Flexible multi-state switch and control method thereof

Abstract

Provided in the invention is a flexible multi-state switch comprising a first isolation transformer (T1), a first controlled voltage source (D11), a direct-current bus voltage-stabilizing capacitor (C1), a second controlled voltage source (D22), a second isolation transformer (T2), and a central controller. A first feeder line (K11) is connected to the first controlled voltage source (D11) throughthe first isolation transformer (T1); a second feeder line (K22) and the second controlled voltage source (D22) ) are connected by the second isolation transformer (T2); and the first controlled voltage source (D11) is connected to the second controlled voltage source (D22) through the direct-current bus capacitor (C1). Various functions including bidirectional circulation of active power betweenfeeder lines, reactive compensation control, short-circuit current suppression, power flow optimization and power quality management and the like are realized by applying different control methods onthe first controlled voltage source (D11) and the second controlled voltage source (D22) of the flexible multi-state switch.

Description

technical field [0001] The invention relates to a power electronic converter. Background technique [0002] In the medium and low voltage transmission feeder network, the network structure is generally open-loop radial. The voltage difference between the beginning and end of the feeder is large, and the current at the beginning of the feeder is relatively large, and the capacity requirements for the wire are relatively high. The ring network can bring better power flow distribution and balance the load of each line, but once a single-phase or three-phase ground short-circuit fault occurs, it will have a chain reaction on other lines and affect the normal power supply of other lines. Therefore, it is necessary to find a device that can not only use the ring network topology, but also ensure that other lines will not be affected when the power grid fails. [0003] With the gradual depletion of fossil energy, people are looking for ways to replace fossil energy for power gener...

AI Technical Summary

Problems solved by technology

However, the mechanical switch used in the traditional way has a limited number of switches, and the adjustment is discrete, so it is necessary to find a device to continuously and actively adjust the power flow of the feeder where the distributed power supply is located.

[0004] Patent CN107104441A proposes a flexible power electronic switch, which solves the problems of unstable AC system frequency, loss caused by reactive power, and reverse power operation in low-voltage parallel power supply systems containing DC microgrids.

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