Intelligent electrical load unbalance compensation device

Abstract

The invention discloses an intelligent electrical load unbalance compensation device, which belongs to the technical field of low voltage power distribution networks. The intelligent electrical load unbalance compensation device comprises a central control device, and a current and voltage sampling device, a zero sequence compensation device and a negative sequence compensation device which are in control connection with the central control device, wherein the current and voltage sampling device is used for collecting current and voltage signals of a load circuit; the zero sequence compensation device consists of a zigzag transformer TR and an impedance dynamic regulation device; and the negative sequence compensation device consists of combination switches FK1 to FK3, and grouped-switched compensation capacitors of each phase. The device can filter zero sequence current to be within 1A in a rated unbalanced load, increase the unbalance of three phases of current to be within 10 percent, ensure high electric energy utilization rate, safe and reliable running and remarkable energy saving effects, reduce loss and cost and improve the economic efficiency. The whole device is connected into a power grid in parallel, and is convenient to arrange, simple to use and applied to the low voltage power distribution networks of industrial mining, enterprises, traffic transportation department, residential areas and the like.

Description

technical field [0001] The invention belongs to the technical field of electric low-voltage distribution network, in particular to an intelligent compensation device for unbalanced electric load. Background technique [0002] In the traditional three-phase four-wire distribution transformer wiring system in China, due to various reasons such as the low-voltage single-phase load cannot be fully divided manually, the actual operating rate of the distributed load is different, and the unbalanced three-phase load is unavoidable. of. And this unbalanced three-phase load will inevitably lead to increased loss, decreased power efficiency, increased zero-sequence current, and shortened service life of equipment. [0003] Harm to the transformer: The unbalanced three-phase load will make the transformer run asymmetrically, which will increase the loss of the transformer. According to the transformer operating regulations, the neutral current of the transformer in operation cannot e...

AI Technical Summary

Problems solved by technology

In addition, the unbalanced three-phase load will cause excessive zero-sequence current of the transformer, increase the temperature of some metal parts, and even cause the transformer to burn out

[0004] Neutral line and neutral point voltage problems: The zero-sequence current of the neutral line is too large, causing the neutral line to burn out, causing problems such as excessive neutral point voltage offset

[0005] Harm to electrical equipment: Unbalanced three-phase voltage will increase the reverse torque in the motor, which will cause the motor to heat up, reduce efficiency, and increase energy consumption.

Therefore, the imbalance of three-phase voltage will shorten the service life of electrical equipment, accelerate the replacement frequency of equipment parts, and increase equipment maintenance costs.

[0006] At present, the phase-separated reactive power compensation device with the best compensation effect on the market can compensate the load, but it can only compensate for the reactive current part in the system, but it is powerless for the asymmetrical active current part. The current imbalance may be even greater, so the power supply department of the electric industry can only use manual branching to adjust the load

[0007] It can be seen from the above that the three-phase imbalance of the power system has very serious harm and influence on transformers, electrical equipment and power systems, especially it constitutes a great obstacle to the full and effective use of electric energy.

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