CN114446622A - Single-isolation contact transition circuit of on-load tap-changer and voltage regulation method - Google Patents

Single-isolation contact transition circuit of on-load tap-changer and voltage regulation method Download PDF

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Publication number
CN114446622A
CN114446622A CN202210138467.7A CN202210138467A CN114446622A CN 114446622 A CN114446622 A CN 114446622A CN 202210138467 A CN202210138467 A CN 202210138467A CN 114446622 A CN114446622 A CN 114446622A
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China
Prior art keywords
switch
main
current
tap
changer
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Chinese (zh)
Inventor
闫晨光
丁凯
刘张衡
席旺旺
李盛涛
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Xian Jiaotong University
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Xian Jiaotong University
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Priority to CN202210138467.7A priority Critical patent/CN114446622A/en
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    • 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
    • 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
    • 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
    • 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

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • High-Tension Arc-Extinguishing Switches Without Spraying Means (AREA)
  • Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)

Abstract

A single-isolation contact transition circuit of an on-load tap-changer and a voltage regulation method comprise a first main through-current switch, a second main through-current switch and a change-over switch; the first main through-flow switch, the first end of the first transition resistor and the first fixed contact of the change-over switch are connected with a first winding tap of a voltage regulating winding of the transformer; the first end of the second main through-flow switch and the second transition resistor and the second fixed contact of the change-over switch are connected with a second winding tap of the transformer voltage-regulating winding; and the second end of the first main through-current switch, the second end of the second main through-current switch, the second end of the third switching element and the second end of the fourth switching element are connected with a neutral point leading-out end of the on-load tap-changer. The invention adopts two transition resistors to limit current, so that the interstage short-circuit current in the switching process is reduced while the recovery voltage of the switching element is lower; meanwhile, the time sequence of symmetrical reciprocating type can be borne, and in the process of switching between positive and negative reciprocating, the action time sequence is in mirror symmetry, and a mechanical rail transfer mechanism is not needed.

Description

Single-isolation contact transition circuit of on-load tap-changer and voltage regulation method
Technical Field
The invention belongs to the technical field of on-load tap-changers, and particularly relates to a single-isolation contact transition circuit of an on-load tap-changer and a voltage regulating method.
Background
The on-load tap changer is a key component in the power transformer, can be operated under the excitation or load state of the transformer, and can realize the regulation of output voltage under the condition of not interrupting load current by changing the effective turn ratio by changing a plurality of tap joints led out from a transformer winding. The on-load tap-changer has wide application range, and is particularly applied to a converter transformer of an extra-high voltage direct-current transmission project to ensure the rated trigger angle of a converter in normal operation.
The on-load tap-changer matched with the early power transformer mostly adopts the high-speed resistance switching principle and carries out load conversion by a copper-tungsten arc contact; the oil-immersed non-vacuum on-load tap-changer has frequent switching, correspondingly serious burning loss of an arc contact and high carbonization and pollution speed of oil, thereby increasing the workload of daily maintenance and regular overhaul for a power supply department. The vacuum type on-load tap-changer mainly uses a vacuum tube to realize arc extinguishing, thereby avoiding carbonization and pollution of arc extinguishing in oil to the oil; because the arc-breaking time of the vacuum tube is short, the arc voltage is low, the energy consumption of the electric arc is low, and the contact metal vapor is re-condensed, the burning loss and corrosion of the contact can be reduced to the minimum. The power electronic on-load tap changer replaces a vacuum tube by a power electronic element so as to realize the operation without breaking electric arcs in the on-load switching process.
The on-load tap-changer consists of a change-over switch, a tap selector and an electric mechanism; the transfer switch is provided with an independent oil chamber, is a key component for realizing on-load switching of the tap switch, and has the core that a transition circuit is adopted. The vacuum type on-load tap-changer can be divided into a single-contact circuit, a double-contact circuit, a three-contact circuit and a four-contact circuit according to different numbers of vacuum tubes; according to the number of transition resistors, the single resistor and the double resistor transition are adopted; single fracture, double fracture, etc. are formed according to the number of the contact fractures; the various combinations can form different types of vacuum type on-load tap-changer transition circuits. The switch element in the transition circuit can be a single-break vacuum contact, a double-break vacuum contact, a power electronic element and the like; different transition circuits have different switching sequences for realizing on-load voltage regulation, and the switching tasks of the switching elements are different. The topological structure of the transition circuit has obvious influence on the reliability of the switching process of the on-load tap-changer, the failure rate of the switch and the electrical service life of the switch.
The existing vacuum type on-load tap-changer transition circuit is asymmetric in control time sequence of switching from a winding tap N to a winding tap N +1 and switching from the winding tap N +1 to the winding tap N, and in the process of mechanical reciprocating motion of a switching core, a cam mechanism needs to realize rail lifting and rail changing, so that the complexity of mechanical manufacturing and the failure rate of switch use are increased.
Disclosure of Invention
The invention aims to provide a single-isolation contact transition circuit of an on-load tap-changer and a voltage regulating method, wherein the transition circuit can effectively limit inter-stage short circuit current in the switching process and can bear a symmetrical and reciprocating time sequence, and the mechanical on-load tap-changer adopting the transition circuit and the voltage regulating method has the action time sequence mirror symmetry in the positive and negative reciprocating switching process and does not need a mechanical track changing mechanism.
The purpose of the invention is realized by the following technical scheme:
a single-isolation contact transition circuit of an on-load tap-changer comprises a first main through-current switch, a second main through-current switch, a first switch element, a second switch element, a third switch element, a fourth switch element, a first transition resistor, a second transition resistor and a change-over switch;
the first end of the first main through-flow switch, the first end of the first transition resistor and the first fixed contact of the change-over switch are connected with a first winding tap of a transformer voltage-regulating winding; the first end of the second main through-flow switch, the first end of the second transition resistor and the second fixed contact of the change-over switch are connected with a second winding tap of a transformer voltage-regulating winding;
the first end of the first switch element and the first end of the second switch element are both connected with the moving contact of the change-over switch;
the second end of the first switching element and the first end of the third switching element are both connected with the second end of the first transition resistor;
a second end of the second switching element and a first end of the fourth switching element are both connected with a second end of the second transition resistor;
and the second end of the first main through-current switch, the second end of the second main through-current switch, the second end of the third switching element and the second end of the fourth switching element are connected with a neutral point leading-out end of the on-load tap-changer.
Furthermore, the first switch element, the second switch element, the third switch element and the fourth switch element are single-break vacuum tubes, double-break vacuum tubes or power electronic elements with controllable on-off functions.
Furthermore, the power electronic element with the on-off controllable function is a thyristor or an insulated gate bipolar transistor.
Further, the first switching element and the second switching element are used for switching off the load current; the third and fourth switching elements are used for breaking interstage circulating current.
Further, the first transition resistor and the second transition resistor are used for limiting inter-stage circulating current when a first winding tap and a second winding tap of a transformer regulating winding are bridged.
Further, when the first main through-current switch, the first switching element and the third switching element are all in a conducting state; the moving contact of the change-over switch is connected with the first fixed contact, and when the second main through-current switch, the second switch element and the fourth switch element are all in a disconnected state, the on-load tap-changer transition circuit can enable load current to flow out from the neutral point leading-out end from the first winding tap through the first main through-current switch; when the second main through-current switch, the second switching element and the fourth switching element are all in a conducting state; the movable contact of the change-over switch is connected with the second fixed contact; when the first main through-current switch, the first switch element and the third switch element are in an off state, the on-load tap changer transition circuit enables load current to flow out from a neutral point leading-out end from the second winding tap through the second main through-current switch.
A voltage regulation method based on the single-isolation contact transition circuit of the on-load tap-changer comprises the following steps:
the first main through-current switch, the first switch element and the third switch element are all in a conducting state, and the moving contact of the change-over switch is connected with the first fixed contact; the second main through-current switch, the second switching element and the fourth switching element are all in an off state;
disconnecting the first main through-flow switch, disconnecting the first switch element, leaving the movable contact of the change-over switch free, connecting the fourth switch element, disconnecting the third switch element, connecting the movable contact of the change-over switch with the second fixed contact, and connecting the second switch element; turning on the second main through-current switch;
the load current flows out from the neutral point leading-out end of the second winding tap through the second main through-flow switch, and the on-load tap-changer is switched from the first winding tap to the second winding tap.
A voltage regulation method based on the single-isolation contact transition circuit of the on-load tap-changer comprises the following steps:
the second main through-current switch, the second switching element and the fourth switching element are all in a conducting state; the movable contact of the change-over switch is connected with the second fixed contact; the first main through-current switch, the first switching element and the third switching element are all in an off state;
and disconnecting the second main through-current switch, disconnecting the second switch element, leaving the movable contact of the change-over switch free, connecting the third switch element, disconnecting the fourth switch element, connecting the movable contact of the change-over switch with the first fixed contact, connecting the first switch element, connecting the first main through-current switch, enabling the load current to flow out from the neutral point leading-out end through the first main through-current switch from the second winding tap, and switching the on-load tap-changer from the second winding tap to the first winding tap.
Compared with the prior art, the invention has the following beneficial effects:
the transition circuit adopts a single isolation change-over switch, uses the first transition resistor and the second transition resistor for current limiting, can effectively limit the interstage short-circuit current in the switching process, and simultaneously can bear a symmetrical and reciprocating time sequence. In the single-isolation contact transition circuit of the on-load tap changer, a change-over switch is adopted, so that the single-isolation contact transition circuit not only can play an electrical isolation role, but also can be used as a protection switch of a switch element, and the fault that the current cannot be cut off after the switch element fails is prevented.
In the voltage regulating method of the transition circuit, the action time sequence is in mirror symmetry in the forward and reverse reciprocating switching process, so that the rail changing operation of a mechanical structure is avoided; the transition circuit adopts two transition resistors to limit current, so that the interstage short-circuit current in the switching process is reduced while the recovery voltage of the switch element is lower. In the invention, the first switching element and the second switching element take the task of switching off the load current in turn, and the third switching element and the fourth switching element take the task of switching off the inter-stage circulating current in turn, so that the working loss degree of a single switching element is reduced, the switching capacity among the switching elements is balanced, and the failure rate of the switching elements is reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art are briefly introduced below; it is obvious that the drawings in the following description are some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.
Fig. 1 is a circuit diagram of an on-load tap changer transition circuit according to an embodiment of the present invention;
fig. 2 is a schematic diagram of an on-load tap changer transition circuit switching process according to an embodiment of the present invention;
fig. 3 is a schematic diagram of an on-load tap changer transition circuit switching process according to an embodiment of the present invention;
fig. 4 is a schematic diagram of an on-load tap changer transition circuit switching process according to an embodiment of the present invention;
fig. 5 is a schematic diagram of an on-load tap changer transition circuit switching process according to an embodiment of the present invention;
fig. 6 is a schematic diagram of an on-load tap changer transition circuit switching process according to an embodiment of the present invention;
fig. 7 is a schematic diagram of an on-load tap changer transition circuit switching process according to an embodiment of the present invention;
fig. 8 is a schematic diagram of an on-load tap changer transition circuit switching process according to an embodiment of the present invention;
fig. 9 is a schematic diagram of an on-load tap changer transition circuit switching process according to an embodiment of the present invention;
fig. 10 is a schematic diagram of an on-load tap changer transition circuit switching process according to an embodiment of the present invention;
fig. 11 is a schematic diagram of the on-off of each switch in the on-load tap changer transition circuit according to the embodiment of the present invention during the process of switching the load from winding tap N to winding tap N + 1;
fig. 12 is a schematic diagram of the on-off of each switch in the on-load tap changer transition circuit according to the embodiment of the present invention during the process of switching the load from winding tap N +1 to winding tap N;
fig. 13 is a circuit diagram of a single isolated contact transition circuit of an on-load tap changer in which the switching elements are power electronic components according to an embodiment of the present invention;
fig. 14 is a circuit diagram of a single isolated contact transition circuit of an on-load tap changer with a switching element that is a dual break vacuum contact in accordance with an embodiment of the present invention.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, shall fall within the protection scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
The present invention is described in further detail below with reference to the attached drawings.
The single-isolation contact transition circuit of the on-load tap-changer of the embodiment of the invention comprises: the current limiting circuit comprises a first main through-current switch, a second main through-current switch, a first switching element, a second switching element, a third switching element, a fourth switching element, a first transition resistor, a second transition resistor and a change-over switch. The first end of the first main through-current switch, the first end of the first transition resistor and the first fixed contact of the change-over switch are all connected with a first winding tap N of a voltage-regulating winding of a transformer; the first end of the second main through-flow switch, the first end of the second transition resistor and the second fixed contact of the change-over switch are connected with a second winding tap N +1 of the transformer voltage-regulating winding; the first end of the first switch element and the first end of the second switch element are both connected with the moving contact of the change-over switch; the second end of the first switching element and the first end of the third switching element are both connected with the second end of the first transition resistor; a second end of the second switching element and a first end of the fourth switching element are both connected with a second end of the second transition resistor; and the second end of the first main through-current switch, the second end of the second main through-current switch, the second end of the third switching element and the second end of the fourth switching element are connected with a neutral point leading-out end of the on-load tap-changer.
Furthermore, the change-over switch forms a single-pole three-throw switch, a moving contact of the change-over switch is connected with a first fixed contact at the N side of the first winding tap to form a first working state of the switch, a moving contact of the change-over switch is connected with a second fixed contact at the N +1 side of the second winding tap to form a second working state of the switch, and a moving contact of the change-over switch is vacant and is not connected with the first fixed contact and the second fixed contact to form a third working state of the switch.
Further, the first switch element, the second switch element, the third switch element and the fourth switch element may be a single-break vacuum tube, a double-break vacuum tube or a power electronic element (such as a thyristor or an insulated gate bipolar transistor) with a controllable on-off function.
In the embodiment of the invention, the first main through-current switch and the second main through-current switch are used for carrying the load current for a long time; the first switch element and the second switch element are used for switching off the load current in turn; the third switching element and the fourth switching element are used for alternately switching off the interstage circulating current. And the first transition resistor and the second transition resistor are used for limiting inter-stage circulating current when a first winding tap N and a second winding tap N +1 of a voltage regulating winding of the transformer are bridged. Illustratively, the actual selected specifications of each element are determined by the actual operating conditions of the transition circuit.
As shown in fig. 1, in the single-isolation-contact transition circuit of the on-load tap-changer according to the embodiment of the present invention, the switching element is described by taking a single-fracture vacuum tube as an example, and includes: the vacuum circuit comprises a first main through-current switch MC1, a second main through-current switch MC2, a first vacuum tube V1, a second vacuum tube V2, a third vacuum tube V3, a fourth vacuum tube V4, a first transition resistor R1, a second transition resistor R2 and a change-over switch T.
The first end of the first main through-current switch MC1, the first end of the first transition resistor R1 and the first stationary contact 11 of the change-over switch are all connected to a first winding tap N of a voltage-regulating winding of a transformer; the first end of the second main through-current switch MC2, the first end of the second transition resistor R2 and the second stationary contact 12 of the change-over switch T are all connected with a second winding tap N +1 of the transformer regulating winding; the first end of the first vacuum tube V1 and the first end of the second vacuum tube V2 are both connected with the movable contact of the change-over switch T; the second end of the first vacuum tube V1 and the first end of the third vacuum tube V3 are both connected with the second end of the first transition resistor R1; the second end of the second vacuum tube V2 and the first end of the fourth vacuum tube V4 are both connected with the second end of the second transition resistor R2; the second terminal of the first main current switch MC1, the second terminal of the second main current switch MC2, the second terminal of the third vacuum tube V3, and the second terminal of the fourth vacuum tube V4 are all connected to a neutral outlet of the on-load tap changer.
In the embodiment of the invention, when the first main through-current switch MC1, the first vacuum tube V1 and the third vacuum tube V3 are all in a conducting state; a moving contact of the change-over switch T is connected with a first fixed contact 11 at the N side of a first winding tap and is in a first working state; when the second main through-current switch MC2, the second vacuum tube V2 and the fourth vacuum tube V4 are all in an off state, the on-load tap-changer transition circuit can enable load current to flow out of a neutral point leading-out end from the first winding tap N through the first main through-current switch MC 1. When the second main through-flow switch MC2, the second vacuum tube V2 and the fourth vacuum tube V4 are all in a conducting state; the moving contact of the change-over switch T is connected with the second fixed contact 12 at the side of the second winding tap N +1 and is in a second working state; when the first main through-current switch MC1, the first vacuum tube V1 and the third vacuum tube V3 are all in an off state, the on-load tap-changer transition circuit can enable load current to flow out of a neutral point leading-out end from the second winding tap N +1 through the second main through-current switch MC 2.
In the embodiment of the invention, the transition circuit adopts the single isolation change-over switch and uses two transition resistors to limit current, so that the interstage short-circuit current in the switching process can be effectively limited, and meanwhile, a symmetrical and reciprocating time sequence can be borne. Specifically, in the single-isolation-contact transition circuit of the on-load tap changer provided by the embodiment of the invention, a change-over switch is designed, which not only can play an electrical isolation role, but also can be used as a protection switch of a vacuum tube, so that a fault that current cannot be switched off after the vacuum tube fails is prevented. The transition circuit and the voltage regulating method thereof have the advantages that in the positive and negative reciprocating switching process, the action time sequences are in mirror symmetry, so that the rail changing operation of a mechanical structure is avoided; the transition circuit is provided with two transition resistors for current limiting, so that the interstage short-circuit current in the switching process is reduced while the recovery voltage of the vacuum tube is lower.
In the embodiment of the invention, the first vacuum tube and the second vacuum tube take the task of switching off load current in turn, and the third vacuum tube and the fourth vacuum tube take the task of switching off inter-stage circulation current in turn, so that the working loss degree of a single vacuum tube is reduced, the switching capacity among the vacuum tubes is balanced, and the failure rate of the vacuum tubes is reduced.
The voltage regulating method of the single-isolation contact transition circuit of the on-load tap-changer in the embodiment of the invention takes a single-fracture vacuum tube as an example, and when the on-load tap-changer is switched from a current transformer winding tap to a preselected new transformer winding tap, the switching process of switching from a first winding tap N to a second winding tap N +1 is as follows:
the first main through-current switch MC1, the first vacuum tube V1 and the third vacuum tube V3 are all in a conducting state; the moving contact of the change-over switch T is connected with a first fixed contact 11 at the N side of the first winding tap and is in a first working state; the second main through-flow switch MC2, the second vacuum tube V2 and the fourth vacuum tube V4 are all in an off state;
turn off first main current switch MC 1;
the first vacuum tube V1 is disconnected, creating an arc;
after the first vacuum tube V1 is completely extinguished, moving the first operating state in which the moving contact of the change-over switch T is connected to the first fixed contact 11 to the third operating state in which the moving contact of the change-over switch is free;
the fourth vacuum tube V4 is conducted;
disconnecting the third vacuum tube to generate an arc;
after the third vacuum tube V3 is completely extinguished, moving the third operating state in which the moving contact of the change-over switch is vacant to the second operating state in which the moving contact of the change-over switch is connected to the second stationary contact 12;
conducting a second vacuum tube V2;
turning on second main current switch MC 2;
and the load current flows out from the neutral point leading-out end from the second winding tap N +1 through the second main through-flow switch, and the switching process of switching the on-load tap-changer from the first winding tap N to the second winding tap N +1 is finished.
The voltage regulation method for the single-isolation contact transition circuit of the on-load tap-changer in the embodiment of the invention takes a single-fracture vacuum tube as an example, and the switching process of the on-load tap-changer from the second winding tap N +1 to the first winding tap N is as follows:
the second main through-flow switch MC2, the second vacuum tube V2 and the fourth vacuum tube V4 are all in a conducting state; the moving contact of the change-over switch T is connected with the second fixed contact 12 at the side of the second winding tap N +1 and is in a second working state; the first main through-flow switch MC1, the first vacuum tube V1 and the third vacuum tube V3 are all in an off state;
turning off the second main through-current switch MC 2;
disconnecting the second vacuum tube V2, creating an arc;
after the second vacuum tube V2 is completely extinguished, moving the second operating state in which the moving contact of the change-over switch T is connected to the second fixed contact 12 to the third operating state in which the moving contact of the change-over switch is empty;
the third vacuum tube V3 is conducted;
disconnecting the fourth vacuum tube V4 to create an arc;
after the fourth vacuum tube is completely extinguished, the third working state that the moving contact of the change-over switch T is vacant is moved to the first working state that the moving contact of the change-over switch T is connected with the first fixed contact 12;
conducting a first vacuum tube V1;
turning on first main through-current switch MC 1;
and the load current flows out from the neutral point leading-out end from the second winding tap N through the first main through-flow switch, and the switching process of the on-load tap-changer for switching from the second winding tap N +1 to the first winding tap N is finished.
The voltage regulating method of the single-isolation-contact transition circuit of the on-load tap-changer in the embodiment of the invention is described by taking a single-fracture vacuum tube as an example; when the on-load tap changer is switched from the winding tap N to the winding tap N +1, the voltage regulating method comprises the following steps:
as shown in fig. 2, the first main through-current switch MC1, the first vacuum tube V1, and the third vacuum tube V3 are all in a conducting state; the moving contact of the change-over switch T is connected with a first fixed contact 11 at the N side of the first winding tap and is in a first working state; the second main through-flow switch MC2, the second vacuum tube V2 and the fourth vacuum tube V4 are all in an off state; winding tap N is switched on and load current flows from the first winding tap N through first main through-flow switch MC1 from the neutral point outlet.
As shown in fig. 3, first main through-current switch MC1 is turned off, and first vacuum tube V1 and third vacuum tube V3 are kept on; the moving contact of the change-over switch T is connected with the first fixed contact 11 at the N side of the first winding tap, and a first working state is kept; the second main through-flow switch MC2, the second vacuum tube V2 and the fourth vacuum tube V4 are kept disconnected; the winding tap N is switched on, and the load current flows out from the neutral point leading-out end through the change-over switch T, the first vacuum tube V1 and the third vacuum tube V3.
As shown in fig. 4, the first main through-current switch MC1 remains open, disconnecting the first vacuum tube V1, creating an arc, and the third vacuum tube V3 remains open; the moving contact of the change-over switch T is connected with the first fixed contact 11 at the N side of the first winding tap, and a first working state is kept; the second main through-flow switch MC2, the second vacuum tube V2 and the fourth vacuum tube V4 are kept disconnected; the winding tap N is switched on, and the load current flows out from the neutral point outlet end through the first transition resistor R1 and the third vacuum tube V3.
As shown in fig. 5, first main through-current switch MC1 remains open, first vacuum tube V1 remains open, and third vacuum tube V3 remains conductive; when the first vacuum tube V1 is completely extinguished, the first working state that the moving contact of the change-over switch T is connected with the first fixed contact 11 is moved to the third working state that the moving contact of the change-over switch is vacant; the second main through-flow switch MC2, the second vacuum tube V2 and the fourth vacuum tube V4 are kept disconnected; the winding tap N is switched on, and the load current flows out from the neutral point outlet end through the first transition resistor R1 and the third vacuum tube V3.
As shown in fig. 6, first main through-current switch MC1 remains open, first vacuum tube V1 remains open, and third vacuum tube V3 remains conductive; the moving contact of the change-over switch T is idle and is in a third working state; the second main through-flow switch MC2 and the second vacuum tube V2 are kept disconnected; the fourth vacuum tube V4 is conducted, the winding tap N and the winding tap N +1 are both switched on, and the load current INThe liquid flows out of the neutral point outlet end through a third vacuum tube V3, a first transition resistor R1, a fourth vacuum tube V4 and a second transition resistor R2 respectively; the transition circuit forms a bridge connection to generate an inter-stage circulating current IC(ii) a Current I flowing through the third vacuum tube V3V3＝IN/2+ICCurrent I flowing through fourth vacuum tube V4V4＝IN/2-IC(ii) a Wherein IC＝US/(R1+ R2), the USIs an on-load tap-changer stage voltage.
As shown in fig. 7, the first main through-current switch MC1 remains open, the first vacuum tube V1 remains open, disconnecting the third vacuum tube V3, creating an arc; the moving contact of the change-over switch T is idle and is in a third working state; the second main through-flow switch MC2 and the second vacuum tube V2 are kept disconnected; the fourth vacuum tube V4 keeps conducting, the winding tap N +1 is switched on, and the load current flows out from the neutral point leading-out end through the second transition resistor R2 and the fourth vacuum tube V4.
As shown in fig. 8, first main through-current switch MC1 remains open, and first vacuum tube V1 and third vacuum tube V3 remain open; the third working state that the movable contact of the change-over switch is vacant is moved to the second working state that the movable contact of the change-over switch is connected with the second fixed contact 12; the second main through-current switch MC2 and the second vacuum tube V2 are kept off, the fourth vacuum tube V4 is kept on, the winding tap N +1 is switched on, and the load current flows out from the neutral point leading-out end through the second transition resistor R2 and the fourth vacuum tube V4.
As shown in fig. 9, first main through-current switch MC1 remains open, and first vacuum tube V1 and third vacuum tube V3 remain open; the moving contact of the change-over switch is connected with the second fixed contact 12 to keep a second working state; the second main through-current switch MC2 keeps off, the fourth vacuum tube V4 keeps on, the second vacuum tube V2 is conducted, the winding tap N +1 is connected, and the load current flows out from the neutral point leading-out end through the second vacuum tube V2 and the fourth vacuum tube V4.
As shown in fig. 10, first main through-current switch MC1 remains open, and first vacuum tube V1 and third vacuum tube V3 remain open; the moving contact of the change-over switch is connected with the second fixed contact 12 to keep a second working state; the second vacuum tube V2 and the fourth vacuum tube V4 are kept conducted, the second main through-current switch MC2 is conducted, the winding tap N +1 is switched on, and the load current flows out from the neutral point leading-out end from the second winding tap N +1 through the second main through-current switch MC 2.
When the on-load tap-changer is switched from the winding tap N +1 to the winding tap N, the switching process is symmetrical to the switching process of the on-load tap-changer from the winding tap N to the winding tap N +1, and the specific voltage regulating method comprises the following steps:
the second main through-flow switch MC2, the second vacuum tube V2 and the fourth vacuum tube V4 are all in a conducting state; the moving contact of the change-over switch T is connected with the second fixed contact 12 at the side of the second winding tap N +1 and is in a second working state; the first main through-flow switch MC1, the first vacuum tube V1 and the third vacuum tube V3 are all in an off state; winding tap N +1 is turned on and load current flows from the second winding tap N +1 through second main through-flow switch MC2 from the neutral point outlet.
The second main through-current switch MC2 is turned off, and the second vacuum tube V2 and the fourth vacuum tube V4 are kept on; the moving contact of the change-over switch T is connected with the second fixed contact 12 at the side of the second winding tap N +1, and a second working state is kept; the first main through-flow switch MC1, the first vacuum tube V1, and the third vacuum tube V3 remain open; and a winding tap N +1 is switched on, and the load current flows out from a neutral point leading-out end through a change-over switch T, a second vacuum tube V2 and a fourth vacuum tube V4.
The second main through-flow switch MC2 is kept off, the second vacuum tube V2 is disconnected, an electric arc is generated, and the fourth vacuum tube V4 is kept on; a moving contact of the change-over switch T is connected with a second fixed contact 12 on the N +1 side of the second winding tap, and a second working state is kept; the first main through-flow switch MC1, the first vacuum tube V1, and the third vacuum tube V3 remain open; the winding tap N +1 is switched on, and the load current flows out from the neutral point leading-out end through a second transition resistor R2 and a fourth vacuum tube V4.
The second main through-flow switch MC2 remains open, the second vacuum tube V2 remains open, and the fourth vacuum tube V4 remains open; when the second vacuum tube V2 is completely extinguished, the second working state of the movable contact of the change-over switch T connected with the second fixed contact 12 is changed to the third working state of the change-over switch with the movable contact free; the first main through-flow switch MC1, the first vacuum tube V1, and the third vacuum tube V3 remain open; the winding tap N +1 is switched on, and the load current flows out from the neutral point leading-out end through a second transition resistor R2 and a fourth vacuum tube V4.
The second main through-flow switch MC2 remains open, the second vacuum tube V2 remains open, and the fourth vacuum tube V4 remains open; the moving contact of the change-over switch T is idle and is in a third working state; the first main through-flow switch MC1, the first vacuum tube V1 remain open; the third vacuum tube V3 is conducted, the winding tap N +1 and the winding tap N are both switched on, and the load current I isNThe neutral point is led out from the terminal through a fourth vacuum tube V4, a second transition resistor R2, a third vacuum tube V3 and a first transition resistor R1 respectively; the transition circuit forms a bridge connection to generate an inter-stage circulating current IC(ii) a Current I flowing through fourth vacuum tube V4V3＝IN/2+ICCurrent I flowing through the third vacuum tube V3V4＝IN/2-IC(ii) a In which IC＝US/(R1+ R2), the USIs an on-load tap-changer stage voltage.
The second main through-flow switch MC2 remains open, the second vacuum tube V2 remains open, and the fourth vacuum tube V4 is opened, creating an arc; the moving contact of the change-over switch T is idle and is in a third working state; the first main through-current switch MC1 and the first vacuum tube V1 remain open; the third vacuum tube V3 keeps conducting, the winding tap N is switched on, and the load current flows out from the neutral point leading-out end through the first transition resistor R1 and the third vacuum tube V3.
The second main through-flow switch MC2 is kept open, and the second vacuum tube V2 and the fourth vacuum tube V4 are kept open; the third working state that the movable contact of the change-over switch is vacant is moved to the first working state that the movable contact of the change-over switch is connected with the first fixed contact 11; the first main through-current switch MC1 and the first vacuum tube V1 are kept off, the third vacuum tube V3 is kept on, the winding tap N is switched on, and the load current flows out from the neutral point leading-out end through the first transition resistor R1 and the third vacuum tube V3.
The second main through-flow switch MC2 is kept open, and the second vacuum tube V2 and the fourth vacuum tube V4 are kept open; the moving contact of the change-over switch is connected with the first fixed contact 11 to keep a first working state; the first main through-flow switch MC1 keeps off, the third vacuum tube V3 keeps on, the first vacuum tube V1 is conducted, the winding tap N is connected, and the load current flows out from the neutral point leading-out end through the change-over switch T, the first vacuum tube V1 and the third vacuum tube V3.
The second main through-flow switch MC2 is kept open, and the second vacuum tube V2 and the fourth vacuum tube V4 are kept open; the moving contact of the change-over switch is connected with the first fixed contact 11 to keep a first working state; the first vacuum tube V1 and the third vacuum tube V3 are kept conducted, the first main through-current switch MC1 is conducted, the winding tap N is connected, and the load current flows out from the neutral point leading-out terminal through the first winding tap N and the first main through-current switch MC 1.
When the on-load tap changer is switched from N tap tapping of the winding to N +1 tap tapping of the winding, the transition circuit switching procedure is as shown in fig. 11;
when the on-load tap changer is switched from N +1 tap tapping to N tap tapping, the transition circuit switching procedure is as shown in fig. 12;
when the internal switch element in the single-isolation contact transition circuit of the on-load tap changer is a power electronic element (such as a thyristor or an insulated gate bipolar transistor) or a double-break vacuum tube with a controllable on-off function, the action time sequence and the voltage regulating method of the switch element are consistent, and further description is omitted.
In an embodiment of the invention, the switching tasks of the on-load tap changer transition circuit using vacuum tubes are as follows:
Figure BDA0003505452970000131
wherein, INIs the load current; u shapeSIs the voltage between poles of the on-load tap-changer; r1 and R2 are both transition resistances.
As shown in fig. 13, only the single-break vacuum tube in fig. 1 is replaced by a power electronic component with controllable on/off, other components are the same as those in fig. 1, the action sequence is the same, and the function and function are the same as those of the transition circuit shown in fig. 1, and are not described again.
As shown in fig. 14, only the single-break vacuum tube in fig. 1 is replaced by a double-break vacuum tube, other elements are the same as those in fig. 1, the action timing is the same, and the function and action are the same as those of the transition circuit shown in fig. 1, and are not described again.
The above description is only for the best mode of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.

Claims (8)

1. The single-isolation contact transition circuit of the on-load tap-changer is characterized by comprising a first main through-current switch, a second main through-current switch, a first switch element, a second switch element, a third switch element, a fourth switch element, a first transition resistor, a second transition resistor and a change-over switch;
the first end of the first main through-flow switch, the first end of the first transition resistor and the first fixed contact of the change-over switch are connected with a first winding tap of a transformer voltage-regulating winding; the first end of the second main through-flow switch, the first end of the second transition resistor and the second fixed contact of the change-over switch are connected with a second winding tap of a transformer voltage-regulating winding;
the first end of the first switch element and the first end of the second switch element are both connected with the moving contact of the change-over switch;
the second end of the first switching element and the first end of the third switching element are both connected with the second end of the first transition resistor;
a second end of the second switching element and a first end of the fourth switching element are both connected with a second end of the second transition resistor;
and the second end of the first main through-current switch, the second end of the second main through-current switch, the second end of the third switching element and the second end of the fourth switching element are connected with a neutral point leading-out end of the on-load tap-changer.
2. The on-load tap changer single isolated contact transition circuit of claim 1, wherein the first switch element, the second switch element, the third switch element and the fourth switch element are single-break vacuum tubes, double-break vacuum tubes or power electronic elements with controllable on-off function.
3. The on-load tap changer single-isolation contact transition circuit according to claim 2, wherein the power electronic component with controllable on-off function is a thyristor or an insulated gate bipolar transistor.
4. The on-load tap changer single isolating contact transition circuit according to claim 1, characterized in that the first switching element and the second switching element are used for breaking a load current; the third and fourth switching elements are used for switching off the inter-stage circulating current.
5. The on-load tap changer single-isolation-contact transition circuit of claim 1, wherein the first transition resistor and the second transition resistor are used for limiting inter-stage circulating current when a first winding tap and a second winding tap of a transformer regulating winding are bridged.
6. The on-load tap changer single isolating contact transition circuit according to claim 1, characterized in that when the first main through-current switch, the first switching element and the third switching element are all in a conducting state; the moving contact of the change-over switch is connected with the first fixed contact, and when the second main through-current switch, the second switch element and the fourth switch element are all in a disconnected state, the on-load tap-changer transition circuit can enable load current to flow out of the neutral point leading-out end from the first winding tap through the first main through-current switch; when the second main through-current switch, the second switching element and the fourth switching element are all in a conducting state; the movable contact of the change-over switch is connected with the second fixed contact; when the first main through-current switch, the first switch element and the third switch element are in an off state, the on-load tap changer transition circuit enables load current to flow out from a neutral point leading-out end from the second winding tap through the second main through-current switch.
7. A voltage regulation method based on the on-load tap-changer single-isolation contact transition circuit of claim 1, characterized by comprising the following steps:
the first main through-current switch, the first switch element and the third switch element are all in a conducting state, and a moving contact of the change-over switch is connected with the first fixed contact; the second main through-current switch, the second switching element and the fourth switching element are all in an off state;
disconnecting the first main through-flow switch, disconnecting the first switch element, leaving the movable contact of the change-over switch free, connecting the fourth switch element, disconnecting the third switch element, connecting the movable contact of the change-over switch with the second fixed contact, and connecting the second switch element; turning on the second main through-current switch;
the load current flows out from the neutral point leading-out end of the second winding tap through the second main through-flow switch, and the on-load tap-changer is switched from the first winding tap to the second winding tap.
8. A voltage regulation method based on the on-load tap-changer single-isolation contact transition circuit of claim 1, characterized by comprising the following steps:
the second main through-current switch, the second switching element and the fourth switching element are all in a conducting state; the movable contact of the change-over switch is connected with the second fixed contact; the first main through-current switch, the first switching element and the third switching element are all in an off state;
and disconnecting the second main through-current switch, disconnecting the second switch element, leaving the movable contact of the change-over switch free, connecting the third switch element, disconnecting the fourth switch element, connecting the movable contact of the change-over switch with the first fixed contact, connecting the first switch element, connecting the first main through-current switch, enabling the load current to flow out from the neutral point leading-out end through the first main through-current switch from the second winding tap, and switching the on-load tap-changer from the second winding tap to the first winding tap.
CN202210138467.7A 2022-02-15 2022-02-15 Single-isolation contact transition circuit of on-load tap-changer and voltage regulation method Pending CN114446622A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114944297A (en) * 2022-06-14 2022-08-26 常州博瑞电力自动化设备有限公司 Split type change-over switch of on-load tap-changer

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114944297A (en) * 2022-06-14 2022-08-26 常州博瑞电力自动化设备有限公司 Split type change-over switch of on-load tap-changer

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