Analysis method and apparatus for harmonic current and harmonic voltage of power grid in access to power distribution network

Abstract

The invention discloses an analysis method and apparatus for harmonic current and harmonic voltage of a power grid in access to a power distribution network. The method comprises the steps that the harmonic model of a microgrid structure is obtained; the models of the power distribution network connected to the microgrid are obtained, wherein the models of the power distribution network comprise a single-feeder-line radiation network and a multi-node chain type power distribution network; when the model of the power distribution network is the single-feeder-line radiation network, the amplitude of higher harmonic current generated in the running of the microgrid after the microgrid is connected to the power distribution network is controlled according to electrical distance between an access node and a PCC node of the microgrid in access to the power distribution network; and when the model of the power distribution network is the multi-node chain type power distribution network, the voltage harmonic distortion rate of the circuit after the microgrid is connected to the power distribution network is determined according to the access distance between the access position and the busbar side when the microgrid is connected to the power distribution network. The technical problem that the harmonic wave in the electric energy interaction process of the power distribution network cannot be monitored when the microgrid is connected to the power distribution network is solved.

Description

technical field [0001] The invention relates to the field of power grids, in particular to a method and device for analyzing harmonic current and voltage when a microgrid is connected to a distribution network. Background technique [0002] The microgrid contains a variety of distributed energy sources, and most of the distributed power sources are connected to the grid through the power electronic interface, and the harmonic current generated by the power electronic device may be injected into the distribution network. In addition, the microgrid is generally dominated by residential electricity, and most household electrical equipment is equipped with rectification circuits or phase control circuits, resulting in high current distortion. Although the microgrid has taken some effective measures, such as suppressing harmonics by linking output filters, increasing switching frequency, and improving control strategies, a small amount of harmonic current is inevitably injected i...

AI Technical Summary

Problems solved by technology

[0004] The main purpose of the present invention is to provide a method and device for analyzing harmonic current and voltage when the microgrid is connected to the distribution network, so as to solve the problem that the microgrid is connected to the distribution network and cannot monitor the harmonics in the process of electric energy interaction

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