Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H63/00—Details of electrically-operated selector switches
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
  • H01H9/0005—Tap change devices
  • H01H9/0038—Tap change devices making use of vacuum switches

Definitions

• the invention relates to a tap changer for uninterrupted switching between different winding taps of a tap transformer according to the preamble of the first claim.
• tap changers are already known from WO 94/02955.
• Step switches are used to adjust the voltage, active and reactive power of electrical networks by changing the gear ratio under load.
• the fixed tap contacts which are each electrically connected to a winding rejection of the tap transformer, are arranged vertically in a line.
• two individually linearly movable selector contacts are provided, which - independently of one another - sweep over the fixed selector contacts.
• the movable selector contacts are actuated by a drive mechanism which essentially consists of a continuously drivable elevator carriage and an output part which can be pulled up by means of a spring energy store. After the spring energy store has been triggered, the stripping part abruptly follows the previous continuous movement of the elevator slide.
• One of the movable selector contacts is fixed to the elevator carriage, the other movable selector contact is located on the driven part.
• at least two, usually three, vacuum switching cells are provided as electrical switching means, which, together with at least one switching resistor, are arranged firmly on the output part and thus also perform its abrupt movement after tripping.
• step switch is known from DE 42 16 034 C1, which also has fixed selector contacts arranged in a track and has movable contacts which are accommodated in a housing and require only one drive.
• This tap changer is a single-phase arrangement, i. H. the housing mentioned encloses all components that are required for the wiring of a phase and forms a so-called single-phase tap changer module. For a three-phase arrangement, three such complete tap changer modules with then three separate housings must be used.
• the known tap changers have proven themselves for the realization of larger switching capacities and are used in larger numbers. However, they are too complicated for certain simpler applications with only low system voltages and switching capacities. It must first be taken into account that the known tap changer is a single-phase module; For the usual three-phase use, three such complete tap changers must be operated together - three complete drive mechanisms, energy storage and actuation mechanisms are therefore also required.
• Another disadvantage is that the output part of the known tap changer, which performs a sudden vertical movement with each changeover, has a very considerable mass due to the many components that are attached to it. This requires complex means for damping movement and for balancing gravity. The synchronous actuation of the individual vacuum switching cells during the switchover sequence also requires highly precise and relatively complicated actuating means.
• the object of the invention is to provide a generic tap changer which, with the simplest possible and robust mechanical construction and using only two vacuum switching cells as electrical switching means, permits safe load switching in the lower and middle switching power range up to tap voltages of the order of approximately 500 V.
• the simple and robust construction is particularly advantageous on the tap changer according to the invention.
• the mechanical as well as the electrical switching means for all phases to be switched are combined in a single housing. This means that only one drive mechanism is required for all phases; there is also only a single energy accumulator, and all vacuum switch cells of all phases as well as all mechanical switch contacts are firmly arranged on a single base plate.
• the tap changer according to the invention has only small moving masses, precisely because, as explained, the other components are fixed and do not have to carry out the movements of the movable selector contacts.
• Another advantage of the tap changer according to the invention is that the two movable selector contacts can no longer be moved independently of one another, but are fixed together and unchangeably in their relative position to one another. This further simplifies the entire mechanical arrangement and also enables a space-saving design.
• these movable selector contacts are actuated in a particularly simple manner by means of a linear Geneva segment or two such Geneva segments.
• a linear Geneva segment or two such Geneva segments.
• these known solutions do not relate to tap changers operating under load, but relate to no-load switching devices (de-energized tap changer).
• Another difference from this embodiment of the invention is that the known toothed racks are actuated by a gear wheel which is constantly in engagement, while the Geneva segment of the described embodiment of the tap changer according to the invention can be driven by a Malta driver which only comes into engagement in a certain position .
• the two movable selector contacts of each phase are fixedly arranged together on a support frame, such that only this support frame can be moved by the Maltese segment described.
• Fig. 1 shows a tap changer according to the invention in a schematic representation from the front
• Fig. 2 is a partial representation of the base plate of this tap changer from behind
• Fig. 2a is a similar representation, in which the roller guide to be explained has been omitted to clarify the arrangement
• Fig. 3 is a partial representation of the base plate of this tap changer from the front
• Fig. 4 is a schematic representation of the interaction of fixed selector contacts and movable contacts
• Fig. 5 shows the electrical circuit on which the tap changer according to the invention is based in detail
• FIG. 6 shows a switching sequence when switching from the winding tap n -2 to the winding tap n -1.
• FIG. 1 The entire device is located in a housing 1, which has a rear, electrically insulating housing plate 2. On this rear housing plate 2 three contact carriers 3 made of electrically insulating material are fastened parallel to each other, each carrying fixed selector contacts 4. A contact carrier 3 is provided for each phase; the individual contact carriers 3 are arranged parallel to one another, and the fixed selector contacts 4 are arranged in an identical manner for each of the three phases. As can be seen from the figure, the individual fixed selector contacts 3 are alternately staggered on a left and a right part of the contact carrier 3. The wiring of the fixed selector contacts 4 will be explained below.
• Longitudinal guides 5 are provided on the side walls of the housing 1, on each of which a Maltese segment 6 is guided so as to be vertically movable.
• a support frame 7 made of electrically insulating material is fastened between the two lateral Maltese segments 6 and carries two movable contacts 8, 9 for each phase.
• the movable contacts 8, 9 of each phase correspond to the fixed selector contacts 4 of the corresponding phase.
• the movable contacts 8, 9 are dimensioned in their longitudinal extent such that when they move together, each time they switch, each of them reaches a new fixed selector contact without the other of them leaving the previous fixed selector contact. This is shown again in FIG. 4; a) shows the position before a movement of the support frame 7 and thus the movable contacts 8, 9; b) shows the position after a completed switching step.
• a drive motor 10 On the side in the housing 1, a drive motor 10 is provided on a mounting 11 and connected to a gear 12.
• a first drive shaft 13 made of electrically insulating material, which penetrates the housing horizontally and is supported in a bearing 15 at the other end, extends from this transmission 12.
• this first drive shaft 13 has a Maltese driver 16, which corresponds to the respective Maltese segment 6.
• the gear 12 is designed so that the first drive shaft 13 performs a rotation of 360 degrees with each changeover in which the drive motor 10 is actuated.
• the two Maltese drivers 16 engage in the respective Maltese segments 6 and move them and thus the support frame 7 fastened between them by a certain way upwards or downwards - this depends on the direction of rotation and thus the switching direction of the tap changer. By shifting the Support frame 7 up and down, the two movable contacts 8, 9 of each phase are moved together up or down.
• movable contacts 8, 9 each slide on electrically conductive contact tracks 17, 18 of each phase, which run parallel to one another and are in turn electrically connected to a first fixed contact 25 and a second fixed contact 26, respectively. This will be explained later.
• the individual contact tracks 17, 18 in turn are spatially fixed in the housing 1 by means of a cross member 52.
• a second drive shaft 14 also leaves the transmission 12 and extends vertically upward in the housing 1.
• This second drive shaft 14 performs a rotation of 180 degrees with each changeover and is connected to an elevator carriage 19 of an energy store.
• This energy accumulator has as essential components precisely this elevator carriage 19, which is tensioned by the second drive shaft 14 against the force of energy storage springs 20, and also an output part 21, which follows the longitudinal movement of the elevator carriage 19 after triggering.
• Such energy accumulators in which an elevator carriage is moved in the longitudinal direction and thus tensioned by the rotary movement of a shaft and in which an output part also suddenly performs a longitudinal movement after being triggered, are already known in principle, so that further details need not be described here.
• Such generic energy accumulators are described in detail in DE-PS 28 06 282 or DE-PS 39 19 596.
• the output part 21 is connected to an output coupling 22, by means of which the abrupt horizontal longitudinal movement after being triggered is transmitted to an actuating slide 23 made of electrically insulating material.
• the function of this actuating slide 23 is also explained below.
• a movable changeover contact 28 is arranged in a bearing 29 there, which has a contact part 31, by means of which one of the two fixed contacts 25, 26 can be electrically connected to the root contact 27; the entire arrangement has the function of an electrical switch.
• the movable changeover contact 28 has an actuating groove 32 in its upper part, which can be actuated by an actuating part 30 fastened to the actuating slide 23 with an actuating pin 33.
• the actuating pin 33 engages in the actuating groove 32 and pivots the entire movable changeover contact 28 around its bearing 29, as a result of which one of the two fixed contacts 25, 26 is switched between the electrical connections and the root contact 27 takes place.
• two vacuum switch cells 34, 35 are fastened to the base plate 24 by means of fastening angles 36, 37 for each phase.
• a transition resistor 49 is also arranged there for each phase.
• the actuating plungers 50, 51 protruding upward from the two vacuum switch cells 34, 35 are each provided with a curved actuating arm 38, 39.
• Each actuating arm 38, 39 has a roller 40, 41 at its free end.
• the actuating arms 38, 39 are in their Geometry designed such that the two rollers 40, 41 of each phase lie one above the other in a vertical line.
• the two rollers 40, 41 each run in a contour 43, 44 of a roller guide 42 which is fastened to the actuation slide 23 for each phase.
• the roller guide 42 has a further, additional contour 53 in which a further roller 54 is guided.
• This further roller 54 is attached directly to the base plate 24 and guides the actuating slide 23 in its horizontal movement after the force accumulator has been triggered.
• a locking plate 47 also fastened to the actuating slide 23, is provided with a common longitudinal guide 48 for each phase, in which the two rollers 40, 41 are also guided. This additional locking plate 47 ensures that the actuating arms 38, 39 can move vertically when the actuating slide 23 and thus the roller guide 42 are moved with their contours 43, 44 and thus actuate the actuating plungers 50, 51 of the vacuum switching cells 34, 35 but cannot deflect sideways.
• This locking plate 47 is arranged between roller guide 42 and actuating slide 23; since it is covered by the roller guide 42 in the illustration according to FIG. 2, this roller guide 42 has been omitted in FIG. 2a.
• the two rollers 40, 41 are in any case dimensioned such that they run simultaneously in one of the contours 43, 44 and in addition the longitudinal guide 48.
• springs 45, 46 are additionally provided on the actuating plungers 50, 51 to compensate for contact erosion.
• the first drive shaft 13 performs a rotation of 360 degrees with each load cut-off, after a certain angle of rotation the two Maltese drivers 16 engage in the respective Maltese segments 6 and move the support frame 7 and thus the movable contacts 8, 9, such that one of the two movable contacts reached the new fixed selector contact to be selected.
• the respective horizontal movement of the driven part 21 is transmitted via the driven coupling 22 to the actuating slide 23, which also flips alternately once to the right and once to the left during the next switchover.
• both the mechanical switching elements on the front of the base plate 24 and the vacuum switch cells 34, 35 on the rear of the base plate 24 are actuated: on the front of the base plate 24, the actuating pin 33 engages in the actuating groove 32 and pivots the movable changeover contact 28, which thus interrupts the electrical connection from the first fixed contact 25 to the root contact 27 and instead instead electrically connects the second fixed contact 26 to the root contact 27 and vice versa.
• the two fixed contacts 25, 26 are electrically connected via the two contact tracks 17, 18 to the fixed selector contacts 4 currently contacted by the movable contacts 8, 9, such that a switchover occurs when the movable changeover contact 28 is actuated from a movable contact 8 to the other movable contact 9 and thus from the previous contacted fixed selector contact to the new fixed selector contact.
• the roller guide 42 which also moves back and forth, actuates the vacuum switching cells 34 through the contours 43, 44 which move with it and in which the rollers 40, 41 of the actuating arms 38, 39 are guided , 35.
• the actuation sequences are precisely defined by a corresponding geometric design of the contours 43, 44, more precisely by their horizontal offset.
• FIG. 6 uses the schematic circuitry according to FIG. 5 to describe an exemplary load switch from n -2 to n -1, more precisely, the sequence in which the individual components are actuated one after the other.
• the current-carrying parts of the electrical circuit are shown by thick lines. Since the arrangement of the components corresponds exactly to that in FIG. 5, the reference numerals have been omitted in FIG. 6 for reasons of clarity.
• a load switchover consists of the following sequential switching steps:
• a) shows the initial situation in which the fixed contact n -2 is connected.
• the movable changeover contact 28 connects the first fixed contact 25 to the root contact 27 and establishes the connection to the load derivation L via the closed first vacuum switching cell 34.
• the second vacuum switch cell 35 is open b) the movable contacts 8, 9 have moved together; the movable contact 8 remains on the fixed selector contact n -2, the movable contact 9 has reached the new fixed selector contact n -1 to be connected.

Landscapes

• Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)
• High-Tension Arc-Extinguishing Switches Without Spraying Means (AREA)
• Electrophonic Musical Instruments (AREA)
• Lock And Its Accessories (AREA)
• Manufacture Of Switches (AREA)
• Oscillators With Electromechanical Resonators (AREA)

Applications Claiming Priority (3)

Publications (2)

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ID=7884685

Family Applications (1)

Country Status (9)

Families Citing this family (15)

Family Cites Families (8)

• 1998
  • 1998-10-16 DE DE19847745A patent/DE19847745C1/de not_active Expired - Fee Related
• 1999
  • 1999-09-14 ES ES99947347T patent/ES2172351T3/es not_active Expired - Lifetime
  • 1999-09-14 EP EP99947347A patent/EP1121696B1/fr not_active Expired - Lifetime
  • 1999-09-14 AU AU60831/99A patent/AU6083199A/en not_active Abandoned
  • 1999-09-14 WO PCT/EP1999/006805 patent/WO2000024013A1/fr not_active Ceased
  • 1999-09-14 KR KR1020017004784A patent/KR20010082232A/ko not_active Abandoned
  • 1999-09-14 AT AT99947347T patent/ATE215728T1/de not_active IP Right Cessation
  • 1999-09-14 CN CN99807740A patent/CN1127104C/zh not_active Expired - Fee Related
  • 1999-09-14 DE DE59901152T patent/DE59901152D1/de not_active Expired - Lifetime
• 2000
  • 2000-10-10 BG BG104832A patent/BG63836B1/bg unknown

Non-Patent Citations (1)

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