CN110783139A

CN110783139A - Coupling type contact switch with variable electrode shape and method

Info

Publication number: CN110783139A
Application number: CN201910973745.9A
Authority: CN
Inventors: 曹辰; 林莘; 徐建源; 刘一潼; 高歌; 王今龙
Original assignee: Shenyang University of Technology
Current assignee: Shenyang University of Technology
Priority date: 2019-10-14
Filing date: 2019-10-14
Publication date: 2020-02-11

Abstract

The invention provides a coupling type contact switch with a variable electrode shape and a method, and relates to the technical field of high-voltage electric appliances. The contact switch comprises a contact moving end a, a contact static end b, a contact moving end c, a contact static end d and a double-acting device. The invention breaks through the design idea of a mechanical switch in a direct current breaker, and the contacts on both sides of the switch are formed by coupling a movable end and a fixed end. The operation speed of the whole switch is improved to 2 times. Through the designed coupling type contact switch structure with the shape of the variable electrode and the provided brand new double-acting operation mode, the over travel is reduced, the opening speed is increased, and meanwhile, the breakdown voltage is also increased. The double-sided contact structure changes continuously with the switching operation process: three positions between the contacts provide closing force during conduction, and the over travel of the switch is reduced to 1/3 while reliable contact is ensured. After the contacts move to the opening position, the electric field uniformity and breakdown voltage between the contacts are greatly improved due to the regular electrode structure between the plates.

Description

Coupling type contact switch with variable electrode shape and method

Technical Field

The invention belongs to the technical field of high-voltage electric appliances, and particularly relates to a coupling type contact switch with a variable electrode shape and a method.

Background

With the appearance of the first direct-current transmission project based on a Voltage Source Converter (VSC) technology in 1997, the flexible direct-current transmission technology has outstanding advantages in the aspects of large power grid interconnection, new energy consumption, long-distance large-capacity transmission and the like, so that the high-voltage direct-current transmission project is rapidly developed and is highly concerned by various countries. At present, 16 countries in europe, america, asia, oceania and africa have 14 flexible direct current transmission projects in operation on the global scale, wherein 4 projects are used for wind power access, 7 projects are used for power grid interconnection, 1 project is used for large city power supply, and 2 projects are used for offshore drilling platform power supply. A plurality of multi-terminal direct-current power grid projects are planned and constructed in China, and the problem of large-scale clean energy collection and delivery caused by weak power grids in northwest regions, coastal regions and other regions is solved: establishing a first +/-30 kV/20MW flexible direct-current transmission demonstration project in China in Shanghai and south in 7 months in 2011; constructing a +/-200 kV/400MW five-terminal flexible direct-current transmission project in Zhoushan of Zhejiang in 2014; establishing a true bipolar flexible direct-current transmission project with highest voltage grade and maximum transmission capacity in the world in 2015 12 months, and establishing a flexible direct-current transmission scientific and technical demonstration project of buildings +/-320 kV/1000 MW; 14 days 12 and 14 months in 2017, the national approval is obtained in the 500kV/3000MW Zhang North flexible direct current transmission test demonstration project, and the project is officially started and constructed in 28 days 2 and 28 months in 2018. Therefore, whether new energy consumption is met, interconnection of alternating current power grids is promoted, or long-distance large-capacity power transmission is realized, high-voltage direct current power transmission is the development direction of future power grids.

However, the most important technical bottleneck restricting the development of the high-voltage direct-current power grid is the rapid isolation technology of the direct-current fault. The main difficulties of the direct current power grid in the aspect of fault isolation are shown in the following aspects: (1) short-circuit current has no polarity change in the fault process, zero crossing points do not exist, and the circuit breaker is difficult to extinguish arcs. (2) The requirement on rapid fault removal is extremely high, the fault removal time of the direct-current power grid generally needs to be controlled within 5ms, and otherwise, the safety of equipment is seriously threatened. In order to ensure safe, reliable and stable operation of a future high-voltage large-capacity flexible direct-current power grid, it is one of the problems to be solved urgently at present to research a high-voltage direct-current circuit breaker capable of realizing a rapid fault isolation function of the direct-current power grid.

At present, a high-voltage direct-current circuit breaker can be classified into a mechanical direct-current circuit breaker, an all-solid-state direct-current circuit breaker and a hybrid high-voltage direct-current circuit breaker according to the types of key cut-off devices in the direct-current circuit breaker. The hybrid direct current circuit breaker has the outstanding advantages of high opening speed, no arc breaking, strong loading capacity, high insulating performance and the like, and becomes a research hotspot and development direction of the direct current circuit breaker in recent years. In order to cut off a fault current of a dc power transmission system in a very short time (within 5 ms), a fast mechanical switch in a hybrid dc circuit breaker is required to have very high operation performance and insulation performance. Therefore, the research on the design of a mechanical switch and a quick separation mechanism in the hybrid direct current circuit breaker is the key for realizing the technology.

With the development of the direct-current transmission technology, the requirements of high withstand voltage, rapid opening, long mechanical life, stable action and the like are provided for the direct-current circuit breaker. However, due to the mechanical switch operating speed, actuator travel and fracture insulation performance, a plurality of mechanical switches must be connected in series in the current high-voltage class of dc circuit breakers, which greatly increases the operating cost of the power grid and the risk of switch operation failure. Therefore, the technical bottlenecks of the opening speed, the stroke of an operating mechanism, the mechanical service life of a switch, the fracture insulation performance and the action reliability of a mechanical switch in the conventional hybrid direct-current circuit breaker are broken through, a novel switch and a rapid isolation mechanism are researched, and the method has important significance for improving the action reliability, the mechanical service life and the voltage level of the direct-current circuit breaker and promoting the safe and stable operation of a power system.

The ABB company internationally develops a world first 80kV direct series connection hybrid direct current circuit breaker prototype with engineering application significance in 2012, wherein the breaking time is 5ms, and the breaking current is 9 kA; the southern power grid company relies on the national 863 project 'direct current breaker key technology research', develops a direct current breaker prototype with the rated voltage of 55kV, the breaking current of 16kA and the breaking time of 5ms at the end of 2014, and is actively promoting the demonstration application of the breaker in the south Australia project through experiments. The ALSTOM company develops a 120kV rated voltage mixed type direct current circuit breaker in 2014, the rated current of the circuit breaker is 1.5kA, the breaking time is 5.5ms, the breaking current is 5.2kA, and the circuit breaker passes test verification. Under the support of scientific and technological projects of national grid companies, national grid intelligent power grid research institutes adopt a self-proposed full-bridge cascade hybrid type direct current circuit breaker topological structure, develop the first international direct current circuit breaker with rated voltage of 200kV, rated current of 2kA, breaking current of 15kA and breaking time of 3ms in 2014, and demonstrate and apply in the Zhoushan five-terminal direct current project in 2016 12 months.

In summary, the current fault isolation technology of the dc power transmission system has advanced to some extent, however, the following technical limitations still exist in the research field of the hybrid dc circuit breaker: (1) the operation speed of a mechanical switch is limited, 4-10 switch modules are required to be connected in series for operation in the conventional hybrid direct-current circuit breaker with the voltage grade of over 160kV, and multiple switches are required to complete switching-off actions simultaneously in a very short time, so that the construction cost is increased, and the problems of dispersion of the multiple switch actions and the like are caused by long-term operation; (2) because the gas switch overtravel is great, influence the separating brake time of switch, mechanical type switch among the present mixed type direct current circuit breaker adopts the vacuum fracture to keep apart, and vacuum isolation fracture has insulating saturated limitation, and in order to improve the insulating properties of switch, present solution generally adopts a plurality of vacuum fractures to establish ties to make sufficient insulating distance, inevitably brought the insulating problem of cooperation synchronism of many fractures, greatly reduced the reliability of switch. Therefore, the mechanical switching and isolation operation technology in the current hybrid dc circuit breaker is difficult to meet the construction requirement and development trend of dc power transmission. With the development of the direct-current transmission technology, requirements of high withstand voltage, rapid opening, stable action and the like are provided for a direct-current circuit breaker. Therefore, in order to meet the requirements of the high-voltage direct-current transmission project, the difficulties of opening speed, insulation performance, action reliability and the like of a mechanical switch in the hybrid direct-current circuit breaker must be overcome.

Disclosure of Invention

In view of the deficiencies of the prior art, the present invention provides a variable electrode shape coupled contact switch and method. The design idea of a mechanical switch in a direct current breaker is broken through, and a coupling type contact switch with a variable electrode shape and a novel double-acting operation mode of the mechanical switch are provided. The double-side contacts of the switch are formed by coupling a movable end and a static end. The operation speed of the whole switch is improved to 2 times. Through the designed coupling type contact switch structure with the shape of the variable electrode and the provided brand new double-acting operation mode, the over travel is reduced, the opening speed is increased, and meanwhile, the breakdown voltage is also increased. The switch is made to meet the DC network operation task of higher voltage class. The double-sided contact structure changes continuously with the switching operation process: three positions between the contacts provide closing force during conduction, and the over travel of the switch is reduced to 1/3 while reliable contact is ensured. After the contacts move to the brake-separating position, the original ring-rod irregular electrode structure is changed into a plate-plate regular electrode structure, and the electric field uniformity and breakdown voltage between the contacts are greatly improved.

The technical scheme adopted by the invention is as follows:

in one aspect, the invention provides a coupling type contact switch with a variable electrode shape, which comprises a contact moving end a, a contact static end b, a contact moving end c, a contact static end d and a double-acting device;

one end of a contact moving end a is in sliding contact with a contact static end b, the other end of the contact moving end a is connected with one end of a double-acting device through a rotating bolt, the other end of the double-acting device is connected with one end of a contact moving end c through a fixed bolt, and one end of the contact moving end c is in sliding contact with a contact static end d;

the contact positions of the movable end and the static end of the contacts on the two sides are of a petal-shaped structure, sufficient closing force is provided at the closing position, and the 4 contacts on the two sides are ensured to be reliably contacted when the switch is switched on.

On the other hand, the method for switching the coupling type contact with the variable electrode shape is realized by the coupling type contact switch with the variable electrode shape, and comprises the following steps:

in a closing state, the movable end a of the contact is in contact conduction with the movable end b of the contact, the movable end a of the contact is in contact conduction with the movable end c of the contact, and the static end b of the contact is in contact conduction with the movable end c of the contact; when the contacts are contacted, the closing position of the contact provides closing force for the movable end a and the static end b of the contact; the contact closing position provides closing force for the contact moving end a and the contact moving end c during closing; the contact closing position provides closing force for the contact moving end c and the contact static end d during closing;

in the switching-on process: the movable end a of the contact moves towards the direction of the double-acting device; the linkage double-acting device moves towards the direction of the movable end a of the contact; the movable end c of the contact is driven to move towards the direction of the static end of the contact under the action of the double-acting device and the fixing bolt of the movable end c of the contact; therefore, the aim that the movable end a of the contact drives the movable end of the contact to move relatively at the same time in the switching-on process is achieved, and the switching-on speed is increased to 2 times of the prior art;

in the brake opening process, the movable end a of the contact moves towards the direction of the static end of the contact; the linkage double-acting device moves towards the opposite direction of the contact moving end a; the movable end c of the contact is driven to move towards the direction of the double-acting device under the action of the double-acting device and the fixing bolt of the movable end c of the contact; therefore, the purpose that the movable end a of the contact drives the movable end of the contact to move in the opposite direction simultaneously in the brake-separating process is achieved, and the brake-separating speed is improved to 2 times of the prior art;

when in the opening state: the movable end a of the contact moves to a brake separating position, and forms a flat electrode structure with the static end b of the contact; the movable end c of the contact moves to a brake separating position, and forms a flat electrode structure with the static end d of the contact; the original circular ring-rod irregular electrode structure between 4 contacts is changed into a plate-plate regular electrode structure, so that the field intensity between the contacts is optimized, and the breakdown voltage is improved while the over travel is reduced.

Adopt the produced beneficial effect of above-mentioned technical scheme to lie in:

(1) the switch structure with the coupling of the moving contact and the static contact at two sides is provided, the closing of 3 positions of 4 contacts is realized, the reliable closing is ensured, the over travel of the switch is reduced to 1/3, and the opening time of the gas switch is reduced.

(2) During closing, the three contacts are simultaneously in contact conduction, compared with the traditional double-contact conduction, the conduction is more reliable, the contact area is larger, the contact resistance is smaller, and the closing is more stable.

(3) The coupling type contact structure with the variable electrode shape and the method form a regular electrode shape between plates by adaptively adjusting the contact structure at the maximum fracture voltage position, can optimize the electric field distribution of the fracture and improve the breakdown voltage.

(4) A novel double-acting operation mode of the mechanical switch is provided, and the opening speed of the whole switch is increased to 2 times of the original opening speed by designing a double-acting structure and an operation mode inside a fracture.

(5) The SF6 double-acting switch with an improved contact structure is invented, the insulation grade of a switch fracture is improved, and the limitation of mechanical switch vacuum fracture insulation saturation in the traditional direct current circuit breaker is broken through.

Drawings

FIG. 1 is a schematic diagram of a variable pole shape coupled contact switch;

in the figure, 1-a contact moving end a, 2-a contact static end b, 3-a contact moving end c, 4-a contact static end d, 5-a double-acting device, 6-a contact closing position in closing, 7-a contact closing position in closing and an effective electric contact area, and 8-a contact closing position in closing;

FIG. 2 is a schematic diagram of an electrode structure at a gate-off position;

fig. 3 is a schematic diagram of a dual-side contact lobe contact structure.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings.

A coupling type contact switch with variable electrode shape is shown in figure 1 and comprises a 1-contact movable end a, a 2-contact static end b, a 3-contact movable end c, a 4-contact static end d, a 5-double-acting device;

1-one end of a movable end a of the contact is in sliding contact with a static end b of the contact 2-, the other end of the movable end a of the contact 1-is connected with one end of a 5-double-acting device through a rotating bolt, the other end of the 5-double-acting device is connected with one end of a movable end c of the contact 3-through a fixed bolt, and one end of the movable end c of the contact 3-is in sliding contact with a static end d of the contact 4-;

the contact positions of the movable end and the static end of the contacts on the two sides are in a petal-shaped structure, and enough closing force is provided at the switching-on position, so that the 4 contacts on the two sides are ensured to be reliably contacted when the switch is switched on;

when in a closing state: the 1-contact moving end a and the 2-contact static end b, the 1-contact moving end a and the 3-contact moving end c, and the 2-contact static end b and the 3-contact moving end c are in contact conduction. In the 7-closing process, three contacts are in contact conduction at the same time in the contact closing position and the effective electric contact area, and in the embodiment, the three contacts are in contact conduction at the same time. When the contact contacts, the contact closing position provides closing force for the 1-contact movable end a and the 2-contact static end b during 6-closing; 7-the contact closing position provides closing force for the 1-contact moving end a and the 3-contact moving end c during closing; 8-the contact closing position provides closing force for the 3-contact moving end c and the 4-contact static end d during closing; compared with the prior art that only one position provides the closing force, the closing force is provided by three positions in the embodiment, the defect that the overtravel needs to be increased in the conventional contact mode that the moving contact and the static contact provide the closing force at a single plugging position is overcome, and the overtravel is reduced to 1/3 while the same closing force is ensured.

In the switching-on process: 1-the movable end a of the contact moves towards the direction of the double-acting device; the linkage 5-the double-acting device moves towards the direction of the contact moving end a; the 3-contact moving end c is driven to move towards the contact static end by the action of the 5-double acting device and the 3-contact moving end c fixing bolt; therefore, the purpose that the 1-contact moving end a drives the 3-contact moving end to move relatively at the same time in the closing process is achieved, and the closing speed is improved to 2 times of the prior art.

In the brake opening process, 1-the movable end a of the contact moves towards the direction of the static end of the contact; the linkage 5-double acting device moves towards the opposite direction of the 1-contact moving end a; the 3-contact moving end c is driven to move towards the 5-double acting device by the action of the 5-double acting device and a fixing bolt of the 3-contact moving end c; therefore, the purpose that the 1-contact moving end a drives the 3-contact moving end to move in the opposite direction in the brake-separating process is achieved, and the brake-separating speed is improved to 2 times of the prior art.

When in the opening state: as shown in fig. 2, the 1-contact moving end a moves to the opening position and forms a flat electrode structure with the 2-contact static end b; 3, moving the movable end c of the contact to a brake separating position to form a flat electrode structure with the static end d of the contact 4; the original ring-rod irregular electrode structure between 4 contacts is changed into a plate-plate regular electrode structure. Therefore, the field intensity between the contacts is optimized, and the breakdown voltage is improved while the over travel is reduced.

In the moving and stationary contact positions (6, 7 and 8) of the double-sided contact, a lobe-like structure is designed as shown in fig. 3, and the closing position provides sufficient closing force. And 4 contacts on both sides are ensured to be reliably contacted when the switch is conducted.

In order to improve the switching-off speed, a novel double-acting operation mode of the mechanical switch is provided, contacts on two sides are formed by coupling a static end and a moving end, and a double-acting device is arranged on a moving end driving rod of the contact on one side of the switch. When the switch is operated to open the brake, the static ends of the contacts at the two sides are static, and the moving ends are separated at high speed in opposite directions at the same time under the action of the operating mechanism and the double-acting device. The operation mode that a single moving contact moves during the original switch operation is improved into the mode that contacts on two sides move simultaneously, and the operation speed of the whole switch is improved to 2 times of the original operation speed.

Because the moving contact of the contact switch has mechanical inertia, in a very short time (within 5 ms), a single motion system is driven to complete an isolation operation task, the response speed of the contact switch is close to the limit, namely the response speed is obviously improved after the operation power of the operating mechanism is increased, and the response time of a single moving contact is shortened. Therefore, the applicant provides a novel double-acting operation mode of a mechanical switch, which improves the motion mode that a moving contact moves and a static contact is static during the operation of the original switch into the motion mode that static ends of contacts on two sides are static and a moving end of a contact on one side moves and a moving end of a contact on the other side moves towards the opposite direction, so that the operation speed of the whole switch is increased to 2 times of the original operation speed. Through the designed coupling type contact switch structure with the shape of the variable electrode and the provided brand new double-acting operation mode, the over travel is reduced, the opening speed is increased, and meanwhile, the breakdown voltage is also increased. The switch is made to meet the DC network operation task of higher voltage class.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit of the corresponding technical solutions and scope of the present invention as defined in the appended claims.

Claims

1. A variable pole shape coupled contact switch, comprising: comprises a contact moving end a, a contact static end b, a contact moving end c, a contact static end d and a double-acting device;

one end of the contact moving end a is in sliding contact with the contact static end b, the other end of the contact moving end a is connected with one end of the double-acting device through a rotating bolt, the other end of the double-acting device is connected with one end of the contact moving end c through a fixed bolt, and one end of the contact moving end c is in sliding contact with the contact static end d.

2. The variable pole shape coupled contact switch of claim 1, wherein:

3. A method for switching a variable pole shape coupling contact, which is implemented by the variable pole shape coupling contact switch of claim 1, wherein: