Transient current limiting method and system for realizing amplitude-frequency combined control based on virtual magnetic flux

Abstract

The invention discloses a transient current limiting method and system for realizing amplitude-frequency combined control based on virtual magnetic flux, and belongs to the field of power systems. The method comprises the steps that S1, terminal voltage virtual magnetic flux T of the grid-connected side of the new energy equipment is obtained through calculation, T = Vt / omegat, and Vt and omegat are the amplitude and frequency of the terminal voltage respectively; s2, an internal potential virtual magnetic flux T'is designed, T '= E / omega, and E and omega are the amplitude and frequency of the internal potential respectively; s3, on the basis of the internal potential virtual magnetic flux E / omega and the terminal voltage virtual magnetic flux Vt / omega t, taking the total current size Ig limited on the filter inductance when the grid of the new energy equipment fails as a constraint relation, and obtaining an active current instruction Igd and a reactive current instruction Igq at the grid-connected side end, and coordinated distribution of active current and reactive current in the transient current limiting process is realized. According to the method, the virtual magnetic flux is introduced to represent the combined change of the voltage amplitude and the frequency, so that the coordinated distribution of reactive current and active current is realized, and finally the combined support of the frequency and the amplitude of the power grid voltage under transient current limiting is realized.

Description

technical field [0001] The invention belongs to the field of power systems, and more specifically relates to a transient current limiting method and system for realizing combined amplitude-frequency control based on virtual magnetic flux. Background technique [0002] In order to build a new power system with new energy power generation as the main body, new energy power generation will gradually replace thermal power generators and become the main power supply of the power system. It is an urgent and realistic demand for new energy power generation to maintain the dynamic stability of voltage amplitude and frequency under various disturbances. However, new energy power generation is limited by the overcurrent capability of its own power electronic devices, and current limiting control is required during grid faults. How to realize the combined support of the voltage amplitude and frequency of the power grid under the current-limiting constraints of new energy power generat...

AI Technical Summary

Problems solved by technology

That is, it is difficult to determine the dynamic amplitude and frequency of the electric potential in new energy power generation with the design idea of ​​transient current limiting control with a single injection of reactive current or active current as the direct design object, so it is not suitable for effective control of the voltage amplitude and frequency of the power grid. joint support

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