CN114446619A - Single-resistor transition circuit for series load of on-load tap-changer and voltage regulation method - Google Patents

Single-resistor transition circuit for series load of on-load tap-changer and voltage regulation method Download PDF

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Publication number
CN114446619A
CN114446619A CN202210138035.6A CN202210138035A CN114446619A CN 114446619 A CN114446619 A CN 114446619A CN 202210138035 A CN202210138035 A CN 202210138035A CN 114446619 A CN114446619 A CN 114446619A
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China
Prior art keywords
switch
switching element
load
tap
main
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Inventor
闫晨光
刘张衡
丁凯
刘苏梅
李盛涛
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Xian Jiaotong University
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Xian Jiaotong University
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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
    • H01H2009/0061—Monitoring tap change switching devices

Abstract

A load single-resistor transition circuit with a series load of an on-load tap-changer and a voltage regulating method thereof comprise a first main through-current switch; the first end of the first main on-off switch is connected with the first end of the first switch element, the second end of the first main on-off switch is connected with the first end of the third switch element, the first end of the transition resistor, the first end of the fourth switch element and the first end of the second main through-current switch, the second end of the first switch element and the second end of the third switch element are connected with the first fixed contact of the change-over switch, the second end of the transition resistor is connected with the movable contact of the change-over switch, the second end of the second main through-current switch is connected with the first end of the second switch element, and the second end of the second switch element and the second end of the fourth switch element are connected with the second fixed contact of the change-over switch. Two load current breaking elements in the transition circuit break load currents in turn, the working loss degrees of the two circulating current breaking elements are consistent, and the reliability and the electrical service life of the on-load tap-changer are improved.

Description

Single-resistor transition circuit for series load of on-load tap-changer and voltage regulation method
Technical Field
The invention relates to the technical field of on-load tap-changers, in particular to a series load single-resistor 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 and changed to connect a plurality of taps led out from a transformer winding to change the effective turn ratio under the excitation or load state of the transformer, and realizes the regulation of output voltage under the condition of not interrupting load current. 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 equipped for 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-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-changer 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 adopts a transition circuit at the core. 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 and the like are formed according to the number of the contact fractures; the various combinations can form various 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 switching 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 on-load tap-changer switching process, the failure rate of the switch and the electrical service life.
The transition circuit of the on-load tap-changer comprises a load current vacuum circuit breaker only bearing the task of breaking load current and a circulating current vacuum circuit breaker only bearing the task of breaking circulating current between stages. In the actual extra-high voltage direct current transmission project, the load current flowing through the on-load tap changer of the converter transformer is about 500-600A, the interstage circulating current flowing through the transition resistor in the switching process is about 900-1000A, the circulating current of the circulating current vacuum circuit breaker which is switched on and off at a single time is obviously larger than the load current of the load current vacuum circuit breaker, and the switching tasks of the load current vacuum circuit breaker and the circulating current vacuum circuit breaker are unbalanced.
Disclosure of Invention
The invention provides a single-resistor transition circuit for series load of an on-load tap-changer and a voltage regulating method, which have the advantages of less transition resistor, dual configuration of a circulating current vacuum circuit breaker and a load current vacuum circuit breaker, alternate current cutting, symmetrical element distribution and symmetrical switching time sequence, and can improve the reliability and switching efficiency of the on-load tap-changer.
The purpose of the invention is realized by the following technical scheme:
a single-resistor transition circuit for series connection of an on-load tap-changer and a load comprises a first main through-current switch, a second main through-current switch, a first switch element and a second switch element which are used as loop current breaking elements, a third switch element and a fourth switch element which are used as load current switch elements, a change-over switch and a transition resistor;
the first end of the first main on-off switch is connected with the first end of the first switch element, the second end of the first main on-off switch is connected with the first end of the third switch element, the first end of the transition resistor, the first end of the fourth switch element and the first end of the second main through-current switch, the second end of the first switch element and the second end of the third switch element are connected with the first fixed contact of the change-over switch, the second end of the transition resistor is connected with the movable contact of the change-over switch, the second end of the second main through-current switch is connected with the first end of the second switch element, and the second end of the second switch element and the second end of the fourth switch element are connected with the second fixed contact of the change-over switch.
Furthermore, the switch also comprises a first isolating switch, and the second end of the third switch element is connected with the first static contact of the change-over switch through the first isolating switch.
Furthermore, the switch also comprises a second isolating switch, and the second end of the fourth switch element is connected with the second static contact of the change-over switch through the second isolating switch.
Further, the first switch element, the second switch element, the third switch element and the fourth switch element are single-break vacuum circuit breakers, double-break vacuum circuit breakers or power electronic elements with controllable on-off functions.
The second end of the second main through-current switch and the first end of the second switch element are connected with a tap of the second on-load tap-changer voltage-regulating winding, and the first end of the first main on-off switch and the first end of the first switch element are connected with a tap N of the first on-load tap-changer voltage-regulating winding.
The first end of the third switching element, the first end of the transition resistor, the first end of the fourth switching element, the second end of the first main through-current switch and the first end of the second main through-current switch are connected with a neutral point leading-out end of the on-load tap-changer.
Further, the third switching element is used for switching off the load current during switching from the first winding tap to the second winding tap, and the fourth switching element is used for switching off the load current during switching from the second winding tap to the first winding tap;
the first switching element is used for switching off the inter-stage circulating current when the transition circuit is bridged in the process of switching from the first winding tap N to the second winding tap, and the second switching element is used for switching off the inter-stage circulating current when the transition circuit is bridged in the process of switching from the second winding tap to the first winding tap;
the transition resistor is used for limiting inter-stage circulating current when the first winding tap and the second winding tap are bridged in the switching process of the transition circuit.
A voltage regulation method based on the on-load tap-changer series load single-resistor transition circuit comprises the following steps:
the first main on-off switch, the third switch element and the first switch element are in a conducting state, and the second main on-off switch, the fourth switch element and the second switch element are in a disconnecting state;
the first main on-off switch is switched off, the change-over switch is switched to the first stationary contact from the idle position, the second switch element is switched on, the third switch element is switched off, the fourth switch element is switched on, the first switch element is switched off, the change-over switch is switched to the idle position from the first stationary contact, the second main on-off switch is switched on, and the on-load tap-changer is switched to the voltage-regulating second winding tap from the voltage-regulating first winding tap.
According to the voltage regulating method based on the on-load tap-changer series load single-resistor transition circuit, a second main on-off switch is in a conducting state, a first main on-off switch is in a disconnecting state, a fourth switch element is in a conducting state, a third switch element is in a disconnecting state, a second switch element is in a conducting state, and a first switch element is in a disconnecting state;
and switching off the second main on-off switch, switching the change-over switch from the idle position to the second stationary contact, switching on the first switch element, switching off the fourth switch element, switching on the third switch element, switching off the second switch element, switching off the change-over switch from the second stationary contact to the idle position, switching on the first main on-off switch, and switching the on-load tap-changer from the voltage-regulating second winding tap to the voltage-regulating first winding tap.
Compared with the prior art, the invention has the following beneficial effects:
the invention provides a single-resistor transition circuit and a voltage regulating method for a series load of an on-load tap-changer, wherein two load current breaking elements exist in the transition circuit, and the load current is cut off in turn; the two circulation cut-off elements are used for cutting off the interstage circulation in the on-load switching process in turn, the switching program is symmetrical, the working loss degrees of the two circulation cut-off elements are consistent, the switching loss of the circulation cut-off elements is reduced, the switching capacity of the load current cut-off elements and the circulation cut-off elements can be balanced, and the electrical service life of the on-load tap-changer is greatly prolonged.
Furthermore, a first isolating switch and a second isolating switch are arranged in the circuit to break the circuit connection when the circuit breaker fails.
Drawings
Fig. 1 is a circuit diagram of a single-resistor transition circuit of an on-load tap-changer series load according to the present invention;
fig. 2 is a schematic diagram of the switching process of the on-load tap-changer series load single-resistor transition circuit of the present invention;
fig. 3 is a schematic diagram of the switching process of the on-load tap-changer series load single-resistor transition circuit of the present invention;
fig. 4 is a schematic diagram of the switching process of the on-load tap-changer series load single-resistor transition circuit of the present invention;
fig. 5 is a schematic diagram of the switching process of the on-load tap-changer series load single-resistor transition circuit of the present invention;
fig. 6 is a schematic diagram of the switching process of the on-load tap-changer series load single-resistor transition circuit of the present invention;
fig. 7 is a schematic diagram of the on-load tap-changer series load single resistance transition circuit switching process of the present invention;
fig. 8 is a schematic diagram of the switching process of the on-load tap-changer series load single-resistor transition circuit of the present invention;
fig. 9 is a schematic diagram of the switching process of the on-load tap-changer series load single-resistor transition circuit of the present invention;
fig. 10 is a schematic diagram showing the on-off of each switch in the single resistance transition circuit of the on-load tap changer series load of the present invention during the process of switching the load from winding tap N to winding tap N + 1;
fig. 11 is a schematic diagram showing the on-off of each switch in the single-resistor transition circuit of the on-load tap-changer series load of the present invention during the process of switching the load from winding tap N +1 to winding tap N;
fig. 12 is a circuit diagram of an on-load tap changer series load single resistance transition circuit with switching elements being power electronic components according to an embodiment of the present invention;
fig. 13 is a circuit diagram of an on-load tap changer series load single resistance transition circuit with a switching element of a dual break vacuum circuit breaker according to an embodiment of the present invention;
fig. 14 is a circuit diagram of an on-load tap-changer series load single-resistor transition circuit according to the present invention, with an example isolation switch added to the circuit, thereby achieving electrical isolation.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings.
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 derived by a person skilled in the art from the embodiments given herein without making any creative effort, 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.
Fig. 1 is a circuit diagram of a single-resistor transition circuit for the on-load tap-changer series load of the present invention. As shown in fig. 1, the present invention provides a single-resistor transition circuit for on-load tap-changer series load, in which two load current breaking elements exist to break load current in turn; the two circulation cut-off elements are used for cutting off the interstage circulation in the on-load switching process in turn, the switching program is symmetrical, the working loss degrees of the two circulation cut-off elements are consistent, the switching loss of the circulation cut-off elements is reduced, the switching capacity of the load current cut-off elements and the circulation cut-off elements can be balanced, and the electrical service life of the on-load tap-changer is greatly prolonged.
Specifically, the on-load tap-changer series load single-resistor transition circuit of the invention comprises: a first main circulating switch MC1 and a second main circulating switch MC2, a first switching element V1 and a second switching element V2 as circulating current breaking elements, a third switching element V3 and a fourth switching element V4 as load current switching elements, a changeover switch T, and a transition resistor R.
Wherein a first terminal of the first main on-off switch MC1 is connected to both the first terminal of the first switching element V1 and the voltage regulating first winding tap N, a second terminal of the first main on-off switch MC1 is connected to both the neutral point outlet, the first terminal of the third switching element V3, the first terminal of the transition resistor R, the first terminal of the fourth switching element V4, the first terminal of the second main through-current switch MC2 and the neutral point outlet, the second terminal of the first switching element V1 and the second terminal of the third switching element V3 are connected to the first stationary contact 11 of the change-over switch T, the second terminal of the transition resistor R is connected to the movable contact of the change-over switch T, the second terminal of the second main through-current switch MC2 is connected to the first terminal of the second switching element V2, the second terminal of the second switching element V2 and the second terminal of the fourth switching element V4 are connected to the second stationary contact 12 of the change-over switch T,
the first terminal of the third switching element V3, the first terminal of the transition resistor R, the first terminal of the fourth switching element V4, the second terminal of the first main through-current switch MC1 and the first terminal of the second main through-current switch MC2 are all connected to the neutral point outlet of the on-load tap-changer.
The second terminal of the second main current switch MC2 and the first terminal of the second switching element V2 are both connected to the on-load tap changer tap N + 1.
Preferably, the switch further comprises a first isolating switch Z1, and the second end of the third switch element V3 is connected to the first stationary contact 11 of the transfer switch T via a first isolating switch Z1.
Preferably, a second isolating switch Z2 is further included, and the second terminal of the fourth switching element V4 is connected to the second stationary contact 12 of the transfer switch T via a second isolating switch Z2.
Preferably, the first switching element V1, the first switching element V2, the third switching element V3 and the fourth switching element V4 are single-break vacuum circuit breakers, double-break vacuum circuit breakers or power electronic elements with controllable on-off functions.
Specifically, the change-over switch T has a first stationary contact 11 and a second stationary contact 12, and an actuating arm (moving contact), the first stationary contact 11 is connected to one end of a first switching element V1 and one end of a third switching element V3, the other end of the first switching element V1 is connected to a first winding tap N, the second stationary contact 12 is connected to one end of a circulating current vacuum circuit breaker V2 and one end of a fourth switching element V4, and the other end of the second switching element V2 is connected to a second winding tap N +1, the actuating arm is connected to either one of the first stationary contact 11 and the second stationary contact 12, and the actuating arm is also in an idle state and is connected to neither the first stationary contact 11 nor the second stationary contact 12.
When the main through-current switch MC1 is used for the on-load tap changer to regulate the long-term current carrying of the load current from the first winding tap N to the neutral point outlet end; the main through-current switch MC2 is used for long-term current carrying of a load current from a tap N +1 of a second winding of the on-load tap changer to a neutral point outlet.
The third switching element V3 is used to switch off the load current during switching from the first winding tap N to the second winding tap N +1, and the fourth switching element V4 is used to switch off the load current during switching from the second winding tap N +1 to the first winding tap N.
The first switching element V1 is used to break the inter-stage circulating current when the transition circuit is bridged during switching from the first winding tap N to the second winding tap N +1, and the second switching element V2 is used to break the inter-stage circulating current when the transition circuit is bridged during switching from the second winding tap N +1 to the first winding tap N.
The transition resistor R is used for limiting inter-stage circulating current when the first winding tap N and the second winding tap N +1 are bridged in the switching process of the transition circuit.
In the on-load tap-changer, an additional isolating switch can be added at any position to play a role in electrical isolation.
Specifically, the working process and principle of the on-load tap-changer series load single-resistor transition circuit of the present invention are described in detail below with reference to the accompanying drawings: when the on-load tap-changer gear is at the first winding tap N, as shown in fig. 1, when the first main on-off switch MC1 is in an on state, the second main on-off switch MC2 is in an off state, the third switch element V3 is in an on state, the fourth switch element V4 is in an off state, the first switch element V1 is in an on state, the second switch element V2 is in an off state, and the transfer switch T has an open arm, the on-load tap-changer transition circuit enables a load current to flow out from the neutral point outlet through the first main on-off switch MC 1.
When the on-load tap-changer is switched from the voltage-regulating first winding tap N to the voltage-regulating second winding tap N +1, taking the first switching element V1, the second switching element V2, the third switching element V3 and the fourth switching element V4 as an example of a single-break vacuum circuit breaker, the operation steps of the transition circuit include:
as shown in FIG. 2, first main through-flow switch MC1 is turned off and load current I is drawnNFlows through the first switching element V1 and the third switching element V3 and flows out from the neutral point.
As shown in fig. 3, the operating arm of the transfer switch T is transferred from the neutral position to the first stationary contact 11.
As shown in fig. 4, the second switching element V2 is turned on.
As shown in fig. 5, the third switching element V3 is turned off to cut off the load current INThe third switching element V3 generates an arc, and after the arc is extinguished, the load current INFlows out from a neutral point sequentially through a first switching element V1, a first fixed contact 11 of a change-over switch T and a transition resistor R, and the recovery voltage U at the two ends of a third switching element V3V1＝IN×R。
After the third switching element V3 has completely extinguished, as shown in fig. 6, the fourth switching element V4 is turned on,the transition circuit is connected with the first winding tap N and the second winding tap N +1 at the same time to form bridging connection and generate inter-stage circulation IC＝USand/R, when the load current is transferred to the second winding tap N +1 to flow out, the load current flows from the neutral point through the second switching element V2 and the fourth switching element V4, and the current in the first switching element V1 is inter-stage circulating current IC。
As shown in fig. 7, the first switching element V1 is turned off to cut off inter-stage circulating current, an arc is generated, and a load current flows from a neutral point through the second switching element V2 and the fourth switching element V4, and the recovery voltage across the first switching element V1 is UV1＝US。
After the first switching element V1 is fully quenched, the transfer switch T arm is switched from the first stationary contact 11 to the neutral position, and the load current flows through the loop second switching element V2 and the loop fourth switching element V4 from the neutral point, as shown in fig. 8.
As shown in FIG. 9, second main through-current switch MC2 is closed and load current I is drawnNFlows out through the second main circulating switch MC2 and is connected with the second switching element V2 and the fourth switching element V4 in parallel, and the switching operation from the voltage-regulating first winding tap N to the voltage-regulating second winding tap N +1 is finished.
The second main on-off switch MC2 is in a conducting state, the first main on-off switch MC1 is in an off state, the fourth switching element V4 is in an on state, the third switching element V3 is in an off state, the second switching element V2 is in an on state, the first switching element V1 is in an off state, the transfer switch T is idle, and the on-load tap-changer transition circuit enables the load current to flow out from the neutral point outlet through the second main through-current switch MC 2.
When the on-load tap-changer is switched from the voltage-regulating second winding tap N +1 to the voltage-regulating first winding tap N, the first switching element V1, the second switching element V2, the third switching element V3 and the fourth switching element V4 are described by taking a single-break vacuum circuit breaker as an example, and the operation steps of the transition circuit include:
second main circulating switch MC2 is turned off and load current I is suppliedNFlows through the second switch element V2 and the fourth switch element V4Discharging the sexual points;
the action arm of the transfer switch T is transferred from the idle position to the second fixed contact 12;
turning on the first switching element V1;
breaking the load current vacuum interrupter V4 to cut off the load current INV4 arc, after the arc is extinguished, the load current INFlows out from a neutral point through a circulating current vacuum circuit breaker V2, a second stationary contact 12 of a change-over switch T and a transition resistor R in sequence, and the recovery voltage U at the two ends of the load current vacuum circuit breaker V4V1＝IN×R；
After the fourth switching element V4 is completely extinguished, the third switching element V3 is conducted, the transition circuit is simultaneously connected with the first winding tap N and the second winding tap N +1 to form bridging, and interstage circulating current I is generatedC＝USand/R, when the load current is transferred to the first winding tap N to flow out, the load current flows from the neutral point through the first switching element V1 and the third switching element V3, and the current in the second switching element V2 is inter-stage circulating current IC；
The second switching element V2 is opened to cut off inter-stage circulation current and generate electric arc, the load current flows from the neutral point through the first switching element V1 and the third switching element V3, and the recovery voltage at two ends of the second switching element V2 is UV2＝US；
After the second switching element V2 is completely extinguished, the action arm of the transfer switch T is switched from the second stationary contact 12 to the neutral position, and the load current flows through the first switching element V1 and the third switching element V3 from the neutral point;
the first main through-flow switch MC1 is closed and the load current I isNFlows out through the first main circulating switch MC1, and is connected in parallel with the first switching element V1 and the third switching element V3, and the switching operation from the voltage regulation second winding tap N +1 to the voltage regulation first winding tap N is completed.
When the internal switch elements in the on-load tap changer series load single-resistor transition circuit are power electronic elements with controllable on-off function and double-break vacuum circuit breakers, the action time sequence of the switch elements is consistent with the voltage regulating method, and the description is omitted.
When the on-load tap changer switches from the first winding tap N to the second winding tap N +1, the transition circuit switching procedure is as shown in fig. 10.
When the on-load tap changer switches from the second winding tap N +1 tap to the first winding tap N tap, the transition circuit switching procedure is as shown in fig. 11.
In an embodiment of the invention, the switching tasks of the on-load tap-changer transition circuit are as follows:
TABLE 1N to N +1 switching task for on-load tap-changer transition circuit
Figure BDA0003505191100000111
Wherein, INIs the load current; u shapeSIs the voltage between the on-load tap-changer stages; r is transition resistance.
Referring to fig. 12, which is a circuit diagram of a single-resistance transition circuit in series connection with a load of an on-load tap changer in which a switching element is a power electronic element according to an embodiment of the present invention, only the single-break vacuum circuit breaker in fig. 1 is replaced with a power electronic element with controllable on/off, other elements are the same as those in fig. 1, the operation timing is the same, and the function and function are also the same as those of the transition circuit shown in fig. 1, and are not repeated herein.
Referring to fig. 13, a circuit diagram of an on-load tap changer series load single resistance transition circuit with a switching element of a dual-break vacuum circuit breaker according to an embodiment of the present invention is shown; only the single-break vacuum circuit breaker in fig. 1 is replaced by a double-break vacuum circuit breaker, other elements are the same as those in fig. 1, the action time sequence is consistent, and the function and action are also the same as those of the transition circuit shown in fig. 1, and the description is omitted here.
Referring to fig. 14, a circuit diagram of an on-load tap changer series load single-resistor transition circuit according to the present invention is shown, in which an example isolation switch is added to the circuit, thereby performing an electrical isolation function; the first isolating switch Z1 and the second isolating switch Z2 are added in the circuit to break the circuit connection when the circuit breaker fails, and the same effect is achieved by adding the isolating switches at the rest positions, and the description is omitted.
In one embodiment of the present invention, a voltage regulation method for a single-resistor transition circuit of a series load of an on-load tap-changer is provided, which includes the following steps: taking a single-break vacuum circuit breaker as an example, the transition circuit comprises a first main through-current switch MC1, a second main through-current switch MC2, a third switching element V3, a fourth switching element V4, a first switching element V1, a second switching element V2, a transfer switch T, and a transition resistor R, and the method comprises the following steps:
the on-load tap-changer switches from the tap N of the first winding of voltage regulation to the tap N +1 of the second winding of voltage regulation, including:
the first main on-off switch MC1 is in an on state, the second main on-off switch MC2 is in an off state, the third switch element V3 is in an on state, the fourth switch element V4 is in an off state, the first switch element V1 is in an on state, the second switch element V2 is in an off state, and the action arm of the change-over switch T is idle;
the first main on-off switch MC1 is turned off;
switching the changeover switch T from the neutral position to the first stationary contact 11;
turning on the second switching element V2;
opening the third switching element V3, generating an arc;
after the third switching element V3 is completely extinguished, turning on the fourth switching element V4;
the first switching element V1 is opened, and an arc is generated;
after the first switching element V1 is completely quenched, the changeover switch T is switched from the first stationary contact 11 to the neutral position;
the second main on/off switch MC2 is turned on.
The on-load tap-changer switches from the tap N +1 of the second winding of the voltage regulation to the tap N of the first winding of the voltage regulation, including:
the second main on-off switch MC2 is in an on state, the first main on-off switch MC1 is in an off state, the fourth switching element V4 is in an on state, the third switching element V3 is in an off state, the second switching element V2 is in an on state, the first switching element V1 is in an off state, and the action arm of the change-over switch T is idle;
the second main on-off switch MC2 is turned off;
switching the changeover switch T from the neutral position to the second stationary contact 12;
turning on the first switching element V1;
the fourth switching element V4 is switched off, generating an arc;
after the fourth switching element V4 is completely extinguished, turning on the third switching element V3;
the second switching element V2 is opened, and an arc is generated;
after the second switching element V2 has completely extinguished, the changeover switch T is switched from the second stationary contact 12 to the neutral position;
the first main on-off switch MC1 is turned on.
When the on-load tap-changer is connected with the internal switch element in the single-resistor load transition circuit in series, the internal switch element has the function of controlling on-off and is a power electronic element with the function of controlling on-off and a double-break vacuum circuit breaker, the action time sequence of the switch element is consistent with the voltage regulating method.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.

Claims (9)

1. An on-load tap changer series load single-resistance transition circuit is characterized by comprising a first main through-current switch (MC1) and a second main through-current switch (MC2), a first switch element (V1) and a second switch element (V2) which are used as circulating current breaking elements, a third switch element (V3) and a fourth switch element (V4) which are used as load current switch elements, a change-over switch (T) and a transition resistor (R);
wherein a first terminal of the first main on-off switch (MC1) is connected to a first terminal of the first switching element (V1), a second terminal of the first main on-off switch (MC1) is connected to a first terminal of the third switching element (V3) and a first terminal of the transition resistor (R), the first end of the fourth switching element (V4) and the first end of the second main current switch (MC2) are connected to each other, the second end of the first switching element (V1) and the second end of the third switching element (V3) are connected to the first fixed contact (11) of the changeover switch (T), the second end of the transition resistor (R) is connected to the movable contact of the changeover switch (T), the second end of the second main current switch (MC2) is connected to the first end of the second switching element (V2), and the second end of the second switching element (V2) and the second end of the fourth switching element (V4) are connected to the second fixed contact (12) of the changeover switch (T).
2. An on-load tap changer series load single resistance transition circuit according to claim 1, characterized in that it further comprises a first disconnector (Z1), and the second end of the third switching element (V3) is connected to the first stationary contact (11) of the change-over switch (T) via the first disconnector (Z1).
3. An on-load tap changer series load single resistance transition circuit according to claim 1 or 2, characterized in that it further comprises a second disconnector (Z2), and the second terminal of the fourth switching element (V4) is connected to the second stationary contact (12) of the diverter switch (T) via a second disconnector (Z2).
4. An on-load tap-changer series load single-resistor transition circuit according to claim 1, characterized in that the first switching element (V1), the first switching element (V2), the third switching element (V3) and the fourth switching element (V4) are single-break vacuum circuit breakers, double-break vacuum circuit breakers or power electronic elements with controllable switching function.
5. An on-load tap-changer series load single-resistance transition circuit according to claim 1, characterized by further comprising an on-load tap-changer voltage-regulating winding, wherein the second end of the second main through-current switch (MC2) and the first end of the second switching element (V2) are both connected to the on-load tap-changer voltage-regulating second winding tap (N +1), and the first end of the first main on-off switch (MC1) and the first end of the first switching element (V1) are both connected to the on-load tap-changer voltage-regulating first winding tap N.
6. An on-load tap changer series load single resistance transition circuit according to claim 1, further comprising an on-load tap changer, wherein the first terminal of the third switching element (V3), the first terminal of the transition resistor (R), the first terminal of the fourth switching element (V4), the second terminal of the first main through-current switch (MC1) and the first terminal of the second main through-current switch (MC2) are all connected to the neutral point outlet of the on-load tap changer.
7. An on-load tap-changer series load single-resistor transition circuit according to claim 1, characterized in that the third switching element (V3) is used to switch off the load current during switching from the first winding tap (N) to the second winding tap (N +1), and the third switching element (V4) is used to switch off the load current during switching from the second winding tap (N +1) to the first winding tap (N);
the first switching element (V1) is used for switching off inter-stage circulation when the transition circuit is bridged during switching from the first winding tap N to the second winding tap (N +1), and the second switching element (V2) is used for switching off inter-stage circulation when the transition circuit is bridged during switching from the second winding tap (N +1) to the first winding tap (N);
the transition resistor (R) is used for limiting inter-stage circulating current when the first winding tap (N) and the second winding tap (N +1) are bridged in the transition circuit switching process.
8. A voltage regulation method based on the on-load tap-changer series load single-resistance transition circuit of claim 1, characterized by comprising the following steps:
the first main on-off switch (MC1), the third switching element (V3), and the first switching element (V1) are placed in an on state, and the second main on-off switch (MC2), the fourth switching element (V4), and the second switching element (V2) are placed in an off state;
the first main on-off switch (MC1) is turned off, the changeover switch (T) is switched from an idle state to the first stationary contact (11), the second switch element (V2) is turned on, the third switch element (V3) is turned off, the fourth switch element (V4) is turned on, the first switch element (V1) is turned off, the changeover switch (T) is switched from the first stationary contact (11) to an idle state, the second main on-off switch (MC2) is turned on, and the on-load tap changer is switched from the voltage-regulating first winding tap (N) to the voltage-regulating second winding tap (N + 1).
9. A voltage regulation method based on the on-load tap-changer series load single-resistor transition circuit of claim 1, characterized in that the second main on-off switch (MC2) is in a conducting state, the first main on-off switch (MC1) is in an off state, the fourth switching element (V4) is in a conducting state, the third switching element (V3) is in an off state, the second switching element (V2) is in a conducting state, and the first switching element (V1) is in an off state;
the second main on-off switch (MC2) is turned off, the changeover switch (T) is switched from the idle position to the second stationary contact (12), the first switch element (V1) is turned on, the fourth switch element (V4) is turned off, the third switch element (V3) is turned on, the second switch element (V2) is turned off, the changeover switch (T) is switched from the second stationary contact (12) to the idle position, the first main on-off switch (MC1) is turned on, and the on-load tap changer is switched from the voltage-regulating second winding tap (N +1) to the voltage-regulating first winding tap (N).
CN202210138035.6A 2022-02-15 2022-02-15 Single-resistor transition circuit for series load of on-load tap-changer and voltage regulation method Pending CN114446619A (en)

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CN202210138035.6A CN114446619A (en) 2022-02-15 2022-02-15 Single-resistor transition circuit for series load of on-load tap-changer and voltage regulation method

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Application Number Priority Date Filing Date Title
CN202210138035.6A CN114446619A (en) 2022-02-15 2022-02-15 Single-resistor transition circuit for series load of on-load tap-changer and voltage regulation method

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CN114446619A true CN114446619A (en) 2022-05-06

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