Three-phase automatic balancing device with reactive compensation

Abstract

The invention discloses a three-phase automatic balancing device with reactive compensation, which is arranged between a load and a transformer and comprises an acquisition unit, a control unit and apower unit. The acquisition unit is connected with the signal input end of the control unit; the control unit is connected with the control end of the power unit, and the power unit is electrically connected with the wire inlet end of the load through an electric reactor; the acquisition unit comprises a current transformer and a voltage transformer; the control unit comprises a DSP main control chip and an FPGA signal generator, and the power unit comprises an H-bridge type multi-level circuit composed of a plurality of insulated gate bipolar transistors; the current transformer and the voltage transformer are connected with the signal input end of the DSP main control chip; the DSP main control chip is connected with the control end of the H-bridge type multi-level circuit through the FPGA signal generator, and the H-bridge type multi-level circuit is connected with the wire inlet end of the load through the reactor so as to output three-phase imbalance compensation currents. The device can automatically solve the problem of unbalanced three-phase loads, manual intervention is not needed, and worry and labor are saved.

Description

technical field [0001] The invention relates to the field of power distribution and utilization, in particular to a three-phase automatic balancing device with reactive power compensation. Background technique [0002] In recent years, my country's distribution network construction investment has continued to increase, and the development of distribution network has achieved remarkable results. However, there is still a gap between the level of electricity consumption and the international advanced level. The development of urban and rural areas is unbalanced, and the quality of power supply needs to be improved. [0003] In the low-voltage three-phase four-wire system of urban residents and rural power supply systems: because most of the power consumers are single-phase loads or mixed single-phase and three-phase loads, and the loads are different and the power consumption time is different. Therefore, the unbalanced current among the three phases in the grid exists objecti...

AI Technical Summary

Problems solved by technology

[0005] 1) The active power or power loss of the line increases

[0006] 2) Increased power loss of distribution transformers

[0007] 3) The output of the distribution transformer is reduced

[0008] 4) The operating temperature of the distribution transformer rises and the service life is shortened

[0009] 5) The neutral point is displaced, and the three-phase voltage of the distribution transformer is unbalanced

[0013] Although these two methods can achieve the purpose of three-phase balance, but the former is adjusted by manual commutation, which requires power failure in the low-voltage station area

Although the installation of an automatic phase change switch does not require a power outage and can automatically reverse the direction, the automatic phase change operation for a single-phase load cannot achieve optimal balance (that is, if the load itself cannot be balanced, no matter how the direction changes, it cannot meet the requirements). The zero-sequence current of the three-phase load is 0), and it is not suitable for use in applications with large load fluctuations, because when the phase is changed frequently, the cut-off during the phase change may cause overvoltage or cause instantaneous voltage interruption

[0014] At present, there is a lack of a device that can automatically adjust the three-phase load and perform continuous compensation without interrupting the user's power supply

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