WO2017107244A1

WO2017107244A1 - Thyristor-assisted arc-extinguishing hybrid on-load tap switch

Info

Publication number: WO2017107244A1
Application number: PCT/CN2015/100275
Authority: WO
Inventors: 高飞; 李金忠; 李鹏; 刘雪丽; 贾鹏飞
Original assignee: 中国电力科学研究院; 国家电网公司
Priority date: 2015-12-21
Filing date: 2015-12-31
Publication date: 2017-06-29
Also published as: CN106898480B; CN106898480A

Abstract

A thyristor-assisted arc-extinguishing hybrid on-load tap switch. The switch comprises a main current loop and a thyristor module connected to the main current loop in parallel. The main current loop comprises a first contact switch, a main loop switch and a second contact switch connected sequentially. The main loop switch comprises two static-state flow guiding contacts separated from each other, and a movable switch moveably connected to the two static-state flow guiding contacts. A thyristor module establishes a trigger condition of a thyristor by means of a potential difference in a mechanical switch contract enabling process so as to make the triggering of the thyristor module more safe and reliable. When a continuous current of the thyristor in the thyristor module lasts for less than 12 milliseconds, arcing does not occur in a triggering process, switch transition is stable, and no arc shock and heat is generated.

Description

Thyristor auxiliary arc extinguishing hybrid on-load tap changer

Technical field

The invention relates to an on-load tap changer, in particular to a hybrid on-load tap changer which utilizes a thyristor to assist arc extinction.

Background technique

The on-load tap-changer is an important component of the power regulating transformer and the industrial voltage regulating transformer. It can adjust the tapping position of the transformer without interrupting the load current, and then realize the fine-tuning of the ratio to change the transformer. Output voltage or output capacity; however, conventional on-load tap-changers generate arcs when switching, and the generation of arcs inevitably leads to energy loss and transformer oil contamination.

The thyristor on-load tap-changer can completely avoid arcing during the gear shifting process. With the continuous development of power electronic devices, performance parameters and reliability indicators are continuously improved. It has become an irresistible trend to optimize the electrical performance of switches by using power electronic devices.

In order to improve the safety of the thyristor switch, Zhao Gang of the School of Electrical Engineering of Xi'an Jiaotong University studied a thyristor-based arc-free on-load tap-changer. The structure is shown in Figure 1. The tap-changer model is in the low-voltage simulation test. It is found that the arc extinguishing switch does not always effectively extinguish the arc, and its arc extinguishing characteristics are related to the arc current direction and the switching action state. The test also finds that the forward and reverse thyristors used for the bypass switch current are triggered and turned on when the switch is closed. The condition is closely related to the sequence in which the nodes 4, 5 are closed and the direction of the arc current at the time of closing. This problem has not been solved in the publication thereof, and the prototype according to the principle has not been commercially applied.

Summary of the invention

In order to solve the above-mentioned deficiencies in the prior art, the present invention provides a new thyristor-assisted arc-extinguishing hybrid on-load tap-changer.

The technical solution provided by the present invention is: a thyristor auxiliary arc extinguishing hybrid on-load tap changer, the switch comprising a main current loop and a thyristor module connected in parallel with the main current loop; the main current loop includes sequentially connected a first contact switch, a main circuit switch and a second contact switch; the improvement is that the main circuit switch comprises two static flow guiding contacts separated from each other and movably connected to two static flow guiding contacts Activity switch.

Preferably, the movable switch comprises a conductive sheet and two trigger contacts respectively fixed perpendicularly on two sides of the lower surface of the conductive sheet; the two trigger contacts are disposed between the two static flow guiding contacts And correspondingly connected to the two static flow guiding contacts.

Further, the first contact switch and the second contact switch both include a static contact and a movable contact that is movably connected to the static contact; a static contact of the first contact switch and the two static diversion One of the contacts is connected to a static flow contact, and the movable contact is connected to one end of the thyristor module; the static contact of the second contact switch and the other of the two static flow guiding contacts are statically guided The flow contact is connected, and the movable contact is connected to the other end of the thyristor module.

Further, a height of the trigger contact in a direction perpendicular to the conductive sheet is greater than a height of the static flow guiding contact in a direction perpendicular to the conductive sheet;

The movable switch is movable in a direction perpendicular to the conductive sheet, and the movable switch is detached from the static flow guiding contact before the trigger contact during the moving process: the conductive piece of the movable switch and the When the two static flow guiding contacts are electrically connected, a current flows through the main current loop, and the thyristor module is short-circuited; the conductive pad of the movable switch is separated from the two static flow guiding contacts, the thyristor The module triggers conduction, a current flows through the thyristor module, and the main current loop is short-circuited; after the trigger contact of the movable switch is separated from the static flow guiding contact, the thyristor module is naturally turned off.

Further, after the trigger contact of the movable switch is separated from the static flow guiding contact for more than 10ms, the first contact switch and the second contact switch are disconnected.

Further, the resistivity of the static flow guiding contact is equal to the electrical resistivity of the conductive sheet; the resistivity of the trigger contact is much larger than the resistivity of the static current guiding contact.

Further, the static current guiding contact has a resistivity of less than 2*10 ^-8 Ω·m.

Further, the resistivity of the trigger contact is greater than 0.1 Ω·m and less than 1 Ω·m.

Preferably, the thyristor module includes a first thyristor and a second thyristor; a cathode of the first thyristor is connected to an anode of the second thyristor and is connected to a movable contact of the first contact switch; An anode of a thyristor is connected to a cathode of the second thyristor and is connected to a movable contact of the second contact switch; a gate of the first thyristor and a gate of the second thyristor pass resistance and high voltage The silicon stack is electrically connected to the active switch.

Further, the gates of the first thyristor and the second thyristor are respectively connected to the cathodes of the two high-voltage silicon stacks, and the anodes of the two high-voltage silicon stacks are respectively connected to two resistors, and the two resistors are respectively versus The conductive sheets of the movable switch are electrically connected.

The invention provides a novel solution based on the conventional technical solution, which is provided with a high-resistivity conductor in addition to the original static flow guiding contact composed of a good conductor (low resistivity). Trigger contacts, the active connection between the two contacts, by setting a specific action time for the two sets of contacts, and finally providing the required voltage for the thyristor trigger in a resistance limit manner, and providing the thyristor gate Sufficient trigger energy completely solves the defects in the technical solution of FIG.

Compared to the closest prior art, the present invention has the following significant advancements:

1) In the prior art, the thyristor-based arcless on-load tap changer does not always effectively extinguish the arc, and the arc extinguishing characteristic is related to the arc current direction and the switching action state. In the present invention, the gate trigger circuit is adopted in the thyristor. The high-low resistivity contact combination of the active connection is added to the structure, and the voltage limit is realized by the current flowing through the resistor, which ensures the phase of the thyristor voltage and the trigger level, and improves the trigger reliability, thereby solving the prior art. The arcless on-load tap-changer does not always have the problem of effectively extinguishing the arc.

2) The thyristor-assisted arc-extinguishing hybrid on-load tap changer provided by the present invention controls the timing of the action between the thyristor cathode-anode terminal contacts (ie, the first contact switch and the second contact switch) and the gate terminal contacts It can effectively control the time when the thyristor is bypassed by the main current loop, so that the thyristor continuous current in the thyristor module is less than 12 milliseconds, which can prevent the arc from burning the contact head, thereby prolonging the maintenance cycle of the on-load tap-changer and improving the load. The reliability of the tap changer.

DRAWINGS

1 is a circuit schematic diagram of a prior art arcless on-load tap changer

2 is a circuit schematic diagram of a thyristor-assisted arc-extinguishing hybrid on-load tap changer when the main current loop is turned on according to the present invention;

FIG. 3 is a schematic circuit diagram of a thyristor-assisted arc-extinguishing hybrid on-load tap changer in a main current loop disconnection process provided by the present invention.

Wherein 1-first thyristor; 2-second thyristor; 20-moving contact of first contact switch; 20'-static contact of first contact switch; 21-conductive sheet; 22-second contact switch Moving contact; 22'-static contact of the second contact switch; A/D-static diversion contact; B/C-trigger contact.

detailed description

The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

In order to thoroughly understand the embodiments of the present invention, a detailed structure will be set forth in the following description. It is apparent that the implementation of the embodiments of the present invention is not limited to the specific details familiar to those skilled in the art. The preferred embodiments of the present invention are described in detail below, but the present invention may have other embodiments in addition to the detailed description.

The thyristor-assisted arc-extinguishing hybrid on-load tap changer provided by the invention is mainly applied to the switching circuit of the arcless on-load tap changer, avoiding the generation of arcing, and preventing the burning of the sub-contact of the transformer oil by the arcing, thereby Improve the maintenance cycle of the on-load tap-changer and increase the reliability of the on-load tap-changer.

The structure of the thyristor auxiliary arc extinguishing hybrid on-load tap changer provided by the present invention is as shown in FIG. 2: the thyristor auxiliary arc extinguishing hybrid on-load tap changer comprises a main current loop and a thyristor connected in parallel with the main current loop a module; the main current loop includes a first contact switch, a main loop switch, and a second contact switch connected in sequence; the main loop switch includes two static flow guiding contacts A and D separated from each other, and two Active switch with active connection of static guide contacts.

The movable switch includes a conductive sheet 21 and two trigger contacts B and C respectively fixed perpendicularly on two sides of the lower surface of the conductive sheet; the two trigger contacts B and C are disposed on the two static guides Between the contacts A and D, and correspondingly connected to the two static flow guiding contacts A and D respectively.

The first contact switch and the second contact switch both include a static contact and a movable contact that movably connects the static contact; the static contact 20 of the first contact switch is connected to the static flow guiding contact A, The movable contact 20' is connected to one end of the thyristor module; the static contact 22' of the second contact switch is connected to the static flow guiding contact D, and the movable contact 22 is connected to the other end of the thyristor module.

The height of the trigger contacts B and C in a direction perpendicular to the conductive sheet 21 is greater than the height of the static flow guiding contacts A and D in a direction perpendicular to the conductive sheet 21.

The movable switch is movable in a direction perpendicular to the conductive sheet 21, and the movable switch 21 is separated from the static contact guiding contacts A and D before the trigger contacts B and C during the moving process: When the conductive strip of the active switch is electrically connected to the two static flow guiding contacts, current flows through the main current loop, and the thyristor module is short-circuited; when the conductive strip of the movable switch is separated from the two static When the flow contact is in contact, the thyristor module triggers conduction, current flows through the thyristor module, and the main current loop is short-circuited; when the trigger contact of the active switch is disengaged from the static flow guiding contact, The thyristor module is naturally turned off.

The resistivity of the static flow guiding contact is equal to the electrical resistivity of the conductive sheet; the resistivity of the trigger contact is much larger than the resistivity of the static current guiding contact.

The static current guiding contact has a resistivity of less than 2*10 ^-8 Ω·m.

The resistivity of the trigger contact is greater than 0.1 Ω·m and less than 1 Ω·m, and the specific parameters depend on the technical parameters of the on-load tap changer.

The thyristor module includes a first thyristor and a second thyristor; a cathode of the first thyristor is connected to an anode of the second thyristor and is connected to a movable contact 20 of the first contact switch; the first thyristor An anode is connected to the cathode of the second thyristor and connected to the movable contact 22 of the second contact switch; the gate of the first thyristor and the gate of the second thyristor both pass through a resistor and a high voltage silicon The stack is electrically connected to the active switch.

The gates of the first thyristor and the second thyristor are respectively connected to the cathodes of the two high-voltage silicon stacks, and the anodes of the two high-voltage silicon stacks are respectively connected to two resistors, and the two resistors are The conductive sheets of the active switch are electrically connected.

The triggering principle of the thyristor auxiliary arc extinguishing hybrid on-load tap changer provided by the invention is as follows:

Under normal power-on conditions, the current passes through the 20-21-22 loop, and the thyristor module does not work, that is, the thyristor loop does not pass current under normal conditions.

Under normal power supply, the current path is the same as A-20'-A-21-D-22'-B shown in Figure 2. When 21 is open, the contact resistance between A and 21, 21 and D gradually increases, resulting in A and 21. 21 and D no longer equipotential. When the AC current is in the direction of AB current at a certain moment, the relationship between A, 21, and D potential is V _A >V ₂₁ >V _D , because 20 and 20', 22 and 22' are closed, then V ₂₀ =V _20' =V _A , V ₂₂ =V _22' =V _D , then V ₂₀ >V ₂₂ , then a forward voltage of 20-22 is established across the thyristor to form a voltage drop loop 20 - thyristor module -22 (At this time, the thyristor module is not triggered, no current), with the 21-conductor opening process, the forward voltage of 20-22 satisfies the thyristor conduction condition, and at the same time, the opening process of 21 conductive sheets V _A >V ₂₁ >V _D , the branch voltage drop loop 21 - the gate level -22-22'-D-21 of the second thyristor 2 is formed, and the gate current of the second thyristor 2 in the thyristor module generates a trigger current, and the magnitude of the current is determined by the nature of the loop, and the trigger current triggering the second thyristor thyristor 2, thus increasing the process of opening 21 with a potential difference, the anode a to the cathode of thyristor modules since K V _20> V ₂₂ generates a forward bias voltage, gate level G Since the cathodes K V _21> V _D and generates a gate bias voltage level is activated by a current, the thyristor triggering conduction condition is satisfied, so that the thyristor is turned on, current from the A-20'-20- second thyristor 2-22- 22'-B, when the A-21-D circuit is short-circuited, no current flows, and no arcing occurs. After the current crosses zero, since B and C are separated from A and D by a distance, that is, the active switch is completely disconnected from A and D, the trigger current is no longer generated, so the thyristor is turned off.

In order to be able to have sufficient trigger energy, the present invention utilizes additional contact resistance contacts to achieve an increase in trigger energy, as shown in Figures 2 and 3, A and D are static flow guiding contacts with low resistivity for normal through flow. Use; B and C are high resistivity trigger contacts for triggering use. That is, when the loop is normally closed, the current path is A-20'-A-21-D-22'-B, and when triggered, A-20'-B-21-C-22'-B, through the high resistivity trigger The resistance of the head is divided to form a positive potential and a trigger potential (see Figure 3), and the width of the trigger pulse is ensured by the high resistivity of the contact terminals B and C and the low resistivity contacts A and D. During the departure process, B and C are disconnected first, and A and D are disconnected. The closing process is to close AD first and then close after BC to ensure reliable triggering.

When the current is reversed, it is similarly known that the first thyristor 1 in the thyristor module can be triggered. In addition, the conductive sheet 21 is triggered in the same manner from the opening to the closing process.

Among them, 20 and 20', 22 and 22' are to prevent the thyristor from being affected by the circuit. It can be turned on after the thyristor is naturally turned off. There must be a disconnection timing requirement, that is, the separation process is B, C and A, D are separated - the thyristor is turned off. - 20 and 20' and 22 and 22' separate, to ensure that 20 and 20' and 22 and 22' do not produce arcing, B, C and A, D separated by more than 10ms after 20 and 20' and 22 and 22' Open; use the telescopic contact technology to control the timing of the action between the thyristor cathode-anode terminal contacts (ie, the first contact switch and the second contact switch) and the gate terminal contacts, by adjusting the elasticity of the elastic members in the telescopic contacts Modulus and mass, controlling the time that the thyristor is bypassed by the main current loop.

It should be noted that the above embodiments are only for explaining the technical solutions of the present invention and are not limited thereto. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still implement the present invention. Modifications or equivalents are intended to be included within the scope of the appended claims.

Claims

A thyristor auxiliary arc extinguishing hybrid on-load tap changer, the switch comprising a main current loop and a thyristor module connected in parallel with the main current loop; the main current loop comprising a first contact switch and a main loop connected in sequence The switch and the second contact switch are characterized in that the main circuit switch comprises two static flow guiding contacts that are separated from each other and a movable switch that is movably connected to the two static flow guiding contacts.
A thyristor-assisted arc-extinguishing hybrid on-load tap-changer according to claim 1, wherein:

The movable switch includes a conductive sheet and two trigger contacts respectively fixed perpendicularly on two sides of the lower surface of the conductive sheet; the two trigger contacts are disposed between the two static flow guiding contacts, and respectively Correspondingly connected to the two static flow guiding contacts.
A thyristor-assisted arc-extinguishing hybrid on-load tap-changer according to claim 2, wherein:

The first contact switch and the second contact switch each include a static contact and a movable contact that movably connects the static contact; a static contact of the first contact switch and the two static flow guiding contacts One of the static flow guiding contacts is connected, and the moving contact is connected to one end of the thyristor module; the static contact of the second contact switch and the other of the two static flow guiding contacts are statically conductive The head is connected, and the movable contact is connected to the other end of the thyristor module.
A thyristor-assisted arc-extinguishing hybrid on-load tap-changer according to claim 2, wherein:

The height of the trigger contact in a direction perpendicular to the conductive sheet is greater than a height of the static flow guiding contact in a direction perpendicular to the conductive sheet;

The movable switch is movable in a direction perpendicular to the conductive sheet, and the movable switch is detached from the static flow guiding contact before the trigger contact during the moving process: the conductive piece of the movable switch and the When the two static flow guiding contacts are electrically connected, a current flows through the main current loop, and the thyristor module is short-circuited; the conductive pad of the movable switch is separated from the two static flow guiding contacts, the thyristor The module triggers conduction, a current flows through the thyristor module, and the main current loop is short-circuited; after the trigger contact of the movable switch is separated from the static flow guiding contact, the thyristor module is naturally turned off.
A thyristor-assisted arc-extinguishing hybrid on-load tap-changer according to claim 4, wherein:

After the trigger contact of the movable switch is separated from the static flow guiding contact for more than 10ms, the first contact switch and the second contact switch are disconnected.
A thyristor-assisted arc-extinguishing hybrid on-load tap-changer according to any one of claims 2-5, characterized in that:

The resistivity of the static flow guiding contact is equal to the electrical resistivity of the conductive sheet; the resistivity of the trigger contact is much larger than the resistivity of the static current guiding contact.
A thyristor-assisted arc-extinguishing hybrid on-load tap-changer according to claim 6, wherein:

The static current guiding contact has a resistivity of less than 2*10 -8 Ω·m.
A thyristor-assisted arc-extinguishing hybrid on-load tap-changer according to claim 6, wherein:

The resistive contact has a resistivity greater than 0.1 Ω·m and less than 1 Ω·m.
A thyristor-assisted arc-extinguishing hybrid on-load tap-changer according to claim 1, wherein:

The thyristor module includes a first thyristor and a second thyristor; a cathode of the first thyristor is connected to an anode of the second thyristor and is connected to a movable contact of the first contact switch; the first thyristor An anode is connected to a cathode of the second thyristor and connected to a movable contact of the second contact switch; a gate of the first thyristor and a gate of the second thyristor are both passed through a resistor and a high voltage silicon stack The activity switches are electrically connected.
A thyristor-assisted arc-extinguishing hybrid on-load tap-changer according to claim 9, wherein:

The gates of the first thyristor and the second thyristor are respectively connected to the cathodes of the two high-voltage silicon stacks, and the anodes of the two high-voltage silicon stacks are respectively connected to two resistors, and the two resistors are The conductive sheets of the active switch are electrically connected.