Second-order cone operation control method for alternating-current and direct-current power distribution network with power electronic transformer

Abstract

The invention discloses a second-order cone operation control method for an alternating-current and direct-current power distribution network containing a power electronic transformer. The method comprises the steps that a PET-containing alternating-current and direct-current hybrid power distribution network multi-period operation control model is constructed; the injection power of different ports of the PET is controlled by utilizing the flexible regulation and control capability of the PET, so that the mutual coordination of the power between the different ports is realized, and the exchange requirement of power balance between an alternating current subnet and a direct current subnet is met; and second-order cone programming and linear approximation are adopted to carry out convex relaxation on the alternating-current and direct-current hybrid power distribution network multi-period operation control model, so that the solving efficiency of the multi-period operation control problem of the alternating-current and direct-current hybrid power distribution network containing PET can be improved. According to the invention, the system loss is effectively reduced, and the system operation economy is improved; and convex relaxation is carried out on an original nonlinear model through second-order cone relaxation and linear approximation, so that the PET-containing alternating-current and direct-current power distribution network second-order cone operation control model is provided, the accuracy is relatively good, and the solving efficiency is improved.

Description

technical field [0001] The invention relates to the field of operation scheduling modeling of an AC-DC distribution network, in particular to a second-order cone operation control method for an AC-DC distribution network containing a power electronic transformer. Background technique [0002] The development of renewable energy technology has brought new challenges and higher requirements to the flexible access and effective regulation of the power system. The AC-DC hybrid distribution network with the power electronic transformer (Power Electronic Transformer, PET) as the core can realize the flexible interconnection between power grids of different voltages and frequencies, and can realize the flexible grid connection of distributed power sources at multiple voltage levels, which is conducive to sustainable development. The plug-and-play and consumption of renewable energy has attracted extensive attention from relevant scholars and engineering circles. But at the same ti...

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Problems solved by technology

[0004]It can be seen that the current research results have improved the operation level of the AC-DC hybrid distribution network containing PET from different aspects, but the utilization of the coordination effect between PET multi-ports needs to be further developed In addition, the droop control distribution network load power is affected by voltage amplitude and frequency changes, and it needs to be described by static load characteristics, which will increase the non-convexity of the model as a nonlinear constraint, and then consider the introduction of the voltage source converter After the strong nonlinear loss characteristic equation, it will further increase the non-convexity of this kind of operation control model, and it is difficult to solve it efficiently

Generally speaking, at this stage, there is a lack of an optimal control model for AC-DC hybrid distribution networks including PET that considers the control strategy of power electronic transformers, and there is also a lack of a reasonable convex relaxation method for such nonlinear models.

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