Alternating-current zero-crossing action non-arc switch and working method thereof

Abstract

The invention relates to an alternating-current zero-crossing action non-arc switch and a working method thereof. The alternating-current zero-crossing action non-arc switch comprises two neodymium-iron-boron strong magnets, an electromagnet, a solenoid and a main contact, wherein the two neodymium-iron-boron strong magnets comprise a first neodymium-iron-boron strong magnet and a second neodymium-iron-boron strong magnet; the two neodymium-iron-boron strong magnets and the electromagnet are arranged in the solenoid, the electromagnet is located between the two neodymium-iron-boron strong magnets, the two neodymium-iron-boron strong magnets with opposite polarities are used as pistons and driven by the electromagnet, and a push-pull piston type high-speed magnetic latching switch driven by the electromagnet is formed. The electromagnet is driven by the current of the solenoid, on and off of the switch are controlled by changing the current direction of the solenoid, a basis is provided for calculation of zero-crossing action, in order to achieve accurate zero-crossing action, the switch is further provided with a voltage zero-crossing detector and a current zero-crossing detector, and calculation data are provided for zero-crossing driving, so that the switch is connected during voltage zero-crossing and disconnected during current zero-crossing, thereby realizing alternating-current arc-free operation.

Description

technical field [0001] The invention relates to an AC zero-crossing action arcless switch and a working method thereof, belonging to the technical field of electric switches. Background technique [0002] The AC switch is one of the most widely used equipment in the power system. At present, the power loads of the power grid are almost all inductive loads. For inductive loads, because the voltage of the inductance can change suddenly, the current cannot change suddenly, so when the switch is turned on, the distance between the contacts decreases rapidly. , When the distance is less than the voltage breakdown distance, an electric spark (arc) will be generated. When the switch is turned off, the contacts will be separated from the contact state quickly, and the contact current will decrease rapidly (di / dt), which will generate a strong self-induced electromotive force , the strength of the self-inductance electromotive force is related to di / dt (current change rate), which is...

AI Technical Summary

Problems solved by technology

[0002] The AC switch is one of the most widely used equipment in the power system. At present, the power loads of the power grid are almost all inductive loads. For inductive loads, because the voltage of the inductance can change suddenly, the current cannot change suddenly, so when the switch is turned on, the distance between the contacts decreases rapidly. , When the distance is less than the voltage breakdown distance, an electric spark (arc) will be generated. When the switch is turned off, the contacts will be separated from the contact state quickly, and the contact current will decrease rapidly (di / dt), which will generate a strong self-induced electromotive force , the strength of the self-inductance electromotive force is related to di / dt (current change rate), which is generally 3 to 10 times the voltage value. Since the contact moves from the contact state to the disconnection state during the switch-off process, the self-induction electromotive force Much higher than the power supply voltage, the arcing time of breakdown is longer, and the arcing is stronger. Therefore, when the traditional switch operates, the arcing is inevitable, and in general, the arcing is stronger when it is turned off than when it is turned on. , the time is longer, the ablation of the contacts by the arc is serious, the life of the switch is shortened, and the reliability of the operation and personal safety are affected. For this reason, scientific workers have not stopped researching on arc prevention and arc extinguishing for many years. , has introduced, digested and promoted the application of medium and high voltage vacuum switches and SF6 high voltage switches. However, at present, vacuum switches can only be used in medium voltage power grids, and high voltage switches mainly use SF6 switches. However, SF6 switches do not meet environmental protection requirements and have not been found so far. Substitutes have become a major problem for power equipment

[0003] At present, low-voltage switches use air switches plus arc-proof covers to prevent arcing, medium-voltage switches use vacuum switches to suppress arcs, and high-voltage switches use SF6 switches to suppress arcs. As the voltage increases, the cost is getting higher and higher, and it is difficult to realize remote control. It is not suitable for the construction of smart grid, and it is still the fetters of smart grid construction

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