CN-224217417-U - Arc striking assembly and direct-current neutral point isolating switch

CN224217417UCN 224217417 UCN224217417 UCN 224217417UCN-224217417-U

Abstract

The arc striking assembly and the direct current neutral point isolating switch are used for solving the problems that the service life and the reliability of the switch are affected due to contact ablation and insulation performance reduction caused by the fact that an arc is difficult to be quickly and stably extinguished by an existing oscillating circuit. The direct-current neutral point isolating switch comprises an operating mechanism, a transmission assembly, a base, operating insulators, contact finger side conductive seats and arc striking assemblies, wherein the output end of the operating mechanism is provided with a transmission rod, the operating insulators are rotatably arranged on the upper portion of the base, the transmission assembly is positioned between the transmission rod and each operating insulator, the contact finger side conductive seats and the contact finger side conductive seats are both fixed on the upper portions of the corresponding operating insulators, square tube supports of the arc striking assemblies are fixedly connected with the corresponding contact finger side conductive seats or the corresponding contact finger side conductive seats, and the square tube supports arranged on the contact finger side conductive seats and the contact finger side conductive seats are driven to rotate when the contact finger side conductive seats and the contact finger side conductive seats rotate. The utility model has four fractures in total, can equally divide the total voltage to each fracture, and obviously reduces the electric field intensity of a single fracture.

Inventors

LIU JIAXIN
Tian changxing
TIAN CHAO
XIN ZIPEI
LU LIFU
Mi Jiushen

Assignees

山东泰开隔离开关有限公司

Dates

Publication Date: 20260508
Application Date: 20250524

Claims (10)

1. The arc striking assembly is characterized by comprising a contact finger side arc striking contact, a contact side arc striking contact, an arc striking rotating shaft, a square tube support and a rotating shaft supporting cylinder, wherein a first end of the contact finger side arc striking contact and a first end of the contact side arc striking contact are respectively provided with a touch plate, a second end of the contact finger side arc striking contact and a second end of the contact side arc striking contact are respectively fixed on the arc striking rotating shaft at the corresponding side, the arc striking rotating shaft penetrates through the rotating shaft supporting cylinder and is rotationally connected with the rotating shaft supporting cylinder, the square tube support is fixed at the lower part of the rotating shaft supporting cylinder, the lower end of the arc striking rotating shaft penetrates through the square tube support, a tension spring is arranged in the square tube support, and the first end of the tension spring is fixedly connected with the square tube support through a first tension spring rod, and the second end of the tension spring is fixedly connected with the lower end of the arc striking rotating shaft through a second tension spring rod.
2. The arc striking assembly of claim 1, wherein the second end of the contact finger side arc striking contact and the second end of the contact side arc striking contact are fixedly connected to the arc striking shaft by a clamping plate.
3. The arc striking assembly of claim 2, wherein the first end of the finger side arc striking contact, the first end of the contact side arc striking contact, and the side wall of the corresponding contact plate each have a slot.
4. The arc striking assembly according to claim 3, wherein the first end of the first tension spring rod is fixedly connected with the square tube support, the first end of the tension spring is hooked at the second end of the first tension spring rod, the first end of the second tension spring rod penetrates through the arc striking rotating shaft, and the second end of the tension spring is hooked at the second end of the second tension spring rod.
5. The direct current neutral point isolating switch comprising the arc striking assembly according to any one of claims 1 to 4 is characterized by comprising an operating mechanism, a transmission assembly, a base, an operating insulator, a contact finger side conductive seat and a contact finger side conductive seat, wherein the operating mechanism is positioned below the base, the output end of the operating mechanism is provided with a transmission rod, the operating insulator is rotatably arranged on the upper part of the base, the transmission assembly is positioned between the transmission rod and each operating insulator, the transmission rod drives the operating insulator to rotate through the transmission assembly when rotating, the contact finger side conductive seat is provided with a contact finger, the contact finger side conductive seat is provided with a contact, the contact finger side conductive seat and the contact finger side conductive seat are respectively fixed on the upper part of the corresponding operating insulator, and a square tube support of the arc striking assembly is fixedly connected with the corresponding contact finger side conductive seat or the contact finger side conductive seat, and the contact finger side conductive seat rotate to drive a square tube support arranged on the contact finger side conductive seat to rotate.
6. The dc neutral-point disconnector of claim 5, in which the operating insulators have two groups, each group comprising three operating insulators disposed in a left-middle-right direction, the contact-side conductive holder being fixed to an upper portion of the intermediate insulator, and the finger-side conductive holder being fixed to upper portions of the operating insulators on the left and right sides.
7. The dc neutral-point disconnector of claim 6, in which the contact-finger-side conductive seats in the upper part of the right-hand operating insulator in the first group and the contact-finger-side conductive seats in the upper part of the left-hand operating insulator in the second group are fixedly connected by a connecting plate.
8. The direct current neutral point isolating switch according to claim 7, wherein the transmission assembly comprises a crank arm, a main knife pull rod, a driving flange, a phase separation pull rod, a pole separation pull rod, a horizontal connecting rod, a first driven flange and a second driven flange, wherein in the first group of operation insulators, the driving flange is fixed at the lower end of the right side operation insulator, the first driven flange is fixed at the lower end of the left side operation insulator, the second driven flange is fixed at the lower end of the middle operation insulator, the first driven flange is fixed at the lower end of the left side operation insulator and the right side operation insulator, the second driven flange is fixed at the lower end of the middle operation insulator, the first end of the crank arm is fixedly connected with the upper end of the transmission rod, the second end of the crank arm is connected with the driving flange through a hinge of the main knife pull rod, the driving flange is connected with the first driven flange on the first group of operation insulator through the phase separation pull rod, the driving flange is connected with the second driven flange on the first group of operation insulator through the pole separation pull rod, the phase separation pull rod is connected with the second driven flange on the first group of operation insulator through a second hinge of the second driven flange on the first group of operation insulator, the second driven flange is connected with the second driven flange through another phase separation pull rod and the second driven flange on the second group of operation insulator through another phase separation pull rod.
9. The dc neutral point disconnector of claim 8, in which the driving flange, the first driven flange and the second driven flange are each rotatably connected to the base via a bearing housing.
10. The direct current neutral point isolating switch as defined in claim 9, wherein the bearing seat comprises a framework oil seal, a gasket, a flange plate supporting bearing, a baffle cover and a shell, the driving flange plate, the first driven flange plate and the second driven flange plate are all provided with flange plate shafts, the flange plate shafts extend into the shell and are provided with two flange plate supporting bearings arranged up and down, the framework oil seal and the gasket are arranged between the upper end of the flange plate shafts and the shell, the lower end of the flange plate shafts are fixedly provided with plates through bolts, and the baffle cover is positioned at the lower end of the shell to seal the shell.

Description

Arc striking assembly and direct-current neutral point isolating switch Technical Field The utility model relates to the technical field of isolating switches, in particular to an arc striking assembly and a direct-current neutral point isolating switch. Background The direct-current neutral point isolating switch NBS is core equipment for realizing neutral bus potential regulation and control, system topology reconstruction and fault quick isolation in a high-voltage direct-current power transmission system. In the scenes of a flexible direct current power grid, offshore wind power direct current collection and the like, NBS is required to complete on-load switching operation in millisecond time, and meanwhile, coupling impact of bidirectional heavy current and high voltage gradient is born. The technical scheme with an oscillating circuit is widely adopted by the existing DC neutral point isolating switch in China, the design can realize basic functions under the traditional working condition, but the technical limitation of (1) the inefficiency of electric arc energy management is gradually shown in a complex electric power system scene, and the oscillating circuit artificially makes a current zero crossing point through current oscillation to assist arc extinction, but the problem of overlong arcing time is faced in a DC system. Studies have shown that when the transfer current exceeds 3000A, the arc plasma temperature can reach above 15000K, whereas the energy dissipation efficiency of conventional oscillating circuits is only about 85%. Under the frequent current impact caused by new energy grid connection, the contact ablation rate is as high as 0.12 mm/thousand times of operation, and the 20000 times of mechanical life requirements are difficult to meet. (2) In the multi-fracture serial structure, the requirement of the oscillating circuit on the fracture opening synchronism is extremely high and is less than or equal to 0.3ms. However, the existing mechanical transmission system is affected by insufficient rigidity of a connecting rod and tolerance accumulation errors, the actual brake-separating time difference is often more than 2ms, so that the first fracture bears more than 75% of system voltage, for example, the first fracture voltage reaches 15.75kV under the 21kV working condition, the first fracture voltage obviously exceeds a 12kV design threshold value, and the risk of dielectric breakdown is caused. (3) The NBS with the tank circuit has an inherent defect in suppressing ferromagnetic resonance. When the system has intermittent arc grounding fault, the high-frequency oscillation current can reach hundreds of amperes, and the traditional scheme can not effectively block the repeated charging and discharging process of the capacitor energy, so that arc overvoltage or resonance overvoltage can reach 3-5 times of rated voltage, and the insulation of equipment is threatened. For example, the ferromagnetic resonance phenomenon of a neutral point ungrounded system is prone to failure such as PT burnout due to lack of an effective energy release channel. (4) The environment adaptability is limited, and the sensitivity of the oscillation loop to the running environment is higher. In offshore wind power scenes, salt spray corrosion can lead contact resistance deviation of a contact to exceed 5 mu omega, oxide film formation is accelerated, meanwhile, mechanical vibration can cause loop parameter deviation, such as fluctuation of an inductance value of +/-10%, and preset oscillation frequency misalignment is caused, and arc extinguishing efficiency is reduced by more than 40%. The existing protective cover mostly adopts common epoxy resin, is difficult to resist arc heat radiation, and obviously increases the risk of surface carbonization and electric leakage. (5) The operation and maintenance economy is bad, the precise inductance element in the oscillation circuit needs to be calibrated regularly, the single maintenance takes more than 72 hours, the core component depends on import, the price of spare parts is 2-3 times of that of domestic substitutes, and (6) the energy consumption is that the oscillation circuit needs to consume auxiliary power continuously, and obvious additional loss is formed in a large-scale direct current power grid. From the technical performance perspective, the NBS switch with the oscillating circuit type has room for improvement in terms of arc extinguishing effect and neutral point potential fluctuation suppression compared with some foreign NBS switches adopting unique innovative structures. When the domestic existing oscillating circuit is used for processing transient current with high amplitude and high frequency, the arc is difficult to be extinguished rapidly and stably, contact ablation and insulation performance reduction are easy to be caused, and therefore the service life and reliability of a switch are affected. Meanwhile, the control precision of the neutr