A Unified Power Quality Conditioner for Medium Voltage Distribution Network

Abstract

The invention discloses a unified power quality regulator used in a medium-voltage distribution network. The invention includes three single-phase energy storage type conversion units corresponding to each phase of the ABC three-phases, and three single-phase multi-windings connected in parallel. type transformer and three single-phase series-connected transformers. The single-phase energy storage type conversion unit includes 2n first units and n second units. The first unit includes a single-phase full-bridge AC-DC converter and a bidirectional DC-DC converter on the power supply side. A DC converter, an energy storage device, and a load-side bidirectional DC-DC converter, and the second unit includes a three-phase six-leg DC-AC converter. The invention is mainly used in medium-voltage distribution networks with medium-level (10kV or 35kV) voltage levels. It can suppress the harmonic current on the load side, balance the three-phase current of the distribution transformer, improve the utilization rate of the transformer, dynamically compensate the reactive power of the load, and improve the distribution efficiency. The network power factor can be quickly compensated for the active power of the load, and the stability and reliability of the user's power supply voltage can be improved.

Description

technical field [0001] The invention relates to the technical field of power systems, in particular to a unified power quality regulator for medium-voltage distribution networks. Background technique [0002] As a secondary energy source that is economical, practical, clean, convenient, and easy to control and convert, electric energy has become an important basis for economic development and people's lives. With the wide application of power electronic equipment, various non-linear, impulsive, fluctuating and asymmetrical loads have increased substantially, resulting in problems such as unbalanced three-phase voltage, voltage sag, harmonics, low power factor, negative sequence Power quality problems such as high current content. At the same time, due to the large variation range of the distribution network load, it is difficult to adjust the distribution network voltage, and the power supply voltage is high or low, and even the voltage exceeds the limit. Therefore, how to...

AI Technical Summary

Problems solved by technology

However, when multiple power quality problems coexist in a power supply area, multiple different target control devices need to be used together. At present, due to the lack of coordination between multiple devices, it may cause repeated compensation for some power quality problems. Or interact with each other, so that the governance of power quality cannot achieve the desired effect

In addition, there may be repeated installation of power quality control devices with similar functions, resulting in waste of control funds

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