Three-phase low voltage distribution voltage-reducing device

Abstract

The invention discloses a three-phase low voltage distribution voltage-reducing device, which comprises two three-phase multi-winding transformers and an electronic combination switch, a detection module, a primary control module and a zero-crossing triggering module, wherein the primary windings of the two transformers are connected in parallel through the combination switch and simultaneously are connected with the three-phase power supply, outgoing lines of secondary windings connected in series are connected with the main power supply and the load; the detection module is used to detect the detection value of voltage output by the transformer;, the primary control module sends out a control signal according to the detection value, thus the zero-crossing triggering module produces a high level or low level signal to control the on and off of the electronic combination switch. Different on-and-off combinations of the electronic combination switch can obtain an 8421 coded combination, so the output voltage of the transformer can realize 16 stage differences and the precise of voltage regulation can be improved; the secondary windings are respectively wound on different iron cores, thus playing the role of a voltage-sharing reactor, balancing three-phase voltage and current, reducing the negative sequence component and zero sequence component of a distribution system and reducing the power consumption.

Description

technical field [0001] The application relates to the technical field of low-voltage power distribution, in particular to a three-phase low-voltage power distribution step-down device. Background technique [0002] In the 380V low-voltage power distribution system, the voltage level is determined by the power supply system and cannot be adjusted according to the needs of power users. The output voltage of the power supply is increased by 5%, so in general, the power supply voltage of the power user is relatively high. When the power consumption is low, the power supply voltage of the power user end can reach 420V-430V, resulting in waste of power. [0003] Since power users cannot adjust the voltage in real time, on the one hand, excessive voltage causes waste of electric energy and shortens the service life of electrical equipment; on the other hand, each power unit has different single-phase loads, which often cause three-phase current The unbalance leads to unbalanced th...

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Problems solved by technology

[0002] In the 380V low-voltage power distribution system, the voltage level is determined by the power supply system and cannot be adjusted according to the needs of power users. The output voltage of the power user is increased by 5%, so in general, the power supply voltage of the power user is relatively high. When the power consumption is low, the power supply voltage of the power user end can reach 420V-430V, resulting in waste of power

[0003] Since power users cannot adjust the voltage in real time, on the one hand, excessive voltage causes waste of electric energy and shortens the service life of electrical equipment; on the other hand, each power unit has different single-phase loads, which often cause three-phase current The unbalance leads to unbalanced three-phase voltage, which causes the neutral point shift of the three-phase system and increases the negative sequence magnetic field loss, thereby increasing the power consumption

[0004] The three-phase low-voltage power distribution step-down device can adjust the voltage value received by the user end. The existing three-phase low-voltage power distribution step-down device usually adopts the form of autotransformer voltage regulation. Since the autotransformer is equipped with several fixed points Connectors, only rough adjustments can be achieved, fine adjustments are difficult to achieve, and the phenomenon of unbalanced three-phase voltages cannot be eliminated

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