US3602807A - Load tap changer apparatus with magnetic transducer protective circuitry - Google Patents

Load tap changer apparatus with magnetic transducer protective circuitry Download PDF

Info

Publication number
US3602807A
US3602807A US29157A US2915770A US3602807A US 3602807 A US3602807 A US 3602807A US 29157 A US29157 A US 29157A US 2915770 A US2915770 A US 2915770A US 3602807 A US3602807 A US 3602807A
Authority
US
United States
Prior art keywords
switching means
switch
tap
transfer switch
tap selector
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
US29157A
Other languages
English (en)
Inventor
Herbert L Prescott
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.)
CBS Corp
Original Assignee
Westinghouse Electric Corp
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 Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Priority to US29157A priority Critical patent/US3602807A/en
Priority to CA108650A priority patent/CA926938A/en
Priority to JP2351371A priority patent/JPS465023A/ja
Priority to FR717113263A priority patent/FR2086115B1/fr
Priority to ZM74/71*UA priority patent/ZM7471A1/xx
Application granted granted Critical
Publication of US3602807A publication Critical patent/US3602807A/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
    • H01F29/04—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
    • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
    • H01H9/0005—Tap change devices
    • H01H2009/0061—Monitoring tap change switching devices

Definitions

  • Load tap changer apparatus including a tap selector switch, a load transfer switch, and a protective circuit having a magnetic transducer which magnetically checks for current flow through a predetermined conductor of the apparatus, while being spaced from the predetermined conductor beyond the voltage jump distance to ground.
  • the protective circuit utilizes an electrical signal from the magnetic transducer to prevent the operation of the tap selector switch when current is flowing through the predetermined conduc- I01.
  • APPARATUS wmr MAGNETIC TRANSDUCER PROTECTIVE CIRCUITRY BACKGROUND OF THE INVENTION lating currents when the tap changer apparatus is bridging two taps, a load transfer switch, such as a vacuum switch, and a bypass switch which shorts the vacuum switch when the tap changer is not ina-tap change cycle, to reduce the heating of the vacuum switch contacts.
  • the bypass switch has first and second contacts connected in first and second branch circuits,
  • the first branch. circuit includes. the first contact arm of the tap selector switch, the
  • the vacuum switch is conv ncctcd between the first and second terminals of the bypass switch.
  • the bypass switch opens a preselected branch circuit, without substantial arcing, as the vacuum switch is closed at this point, with. the current flow transferring from the opening side of the bypass switch to the vacuum switch.
  • the vacuum switch then opens its contacts to isolate the selected branch circuit, allowingthe tap selector contact arm connected in the isolated branch circuit to move to a new tap position without arcing.
  • the present invention is a loadtap changersy'stem which includes new and improved protective apparatus for monitoring the operation of the tap changer and preventing the operation of its no-load tap selector switch when current is flowing through the contact arm of the transfer switch scheduled to move to a different tap position in a tap change cycle.
  • the protective apparatus includes a magnetic transducer disposed in the magnetic field produced by current flow through a predetermined conductor of the tap changer apparatus, which conductor should not have current flow therein when the tap selector switch is operated.
  • An output signal from the magnetic transducer, immediately prior to the scheduled operation of the tap selector switch contact arm, is usedto either deenergize the transformer the tap changer system is "operated with, or to disable the tap changer and prevent the operation of the tap selector switch. Or, it may be used to initiate any type of desired protective function.
  • the magnetic transducer while being within, and sensitive to, the magnetic field provided by current flow through the predetermined conductor, is spaced therefrom beyond the voltage jump distance to ground, enabling the protective apparatus to be operated near ground potential without being insulated for the voltage of the tap changer system to ground BRIEF DESCRIPTION OF THE DRAWING and protective circuitry constructed according to a first em-' bodiment of the invention; and,
  • FIG. 2 is a schematic diagram of load tap changer apparatus and protective circuitry constructed according to another em bodiment of the invention.
  • tap changer apparatus 10 which may utilize the teachings of the invention.
  • tap changer system 10 may be connected to the windings 12, I4 and i an electrical transformer.
  • the transformer may be single or polyphas'e, and either of the autotransformer or isolated winding type, with only a portion of a single phase being illustrated in FIG. 1, as other phases would. be similarly arranged.
  • the tap changer system 10 is of the type which includes a no-load type tap selector switch 20, having a plurality of sta tionary contacts Ct through C8- connecmd to taps Tl through T8, respectively, on winding l4, and a stationary contact C9 connected to winding 16.
  • Tap selector switch 20 has a pair of movable contact arms 22- and 24 for selectively and sequen tially' moving between the spaced stationary contacts CI through C9.
  • the ends oi? tapped winding 14 are connected to the stationary contacts-'26 and 28 of a reversing switch 30,- wltich hasa movable contact arm 32 connected to winding.
  • the reversing switch 30 may be actuated to change its movable contact arm 32 from one stationary contact to the other, when one of the movable contact arms 22 and 24 of the tap selector switch 20 is in engagement with the stationary contact (11am! the other contact arm is in transition to orfr'om contact C9, to add the tap voltage to, or subtract it from, the voltages of windings l1 and I6, depending upon .the position of the reversing switch 30'.
  • a single arcing duty load transfer switch such as the normally closed vacuum switch 50 shown in FIG. 1, and a bypass switch 52, complete the tap changer system 10, with the bypass switch 52 having first and second stationary contacts 54 and 56, and a movable contact 58.
  • the movable contact 58 is connected to winding 12, and the stationary contacts 54 and 56 are connected to winding portions 42 and 44 of reactor 40.
  • the movable contact 58 is arranged to engage both stationary contacts 54 and 56, or to individually select either of the stationary contacts.
  • the vacuum switch 50 has contacts 62 and 64 disposed within an evacuated envelope, with one of the contacts being movable relative to the other via a bellows, which maintains the vacuum seal.
  • the vacuum switch 50 is connected across the contacts 54 and 56 of the bypass switch 52, via conductors 55 and 57.
  • the power circuit of the transformer When the tap changer system is in a steady state position, the power circuit of the transformer includes winding 16, the portion of winding 14 between the selected position of reversing switch 30 and the tap or taps selected by the contact arms 22 and 24, through the two branch circuits of the contact arms, and winding l2.
  • the first branch circuit includes contact arm 24, winding section 42, and the position of the bypass switch 52 which includes stationary contact 54; and, the second branch circuit includes contact arm 22, winding section 44, and the position of bypass switch 52 which includes stationary contact 56.
  • the branch circuits combine in the movable contact 58 of bypass switch 52, and the power circuit continues to winding 12. Instead of having tapped winding 14 connected between two windingsof the transformer, it may also be disposed at either end of a main transformer winding.
  • the vacuum switch 50 has its contacts normally closed, but since it is normally shorted by the bypass switch 50, there is negligible current flow therethrough. Therefore, the contacts of the vacuum switch are not heated by the current flowing in the transformer windings.
  • Tap changer apparatus 10 includes protective apparatus 70 for monitoring the operation of the tap changer, and for protecting the tap selector switch 20 against operation while load current is flowing through the contact arm to be moved.
  • Protective apparatus 70 includes a magnetic transducer 72 of the type which provides an electrical output signal when it is subjected to a magnetic field produced by current flowing in a conductor, and which has a sensitivity which enables it to be responsive to the magnetic field produced by the current flow, while being spaced from the conductor beyond the voltage jump distance.
  • a magnetic transducer which may be used is disclosed in US. Pat. No.
  • 3,389,230 which describes a magnetically sensitive transistor having a base electrode b, an emitter electrode e, and first and second collector electrodes C, and C
  • the emitter current flow divides equally between the two collector electrodes C and (3,.
  • a bias circuit may be added to insure balanced flow in the absence of current in the conductor to be monitored.
  • the presence of a magnetic field due to current flow through the conductor to be monitored results in more current flowing to one of the collector electrodes than'to the other.
  • the collector electrodes C and C are connected to a sourceof electrical potential at terminal 76, via resistors 78 and 80 respectively.
  • the base electrode b is connected to a source of electrical potential at terminal 82
  • the emitter electrode e is connected to a source of electrical potential at terminal84.
  • Typical power supply voltage magnitudes for transducer 72 are sbowninFiGB.
  • transducer 72 is disposed in the magnetic filed 86 produced by current flowing through the vacuum switch 50, such as adjacent conductor 57, but the transducer 72 is spaced from conductor 57 beyond the voltage jump distance therefrom for the particular voltage magnitude applied to conductor 57.
  • Typical clearances are 6.5 inches for 69 kv. and 14.5 inches for 115 kv.
  • transducers having the required sensitivity may be used, such as transducers of the Hall generator type.
  • the unbalanced current flow to the two collector electrodes of transducer 72, when transducer 72 is subjected to a magnetic field, may be detected and amplified by'differential amplifier 74, which is connected to collector ele'ctrodesC and C via conductors 88 and 90 respectively, and the'output of the differential amplifier 74 is applied to the electromagnetic coil 92 of a solenoid 94, via a cam operated switch 96.
  • Solenoid 94 mechanically actuates its contacts 98 to their closed position, when the electromagnetic coil 92 is energized, with the contacts 98, in this embodiment, being connected in an electrical circuit associated with the tap changer drive means 100.
  • the tap changer drive means 100 may include a reversible electric motor and control shaft, with suitable mechanical linkages and cams being associated with the control shaft for operating the bypass switch 52, vacuum switch 50, tap selector switch 20, and switch 96, in a predetermined sequence, when it is desired to change tap connections.
  • the mechanical linkages and cams between the drive means 100 and these devices are shown generally by the dotted lines 102.
  • the protective apparatus 70 magnetically monitors the current flow through the transfer switch 50, and it checks for current flow immediately prior to the operation of the tap selector switch 20 during a tap change cycle, via the cam operated switch 96, which is mechanically closed-by the tap changer drive 100.
  • An output signal from differential amplifier 74 indicates current flow through the transfer switch 50, and the impending operation of the tap selector switch should be prevented.
  • the contacts 98 of solenoid 94 are shown connected in a circuit associated with the drive means 100', to disable the drive means 100 and prevent the operation of the tap selector switch 20.
  • the output signal from differential amplifier 74 may by used in other suitable circuits, such as a circuit which deenergizes the transformer, if the application is such that deenergizing the transformer is not detrimental to the load.
  • solenoid 94 While the contacts 98 of solenoid 94 are shown normally open, they may also be normally closed and used in a circuit designed to effect the desired protective function with normally closed contacts. Also, the switch 96 is illustrated as being normally open, but it could be normally closed and opened by the drive means only when it is desired to check for current flow through the transfer switch. For example, the switch 96 could be normally closed and connected across the output terminals of differential amplifier 74, opening in response to drive means 100 just prior to the operation of the tap selector switch 20.
  • tap changer drive means 100 will sequentially operate bypass switch 52 to open the second series branch, since tap selector arm 22 must eventually move to contact C
  • bypass switch 52 opens the second series branch
  • the circuit through winding section 44 and tap selector switch contact arm 22 is maintained through the vacuum switch 50, thus creating very little arcing at the contacts of the bypass switch 52.
  • the vacuum switch 50 is actuated to open its contacts and completely isolate the second series branch. Arcing occurs at the contacts of the vacuum switch, but the arc is quickly extinguished due to the vacuum environment surrounding its contacts 62 and 64.
  • switch 96 is closed by drive means 100, to initiate the protective function of protective apparatus 70. If there has been no malfunction in the prior steps of the tap change cycle, i.e., the vacuum switch operating mechanism opened the contacts of the vacuum switch 50, and there has been no loss of vacuum in the vacuum switch there will be no current flow in conductor 5.7 and the output of transducer 72 will be balanced. Thus, there will beno output from differential amplifier 74 and the solenoid 94 will not be energized when switch 96 is closed. The tap change cycle is, therefore, allowed to continue.
  • transducer 72 If current is flowing in conductor 57 when switch 96 is closed by drive means 100, the output of transducer 72 will be unbalanced, resulting in an output voltage from differential amplifier 74 which energizes the electromagnetic coil 92 of solenoid 94, causing it to close its contacts 98 and disable the tap changer drive means 100.
  • contact am 22 will then move to contact C vacuum switch 50 will close its contacts to reestablish the circuit through winding portion 44 of reactor 40 and through the contact arm 22, and bypass switch 52 will reestablish the second branch circuit.
  • a tap change involving movement of contact arm 24 would be similar to that described for movement of contact arm 22, except the bypass switch would open the first series branch, instead of the second series branch.
  • FIG. 1 is a schematic diagram of tap changer apparatus having protective apparatus 70 and 70' which provides complete protection for the tap selector switch 20, protecting it against malfunction of both the bypass switch 52 and of the vacuum switch50.
  • the tap changer systems 10 and 10 shown in FIGS. 1 and 2, respectively, are similar in construction, with like reference numerals being used to indicate like components.
  • the protective apparatus 70wshown in FIG. 2 is the same as the protective apparatus 70-, shown in FIG. 1, except transducer 72 is disposed to be responsive to a magnetic field 110 produced by current flow through the second branch circuit, including the contact arm 22,..and a similar protective circuit 70' includes a magnetic transducer 72"disposed to be responsive to a magnetic field 112 produced by current flow through the first branch circuit, including contact arm 24. Similar to the first embodiment of the invention it is important that the magnetic transducers 72 and 72' be spaced from their associated branch circuits beyondthe voltage jump distance.
  • Switches 96 and 96 are responsive to drive means 100, with the switches closing just prior to, the operation of the tap selector switch associated with the series branch which they are monitoring. lnother words, if contact arm 22, associated with the second series branch,is to be moved, the drive means 100 will close switch 96 just prior to the operation of contact arm 22. if contact arm24, associated with the first branch circuit, is to be moved during the tap change cycle, the drive means 100 will close switch 6' just prior to the scheduled operation of contact arm 24.
  • a load tap changer system comprising:
  • tap selector switching means having first and second contact arms selectively movable between a plurality of electrical contacts connected to taps on said winding, reactor means having first andsecond winding portions; bypass switching means having first, second and third terminals, actuable to connect the third terminal to either or both of the first and second terminals, said third terminal being connected in said electrical circuit, I i
  • a load transfer switch connected between the first and second terminals of said bypass switching means, drive means for operating said bypass switching means, said transfer switch, and said tap selector switching means in a predetermined sequence, when it is desired to change the operating position of said tap selector switching means
  • the load tap changer system of claim 1 wherein the load transfer switch is a vacuum switch.
  • the protective means includes a camoperated switch actuatedby the drive means prior to the operation of the tap selector switching means, to check for current flow through the transfer switch, said cam operated switch being connected to render the protective means operative to prevent the operation of the tap selector switching means while current is flowing through the transfer switch.
  • a load tap changer system comprising: an electrical circuit including a windinghaving a plurality of taps,
  • tap'selector switch means having first and second contact arms selectively movable between a plurality of electrical contacts'connected to taps on said windin g,
  • reactor means having first and second winding portions
  • bypass switching means having first, second and-third terminals, actuable to connect the third terminal to either or both of the first and second terminals, said third terminal being connected in said electrical circuit,
  • first and second magnetic transducer means disposed in the magnetic field produced by current flowing through said first and second series branches, respectively, but spaced from said first and second series branches beyond the voltage jump distance to ground, said first and second magnetic transducer means providing electrical output signals in response to current flow through said first and second series branches, respectively,
  • the protective means includes first and second cam operated switches, operated by the drive means prior to the movement of the first and second contact arms, respectively, of the tap selector switching means, to check for current flow through the first and second series branches, respectively, and render the protective means operative to prevent operation of a contact arm when current is flowing therethrough.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • High-Tension Arc-Extinguishing Switches Without Spraying Means (AREA)
US29157A 1970-04-16 1970-04-16 Load tap changer apparatus with magnetic transducer protective circuitry Expired - Lifetime US3602807A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US29157A US3602807A (en) 1970-04-16 1970-04-16 Load tap changer apparatus with magnetic transducer protective circuitry
CA108650A CA926938A (en) 1970-04-16 1971-03-25 Load tap changer apparatus
JP2351371A JPS465023A (en) 1970-04-16 1971-04-15 Load tap changer apparatus
FR717113263A FR2086115B1 (fr) 1970-04-16 1971-04-15
ZM74/71*UA ZM7471A1 (en) 1970-04-16 1971-06-07 Antibiotics and processes for their production

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US29157A US3602807A (en) 1970-04-16 1970-04-16 Load tap changer apparatus with magnetic transducer protective circuitry

Publications (1)

Publication Number Publication Date
US3602807A true US3602807A (en) 1971-08-31

Family

ID=21847555

Family Applications (1)

Application Number Title Priority Date Filing Date
US29157A Expired - Lifetime US3602807A (en) 1970-04-16 1970-04-16 Load tap changer apparatus with magnetic transducer protective circuitry

Country Status (5)

Country Link
US (1) US3602807A (fr)
JP (1) JPS465023A (fr)
CA (1) CA926938A (fr)
FR (1) FR2086115B1 (fr)
ZM (1) ZM7471A1 (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3735243A (en) * 1972-04-03 1973-05-22 Gen Electric Control system for tap changer with vacuum interrupter
US4061963A (en) * 1976-04-27 1977-12-06 Westinghouse Electric Corporation Load tap changer system
US4090225A (en) * 1977-01-21 1978-05-16 Mcgraw-Edison Company Fail-safe circuit for tap-changing transformer regulating system
US4388664A (en) * 1980-08-04 1983-06-14 Fuji Electric Co., Ltd. Apparatus for protecting vacuum interrupter type on-line tap changer
US6124726A (en) * 1997-10-08 2000-09-26 Maschinenfabrik Reinhausen Gmbh Method of monitoring a tap selector
US20050057878A1 (en) * 2003-09-12 2005-03-17 General Electric Company Automatic transfer switch and protection device
US9143072B2 (en) 2011-03-27 2015-09-22 Abb Technology Ag Tap changer with an improved drive system
US9697962B2 (en) 2011-03-27 2017-07-04 Abb Schweiz Ag Tap changer with an improved monitoring system

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE390370C (sv) * 1972-12-15 1986-06-23 Arla Ekonomisk Foerening Forfaringssett for framstellning av lagkalorimargarin med hog proteinhalt, varvid vattenfasen framstelles av ett proteinkoncentrat utvunnet ur pa bakteriell veg syrad kernmjolk och varvid den ferdigbildade emulsionen pa
JP2902763B2 (ja) * 1990-10-04 1999-06-07 旭電化工業株式会社 練り込み用油中水型乳化油脂組成物

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3735243A (en) * 1972-04-03 1973-05-22 Gen Electric Control system for tap changer with vacuum interrupter
US4061963A (en) * 1976-04-27 1977-12-06 Westinghouse Electric Corporation Load tap changer system
US4090225A (en) * 1977-01-21 1978-05-16 Mcgraw-Edison Company Fail-safe circuit for tap-changing transformer regulating system
US4388664A (en) * 1980-08-04 1983-06-14 Fuji Electric Co., Ltd. Apparatus for protecting vacuum interrupter type on-line tap changer
US6124726A (en) * 1997-10-08 2000-09-26 Maschinenfabrik Reinhausen Gmbh Method of monitoring a tap selector
US20050057878A1 (en) * 2003-09-12 2005-03-17 General Electric Company Automatic transfer switch and protection device
WO2005029668A2 (fr) * 2003-09-12 2005-03-31 General Electric Company Commutateur de transfert automatique et dispositif de protection
WO2005029668A3 (fr) * 2003-09-12 2005-06-09 Gen Electric Commutateur de transfert automatique et dispositif de protection
US6944002B2 (en) * 2003-09-12 2005-09-13 General Electric Company Automatic transfer switch and protection device
CN1879273B (zh) * 2003-09-12 2010-12-08 通用电气公司 自动转换开关和保护装置
US9143072B2 (en) 2011-03-27 2015-09-22 Abb Technology Ag Tap changer with an improved drive system
US9697962B2 (en) 2011-03-27 2017-07-04 Abb Schweiz Ag Tap changer with an improved monitoring system
US10840033B2 (en) 2011-03-27 2020-11-17 Abb Power Grids Switzerland Ag Tap changer with an improved monitoring system

Also Published As

Publication number Publication date
FR2086115B1 (fr) 1974-02-15
CA926938A (en) 1973-05-22
ZM7471A1 (en) 1973-03-21
JPS465023A (en) 1971-11-24
FR2086115A1 (fr) 1971-12-31

Similar Documents

Publication Publication Date Title
US3622867A (en) Load tap changer system including protective apparatus for monitoring the operation thereof
US3944888A (en) Selective tripping of two-pole ground fault interrupter
US3602807A (en) Load tap changer apparatus with magnetic transducer protective circuitry
US10784673B2 (en) Current protection device with mutual reactor
US4061963A (en) Load tap changer system
US3358104A (en) Heating means for compressed-gas circuit interrupters
US3544884A (en) Load tap changer apparatus employing parallel circuits comprising vacuum and no-load switches
US3206580A (en) Fluid immersed tap changing switching system for transformers
US3215866A (en) Synchronous circuit-interrupting devices
JP2677584B2 (ja) 大電流開閉器
US5617281A (en) Low cost circuit controller
US6445268B1 (en) Instantaneous trip power transformer
US3227925A (en) Control for switch means
US3210648A (en) Regulating and current limiting transformer system
US3783206A (en) Tap changing apparatus with improved contact structure to eliminate electrical fields across open interrupter switches
US3452311A (en) Interleaved winding having a tapped section and switch
KR20190002864A (ko) 한류 및 차단이 가능한 자기결합을 이용한 한류기
EP0074186A1 (fr) Dispositif limiteur de courant
SU561529A3 (ru) Силовой переключатель отпаек трансформатора
US1835550A (en) System of motor control
US2370037A (en) Protective device for electrical apparatus and systems
US3454831A (en) Quick-opening,low cost,current limiting circuit breaker
US3252014A (en) Switching device with arc suppressor
US3806735A (en) Tap changing transfer switch having series breaks
KR100228519B1 (ko) 사고전류 억제장치(事故電流 抑制藏置)