Special-shaped contact with self-repairing function

Abstract

The invention provides a special-shaped contact with a self-repairing function, which relates to the field of electricity, and adopts the scheme that the special-shaped contact comprises an upper wiring terminal, a lower wiring terminal and a contact, the contact is provided with a supporting core rod, and the supporting core rod penetrates through the contact and extends into a gap between the upper wiring terminal and the lower wiring terminal; the supporting core rod is located between the upper wiring terminal and the lower wiring terminal. The contact is provided with a contact contact surface, the contact contact surface is a curved surface or a special-shaped inclined surface structure formed by at least two inclined surfaces arranged at an angle, the upper wiring terminal and the lower wiring terminal are provided with terminal contact surfaces matched with the contact contact surface, and the contact contact surface and the terminal contact surfaces form an occlusion structure. A series of defects existing in a common direct-current switch contact and major potential safety hazards easily occurring during operation can be effectively eliminated.

Description

technical field [0001] The invention relates to the field of electrical technology, in particular to a special-shaped contact with self-repairing function. Background technique [0002] With the rapid development of modern industry, there is more and more demand for DC large current on-circuit switches, such as aluminum electrolysis process. According to the current situation of my country's aluminum and power process, the production capacity and scale of the series are continuously increasing, and the series current is also expanding. At present, the new series Some of the currents have reached 670KA, and the number of busbars in the series has also increased to 7. Each busbar has a DC current of nearly 100,000 amperes. Facing such a large amount of current, it is a huge challenge for the on-line control of its load on-off. The design and manufacture of the switch brings great difficulty. [0003] The particularity of direct current, the damage of high current to switch cont...

AI Technical Summary

Problems solved by technology

[0004] As we all know, direct current is different from alternating current in that it has no zero-crossing point and cannot be switched on and off at zero point, that is, zero voltage and zero current (that is, zero load operation). When controlling the switching of a DC circuit, it needs to be at full voltage and full current. (i.e.: full load operation), that is to say, in the on-off process, as a switch to control it, it needs to withstand the impact of DC current, especially in places with high currents (such as the above-mentioned control series busbar on and off operations) suffer The current impact of the switch will be very strong, because this kind of switch needs to control the on-off DC current is huge, in order to reduce the internal resistance, reduce the loss, and reduce the temperature rise, then it should have a large enough contact area and pressing force. In order to ensure that the dynamic and static contacts can carry a strong current and can work safely and reliably for a long time, otherwise the contact surface will be too small and the current density flowing between the contacts will be too large, which will increase the internal resistance and reduce power consumption. Increase, and make its temperature rise accordingly, if this situation exists and due to the positive temperature coefficient of the metal, as the contact temperature increases, its internal resistance will further increase, and its power consumption will also become exponential As the temperature increases, the temperature rise rate of the contacts will be faster, which forms a vicious cycle of accelerating temperature rise with the temperature rise: to a certain limit, the switch contacts will be melted and burned by the sharply increased high temperature, completely blocking the The circulating working current forms an open circuit. Due to the huge current it carries, a huge amount of energy will be released at the moment when the contact is burned. Under the impact of this energy, the switch will explode instantly and cause an accident, causing (serious) immeasurable damage to the factory. Therefore, in order to ensure the safe and reliable operation of this high-current DC switch, it must have a sufficiently large contact area, a sufficiently large cross-sectional area of ​​the conductor, a reasonable physical structure and a suitable metal properties, in order to effectively reduce the current density passing through it within the allowable range, so that its voltage drop, loss, and temperature rise are always controlled within a safe range, so as to ensure that dangerous accidents will not occur when the switch is closed with a large current load, and the protection It can be safely and smoothly turned on and off in a DC high current environment, but it will face many thorny problems and difficulties while increasing the contact area. If it is not solved, its effectiveness, safety and reliability cannot be guaranteed. In response to this problem, we have developed a set of safe and effective high-current DC switch contact protection mechanism according to the actual situation, which can effectively solve the above situation and avoid fusing accidents that are prone to occur when high-current DC switches are turned on and off. Eliminate the major safety hazards existing in its work, and successfully overcome the current thorny problem. For this, we make the following detailed analysis: 1. When increasing the contact area, due to the limitation of the process, it is difficult to do due to the existence of tolerances. The contact surfaces to the dynamic and static contacts are on the same mirror surface. Even on the same mirror surface, due to environmental and working conditions, it is difficult to ensure that they can be crimped together 100% (environmental particles enter, deformation caused by temperature difference, sparks generated during on-off Ablation traces, deviations of mechanical control mechanisms, etc.), when this situation occurs, the static and dynamic contacts will form single-point or multi-point partial contact, and cannot form a complete integration. When passing through, all the current will gather and flow between the local contact points, so that the current density of the contact points will seriously exceed the limit, forming a vicious circle of the above situation and causing major accidents

2. In view of the above, in actual use, multiple groups of small contacts are often connected in parallel, so that multiple small contacts are connected in parallel to increase their contact area and reduce their current density, so as to ensure their high performance when passing large currents. Safety factor, but there will be many problems in this way, (1) Since the current speed is close to the speed of light, it is difficult to synchronize with the electronic movement speed when multiple sets of contacts are closed and disconnected. When it is on, the DC current that should have flowed through all the contacts will all converge to pass through the contacts that are first closed and connected, then this group of contacts will instantly withstand a current impact that is many times larger than it, because the current density seriously exceeds Within the range it allows, this will cause severe sparking and burning damage between this group of contacts. In the slightest, the surface of the contacts will be burned, resulting in concave and convex ablation points, which will reduce the contact bonding efficiency and service life. In severe cases, it will melt instantly Burning, as the subsequent contacts that are continuously connected will form a stepped chain reaction, the contacts in the entire switch group will be damaged one by one, causing all contacts in the entire DC switch group to fail to achieve good closure and connection. As a result, the entire switch group forms a high resistance or open circuit phenomenon, prompting more serious accidents. When the DC switch group is disconnected, it is the same as the above situation; (2) With the increase of the set switch contacts, the control system and the arc extinguishing system will It becomes relatively complicated, the volume will increase accordingly, the failure rate will also increase accordingly, the safety factor will inevitably decrease accordingly, and it will inevitably lead to chain failures and cause losses over time

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