US3359485A - Tap changing device for transformer windings without interrupting the load current - Google Patents

Tap changing device for transformer windings without interrupting the load current Download PDF

Info

Publication number
US3359485A
US3359485A US39481164A US3359485A US 3359485 A US3359485 A US 3359485A US 39481164 A US39481164 A US 39481164A US 3359485 A US3359485 A US 3359485A
Authority
US
United States
Prior art keywords
contact
tap
circuit
contacts
diverter switches
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
Other languages
English (en)
Inventor
Karl J Buhler
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BBC Brown Boveri AG Germany
Original Assignee
Bbc Brown Boveri & Cie
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bbc Brown Boveri & Cie filed Critical Bbc Brown Boveri & Cie
Application granted granted Critical
Publication of US3359485A publication Critical patent/US3359485A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • H01F29/025—Constructional details of transformers or reactors with tapping on coil or windings
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/50—Means for increasing contact pressure, preventing vibration of contacts, holding contacts together after engagement, or biasing contacts to the open position
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H3/00—Mechanisms for operating contacts
    • H01H3/22—Power arrangements internal to the switch for operating the driving mechanism
    • H01H3/222—Power arrangements internal to the switch for operating the driving mechanism using electrodynamic repulsion
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H77/00—Protective overload circuit-breaking switches operated by excess current and requiring separate action for resetting
    • H01H77/02—Protective overload circuit-breaking switches operated by excess current and requiring separate action for resetting in which the excess current itself provides the energy for opening the contacts, and having a separate reset mechanism
    • H01H77/10—Protective overload circuit-breaking switches operated by excess current and requiring separate action for resetting in which the excess current itself provides the energy for opening the contacts, and having a separate reset mechanism with electrodynamic opening
    • 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

Definitions

  • a tap changing device for a transformer winding without interrupting the load current comprises two sets of tap points each of which is associated with a tap changing switch for selecting different taps. Diverter switches are associated with each tap changing switch and connected in series with these diverter switches are a plurality of series connected circuit breakers. The contacts of these circuit breakers are biased to a closed position and remain closed for normal load currents taken off the transformer winding.
  • the present invention relates to a tap changer for controllable transformers comprising mechanically operable switch means for switching the load from tap to tap.
  • a tap changer for controllable transformers comprising mechanically operable switch means for switching the load from tap to tap.
  • the portion of the transformer winding between the taps is momentarily short-circuited. This is necessary to prevent the load circuit from being momentarily broken.
  • conventional on-load tap changers are provided with supplementary contacts and diverter resistors. Although the short circuit current is thus replaced by a reduced circulating current the on-load switch means are nevertheless called upon to rupture heavy currents.
  • the design of the contact fingers of the tap changer as well as of the diverter resistors therefore involves expensive forrns of construction.
  • a tap changer which lacks diverting resistors has already been proposed in which means are provided whereby the arcing voltage at the tapping switches exceeds the voltage induced in the inductive circuit between the two taps.
  • the time between rupturing and remaking the connections at the taps must be very short in order to prevent the short circuit current between the taps from exceeding a fraction of its maximum value. This necessity requires mechanically complicated and expensive forms of construction of the means for actuating the contact fingers.
  • the object of the present invention is to provide a simple and cheap arrangement which avoids the known disadvantages of known forms of construction.
  • the improved tap changing arrangement comprises mechanically operable switching contacts for stepping the load current from one tap to another on the transformer Winding.
  • the invention proposes to provide circuit breakers which during the tap change are temporarily electrically included in the short circuit between the taps in series with mechanically operable contacts, the circuit breakers being shortly thereafter opened at high speed by the electrodynamic effect of the step short circuit current and then automatically reclosed by spring means which normally bias the contacts of the circuit breakers to their closed position.
  • FIG. 1 is a somewhat schematic representation of an embodiment of the proposed tap changing equipment
  • FIG. 2 is an embodiment shown on a larger scale of an automatically rupturing circuit breaker used in the ar' rangement of FIG. 1.
  • FIG. 3 illustrates the structural combination of an automatically rupturing circuit breaker and of mechanical actuating gear and locking means.
  • FIG. 1 part of the tapped winding of a transformer is shown at ll. It is provided with several taps 1a to 1d connected to the contact elements 2a to 2d of a tap changing switching means 2.
  • 2e and 2' are the movable contact fingers of the tap changer 2 for connecting the contact elements 2a to 2d to bars 2g, 2h in such manner that 2e permits either contact element 2a or 2c to be connected to bar 2g and contact element 2]) or 2:! to be connected to bar 2h by 2
  • the two bars 2g and 2h are connected by lead olf conductors 3 and 4 to contacts 5 and 7 and to 6 and 3 respectively.
  • the output 15 of the tap changer is connected to tap point la of the transformer winding 1, the major portion of the load current flowing through contact arm 9.
  • contact arm 9 is first switched over from contact 5 to contact 6, the load current being momentarily diverted through the parallel path formed by 7, 1t), 14, 12a to 1221.
  • arm 9 makes contact with contact 6 a rapidly rising short circuit current builds up in the circuit formed by 1a, 2a, 26, 2g, 3, 7, ltl, 14, 12a to 12m, 13, 9, 6, 4, 2h, 2f, 2]), 1b and the winding between la and lb.
  • the circuit breakers 12a to 1221 are automatically opened by the electrodynamic effect of the short circuit current they carry. Arcs are struck and the sum of the arcing voltages rises beyond the value of the potential difference between the two taps 1a and 112 so that the short circuit current falls to Zero. At the same time as contact arm 9 closes on contact 6 contact arm 19 moves away from contact 7. The voltage of the are between 7 and all augments that between the circuit breaker contacts 12a to 12:1 and therefore supports its effect.
  • contact arm 10 as well as the circuit breakers 12a to 1211 may be advantageously designed for a lower rated current than contact arm 9 and the tap changer 2 because contrary to the latter they are required to conduct current only for a short time whilst the load is being transferred.
  • this provides the advantageous possibility of light weight construction with small moving masses and correspondingly high rupturing speeds.
  • FIG. 2 exemplifies a circuit breaker which is automatically opened by the short circuit current.
  • 16 and 17 are two contact members each pivotally mounted at 18 and held in contacting position by springs 19.
  • 20 are flexible connections which feed the contact members 16 and 17 with current.
  • the bottom end of each contact member 16 and 17 is linked by an articulation 21 to a piston 22 slidably guided in a cylinder 23 which is pivotably mounted at 24.
  • the floor of the cylinder is provided with openings 25 controlled by a non-return valve 26.
  • the springs 19 are designed to keep the contact members 16 and 17 in contacting position so long as they carry the normal current. However, when the short circuit current initiated by a tap change rises beyond the rated value of the load current the contact members 16 and 17 are thrust apart by the electrodynarnic repulsion due to the current. The path of the current is indicated by the discontinuous line 27.
  • each cylinder 23 and its piston 22 functions as a one way dashpot.
  • circuit breakers 12a and 1211 should be associated with locking means which prevent these members from opening automatically until shortly before the contact arm 9 engages contact 6.
  • FIGURE 3 illustrates an embodiment in which the same reference numbers are used as in FIG. 2 to indicate the same parts as in FIG. 2.
  • Contact member 16 is constructed in the same way as in FIG. 2, but it is provided with a supplementary abutment 16a which cooperates with an external stop 28. Moreover, another abutment 29 cooperates with the bottom end of the contact member.
  • contact member 17 is pivotably mounted at 18a on a lever 30 which is itself pivotably mounted at 31.
  • a spring 19' is interposed between parts 17 and 30, and a further spring 32 is attached to the upper end of lever 30 for cooperation with an abutment 17a.
  • Spring 32 serves as a locking means to delay opening of the contacts 16, 17 of the circuit breakers until shortly before contact arm 9 engages contact 6.
  • a piston 22a is linked to the contact member by a rod 22b and a pin 220.
  • the piston is slidably guided in a cylinder 23a which is firmly aflixed to lever 30.
  • lever 30 is attached at 34 to an actuating rod 35, and lever 30 also carries a pin 33 engageable with the lower portion of contact member 17.
  • a two-way switching device can be provided in a manner known to the art. Sometime it may be advisable to include a current limiting inductance 36 in the short circuit, for instance between point 14 and circuit breaker 12m in FIG. 1. The rise of the short circuit current can thus be limited or adapted to the rupturing speed of the circuit breakers 12a to 12n.
  • a tap changer device for a controllable transformer having a winding provided with first and second sets of tap points, first and second tap changing switching means for connecting selected tapping points of said first and second sets respectively to first and second lead ofl? conductors, a pair of diverter switches, each said diverter switch including a first contact member movable into selective engagement with a second or third contact member, circuit means connecting said second contact members of said diverter switches with said first lead off conductor, circuit means connecting said third contact members of said diverter switches with said second lead off conductor, an output lead connected to a first contact member of one of said diverter switches, a plurality of circuit breakers connected in series between said first contact members of said diverter switches, means biasing the contacts of said circuit breakers to a closed position, said circuit breaker contacts remaining closed when traversed by normal load currents taken off said tapped transformer winding but opening automatically by electrodynamic effect of the current carried thereby when said current rises above the normal load level as a result of a short circuit established through a portion of said transformer wind
  • a tap changer device as defined in claim 1 wherein said means biasing the contacts of each circuit breaker to a closed position is constituted by a spring.
  • a tap changer device as defined in claim 1 and wherein means are provided for locking the contacts of 10 said circuit breakers against opening, said locking means being coupled with said diverter switches and being released just prior to the creation of said short circuit.
  • JOHN F. COUCH Primary Examiner.
  • A. D. PELLINEN Assistant Examiner.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Breakers (AREA)
US39481164 1963-09-27 1964-09-08 Tap changing device for transformer windings without interrupting the load current Expired - Lifetime US3359485A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH1193963A CH403075A (de) 1963-09-27 1963-09-27 Stufenschalteinrichtung für Regeltransformatoren

Publications (1)

Publication Number Publication Date
US3359485A true US3359485A (en) 1967-12-19

Family

ID=4378313

Family Applications (1)

Application Number Title Priority Date Filing Date
US39481164 Expired - Lifetime US3359485A (en) 1963-09-27 1964-09-08 Tap changing device for transformer windings without interrupting the load current

Country Status (5)

Country Link
US (1) US3359485A (de)
AT (1) AT242248B (de)
BE (1) BE653573A (de)
CH (1) CH403075A (de)
GB (1) GB1017916A (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3436646A (en) * 1966-08-02 1969-04-01 Westinghouse Electric Corp Load tap changer systems including protective apparatus for monitoring the operation of the transfer switches
US3492609A (en) * 1967-01-27 1970-01-27 Terasaki Denki Sangyo Kk Circuit interrupter trip contact resetting means
US3594631A (en) * 1969-04-02 1971-07-20 Bbc Brown Boveri & Cie Hydraulic tap changer
US3628128A (en) * 1969-03-11 1971-12-14 Bbc Brown Boveri & Cie Step-switching arrangement
US4346357A (en) * 1979-12-17 1982-08-24 Gould Inc. Current-limiting circuit breaker adapter
US4384247A (en) * 1981-05-08 1983-05-17 Trw Inc. Under-load switching device particularly adapted for voltage regulation and balance
US4464642A (en) * 1981-03-12 1984-08-07 Mitsubishi Denki Kabushiki Kaisha Circuit breaker

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1626970A (en) * 1925-03-18 1927-05-03 Asea Ab Voltage regulator-for transformers
US2138652A (en) * 1935-07-10 1938-11-29 Gen Electric Electric switching
US2394102A (en) * 1944-09-19 1946-02-05 Westinghouse Electric Corp Electrical apparatus
DE767731C (de) * 1933-12-08 1953-04-16 Aeg Regeleinrichtung fuer Stufentransformatoren
US2715706A (en) * 1949-11-30 1955-08-16 Continental Engineering Corp Motor control circuit
FR1161940A (fr) * 1955-12-02 1958-09-08 Bbc Brown Boveri & Cie Véhicule de traction à moteurs à courant continu
US3005073A (en) * 1958-07-30 1961-10-17 Licentia Gmbh High speed circuit breaker
CA654913A (en) * 1963-01-01 Buhler Karl Load tapchanger
US3092699A (en) * 1958-12-23 1963-06-04 Merlin Gerin Electrodynamic force-compensation pressure contacts for circuit breakers
US3127488A (en) * 1960-07-18 1964-03-31 Ite Circuit Breaker Ltd Current limiting circuit breaker having both contacts movable

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA654913A (en) * 1963-01-01 Buhler Karl Load tapchanger
US1626970A (en) * 1925-03-18 1927-05-03 Asea Ab Voltage regulator-for transformers
DE767731C (de) * 1933-12-08 1953-04-16 Aeg Regeleinrichtung fuer Stufentransformatoren
US2138652A (en) * 1935-07-10 1938-11-29 Gen Electric Electric switching
US2394102A (en) * 1944-09-19 1946-02-05 Westinghouse Electric Corp Electrical apparatus
US2715706A (en) * 1949-11-30 1955-08-16 Continental Engineering Corp Motor control circuit
FR1161940A (fr) * 1955-12-02 1958-09-08 Bbc Brown Boveri & Cie Véhicule de traction à moteurs à courant continu
US3005073A (en) * 1958-07-30 1961-10-17 Licentia Gmbh High speed circuit breaker
US3092699A (en) * 1958-12-23 1963-06-04 Merlin Gerin Electrodynamic force-compensation pressure contacts for circuit breakers
US3127488A (en) * 1960-07-18 1964-03-31 Ite Circuit Breaker Ltd Current limiting circuit breaker having both contacts movable

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3436646A (en) * 1966-08-02 1969-04-01 Westinghouse Electric Corp Load tap changer systems including protective apparatus for monitoring the operation of the transfer switches
US3492609A (en) * 1967-01-27 1970-01-27 Terasaki Denki Sangyo Kk Circuit interrupter trip contact resetting means
US3628128A (en) * 1969-03-11 1971-12-14 Bbc Brown Boveri & Cie Step-switching arrangement
US3594631A (en) * 1969-04-02 1971-07-20 Bbc Brown Boveri & Cie Hydraulic tap changer
US4346357A (en) * 1979-12-17 1982-08-24 Gould Inc. Current-limiting circuit breaker adapter
US4464642A (en) * 1981-03-12 1984-08-07 Mitsubishi Denki Kabushiki Kaisha Circuit breaker
US4384247A (en) * 1981-05-08 1983-05-17 Trw Inc. Under-load switching device particularly adapted for voltage regulation and balance

Also Published As

Publication number Publication date
GB1017916A (en) 1966-01-26
AT242248B (de) 1965-09-10
CH403075A (de) 1965-11-30
BE653573A (de) 1965-01-18

Similar Documents

Publication Publication Date Title
US3005073A (en) High speed circuit breaker
US3873950A (en) Air circuit breaker
US3538278A (en) High voltage electric circuit breaker
DE1239394B (de) Schaltanordnung fuer Lastumschalter von Stufenschaltern bei Regeltransformatoren
ES349090A1 (es) Perfeccionamientos en la disposicion para la conmutacion o bajo carga, sin interrupcion, en transformadores escalona- dos.
US2214471A (en) Circuit breaker
US2470628A (en) Circuit interrupter
US4733031A (en) Switching apparatus protected against short circuit currents
US2892913A (en) Air blast switch with auxiliary point of interruption for shunt resistance
US3564336A (en) Sequential switching system with current limiting shunt path
US3390240A (en) Circuit breaker with piston gas flow and selective synchronous operation
US2303492A (en) Circuit-breaker mechanism
GB1576877A (en) Apparatus for the rapid interruption of currents
US3813503A (en) Transfer switch for tap-changing regulating transformers
US3655931A (en) Synchronously operating circuit breaker with improved circuit breaker operating mechanism
US3614687A (en) Circuit interrupting apparatus
US3602668A (en) Interrupter switch usable as a sectionalizer in high voltage systems
US2904660A (en) Air blast circuit breakers
US3158711A (en) Current limiting circuit breaker
US3555404A (en) Tap-changing transformer system including vacuum switch units
US2593225A (en) Polyphase circuit interrupter
US2700081A (en) Automatic reclosing circuit breaker
DE3133221A1 (de) "leitungsschutzschalter"
US3082358A (en) Electro-magnetic control device
US3806735A (en) Tap changing transfer switch having series breaks