US3254296A - Transfer switch for tap changers for regulating transformers - Google Patents

Transfer switch for tap changers for regulating transformers Download PDF

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Publication number
US3254296A
US3254296A US275583A US27558363A US3254296A US 3254296 A US3254296 A US 3254296A US 275583 A US275583 A US 275583A US 27558363 A US27558363 A US 27558363A US 3254296 A US3254296 A US 3254296A
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United States
Prior art keywords
switch
pair
tap
over
contacts
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Expired - Lifetime
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US275583A
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English (en)
Inventor
Breuer Wolfgang
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Maschinenfabrik Reinhausen Gebrueder Scheubeck GmbH and Co KG
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Maschinenfabrik Reinhausen Gebrueder Scheubeck GmbH and Co KG
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    • 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
    • H01H9/54—Circuit arrangements not adapted to a particular application of the switching device and for which no provision exists elsewhere
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F29/00—Variable transformers or inductances not covered by group H01F21/00
    • H01F29/02—Variable transformers or inductances not covered by group H01F21/00 with tappings on coil or winding; with provision for rearrangement or interconnection of windings
    • H01F29/04—Variable transformers or inductances not covered by group H01F21/00 with tappings on coil or winding; with provision for rearrangement or interconnection of windings having provision for tap-changing without interrupting the load current

Definitions

  • Still another object of the invention is to provide improved tap-changing regulating transformers, and transfer switches therefor, wherein arc-quenching is effected by compact saturable reactor means rather than by bulky arc-chute means.
  • a further object of this invention is to provide compact tap-changing regulating transformers, and transfer switches therefor, known as Jansen-type regulating transformers, and Jansen-type transfer switches, respectively, which transfer switches have a drastically increased current switching capacity.
  • Another object of this invention is to provide Jansentype tap-changing regulating transformers having improved high switching capacity FLAG transfer switches, PENNANT transfer switches, or FLAG-PENNANT transfer switches.
  • PENNANT transfer switch and FLAG-PENNANT transfer switch are generally used to designate particular designs of transfer switches for transformers. These terms have also been fully explained and defined in the copending patent application of Alexander Bleibtreu, filed January 31, 1963; Ser. No. 255,291 for Transfer Switch for Tap Changers for Regulating Transformers, now U.S. Patent 3,174,097.
  • Tap-changing regulating transformers include selector switches and transfer switches.
  • the former serve the purpose of selecting a particular tap on a tapped trans' former winding intended to be connected into an electric circuit.
  • Selector switches are not required to interrupt, or close, on current carrying circuits. This task is left to the transfer switches.
  • the latter perform all switch- .ing operations under load, including switching of overload currents. Hence all arcing is kept away from the selector switches and occurs only at the transfer switches.
  • Transfer switches according to this invention may be constructed either for single phase service or for polyphase service.
  • FIG. 1 is a diagrammatic representation of a single phase of a tap-changing regulating transformer embodying the present invention including its transfer switch, its selector switch having been omitted for the sake of simplicity;
  • FIG. 2a shows, occurring incident to a tap-changing operation
  • FIG. 2b shows, diagrammatically, another current transient occurring incident to a tap-changing operation
  • FIG. 20 shows, diagrammatically, a voltage transient occurring incident to the same tap-changing operation to which FIGS. 2a and 2 h refer;
  • FIG. 2d shows, diagrammatically, the transient recovery voltage occurring across a pair of parting main contacts of the transfer switch during the same tap-changing operation to which FIGS. 2a to 2c refer;
  • FIG. 3 shows the magnetic flux in a saturable reactor forming an integral part of the circuitry of FIG. 1 plotted against the magnetizing current.
  • reference character T has been applied ,to indicate a portion of a tapped transformer winding
  • a selector switch is interposed between the taps, or tap terminals, of a tapped transformer winding and the transfer switch which is associated with the tapped transformer winding, but in drawing FIG. 1 the selector switch has been omitted and the tapped transformer winding T has been shown as being directly connected to a transfer switch which includes switches 1, 2; 3; 4; 5, 6.
  • Switches 1, 2 and 5, 6, respectively, are main switches each comprising two pairs of cooperating separable contacts.
  • the movable contacts of switches 1, 2 and 5, 6 are adapted to be operated sequentially.
  • the transfer switch further comprises a pair of switch-over switches 3, 4, each comprising a plurality of pairs of cooperating separable contacts.
  • the movable contacts of switch 3 are gang operated to open and close simultaneously. To the same end the movable contacts of switch 4 are gang operated.
  • the contacts of switch-over switch 3 define a plurality of parallel current paths.
  • the contacts of switch-over switch 4 define a plurality of parallel current paths, the number of parallel current paths defined by switches 3 and 4 being equal.
  • Reference characters R, and R have been applied to indicate a pair of switch-over resistors. Each switch-over resistor R and R is sub-divided into four sub-resistors R R .,'respectively.
  • Tap A is conductively connected to main switch 1, 2 by the intermediary of a saturable reactor L,,.
  • tap B is conductively connected to main switch 5, 6 by the intermediary of a saturable reactor L
  • Each saturable'reactor L L comprises a ferrous magnetizable core providing a complete magnetic flux path for the magnetic flux established by the winding of the respective saturable reactor.
  • Each saturable reactor L L has one end conductively connected to one of taps A, B and another end conductively connected to one of the pair of main switches 1, 2 and 5, 6, respectively.
  • each saturable reactor L,,, L is conductively connected to one of the subresistors R and R by the intermediary of magnetizing current control resistors R and R
  • the latter are resistors having a high ohmic value being a multiple of that of resistors R R
  • each pair of cooperating contacts of switches 1, 2; 3; 4; 5, 6 comprises a movable contact and a stationary contact.
  • the stationary contacts of the transfer switch are arranged at the transformer side of the latter, and all the movable contacts of the transfer switch are conductively connected diagrammatically, a current transient by an appropriate lead to a point M.
  • point M may be considered to be the neutral point of the system.
  • Taps A and B are further conductively connected to switch-over resistors R and R of which each comprises four sub-resistors connected in parallel. The current path through each sub-resistor is controlled by a pair of cooperating contacts pertaining to either of the two switch-over switches 3 and 4.
  • tap A and main switch 1, 2 applies to tap B and main switch 5, 6 when the latter is closed while the former is open.
  • the pair of contacts of main switch 1, 2 are initially closed, and that the pair of contacts of main switch 5, 6 are initially open.
  • tap A is initially included into the load circuit of the tap-changing transformer and that tap B is not included in that circuit.
  • the operation of the circuitry of FIG. 1 will now be explained by setting forth the consecutive steps involved in changing from tap A to tap B.
  • the first such step is opening of the pair of contacts 1 of main switch 1, 2.
  • the entire load current is henceforth carried by the pair of contacts 2 of switch 1, 2.
  • the group of contacts 3 is being closed and substantially simultaneously the pair of contacts 2 opened.
  • an arc is kindled between these contacts. This arc subsists approximately until the time of current zero at which time the magnetization of the saturable reactor L is reversed, causing the latter to intervene in the switching operation by virtue of the inductive voltage U resulting from the reversal of magnetization.
  • the trace marked i represents the current flowing through saturable reactor L and the pair of contacts 2 of switch 1, 2 which are serially connected with the saturable reactor L
  • the path of this current has also been indicated in FIG. 1 by reference character i Shortly prior to the time of a natural current zero of the sinusoidal current wave i saturable reactor L which was previously saturated is being demagnetized and thereupon re-magnetized in reverse direction.
  • the voltage between the two taps has been indicated by the reference character U and the voltage across the saturable reactor L has been indicated by the reference character U During the interval of time from t to 1 the voltage U across the saturable reactor is equal to the voltage drop of the load current i across the composite resistor R
  • the magnetizing current of the saturable reactor L flows through the magnetizing current control resistor R Since the magnetizing current of saturable reactor L is very. small, the voltage drop across resistor R is likewise very small and may be neglected.
  • the core of saturable reactor L is made of a magnetizable material which has a very steepmagnetizing characteristic as clearly shown in FIG. 3.
  • the transient recovery voltage across the parted pair of contacts 2 is equal to the voltage drop across resistor R which is negligibly small, as mentioned above.
  • T herefore the transient recovery voltage across the pair of separated contacts 2 will be virtually zero during the interval of time t and t during which the saturable reactor L, is unsaturated.
  • This zero recovery voltage pause across the gap formed between the pair of separated contacts 2 is conducive to a high degree of dielectric recovery. This, in turn, minimizes the likelihood of a reignition or restrike following the reappearance at the time t;; of the recovery voltage across the separated pair of contacts 2.
  • FIG. 2d clearly shows the transient recovery voltage zero in the interval of time between t and t and the rise of the recovery' voltage at the time t when the saturable reactor L becomes again saturated.
  • the saturable reactor L must be designed in such a fashion that the time t t of zero recovery voltage is sufliciently long to safely preclude any reignition or restrike of the circuit including the separated pair of contacts 2.
  • FIG. 20 illustrates the inductive voltage U generated by the saturable reactor L during the cycle of demagnetization and remagnetization in opposite direction. It will be noted that the voltage spikes at the times t and t are of different magnitude.
  • FIG. 2a shows the shunt current i to rise from zero at the time t and then to follow a more or less sinusoidal course.
  • the transient recovery voltage across the gaps formed between the pairs of separated contacts of group 3 is sufficiently high to cause reignition following the first natural zero of the current wave and following closing of the two pairs of contacts 5 and 6.
  • the entire load current derived from tap B is carried by the pair of contacts 6 upon closing thereof. If arcing across the gaps formed between the pairs of contacts pertaining to group 3 still continues at the time at which the cooperating pair of contacts 5 engages, a circulating current is caused to flow the magnitude of which is limited by the presence of switch-over resistor R
  • the circuitry shown in FIG. 1 includes a pair of main switches 1, 2 and 5, 6. Each of these switches includes a pair of movable contacts 1, 2 and 5,' 6 adapted to be operated sequentially and to establish parallel current paths.
  • the circuitry of FIG. 1 further comprises a pair of switchover switches 3 and 4. Each of these switch-over switches includes a plurality of gang-operated simultaneously operable movable contacts adapted to establish a plurality of current paths in parallel.
  • Each switch-over switch 3 and 4 is operatively associated with a group R. and R respectively, of switch-over resistors. Each group R R of switch-over resistors comprises a plurality of subresistors connected in parallel to form one of the groups R, and R5.
  • Each tapA, B is connected to one of the main switches 1, 2 and 5, 6, respectively, by the intersub-resistor R remote from tap A, or tap terminal A, I
  • main switches 1, 2 and 5, 6 and switchover switches 3, 4 might be operated manually in the aforementioned proper sequence. quential operation of these switches is effected by automatic means which are well known in the art. Such means have been described, for instance, in US. Patent 2,680,790 to Bernhard Jansen, June 8, 1954 for Load Changeover Switch for Tapped Transformers, and reference may be had to this patent for additional information in regard to the aforementioned automatic switchoperating or contact-operating means.
  • a transfer switch for tap-changers for regulating transformers comprising in combination:
  • a second switch-over resistor means conductively conneting the other of said :pair of tap terminals to said second switch-over switch
  • a transfer switch for tap changers for regulating transformers comprising:
  • a first main switch means including a pair of movablecontacts adapted to be operated sequentially and to establish lparallel paths;
  • a second main switch including a pair of movable contacts adapted to be operated sequentially and to establish parallel current paths;
  • a first main switch including a pair of movable contacts adapted to be operated sequentially and to establish parallel current paths;
  • a second main switch including a pair of movable contacts adapted to be operated sequentially and to establish parallel current paths;
  • a first switch-over switch including a plurality of movable contacts adapted to be operated simultaneously and to establish a plurality of current paths in parallel;
  • a second switch-over switch including a plurality of movable contacts adapted to be operated simultaneonsly and to establish a plurality of current paths in parallel;
  • a first magnetizing current control resistor having a resistance being a multiple of the resistance of said first plurality of switch-over resistors connected in parallel, said first magnetizing current control resistor conductively connecting the end of said first saturable reactor remote from said one of said pair of tap terminals to the end of one of said first plurality of switch-over resistors remote from said one of said pairs of tap terminals;
  • a pair of switch-over resistor means each conductively connecting one of said pair of taps to one of said pair of switch-over switches
  • a pair of switch-over switches each including a plurality of movable contacts adapted to be operated simultaneously and to establish a plurality of current paths in parallel;

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Electromagnets (AREA)
  • Control Of Electrical Variables (AREA)
  • Coils Of Transformers For General Uses (AREA)
US275583A 1962-05-25 1963-04-25 Transfer switch for tap changers for regulating transformers Expired - Lifetime US3254296A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEM52987A DE1265290B (de) 1962-05-25 1962-05-25 Lastumschalter fuer Stufenschalter von Stufentransformatoren

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DE (1) DE1265290B (sv)
GB (1) GB1017208A (sv)
NL (1) NL293956A (sv)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100423397C (zh) * 2005-10-12 2008-10-01 广西大学 三相稳压调控装置补偿线圈降感应电压及触点消弧的方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2237008A (en) * 1939-08-04 1941-04-01 Gen Electric Control system
US2611117A (en) * 1949-04-19 1952-09-16 Westinghouse Electric Corp Control system for electricallyoperated vehicles
US3039041A (en) * 1956-09-28 1962-06-12 Jansen Bernhard Load transfer switch with non-linear switching resistors
US3174097A (en) * 1962-02-08 1965-03-16 Reinhausen Maschf Scheubeck Transfer switch for tap changers for regulating transformers

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE582439C (de) * 1933-08-15 Sachsenwerk Licht & Kraft Ag Regelschaltwerk zum Veraendern der Spannung von Transformatoren durch Umschalten unter Last
DE822572C (de) * 1949-10-20 1951-11-26 Siemens Schuckertwerke A G Lastschalter fuer Regeleinrichtungen von Transformatoren u. dgl.
DE960559C (de) * 1952-03-26 1957-03-21 Siemens Ag Schaltdrossel
AT196974B (de) * 1956-01-07 1958-04-10 Bernhard Dr Ing Jansen Lastumschalter für Stufentransformatoren

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2237008A (en) * 1939-08-04 1941-04-01 Gen Electric Control system
US2611117A (en) * 1949-04-19 1952-09-16 Westinghouse Electric Corp Control system for electricallyoperated vehicles
US3039041A (en) * 1956-09-28 1962-06-12 Jansen Bernhard Load transfer switch with non-linear switching resistors
US3174097A (en) * 1962-02-08 1965-03-16 Reinhausen Maschf Scheubeck Transfer switch for tap changers for regulating transformers

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100423397C (zh) * 2005-10-12 2008-10-01 广西大学 三相稳压调控装置补偿线圈降感应电压及触点消弧的方法

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GB1017208A (en) 1966-01-19
DE1265290B (de) 1968-04-04
NL293956A (sv)

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