Sleeve variable resistance sliding pressure type large capacity arc extinguishing circuit breaker and circuit breaker device

Abstract

The present invention relates to a sleeve variable-resistance sliding compression type large-capacity arc extinguishing circuit breaker and a breaking device. The object of the present invention is to provide a sleeve variable-resistance sliding compression type large-capacity arc extinguishing circuit breaker and a breaking device with simple structure, convenient manufacturing, safety and reliability. The technical solution of the present invention is: a sleeve variable-resistance sliding compression type large-capacity arc extinguishing circuit breaker, characterized by comprising: a static contact; a moving contact, the resistance value between which and the static contact is 0 when the power grid is normal; a transition unit, which can connect a resistor between the static contact and the moving contact when the power grid is short-circuited, and the resistance value of the resistor gradually increases from 0, and after the resistance value reaches a certain value, the static contact and the moving contact are disconnected. The present invention is applicable to the field of manufacturing high-voltage electrical equipment in the power system.

Description

Technical Field

[0001] The present invention relates to a sleeve variable resistance sliding compression type large-capacity arc extinguishing circuit breaker and a breaking device, which is applicable to the field of manufacturing high-voltage electrical equipment in the power system. Background Art

[0002] A high-voltage circuit breaker is a switching device dedicated to disconnecting or connecting a circuit. It has the ability to extinguish arcs under large currents. It can not only switch on and off load currents normally, but also cut off short-circuit currents under the action of protection devices in case of short-circuit faults.

[0003] With the rapid development of the power system, the short-circuit current level has increased sharply, and the breaking capacity of the original switching equipment will no longer meet the requirements. The short-circuit current in the power system is also getting larger and larger. Especially after the short-circuit current in 500 kV substations has increased sharply, the breaking capacity of the installed equipment in the substations is insufficient. The short-circuit current in the long-term vision of the power grid company will reach 80 kA for 500 kV, and the short-circuit current in the 220 kV system may exceed 100 kA, which exceeds the breaking capacity of the domestic largest-breaking-capacity circuit breaker, which is 63 kA at most. The circuit breaker parallel technology can multiply the breaking capacity of the circuit breaker. The breaking capacity of the circuit breaker is improved by paralleling multiple arc extinguishing chambers. However, directly paralleling circuit breakers has the problem of out-of-phase operation and still cannot solve the problem of excessive short-circuit current.

[0004] At present, the commonly used sulfur hexafluoride circuit breaker is a circuit breaker that uses sulfur hexafluoride (SF6) gas as the arc extinguishing medium and the insulating medium, abbreviated as SF6 circuit breaker. The use of SF6 as the arc extinguishing medium in circuit breakers began in the early 1950s. Due to the excellent characteristics of this gas, the single-break of this circuit breaker is much higher than that of compressed air circuit breakers and oil circuit breakers in terms of voltage and current parameters. In the 1960s and 1970s, SF6 circuit breakers were widely used in ultra-high voltage and large-capacity power systems. SF6 gas is extremely harmful to the environment. Its ability to damage the atmospheric ozone layer is 29,000 times that of CO2. Therefore, strict requirements are needed for the application, management, and operation of SF6 gas for SF6 circuit breakers.

[0005] SF6 circuit breaker is one of the best arc extinguishing and insulating media used in current switchgears, and has the characteristics of colorless, odorless, non-toxic, and non-flammable. SF6 gas is 5.135 times heavier than air. Below 150 °C, SF6 has good chemical stability and does not chemically react with the common metals, plastics, and other materials in circuit breakers.

[0006] When SF6 gas is dissociated by arc ionization, highly toxic additional gases will be produced, which have a great impact on the atmospheric environment. The density of SF6 gas is about five times that of air. If SF6 gas leaks, it will surely deposit in low-lying areas, such as cable trenches. If the concentration is too high, there will be a risk of suffocation. This situation should be considered when designing indoor ventilation devices. What is more serious is that the decomposition products of SF6 under the action of high-voltage arcs, such as SF4, S2F2, SF2, SOF2, SO2F2, SO2F4, and HF, etc., all have strong corrosiveness and toxicity.

[0007] Moreover, the maximum breaking capacity of existing SF6 circuit breakers with a voltage level of 500 kV is 80 kA, while the current requirements of the power grid have reached 110 kA - 120 kA, which cannot meet the requirements of the short-circuit current of the new large-scale power grid. Therefore, there is an urgent need to develop a circuit breaker device with a breaking capacity greater than 100 kA for voltage levels of 500 kV and above with a large short-circuit current breaking capacity. Summary of the Invention

[0008] The technical problem to be solved by the present invention is: in view of the above problems, to provide a sleeve variable resistance sliding compression type large-capacity arc extinguishing circuit breaker and circuit breaking device with a simple structure, convenient manufacturing, safety and reliability.

[0009] The technical solution adopted by the present invention is: a sleeve variable resistance sliding compression type large-capacity arc extinguishing circuit breaker, which is characterized by having:

[0010] A static contact;

[0011] A moving contact, the resistance value between which and the static contact is 0 when the power grid is normal;

[0012] A transition unit, which can connect a resistor between the static contact and the moving contact when the power grid is short-circuited, and the resistance value of the resistor gradually increases from 0. After the resistance value reaches a certain value, the static contact and the moving contact are disconnected.

[0013] The transition unit has an insulating rod, a resistance wire and an operating mechanism;

[0014] The insulating rod is divided into an insulating section at the upper end and a resistance section at the lower end. Among them, a threaded groove wound around the insulating rod is formed on the side wall of the resistance section, and a resistance wire is embedded in the groove, and the surface of the resistance wire is flush with the side wall of the insulating rod;

[0015] The static contact is sleeved and fixed at the lower end of the insulating rod and is electrically connected to the resistance wire on the insulating rod;

[0016] The moving contact is sleeved on the insulating rod and can move axially along the insulating rod. The moving contact has a conductive sleeve coaxially sleeved on the insulating rod. A contact ring is fixed at the lower end of the conductive sleeve, which is coaxially sleeved on the insulating rod and can contact and conduct electricity with the static contact below. An arc extinguishing ring is made inside the contact ring, which is coaxially sleeved on the insulating rod. A contact mechanism is made on the inner wall of the conductive sleeve, which can contact and conduct electricity with the resistance wire on the insulating rod.

[0017] The operating mechanism is connected to the moving contact and is used to drive the moving contact to move axially along the insulating rod.

[0018] When the power grid is normal, the conductive sleeve in the moving contact is directly conducted with the static contact through the contact ring.

[0019] When a short - circuit fault occurs in the power grid, the operating mechanism drives the moving contact to move axially along the insulating rod in a direction away from the static contact. The contact ring in the moving contact is separated from the static contact. The conductive sleeve in the moving contact is directly conducted with the static contact through the contact mechanism and the resistance wire. And as the moving contact moves, the resistance value of the resistance wire connected between the conductive sleeve and the static contact gradually increases. After the operating mechanism drives the moving contact to move to the insulating section of the insulating rod, the contact mechanism on the conductive sleeve only contacts the side wall of the insulating rod, and the circuit between the conductive sleeve and the static contact is interrupted.

[0020] The contact mechanism has a number of balls evenly arranged on the inner wall of the conductive sleeve. The balls are installed in the installation holes on the inner wall of the conductive sleeve. A copper wire spring is arranged in the installation hole to push the balls towards the insulating rod to contact the side wall of the insulating rod.

[0021] There is a vacuum cover body, and the insulating rod, the static contact and the moving contact are all arranged inside the vacuum cover body.

[0022] A corrugated pipe is arranged inside the vacuum cover body. One end of the corrugated pipe is connected to one end inside the vacuum cover body. The other end of the corrugated pipe is connected to the moving contact through a cover. The operating pull rod between the moving contact and the operating mechanism is arranged inside the corrugated pipe.

[0023] The insulating rod is made of a ceramic rod; the resistance wire is made of an alloy wire with a high resistivity. The resistance value of the resistance wire on the insulating rod is 0.001Ω - 0.25Ω; the arc extinguishing ring is made of high - temperature - resistant ceramics such as alumina and magnesia or a high - temperature - resistant insulating material of polytetrafluoroethylene.

[0024] A plurality of holes for absorbing electric arcs are made on the inner wall of the arc extinguishing ring.

[0025] The static contact includes a spring - type pressure electrode at the upper end and a base at the lower end.

[0026] A circuit breaker, characterized in that it has a number of the sleeve variable - resistance sliding - pressing - type large - capacity arc - extinguishing circuit breakers connected in parallel or in series.

[0027] The beneficial effects of the present invention are as follows: When a fault occurs in the power grid, the present invention connects a resistor between the static contact and the moving contact through a transition unit, and the resistance value of this resistor gradually increases, consuming the large short-circuit current, and making the static contact and the moving contact open circuit after the resistance value increases to a certain value. Different from the existing circuit breakers that directly open circuit after a short circuit in the circuit, the present invention consumes the influence of the short-circuit current by connecting a resistor with a gradually increasing resistance value, avoiding the damage caused by the current concentrating on a certain circuit breaker that opens later due to the incomplete synchronization of the opening time of the existing circuit breakers. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic structural diagram of Embodiment 1.

[0029] Figure 2 It is a schematic diagram of the insulating rod in Embodiment 1.

[0030] Figure 3 It is a schematic connection diagram of the static contact and the insulating rod in Embodiment 1.

[0031] Figure 4 It is a schematic connection diagram of the moving contact and the insulating rod in Embodiment 1.

[0032] Figure 5 It is a schematic diagram of the conductive sleeve in Embodiment 1.

[0033] Figure 6 It is a cross-sectional schematic diagram of the conductive sleeve in Embodiment 1

[0034] Figure 7 It is a schematic diagram of the working state of Embodiment 1.

[0035] Figure 8 It is an equivalent circuit diagram of the working state of Embodiment 1.

[0036] Figure 9 It is a schematic structural diagram of Embodiment 2.

[0037] Figure 10 It is a schematic structural diagram of Embodiment 3.

[0038] Figure 11 It is an equivalent circuit schematic diagram of Embodiment 3.

[0039] 1. Static contact; 1-1. Base; 1-2. Spring-type pressure electrode; 2. Moving contact; 2-1. Conductive sleeve; 2-1-1. Mounting hole; 2-1-2. Ball; 2-2-3. Copper wire spring; 2-2. Contact ring; 2-3. Arc extinguishing ring; 3. Insulating rod; 3-1. Groove; 3-2. Resistance wire; 4. Operating pull rod; 5. Connecting wire; 6. Vacuum cover; 7. Bellows. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] Example 1: This example is a circuit breaker device, which is equipped with dozens or hundreds of pairs of sleeve variable resistance sliding pressure type large-capacity arc-extinguishing circuit breakers depending on the short-circuit current capacity of the power grid. The circuit breakers are connected in series or parallel to meet the shunt capacity requirements.

[0041] In this example, the sleeve variable resistance sliding pressure type large capacity arc extinguishing circuit breaker comprises a static contact, a moving contact and a transition unit, and the transition unit comprises an insulating rod, a resistance wire and an operating mechanism.

[0042] In this embodiment, the lower sidewall of the insulating rod is formed with a threaded groove that winds around the rod. A resistance wire is embedded in the groove, and its surface is flush with the sidewall of the rod. In this embodiment, the resistance wire is located in the lower section of the insulating rod. The portion of the insulating rod with the resistance wire is the resistance section, and the upper portion of the insulating rod without the resistance wire is the insulation section.

[0043] In this embodiment, the static contact has a base and a spring-type pressure electrode located on the upper end surface of the base. The base and the spring-type pressure electrode are coaxially fixed to the lower end of the insulating rod. The spring-type pressure electrode contacts the resistance wire on the insulating rod and can conduct electricity.

[0044] In this example, the moving contact has a conductive sleeve, a contact ring and an arc extinguishing ring, wherein the conductive sleeve is coaxially sleeved on the insulating rod and can move back and forth along the axial direction of the insulating rod, and the inner wall of the conductive sleeve is provided with a contact mechanism that contacts the side wall of the insulating rod and the resistance wire on the insulating rod. When the contact mechanism contacts the resistance wire on the insulating rod, the resistance wire and the conductive sleeve are connected; the contact ring can be sleeved on the insulating rod and can move back and forth along the axial direction of the insulating rod, and the contact ring is fixed to the lower end of the conductive sleeve. When the contact ring moves downward to contact the spring-loaded pressure electrode on the static contact, direct conduction is achieved between the moving contact and the static contact; a plurality of holes for absorbing arcs are provided on the inner wall of the arc extinguishing ring, and the arc extinguishing ring can be sleeved on the insulating rod and can move back and forth along the axial direction of the insulating rod, and the arc extinguishing ring is fixed on the inner wall of the contact ring.

[0045] In this example, the contact mechanism has a number of balls evenly arranged on the inner wall of the conductive sleeve. The balls are installed in the mounting holes on the inner wall of the conductive sleeve. A copper wire spring is provided in the mounting hole. The copper wire spring pushes the balls toward the insulating rod so that the balls contact the side wall of the insulating rod or the resistance wire on the insulating rod.

[0046] In this embodiment, the moving contact is connected to the operating mechanism via the operating pull rod, and the operating mechanism can drive the moving contact to move back and forth along the axial direction of the insulating rod.

[0047] In this embodiment, the insulating rod is made of ceramic, and the resistance wire material is iron-nickel-chromium alloy wire, titanium, or alloy wire with high resistivity such as iron, chromium, and aluminum alloys. The resistance value of the resistance wire on each minute unit screw rod is 0.001 Ω to 0.25 Ω. The cross-sectional area of the resistance wire selected should also meet the requirements of thermal stability of short-circuit current (iron-chromium-aluminum alloy or titanium wire, typical model OCr27A17M02).

[0048] The working principle of this embodiment is as follows:

[0049] When the power grid is normal, when the moving contact, the contact ring on the static contact, and the spring-type pressure electrode are completely closed, the sleeve-type electrode pair is completely connected. At this time, the circuit breaker contact group unit is in the closing state, and the resistance is zero during closing.

[0050] When the power grid is short-circuited, the operating mechanism drives the moving contact to move upward along the insulating rod and separate from the static contact. When the moving contact moves to the middle position of the resistance section on the insulating rod, the moving contact contacts the resistance wire on the insulating rod through the contact mechanism, and one section of the resistance wire is connected in series to the main circuit. At this time, it is in the process of opening, and the resistance value of the electrode is in the process of changing from small to large during the opening process.

[0051] When the operating mechanism pulls the moving contact upward and continues to move to the last turn position at the top of the resistance wire, the resistance value of the resistance wire connected in series is at the maximum value. Continuing to move upward will completely separate the electrical connection between the moving and static contacts. An arc will be generated when the contacts are separated, and the arc extinguishing ring slides and presses to extinguish the arc. The moving contact stops after moving to the set position L1, forming an insulating distance d. This position is called the opening state of the circuit breaker.

[0052] Embodiment 2: This embodiment is basically the same as Embodiment 1, except that in this embodiment, the insulating rod, the static contact, and the moving contact are all arranged in a vacuum housing. A bellows is provided in the vacuum housing. One end of the bellows is connected to one end in the vacuum housing, and the other end of the bellows is connected to the moving contact through a cover. The operating pull rod between the moving contact and the operating mechanism is arranged in the bellows.

[0053] Embodiment 3: This embodiment is basically the same as Embodiment 1 or Embodiment 2, except that in this embodiment, the insulating rod is axially divided into several minute units along its axis. Each minute unit has a resistance section and an insulating section. A static contact and a moving contact are provided corresponding to each minute unit. The static contact is sleeved and fixed at the lower end of the minute unit, and the moving contact is movably sleeved on the minute unit. The moving contact and the static contact on the adjacent minute unit are conductively connected through a connecting wire. The moving contacts on the insulating rod are jointly connected to the operating mechanism. In this embodiment, the operating mechanism drives the moving contact to move a short distance to connect a larger resistance to the circuit.

[0054] Design a high-voltage circuit breaker device with a rated voltage of 220 kV and a short-circuit breaking current of 80 kA.

[0055] According to this design scheme, the breaking current is 80 kA. Each branch is designed to break a short-circuit current of 1500 A, and the normal load current is 75 A. Therefore, the circuit breaker needs

[0056] parallel branches to achieve the breaking capacity.

[0057] Design a vacuum sleeve type resistance electrode pair for the switch unit. 2 Design an insulating rod with a diameter of Φ = 60 mm. Wind a rectangular resistance wire on the insulating rod with dimensions: area S = 4.2 mm × 6 mm = 25.2 mm

[0058] The resistance value of this resistance is taken as R = 0.1 Ω / m per meter.

[0059] The thread pitch of the insulating rod is processed to be 10 mm. Select a resistance wire of Fe-Cr-Al type 1Cr13A14 or titanium wire material. The embedded length of the resistance wire in the ceramic column is 9 cm, and it is wound around the lead screw for a total of 8 turns. The length of each turn L = πD = 3.14 × 6 cm ≈ 18.8 cm. The resistance value of each turn R1 = 0.014 Ω. When there are 2 turns, the resistance R2 = 0.028 Ω. The resistance value when there are all 8 turns.

[0060] R8 = 8 × 0.188 × 0.075 = 0.112 Ω

[0061] Design of the insulation gap

[0062] Set the space gap d1 generated after each sub-unit moves from the moving contact to the static contact of the upper-level sub-unit to be 3 cm. In this way, the total stroke length L of the operating pull rod = 3 + 9 = 11 cm. After the lead screw moves 11 cm, a gap distance of 3 cm can be generated on each sub-unit. When there are 16 levels, the total gap value. δ = 3 × 16 = 48 cm. This gap value can meet the insulation requirements of a 220 kV high-voltage switch. Usually, a gap of 15 - 20 cm in vacuum can meet the requirements.

[0063] It can be seen from the above that the operating pull rod has an insulation stroke amplification effect, that is, the pull rod only runs 11 cm, but generates an actual insulation distance of 48 cm. The insulation effect generated by the lengthened gap is very obvious, which has an obvious operating advantage compared with the 1:1 stroke gap break distance in traditional circuit breakers. Such a method can greatly improve the operating speed of the switch and shorten the breaking time of the circuit breaker.

[0064] After 16 sub-units are connected in series and assembled into the vacuum glass sleeve, and upper and lower conductive rods and upper and lower bellows are set, the basic shunt branch of this circuit breaker is formed, and the sleeve-type resistance electrode pairs the switching unit.

[0065] 2.5 The number of stages in multi-stage series is determined by the insulation resistance level, such as:

[0066] For 110 kV, the length is 20 cm and the number of series stages is 5;

[0067] For 220 kV, the length is 30 cm and the number of series stages is 10;

[0068] For 500 kV, the length is 50 cm and the number of series stages is 20;

[0069] The air gap is 3×20 = 60 cm

[0070] The method of multi-stage series is used to solve the problem of long insulation gap. According to the principle of stroke amplification, when the stroke of the operating rod is 10 cm, the generated gap can reach the effect of 50 - 60 cm. This creates favorable conditions for the relationship between the pull rod and the hydraulic speed and length, and an air gap of 30 - 60 cm can be generated within a 10-cm stroke to achieve the rapidity of the switch.

Claims

1. A sleeve variable resistance sliding compression type large-capacity arc extinguishing circuit breaker, characterized in that, It has: a static contact; a moving contact, with a resistance value of 0 between it and the static contact when the power grid is normal; a transition unit, which can connect a resistor between the static contact and the moving contact when the power grid is short-circuited, and the resistance value of the resistor gradually increases from 0. After the resistance value reaches a certain value, the static contact and the moving contact are disconnected; the transition unit has an insulating rod, a resistance wire and an operating mechanism; the insulating rod is divided into an insulating section at the upper end and a resistance section at the lower end. A threaded groove wound around the insulating rod is formed on the side wall of the resistance section, and a resistance wire is embedded in the groove, and the surface of the resistance wire is flush with the side wall of the insulating rod; the static contact is sleeved and fixed at the lower end of the insulating rod and is electrically connected to the resistance wire on the insulating rod; the moving contact is sleeved on the insulating rod and can move axially along the insulating rod. The moving contact has a conductive sleeve coaxially sleeved on the insulating rod. A contact ring coaxially sleeved on the insulating rod and capable of contacting and conducting electricity with the lower static contact is fixed at the lower end of the conductive sleeve. An arc extinguishing ring coaxially sleeved on the insulating rod is formed inside the contact ring. A contact mechanism capable of contacting and conducting electricity with the resistance wire on the insulating rod is formed on the inner wall of the conductive sleeve; the operating mechanism is connected to the moving contact and is used to drive the moving contact to move axially along the insulating rod; when the power grid is normal, the conductive sleeve in the moving contact is directly conducted through the contact ring with the static contact; when a short-circuit fault occurs in the power grid, the operating mechanism drives the moving contact to move axially away from the static contact along the insulating rod. The contact ring in the moving contact is separated from the static contact. The conductive sleeve in the moving contact is directly conducted through the contact mechanism and the resistance wire with the static contact. And as the moving contact moves, the resistance value of the resistance wire connected between the conductive sleeve and the static contact gradually increases; after the operating mechanism drives the moving contact to move to the insulating section of the insulating rod, the contact mechanism on the conductive sleeve only contacts the side wall of the insulating rod, and the conductive sleeve is disconnected from the static contact.

2. The sleeve variable resistance sliding compression type large-capacity arc extinguishing circuit breaker according to claim 1, characterized in that: the contact mechanism has a number of balls evenly arranged on the inner wall of the conductive sleeve. The balls are installed in the installation holes on the inner wall of the conductive sleeve, and a copper wire spring for pushing the balls towards the insulating rod to contact the side wall of the insulating rod is arranged in the installation holes.

3. The sleeve variable resistance sliding compression type large-capacity arc extinguishing circuit breaker according to claim 1, characterized in that: It has a vacuum cover body, and the insulating rod, the static contact and the moving contact are all arranged in the vacuum cover body.

4. The sleeve variable resistance sliding compression type large-capacity arc extinguishing circuit breaker according to claim 3, characterized in that: a bellows is arranged in the vacuum cover body. One end of the bellows is connected to one end in the vacuum cover body, and the other end of the bellows is connected to the moving contact through a cover. The operating pull rod between the moving contact and the operating mechanism is arranged in the bellows.

5. The sleeve variable resistance sliding compression type large-capacity arc extinguishing circuit breaker according to claim 1, characterized in that: the insulating rod is made of a ceramic rod; the resistance wire is made of an alloy wire with a high resistivity. The resistance value of the resistance wire on the insulating rod is 0.001Ω~0.25Ω; the material of the arc extinguishing ring is alumina or magnesia high-temperature resistant ceramic, or a polytetrafluoroethylene high-temperature resistant insulating material.

6. The sleeve variable resistance sliding compression type large-capacity arc extinguishing circuit breaker according to claim 1, characterized in that: a number of holes for absorbing electric arcs are formed on the inner wall of the arc extinguishing ring.

7. The sleeve variable resistance sliding compression type large-capacity arc extinguishing circuit breaker according to claim 1, characterized in that: the static contact includes a spring-type pressure electrode at the upper end and a base at the lower end.

8. An open circuit device, characterized in that: There are a number of sleeve variable resistance sliding compression type large-capacity arc extinguishing circuit breakers as described in any one of claims 1 to 7 connected in parallel or in series.

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