CN114446619A - A kind of on-load tap changer series load single resistance transition circuit and voltage regulation method - Google Patents

Abstract

An on-load tap changer series-loaded single-resistor transition circuit and a voltage regulation method, comprising a first main current on-off switch; a first end of the first main on-off switch is connected with a first end of a first switching element, and the first main The second end of the on-off switch is connected to the first end of the third switching element, the first end of the transition resistor, the first end of the fourth switching element and the first end of the second main current-passing switch, and the first switching element The second end of the transition resistor and the second end of the third switch element are connected to the first static contact of the transfer switch, the second end of the transition resistor is connected to the moving contact of the transfer switch, and the second end of the second main current switch The terminal is connected to the first terminal of the second switch element, and the second terminal of the second switch element and the second terminal of the fourth switch element are both connected to the second stationary contact of the transfer switch. The two load current breaking elements in the transition circuit alternately break the load current, and the working loss of the two circulating current breaking elements is the same, which improves the reliability and electrical life of the on-load tap-changer.

Description

A kind of on-load tap changer series load single resistance transition circuit and voltage regulation method

technical field

The invention relates to the technical field of on-load tap changers, in particular to an on-load tap changer series-loaded single-resistor transition circuit and a voltage regulation method.

Background technique

The on-load tap-changer is a key component inside the power transformer. It can operate under the transformer excitation or load state, change the effective turns ratio by changing several taps drawn from the transformer winding, and adjust the output without interrupting the load current. Voltage. The on-load tap-changer has a wide range of applications, especially in the converter transformer of the UHV DC transmission project to ensure the rated firing angle of the converter during normal operation. Most of the on-load tap-changers equipped with early power transformers adopted the principle of high-speed resistance switching, relying on copper-tungsten arc contacts for load switching. This type of oil-immersed non-on-load tap-changer switches frequently, the arc contact burns relatively seriously, and the oil is carbonized and polluted quickly, thus increasing the daily maintenance and regular maintenance workload for the power supply department. The vacuum type on-load tap-changer mainly uses the vacuum tube to realize the arc extinguishing, which avoids the carbonization and pollution of the oil caused by the arc extinguishing in the oil; The re-condensation of the compound, the contact burning and corrosion can be reduced to a minimum. The power electronic on-load tap-changer replaces the vacuum tube with power electronic components to realize the arc-free operation during the on-load switching process.

The on-load tap-changer consists of a diverter switch, a tap selector and an electric mechanism. Among them, the switch has an independent oil chamber, which is the key component for the on-load switching of the tap changer. The core of the switch is the use of a transition circuit. Vacuum on-load tap-changers can be divided into single-contact circuit, double-contact circuit, three-contact circuit and four-contact circuit according to the number of vacuum tubes; according to the number of transition resistances, there are single resistance, double resistance There are two types of transition; according to the number of contact fractures, there are single fracture, double fracture, etc. The above combinations can form various transition circuits of vacuum on-load tap-changers. The switching elements in the transition circuit can be single-break vacuum contacts, double-break vacuum contacts, power electronic components, etc.; different transition circuits have different switching sequences in order to realize on-load switching and voltage regulation, and the switching tasks of each switching element will also be different. The topology of the transition circuit has a significant impact on the reliability of the on-load tap-changer switching process, as well as on the failure rate and electrical life of the switch.

In the transition circuit of the on-load tap-changer, there are load current vacuum circuit breakers that only undertake the task of breaking the load current and circulating current vacuum circuit breakers that only undertake the task of breaking the circulating current between stages. In the actual UHVDC transmission project, the load current flowing through the on-load tap-changer of the converter transformer is about 500-600A, and the interstage circulating current flowing through the transition resistance during the switching process is about 900-1000A. The circulating current of the secondary breaking is obviously larger than the load current of the load current vacuum circuit breaker, which leads to the imbalance of the breaking tasks of the load current vacuum circuit breaker and the circulating current vacuum circuit breaker.

SUMMARY OF THE INVENTION

The invention proposes an on-load tap-changer series load single-resistance transition circuit and a voltage regulation method, which have the advantages of less transition resistance, dual configuration of circulating current vacuum circuit breaker and load current vacuum circuit breaker, alternating current cutoff, and symmetrical distribution of components , the switching sequence is symmetrical, which can improve the reliability and switching efficiency of the on-load tap-changer.

The object of the present invention is achieved through the following technical solutions:

An on-load tap changer series load single-resistor transition circuit, comprising a first main current switch and a second main current switch, a first switch element and a second switch element as circulating current breaking elements, as load current switch elements The third switching element and the fourth switching element, the transfer switch and the transition resistance;

Wherein, the first end of the first main on-off switch is connected with the first end of the first switching element, the second end of the first main on-off switch is connected with the first end of the third switching element, the first end of the transition resistance, The first end of the fourth switch element is connected to the first end of the second main current switch, and the second end of the first switch element and the second end of the third switch element are both connected to the first static contact of the transfer switch. connected, the second end of the transition resistor is connected to the moving contact of the transfer switch, the second end of the second main current switch is connected to the first end of the second switch element, the second end of the second switch element is connected to the fourth switch The second ends of the elements are all connected with the second stationary contact of the transfer switch.

Further, it also includes a first isolating switch, and the second end of the third switching element is connected to the first static contact of the transfer switch via the first isolating switch.

Further, a second isolating switch is also included, and the second end of the fourth switching element is connected to the second static contact of the transfer switch via the second isolating switch.

Further, the first switching element, the second switching element, the third switching element and the fourth switching element are single-break vacuum circuit breakers, double-break vacuum circuit breakers or power electronic components with controllable on-off functions.

Further, it also includes a voltage regulating winding of the on-load tap-changer, the second end of the second main current switch and the first end of the second switching element are both connected to the tap of the second winding of the on-load tap-changer voltage regulating, the first The first end of the main on-off switch and the first end of the first switching element are both connected to the tap N of the first winding for voltage regulation of the on-load tap changer.

Further, it also includes an on-load tap changer, 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 current switch and the second main The first ends of the current-passing switch are all connected with the neutral point lead-out end of the on-load tap changer.

Further, the third switching element is used to interrupt the load current during the process of switching from the first winding tap to the second winding tap, and the fourth switching element is used to interrupt the load current during the process of switching from the second winding tap to the first winding tap. ;

The first switching element is used for switching off the interstage circulating current when the transition circuit is bridged during the process of switching from the first winding tap N to the second winding tap, and the second switching element is used for switching from the second winding tap to the first winding tap. , the inter-stage circulating current when the transition circuit is bridged;

The transition resistance is used to limit the inter-stage circulating current when the first winding tap and the second winding tap are bridged during the switching process of the transition circuit.

A voltage regulation method based on the above-mentioned on-load tap-changer series load single-resistance transition circuit, comprising the following steps:

The first main on-off switch, the third switch element and the first switch element are placed in an on state, and the second main on-off switch, the fourth switch element and the second switch element are placed in an off state;

Turn off the first main on-off switch, switch the transfer switch from vacant to the first static contact, turn on the second switching element, turn off the third switching element, turn on the fourth switching element, and turn the first switching element on. The switching element is turned off, the transfer switch is switched from the first static contact to the idle, the second main on-off switch is turned on, and the on-load tap changer is switched from the tap of the first winding of the voltage regulation to the tap of the second winding of the voltage regulation.

A voltage regulation method based on the above-mentioned on-load tap changer series load single-resistance transition circuit, the second main on-off switch is in an on state, the first main on-off switch is in an off state, and the fourth switch element is in a conductive state state, the third switch element is in the off state, the second switch element is in the on state, and the first switch element is in the off state;

Turn off the second main on-off switch, switch the transfer switch from vacant to the second static contact, turn on the first switching element, turn off the fourth switching element, turn on the third switching element, and turn the second switching element on. The switching element is turned off, the transfer switch is switched from the second static contact to the vacant position, the first main on-off switch is turned on, and the on-load tap changer is switched from the tap of the second winding of the voltage regulation to the tap of the first winding of the voltage regulation.

Compared with the prior art, the present invention has the following beneficial effects:

The invention provides an on-load tap changer series load single-resistance transition circuit and a voltage regulation method. There are two load current interrupting elements in the transition circuit, and the load current is interrupted in turn; there are two circulating current interrupting elements, which alternately open Inter-stage circulating current is interrupted in the process of on-load switching, the switching procedure is symmetrical, the working loss of the two circulating current interrupting elements is the same, the switching loss of the circulating current interrupting element is reduced, and the switching of the load current interrupting element and the circulating current interrupting element can be balanced. capacity, greatly improving the electrical life of the on-load tap-changer.

Further, a first isolating switch and a second isolating switch are arranged in the circuit, so as to disconnect the circuit when the circuit breaker fails.

Description of drawings

Fig. 1 is the circuit diagram of the on-load tap changer series load single resistance transition circuit of the present invention;

Fig. 2 is the schematic diagram of the switching process of the on-load tap changer series load single-resistance transition circuit of the present invention;

3 is a schematic diagram of the switching process of the on-load tap-changer series load single-resistance transition circuit of the present invention;

4 is a schematic diagram of a switching process of an on-load tap-changer connected in series with a single-resistor transition circuit of the present invention;

5 is a schematic diagram of the switching process of the on-load tap changer series load single-resistance transition circuit of the present invention;

6 is a schematic diagram of the switching process of the on-load tap changer series load single-resistance transition circuit of the present invention;

7 is a schematic diagram of a switching process of an on-load tap-changer connected in series with a single-resistor transition circuit of the present invention;

8 is a schematic diagram of a switching process of an on-load tap changer connected in series with a single-resistor transition circuit of the present invention;

9 is a schematic diagram of a switching process of an on-load tap-changer connected in series with a single-resistor transition circuit of the present invention;

10 is a schematic diagram of the on-off of each switch in the on-load tap-changer series load single-resistance transition circuit of the present invention during the process of switching the load from the winding tap N to the winding tap N+1;

11 is a schematic diagram of the on-off of each switch in the on-load tap-changer series load single-resistance transition circuit of the present invention during the process of switching the load from the winding tap N+1 to the winding tap N;

12 is a circuit diagram of an on-load tap-changer series-loaded single-resistor transition circuit in which the switching element is a power electronic element according to an embodiment of the present invention;

13 is a circuit diagram of an on-load tap-changer series-loaded single-resistance transition circuit in which the switching element is a double-break vacuum circuit breaker according to an embodiment of the present invention;

14 is a circuit diagram of an on-load tap-changer connected in series with a load single-resistance transition circuit according to the present invention, and an example isolation switch is added to the circuit to achieve electrical isolation.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings.

In order to make those skilled in the art better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only Embodiments are part of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts 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 the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific sequence or sequence. It is to be understood that the data so used may be interchanged under appropriate circumstances such that the embodiments of the invention described herein can be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having", and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those expressly listed Rather, those steps or units may include other steps or units not expressly listed or inherent to these processes, methods, products or devices.

FIG. 1 is a circuit diagram of an on-load tap changer connected in series with a single-resistor transition circuit of the present invention. As shown in FIG. 1 , the present invention provides an on-load tap-changer series load single-resistance transition circuit. There are two load current interrupting elements in the transition circuit, and the load current is interrupted in turn; there are two circulating current interrupting elements, The inter-stage circulating current in the on-load switching process is alternately interrupted, the switching procedure is symmetrical, the working loss of the two circulating current interrupting elements is the same, the switching loss of the circulating current interrupting element is reduced, and the load current interrupting element and the circulating current interrupting element can be balanced. The switching capacity of the switch greatly improves the electrical life of the on-load tap-changer.

Specifically, the on-load tap-changer series load single-resistance transition circuit of the present invention includes: a first main current switch MC1 and a second main current switch MC2, and a first switching element V1 and a second switching element V1 serving as circulating current breaking elements The switching element V2, the third switching element V3 and the fourth switching element V4 as load current switching elements, the changeover switch T and the transition resistance R.

The first end of the first main on-off switch MC1 is connected to the first end of the first switching element V1 and the voltage regulating first winding tap N, and the second end of the first main on-off switch MC1 is connected to the neutral point. terminal, the first terminal of the third switching element V3, the first terminal of the transition resistance R, the first terminal of the fourth switching element V4, the first terminal of the second main current switch MC2 and the neutral point lead terminal are all connected, The second end of the first switching element V1 and the second end of the third switching element V3 are both connected to the first static contact 11 of the transfer switch T, and the second end of the transition resistor R is connected to the moving contact of the transfer switch T. , the second end of the second main current switch MC2 is connected to the first end of the second switch element V2, the second end of the second switch element V2 and the second end of the fourth switch element V4 are both connected to the first end of the transfer switch T The two static contacts 12 are connected,

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 current switch MC1, and the first terminal of the second main current switch MC2 The terminals are all connected to the neutral point terminal of the on-load tap-changer.

The second end of the second main 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.

Preferably, a first isolating switch Z1 is also included, and the second end of the third switching element V3 is connected to the first stationary contact 11 of the transfer switch T via the first isolating switch Z1.

Preferably, a second isolating switch Z2 is also included, and the second end of the fourth switching element V4 is connected to the second stationary contact 12 of the transfer switch T via the 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 components with controllable on-off functions.

Specifically, the transfer switch T has a first stationary contact 11, a second stationary contact 12 and an action arm (moving contact), the first stationary contact 11 is connected to one end of the first switch element V1 and the One end of the third switching element V3, the other end of the first switching element V1 regulates the first winding tap N, the second stationary contact 12 is connected to one end of the circulating current vacuum circuit breaker V2 and one end of the fourth switching element V4, the first The other end of the two switching elements V2 regulates the second winding tap N+1, the action arm is connected to any one of the first static contact 11 and the second static contact 12, and the action arm can also be in an idle state, neither connected The first stationary contact 11 is also not connected to the second stationary contact 12 .

When in use, the first main current switch MC1 is used for the on-load tap changer to adjust the load current from the tap N of the first winding to the long-term current carrying of the load current from the neutral point terminal; the main current switch MC2 is used for the on-load tap changer. Connect the switch to adjust the load current from the second winding tap N+1 to the neutral point lead-out end for long-term current carrying.

The third switching element V3 is used for switching 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 for switching from the second winding tap N+1 to the first winding tap The load current is interrupted during the N process.

The first switching element V1 is used to switch off the interstage circulating current when the transition circuit is bridged during the process of switching from the first winding tap N to the second winding tap N+1, and the second switching element V2 is used to tap the N+ from the second winding tap 1 In the process of switching to the first winding tap N, the inter-stage circulating current when the transition circuit is bridged is disconnected.

The transition resistance R is used to limit the inter-stage circulating current when the first winding tap N and the second winding tap N+1 are bridged during 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 the role of electrical isolation.

Specifically, the working process and principle of the on-load tap-changer series-loaded single-resistance transition circuit of the present invention will be described in detail below with reference to the accompanying drawings: when the on-load tap-changer is in 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 switching element V3 is in an on state, the fourth switching element V4 is in an off state, and the first switching element V1 In the on state, the second switch element V2 is in the off state, the action arm of the transfer switch T is vacant, and the on-load tap changer transition circuit can make the load current flow out from the neutral point terminal through the first main on-off switch MC1.

When the on-load tap-changer switches from the voltage regulating first winding tap N to the voltage regulating second winding tap N+1, the first switching element V1, the second switching element V2, the third switching element V3 and the fourth switching element V4 Taking the single-break vacuum circuit breaker as an example, the operation steps of the transition circuit include:

As shown in FIG. 2 , the first main current switch MC1 is turned off, and the load current _IN flows 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 action arm of the change-over switch T is changed over from idle 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, the load current IN is _cut off, and the third switching element V3 generates an arc. After the arc is extinguished, the load current IN _passes through the first switching element V1 and the first switching switch T in sequence. The static contact 11 and the transition resistance R flow out from the neutral point, and the recovery voltage at both ends of the third switching element V3 is U _{V1 =IN} ×R.

As shown in Fig. 6, after the arc is completely extinguished in the third switching element V3, the fourth switching element V4 is turned on, and the transition circuit connects the first winding tap N and the second winding tap N+1 at the same time to form a bridge and generate a stage The circulating current I _C =U _S /R, the load current is transferred to the second winding tap N+1 and flows out, the load current flows through the second switching element V2 and the fourth switching element V4 and flows out from the neutral point, and the first switching element V1 The current in is the interstage circulating current I _C .

As shown in FIG. 7 , the first switching element V1 is turned off, the inter-stage circulating current is cut off, and an arc is generated. The load current flows through the second switching element V2 and the fourth switching element V4 and flows out from the neutral point. The first switching element V1 has two The recovery voltage of the terminal is U _V1 =U _S .

As shown in FIG. 8 , after the arc is completely extinguished in the first switching element V1, the action arm of the transfer switch T is switched from the first stationary contact 11 to empty, and the load current flows through the second switching element V2 and the fourth switching element V4 flows from the neutral point.

As shown in FIG. 9 , the second main current switch MC2 is closed, the load current I _N flows through the second main current switch MC2 and flows out, and the second switching element V2 and the fourth switching element V4 are connected in parallel, and the first switching element V2 and V4 are connected in parallel. The switching operation of switching the winding tap N to the voltage regulating second winding tap N+1 ends.

The second main on-off switch MC2 is in the on state, the first main on-off switch MC1 is in the off state, the fourth switching element V4 is in the on state, the third switching element V3 is in the off state, and the second switching element V2 is in the off state In the on state, the first switch element V1 is in the off state, the action arm of the transfer switch T is vacant, and the on-load tap changer transition circuit can make the load current flow out from the neutral point terminal through the second main current switch MC2.

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 Taking the single-break vacuum circuit breaker as an example, the operation steps of the transition circuit include:

Disconnect the second main current switch MC2, the load current _IN flows through the second switching element V2, and the fourth switching element V4 flows out from the neutral point;

Convert the action arm of the transfer switch T from the idle to the second stationary contact 12;

Turn on the first switching element V1;

Disconnect the load current vacuum circuit breaker V4, cut off the load current _IN , and V4 generates an arc. After the arc is extinguished, the load current IN _passes through the circulating vacuum circuit breaker V2, the second static contact 12 of the transfer switch T, and the transition resistance R in turn. The neutral point flows out, and the recovery voltage at both ends of the load current vacuum circuit breaker V4 is U _{V1 =IN} ×R;

After the arc is completely extinguished in the fourth switching element V4, the third switching element V3 is turned on, and the transition circuit connects the first winding tap N and the second winding tap N+1 at the same time to form a bridge, resulting in an inter-stage circulating current I _C =U _S /R, at this time, the load current is transferred to the first winding tap N and flows out, the load current flows through the first switching element V1 and the third switching element V3 and flows out from the neutral point, and the current in the second switching element V2 is the interstage circulating current I _C ;

Disconnect the second switching element V2, cut off the inter-stage circulating current, and generate an arc. The load current flows through the first switching element V1 and the third switching element V3 and flows out from the neutral point. The recovery voltage across the second switching element V2 is U _V2 = _US ;

After the arc is completely extinguished in the second switching element V2, the action arm of the transfer switch T is switched from the second static contact 12 to vacant, and the load current flows through the first switching element V1 and the third switching element V3 and flows out from the neutral point;

The first main current switch MC1 is closed, and the load current I _N flows through the first main current switch MC1 and flows out. At the same time, the first switching element V1 and the third switching element V3 are connected in parallel, and the voltage regulation second winding tap N+1 is switched. The switching operation to the voltage regulating first winding tap N ends.

When the internal switching elements in the on-load tap-changer series load single-resistance transition circuit are power electronic elements with controllable on-off function and double-break vacuum circuit breakers, the action sequence of the switching elements and the voltage regulation method are the same, and no longer Repeat.

When the on-load tap-changer switches from the first winding tap N tap to the second winding tap N+1 tap, the transition circuit switching procedure is shown in Figure 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 shown in Figure 11.

In the embodiment of the present invention, the switching tasks of the on-load tap-changer transition circuit are shown in Table 1 below:

Table 1 N to N+1 switching tasks of the on-load tap-changer transition circuit

Among them, I _N is the load current; U _S is the voltage between the stages of the on-load tap-changer; R is the transition resistance.

Referring to FIG. 12, it is a circuit diagram of an on-load tap-changer series load single-resistance transition circuit in which the 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 controllable on-off The other components are the same as the components in FIG. 1, the action sequence is consistent, and the functions and functions are the same as those of the transition circuit shown in FIG. 1, and will not be repeated here.

Referring to FIG. 13, it is a circuit diagram of an on-load tap-changer series load single-resistance transition circuit in which the switching element is a double-break vacuum circuit breaker according to an embodiment of the present invention; only the single-break vacuum circuit breaker in FIG. 1 is replaced with a double-break vacuum circuit breaker The other components of the circuit breaker are the same as those in FIG. 1 , the action sequence is consistent, and the functions and functions are the same as those of the transition circuit shown in FIG. 1 , and will not be repeated here.

Referring to FIG. 14, it is a circuit diagram of an on-load tap-changer series load single-resistance transition circuit according to the present invention, adding an example isolating switch in the circuit, so as to play the role of electrical isolation; adding an example first isolating switch Z1 and The second isolating switch Z2 is used to disconnect the circuit when the circuit breaker fails. Adding isolating switches at other positions also has the same effect, which will not be repeated here.

In one embodiment of the present invention, there is provided a voltage regulation method for an on-load tap-changer connected in series with a single-resistor transition circuit, including the following steps: taking a single-break vacuum circuit breaker as an example, the transition circuit includes a first main current switch MC1 and the second main current switch MC2, the third switching element V3 and the fourth switching element V4, the first switching element V1 and the second switching element V2, the transfer switch T, and the transition resistance R, the method is as follows:

The on-load tap-changer switches from tap N of the first winding of voltage regulation to 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 switching element V3 is in an on state, the fourth switching element V4 is in an off state, and the first switching element V1 is in an off state. In the on state, the second switch element V2 is in the off state, and the action arm of the transfer switch T is vacant;

Disconnect the first main on-off switch MC1;

Switch the transfer switch T from vacant to the first stationary contact 11;

Turn on the second switching element V2;

Disconnect the third switching element V3 to generate an arc;

After the arc is completely extinguished in the third switching element V3, the fourth switching element V4 is turned on;

Disconnect the first switching element V1 to generate an arc;

After the arc is completely extinguished in the first switching element V1, the transfer switch T is switched from the first static contact 11 to vacant;

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 the on state, the first main on-off switch MC1 is in the off state, the fourth switching element V4 is in the on state, the third switching element V3 is in the off state, and the second switching element V2 is in the off state In the on state, the first switch element V1 is in the off state, and the action arm of the transfer switch T is vacant;

Disconnect the second main on-off switch MC2;

Switch the transfer switch T from vacant to the second stationary contact 12;

Turn on the first switching element V1;

Disconnect the fourth switching element V4 to generate an arc;

After the arc is completely extinguished in the fourth switching element V4, the third switching element V3 is turned on;

Disconnect the second switching element V2 to generate an arc;

After the arc is completely extinguished in the second switching element V2, the transfer switch T is switched from the second stationary contact 12 to vacant;

The first main on-off switch MC1 is turned on.

When the internal switching elements in the on-load tap changer series-loaded single-resistance transition circuit are power electronic elements with controllable on-off function and double-break vacuum circuit breakers, the action sequence of the switching elements and the voltage regulation method are consistent.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the present invention can still be Modifications or equivalent replacements are made to the specific embodiments of the present invention, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (9)

1. An on-load tap-changer series load single-resistance transition circuit is characterized in that, comprising a first main current switch (MC1) and a second main current switch (MC2), as the first switch of the circulating current breaking element element (V1) and second switching element (V2), third switching element (V3) and fourth switching element (V4) as load current switching elements, transfer switch (T) and transition resistance (R); Wherein, the first end of the first main on-off switch (MC1) is connected with the first end of the first switching element (V1), and the second end of the first main on-off switch (MC1) is connected with the third switching element (V3) The first end 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 all connected, and the first switching element (V1) The second end of the transition resistor (R) and the second end of the third switching element (V3) are connected to the first static contact (11) of the transfer switch (T), and the second end of the transition resistor (R) is connected to the transfer switch (T) The moving contact 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) is connected to the fourth switching element ( The second ends of V4) are all connected to the second stationary contact (12) of the transfer switch T. 2. An on-load tap changer series load single-resistance transition circuit according to claim 1, characterized in that, further comprising a first isolation switch (Z1), and the second end of the third switching element (V3) is passed through the first isolation switch (Z1). An isolating switch (Z1) is connected to the first stationary contact (11) of the transfer switch (T). 3. An on-load tap changer series load single-resistance transition circuit according to claim 1 or 2, characterized in that, further comprising a second isolating switch (Z2), the second end of the fourth switching element (V4) It is connected with the second static contact (12) of the transfer switch (T) via the second isolating switch (Z2). 4. An on-load tap changer series load single-resistance 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 first switching element (V2) The four switching elements (V4) are single-break vacuum circuit breakers, double-break vacuum circuit breakers or power electronic components with controllable on-off functions. 5. An on-load tap-changer series load single-resistance transition circuit according to claim 1, characterized in that, further comprising the on-load tap-changer voltage regulating winding, the second main current-passing switch (MC2) of the second The terminal and the first terminal of the second switching element (V2) are both connected to the tap (N+1) of the second winding of the on-load tap changer, and the first terminal of the first main on-off switch (MC1) and the first switch The first ends of the element (V1) are all connected to the tap N of the first winding of the on-load tap changer. 6. A kind of on-load tap changer series load single-resistance transition circuit according to claim 1 is characterized in that, also comprises an on-load tap changer, the first end of the third switching element (V3), the transition resistance ( The first end of R), the first end of the fourth switching element (V4), the second end of the first main current switch (MC1) and the first end of the second main current switch (MC2) are all connected to the load The neutral point terminals of the tap changer are connected. 7. An on-load tap changer series load single-resistance transition circuit according to claim 1, characterized in that the third switching element (V3) is used to switch from the first winding tap (N) to the second winding tap In the process of (N+1), the load current is interrupted, and the third switching element (V4) is used to interrupt the load current in the process of switching from the second winding tap (N+1) to the first winding tap (N); The first switching element (V1) is used to switch off the interstage circulating current when the transition circuit is bridged during the process of switching from the first winding tap N to the second winding tap (N+1), and the second switching element (V2) is used to switch from In the process of switching the second winding tap (N+1) to the first winding tap (N), the interstage circulating current when the transition circuit is bridged; The transition resistance (R) is used to limit the inter-stage circulating current when the first winding tap (N) and the second winding tap (N+1) are bridged during the switching process of the transition circuit. 8. A voltage regulation method based on the on-load tap changer series load single-resistance transition circuit according to claim 1, characterized in that, 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 a conducting state, the second main on-off switch (MC2), the fourth switching element (V4) and the first The second switching element (V2) is placed in the off state; Turn off the first main on-off switch (MC1), switch the transfer switch (T) from vacant to the first static contact (11), turn on the second switching element (V2), turn on the third switching element (V3) ) is turned off, the fourth switch element (V4) is turned on, the first switch element (V1) is turned off, the transfer switch (T) is switched from the first static contact (11) to vacant, and the second main switch The disconnect switch (MC2) is turned on, and the on-load tap-changer switches from the tap (N) of the first winding of the voltage regulation to the tap of the second winding of the voltage regulation (N+1). 9. A voltage regulation method based on the on-load tap changer series load single-resistance transition circuit according to claim 1, characterized in that, the second main on-off switch (MC2) is in a conducting state, and the first main on-off switch The switch (MC1) is in an off state, the fourth switch element (V4) is in an on state, the third switch element (V3) is in an off state, the second switch element (V2) is in an on state, and the first switch element ( V1) is disconnected; Disconnect the second main on-off switch (MC2), switch the transfer switch (T) from vacant to the second static contact (12), turn on the first switching element (V1), and switch the fourth switching element (V4) ) is turned off, the third switching element (V3) is turned on, the second switching element (V2) is turned off, the transfer switch (T) is switched from the second static contact (12) to vacant, and the first main The disconnect switch (MC1) is turned on, and the on-load tap-changer switches from the tap (N+1) of the second winding of the voltage regulation to the tap of the first winding of the voltage regulation (N).

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