further provided four fingers or jaws gripping and immobilizing the gripping bar 1, including: two insulating fingers 4,5 which are placed relative to the bar 1 5 1, the same side as the series of contact blades in Silver 3; two other fingers 6,7, the first 6 of which is itself also insulating while the other 7 is made of conductive material such as copper, which are both placed on the same side as the blade set 2 so as to cooperate, for the prior immobilization of the

  1 bar, with the first fingers 4,5.

  The conductive finger 7 is placed at a good distance from the contact 2, and it has, in addition to its gripping function, a "spark arrester" function. It is therefore connected to the potential of the female contact 2, 3 by a metal braid. 8 and, as will be seen below, is arranged to make electrical contact with the male element 1 before it comes into contact with the female contact 2,3, which allows it to operate as a spark arrester . All elements 2 to 7 are furthermore mounted on powerful respective pressure springs 9 to 14 which are here

  symbolically represented by arrows.

  The preliminary spark arrester contact between the conductive finger 7 and the bar 1 is effected here on a removable sheath 15, made of a material different from the copper of which this finger 7 is made, and preferably of stainless steel, this sheath constituting a Consumable and easily interchangeable part which is tightly fixed around the bar 1 This difference in materials makes it possible to avoid welding phenomena by copper-on-copper welding. These gripping jaws and spark arresting contact 4 to 6 and 7 are carried by the particular operating system of the disconnector, for example by the two branches of the pantograph if this is the case, so as to function, for example when an opening maneuver, as illustrated by the following Figures 1 to 3: According to Figure 1, the two branches (not shown) of the pantograph are almost arrived at the end of the race, but the fingers 4 to 7, as well as the female contacts 2,3, are still

  all slightly distant from the male bar 1.

  The two branches of the pantograph continuing their closing movement, the device is arranged so that the four fingers come, while the blades 2,3 remain spaced apart from the bar 1, to press strongly, under pressure of their respective springs 11 to 14, against the rod 1, then completely immobilizing it. Moreover, the fact that, in the latter movement, the metal finger 7 comes to press strongly against the stainless steel sleeve 15, makes a preliminary electrical connection between the bar of 1, which is connected to one of the two high voltage terminals to be connected (between which there is only a potential difference of the order of 2500 volts), and the other high voltage terminal, which is connected to this

  finger 7 and the main female contact 2,3.

  The spark which eventually occurs then bursts between the two consumable accessory elements 7, 15 which are easily replaceable, and which are situated at a good distance from the main contact 3 O which together form the blades 2, 3 and the part of the

bar 1 that they enclose.

  In the final closing phase, that is to say at the end of the pantograph run, the female contact 2,3 comes, as shown in FIG. 3, in turn to press firmly against the bar 1, at the intended place for this purpose, far from the consumable sleeve 15 There is no spark at this point, since the voltage at the terminals of this main contact is then practically negligible (equal to the voltage drop in the predetermined contact 7/15) Moreover, all the problems relating to the spark arrester devices of the prior art are avoided because the bar 1 is then immobilized, which was not the

case before.

  Of course, the opening operation of this disconnector

  is carried out by the movements, and with the phenomena, inverses.

  The female contacts 2,3 firstly separate the male bar 1 i O 1 while it is still firmly held between the fingers 4 to 7 (Figure 2) Thus is guaranteed a total immobilization of the bar 1 at the opening the main contact, as well as a virtually zero voltage at the opening (no spark at the main contact) It is only then (Figure 1) that the bar 1 5 is released, the spark at the opening then occurring only

  between the consumable parts 7 and 15.

  Note that before changing the sleeve 15, it is first of all advantageously possible to practically "renovate" a

  or several times just by turning it on him-

  2 O even an angle guaranteeing a rotation less than 360 degrees from its very first position This can be achieved each time or, without touching the fixing flanges of the bar 1, by rotating the sleeve 15 around this the bar remaining fixed, after having of course loosened previously the 29 screws 29 blocking this sleeve on the bar, or by rotating the bar 1 all-integer, so without touching the sheath 15 itself, after having loosened loosening the fixing clamps this rod on its trapeze support. 3 O The metal finger 7 changes quickly and easily

  with the pantograph in the fully open position.

  A practical example of realization, using the general means which has just been described by means of these FIGS. 1 to 3, will be

  now described with reference to Figures 4 to 8.

  Figures 4 and 6 show this disconnector in its fully open position, with its semi-pantograph actuating 16 in extreme low position, ie

totally folded.

  The above-mentioned gripping bar 1 (constituting a high-voltage terminal) is conventionally elastically suspended from the line bar 17 by means of the trapezium 18. The upper arm 19 of the conventional semi-pantograph 16 carries the high-voltage contactor 20 conforming to FIG. invention, this contactor comprising, like that according to Figures 1 to 3, the female contact blades 2 and 3, the two jaws or insulating fingers 4 and 5, and the other two jaws or fingers that cooperate with these last, including on the one hand the insulating finger 6 and on the other hand the conductive finger

  7, which is connected to the potential (constituting the other high

  tension) of the head 20 of the pantograph by the aforementioned metal braid 8. Conventionally, the head 20 comprises a yoke 22, integral with the free end of the arm 19 and in which can tilt a part 23 having two flanges 24,25 on either side of the contact blades 2, they even integral of the metal frame 21 of the head 20 This metal frame carries two insulating end plates 2 O 27,28 on which the bar 1 rests during and

  after the closing operation of the disconnector.

  The part 23 carries the insulating fingers 4 and 5, as conventionally the second set of contact blades 3, and it tilts progressively by almost 180 degrees in the counterclockwise direction 25 during the raising movement of the semi-pantograph, under the

  traction which is conventionally exerted on it by a tie 26.

  During this raising movement, the contactor 20 of the invention "closes" gradually to reach the position of total closure which is shown in Figures 5, 7 3 O and 8, and which corresponds to that of Figure 3, after being, just before, passed through the successive positions, in accordance with

  the invention, immobilization of the bar 1, with the effect of

  spark, which correspond to those previously described in

reference to Figures 1 and 2.

  Note that the four fingers 4 to 7 are mounted as shown on their respective springs 11 to 14 The springs 9 I-1 and 10 of Figure 3 are here naturally included in the elasticity

contact blades 2 and 3.

  As goes without saying, the invention is in no way limited to the embodiment which has just been described. The number of retaining fingers may be different. It is preferable to provide only one conductive finger to limit the point of wear by sparks, but in fact the insulating nature of the other fingers is not really mandatory Conversely, all the immobilizing jaws can be provided insulating, and preliminary contact 1 i O preliminary spark arrester can, in this case as in the general case, be provided on a conductive terminal which itself does not participate in the immobilization of the bar, or other male contact The general means 1 of the invention is easily adaptable to all types of disconnectors: semi- pantographs, pantographs, 1 5 "two-columns", etc.

Claims (7)

  1 High-voltage disconnector adapted to set and cut the transfer currents of bars in a "loop" supply circuit, this disconnector generally comprising means (16) for opening or closing a female contact (2). , 3) on a male contact (1) by disconnecting or connecting two terminals of one and the same line bar (17) which are connected to this male contact (1) and the other connected to this female contact ( 2,3), characterized in that other means (4 to 8, 11 to 14) are provided on this disconnector to, at closure, first immobilize this male contact (1) between at least two jaws ( 4 to 7) and, according to a spark arrester principle, establish a preliminary electrical connection, by a separate conductive member (7), between this male contact (1) and said other terminal, and then only to make the direct electrical connection proper   between this female contact (2,3) and this male contact (1), and vice versa.   versa for the opening operation of this isolator.   2 high-voltage disconnector according to claim 1, characterized in that one of the immobilizing jaws is constituted by   said separate conductive member (7).   3 high-voltage disconnector according to claim 2, characterized in that the one or more other jaws (4,5,6) are electrically insulating. High-voltage disconnector according to claim 1, characterized in that these immobilization jaws are electrically insulating.   High-voltage disconnector according to one of Claims 1 to 4,   characterized in that said male contact comprises a conductive wear part 3 O (15) on which said connection is established preliminary electric.   6 disconnector according to claim 4, characterized in that this wear part (15) is a metal different from that of said male contact (1).   Disconnector according to claim 5 or claim 6,   characterized in that this wear part (15) is interchangeable.   8 disconnector according to one of claims 5 to 7, characterized in   what this wear part is constituted by a sheath metal (15).   9 disconnector according to one of claims 5 to 8, characterized in   means are provided for "renovating" the wear part (15) one or more times by turning it on itself at an angle defining a rotation less than 360   degrees from its very first position.   Disconnector according to one of Claims 1 to 9, characterized   in that said separate conductive member (7) is constituted by a interchangeable piece.