Classifications

• • 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
  • H01H9/0016—Contact arrangements for tap changers
• • 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
  • H01H9/0027—Operating mechanisms

Definitions

• the invention relates to an on-load tap-changer with preselector for the uninterrupted control of a regulating transformer.
• Selectors also called inverters and coarse selectors, are generally used in on-load tap-changers to expand the control range of a control transformer. Turners make it possible to switch the control windings of a control transformer to or against a main winding. With the help of a coarse selector, it is possible to switch off or switch on a larger part of a main winding, a so-called coarse step, of a control transformer.
• Both the step winding of a tapped transformer and the coarse step are briefly separated galvanically from the main winding during their switching by turning or coarse selector. They assume a potential which results from the voltages of the adjacent windings and the coupling capacitances to these windings or grounded parts.
• the resulting differential voltages are sometimes very significant; they claim the switching path of the opening preselector contacts and can lead to unacceptable Entiadungserscheinept with the appropriate amount.
• Such discharge phenomena, also called arcs cause gas formation in Isoiieröl. This is undesirable, especially as the system voltage increases, the amount of unwanted gases increases.
• polarity switches are used, which hold the tap winding at a desired and defined potential by means of an ohmic resistor, which is switched on only during the switching phase of the inverter or coarse selector.
• FIG. 1 known from FIG. 2 of DE 10 2009 060 132 B3, a poling arrangement is explained. Shown is a main winding 1 and a tap winding 2 of a variable transformer T. At the tap winding 2, an on-load tap changer is connected, which has a selector 3. The selector 3 initially selects the new winding tapping of the tap winding 2, which is to be switched over, before switching over. The switching itself is done by a known diverter switch 4 of the on-load tap-changer, which will not be discussed in detail here. Furthermore, the tap changer on a turner 5, through which to increase the control range of At the beginning of 10 or the end 13 of the tap winding 2 can be switched to the end of the main winding 1.
• a first polarity resistor 1 1 is provided, which is connected by means of a first polarity switch 12 with the load discharge.
• a second polarity resistor 14 is further provided at the end 13 of the step winding 2, which is in turn connected to the load discharge line 9 via a second polarity switch 15.
• the two polarity switches 12, 15 are only briefly turned on before the start of the operation of the preselector 5, so that only briefly the beginning 10 and the end 13 of the tap winding 2 are hinged to a defined potential.
• the main winding 1 has two physical contacts, namely the "0" contact and the "K" contact (commutation contact).
• Structural designs of a polarity switch are, as known from DE 19 42 567 A, for example, arranged coaxially to the preselection and Feinrichlertitlesystemen the tap changer below the tap selector or they are, as known from DE 28 15 736 C2, laterally attached to additional arms insulating bars in addition to the actual tap selector or the selection.
• there are undesirably large overall lengths for the tap selector in the second case also undesirable large horizontal expansions of the entire tap changer.
• the zugschalteten ohmic resistors also called Polungswiderthe are usually mounted below the selector on a cylinder. These require, depending on the power class of the on-load tap-changer, also installation space and have a significant effect on the manufacturing cost of an on-load tap-changer. Due to the applied unwanted differential voltage across the resistors, the oil of the on-load tap-changer and therefore also that of the transformer is additionally heated up. Since heating shortens the life of the transformers, this effect is also undesirable.
• the object of the invention is therefore to provide an on-load tap-changer with preselector for uninterrupted control of control transformers, in which the preselector has a small space and yet the discharge phenomena of the opening preselector contacts, caused by the differential voltages, withstand.
• the subclaims relate to particularly advantageous developments of the invention.
• the general inventive idea is to equip the preselector with a separate energy storage, which is driven by the motor drive of the on-load tap-changer, so as to be able to perform a quick changeover from the "+" position to the "-" position of the preselector contacts.
• the energy accumulator is connected via a coupling element with a pivotally mounted contact rod.
• the actuation takes place via a fork attached to the coupling element with two fork rollers which correspond positively and non-positively to an armature driven by a motor drive.
• the anchor has two freewheels on the underside.
• the energy accumulator is triggered when the rollers reach the freewheels.
• the further rotation of the fork is effected by a arranged between the freewheels of the armature anchor roller which engages in a arranged between the fork rollers fork contour.
• Upon further rotation of the fork of the energy storage is raised again.
• the switching "0" contact is combined with the so-called "K” contact (commutation contact) and designed as a movable contact rod.
• the energy storage of the preselector is designed as a leg spring.
• the armature is driven by a motor drive.
• the anchor is at the top, i. arranged at the top of the on-load tap-changer.
• the on-load tap-changer is designed as a load selector.
• the selection consists among other things of a first contact rod, a second contact rod and a third contact rod.
• three contacts are provided, each of which corresponds to a contact with a phase or a strand of the current.
• the first contact rod thus has three fixed contacts.
• At the second contact rod also three fixed contacts are arranged.
• the third contact rod is designed to be pivotable and trät three sliding contacts, which can be connected to the corresponding fixed contacts or separated from them.
• Figure 1 shows an arrangement according to the prior art
• Figure 2 shows a preselector according to the invention
• Figure 3 is a plan view of the preselector according to the invention.
• Figure 4 shows a preselector according to the invention with an anchor
• FIG. 5 is a detail view of the anchor
• FIG. 2 shows a preselector 20 according to the invention in the form of a reverser.
• This consists, inter alia, of a first contact rod 21, a second contact rod 23 and a third contact rod 25 on the first contact rod 21 are three fixed contacts 22, so each a fixed contact 22 per phase attached.
• the fixed contacts 22 are conductively connected to the respective step winding 2.
• Fixed contacts 24 are likewise arranged on the second contact rod 23. Again, each phase is assigned a fixed contact 24.
• These fixed contacts 24 are connected on a second outer side 23 A, here outside on the contact rod 23, with the step windings 2.
• the fixed contacts 22 of the first contact rod 21 are conductively connected to the beginning 10 of the tap winding 2.
• the fixed contacts 24 of the second contact rod 23 are connected to the end 13 of the tap winding 2.
• sliding contacts 26 make an electrically conductive connection either with the fixed contacts 22 of the "+” position or the fixed contacts 24 of the "-" position.
• the sliding contacts 26 are formed in two parts, so that when contacting each part of the respective fixed contact 22, 24 touches from above and below. It would also be conceivable to form the fixed contacts 22, 24 as sliding contacts and the sliding contacts 26 as fixed contacts. Due to the two-part design of the sliding contact 26, two contact points to the respective fixed contact 22, 24 can flow through the current.
• the third contact rod 25, in particular the sliding contacts 26, combine the so-called "0" contact and "K” contact in one.
• the "0" contact has been translated by a separate contact rod located between the first and second contact bars 21, 23.
• the switching from one position to the next and back again is realized such that the third contact rod 25 is pivotally mounted in two directions about a vertical axis A.
• the drive takes place via a force accumulator 27 which is intended only for the third contact rod 25. This is realized in FIG. 2 by a leg spring.
• Both the first and second contact bars 21, 23 are fixedly attached to a frame 28.
• the pivotable contact rod 25 is movably connected to the frame 28 via the energy accumulator 27.
• FIG. 3 shows the preselector according to the invention from above.
• the sliding contact 26 is in a middle position between the fixed contacts 22 and 24.
• the coupling element 29 via a fork 30 with a first and a second fork roller 31, 32, and arranged therebetween Fork contour 33, via an armature 34, on the underside of a first and a second freewheel 35, 36, and an armature roller 37 are actuated.
• the armature 34 is in the upper region, ie on the tap changer head, arranged and is driven by a motor drive, not shown here.
• the armature roller 37 engages positively in the fork contour 33 and thereby pulls the energy storage 27 when turning the fork 30.
• the fork rollers 31, 32 leave the freewheels 35, 36 and take a non-positive and positive connection with the armature 34 a.
• the rotational movement of the armature 34 via the armature roller 37 and the fork contour 33 is terminated upon reaching the "-" position, i.e. after establishing an electrically conductive connection between the fixed contacts 23 and the sliding contacts 26.
• the armature 34 When switching back to the "+" position, the armature 34 is rotated in the opposite direction, resulting in a rapid pivotal movement of the third contact rod 25 as soon as the fork rollers 31, 32 have reached the freewheels 35, 36 on the underside of the armature 34 As a result of the further rotation of the armature 34, the armature roller 37 engages in the fork contour 33, thereby pivoting the third contact rod 25 into the "+” position, thereby pulling on the energy store 27.
• the omission of the polarity resistors brings an enormous space saving with it.
• the entire on-load tap-changer is thereby shorter and thus more compact.
• the heat generated by the poling resistors is no longer available.
• the insulating oil of the transformer to be controlled is not additionally heated by this source. Since the transformer is then exposed to lower temperature fluctuations, this has a positive effect on the service life. Also, the additional costs caused by the polarity resistors omitted, so that the on-load tap-changer is cheaper overall.
• the preselection By combining the contact rod for the "0" contacts with that for the "K” contacts in the form of the third contact rod 25, the preselection also becomes smaller. Thus, the entire on-load tap-changer becomes more compact and takes up less space in the transformer tank.

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• Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)

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ID=49115489

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Citations (6)

Family Cites Families (3)

• 2012
  • 2012-09-27 DE DE102012109174.9A patent/DE102012109174A1/de not_active Withdrawn
• 2013
  • 2013-08-26 WO PCT/EP2013/067611 patent/WO2014048650A1/fr not_active Ceased

Patent Citations (6)

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