A dynamic voltage restorer for three-phase four-wire distribution network

Abstract

The invention provides a dynamic voltage restorer for a three-phase four-wire distribution network, comprising a coupling unit connected in series between the power grid and the output end of the restorer, a bridge inverter connected to the coupling unit, a filter unit, the DC energy storage unit and the charging unit for charging the DC energy storage unit, the secondary sides of the three isolated single-phase transformers TA, TB, and TC of the coupling unit are respectively connected in series with the three-phase power supply grid, and the three single-phase transformers The primary sides of TA, TB, and TC are connected to the filter unit on the inverter side, and the three bidirectional thyristors are respectively connected in parallel to the secondary sides of three single-phase transformers TA, TB, and TC as electronic switches. The three contactors are used to control the switching of the three bidirectional thyristors. The input terminals of the three single-phase bridge inverters are connected in parallel to the super energy storage capacitor C1, and the super energy storage capacitor C1 is connected to the output terminal of the three-phase full-bridge rectifier circuit through the charging resistor R, and the three-phase full-bridge rectifier circuit The input terminal of is connected to the access grid terminal Us through a three-phase transformer T.

Description

technical field [0001] The invention relates to a dynamic voltage restorer used in a three-phase four-wire distribution network, belonging to the technical field of power electronics. It is a technology that studies the application of power semiconductor switching devices to realize the conversion and control of electric energy, also known as power electronics technology. Background technique [0002] The application of modern power electronics technology can realize the control of power quality and provide users with specific power supply. At present, the main devices used are static compensator of power distribution system, active power filter, dynamic voltage restorer (DVR) and so on. A dynamic voltage restorer (DVR) is a series compensation device with an energy storage device, which has the ability to compensate active power in addition to reactive power. [0003] When the system voltage is disturbed, it often causes the voltage on the load side to drop or rise suddenl...

AI Technical Summary

Problems solved by technology

[0005] When a voltage asymmetry fault occurs in a three-phase four-wire distribution network, in order to ensure that the voltage waveform on the load side is not affected, the zero-sequence component needs to be compensated. In the past, three independent dynamic voltage restorers (DVR) were used for compensation. The problem of large investment and operation loss

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