Three-phase unbalance adjusting device

Abstract

The invention discloses a three-phase unbalance adjusting device, comprising: an acquisition module for acquiring current signals from a power grid, a controller, a three-level converter, a driving module, a plurality of capacitors and a group switch. The converter is used for connecting capacitors to the each phase by the group switch so as to transfer active current of each phase; the converteris also used for analyzing current signals to obtain a positive sequence component, a negative sequence component and a zero sequence component of the unbalanced current, and generating a drive signalaccording to the positive sequence component, the negative sequence component and the zero sequence component; the driving module is used for driving the three-level converter to output compensationcurrent which is opposite to the negative sequence component and the zero sequence component after receiving the drive signal. According to the three-phase unbalance adjusting device, three-phase unbalanced current is firstly passive compensated, then three-phase unbalanced current is active compensated, three-phase equilibrium state of the current of the power grid side is reached, the negative sequence component and the zero sequence component are eliminated, power supply quality can be improved, and stability of safe operation of the power grid can be improved.

Description

technical field [0001] The invention relates to the field of power distribution, in particular to a three-phase unevenness regulating device. Background technique [0002] Three-phase unbalance means that the three-phase current (or voltage) amplitudes in the power system are inconsistent, and the amplitude difference exceeds the specified range. In the low-voltage three-phase four-wire rural power supply system, most of the distribution transformers use three-phase transformers. The three-phase load at the transformer outlet should be symmetrical in theory, but because most of the users are single-phase loads, the load distribution is uneven. Balanced, it is easy to generate a large amount of unbalanced current, which will reduce the quality of power supply, and at the same time, the safe operation of low-voltage power grid and electrical equipment will be seriously threatened. [0003] Therefore, how to provide a solution to the above technical problems is a problem that ...

AI Technical Summary

Problems solved by technology

In the low-voltage three-phase four-wire rural power supply system, most of the distribution transformers use three-phase transformers. The three-phase load at the transformer outlet should be symmetrical in theory, but because most of the users are single-phase loads, the load distribution is uneven. Balanced, it is easy to generate a large amount of unbalanced current, which reduces the quality of power supply, and at the same time, the safe operation of low-voltage power grid and electrical equipment is seriously threatened

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