Crowbar protection considered doubly-fed power generator simulation system and method

Abstract

Disclosed is a crowbar protection considered doubly-fed power generator simulation system and method. The crowbar protection considered doubly-fed power generator simulation system comprises a fault data collection module, a positive sequence flux linkage calculation module, a positive sequence current calculation module, a negative sequence flux linkage calculation module, a negative sequence current calculation module and a fault current output module; the fault data collection module is used for collecting the terminal positive sequence voltage and the terminal negative sequence voltage and unit state parameters before and after a fault; the positive sequence flux linkage calculation module and the negative sequence flux linkage calculation module are connected onto the positive sequence current calculation module and the negative sequence current calculation module respectively; the positive sequence current calculation module is used for calculating positive sequence components of the short circuit current; the negative sequence current calculation module is used for calculating negative sequence components of the short circuit current; the fault current output module is used for calculating and outputting the short circuit current. According to the crowbar protection considered doubly-fed power generator simulation system and method, the transient state characteristics of a doubly-fed power generator under various short circuit faults can be accurately described.

Description

technical field [0001] The invention relates to the technical field of power systems, in particular to power system relay protection equipment and methods. Background technique [0002] At present, in the grid-connected guidelines of wind farms formulated by countries all over the world, it is clearly required that wind turbines have low-voltage ride-through capabilities. The doubly-fed induction generator (DFIG) has the characteristics of small capacity and small size of the excitation frequency conversion device, so it is widely used. DFIG is essentially a wound rotor motor. Because its stator and rotor are both It can feed power to the grid, so it is called double-fed generator. The stator voltage of DFIG is provided by the grid, and the rotor voltage is provided by the converter. The DFIG system allows variable speed operation within a defined wide range. The converter compensates for the difference between the mechanical frequency and the electrical frequency by inje...

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Problems solved by technology

Generally speaking, in the prior art, in the DFIG simulation analysis method considering crowbar protection, the unit transient characteristics analysis for asymmetric faults is less, and some approximations and assumptions are made in the analysis of the flux linkage process of the stator and rotor, and the derivation The accuracy of the short-circuit current expression is low, and there is no analysis of the influence of crowbar circuit resistance and motor speed on the flux amplitude, phase and characteristic root, so it is impossible to effectively analyze the transient characteristics of DFIG taking crowbar protection into account. analyze

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