Method and system for determining negative-sequence current of doubly-fed fan under short-circuit fault of power grid

• Main Authors: LU YI, ZHOU PEIPENG, HAN BIN, HUO QIDI, LIU CHANGQING, XU WENJIA
• Format: Patent
• Language: Chinese; English
• Published: 08.09.2023
• Subjects: CALCULATING; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTINGELECTRIC POWER; COMPUTING; CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORSOR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; COUNTING; DATA PROCESSING SYSTEMS OR METHODS, SPECIALLY ADAPTED FORADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL, SUPERVISORYOR FORECASTING PURPOSES; ELECTRIC DIGITAL DATA PROCESSING; ELECTRICITY; EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS; GENERATION; PHYSICS; SYSTEMS FOR STORING ELECTRIC ENERGY; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE,COMMERCIAL, FINANCIAL, MANAGERIAL, SUPERVISORY OR FORECASTINGPURPOSES, NOT OTHERWISE PROVIDED FOR

The invention discloses a method and system for determining the negative sequence current of a doubly-fed fan under a short-circuit fault of a power grid, and belongs to the technical field of electrical equipment and electrical engineering. The method comprises the following steps: establishing a first DFIG equivalent negative sequence impedance model under the condition that a Crowbar protection loop is not put into a power grid DFIG rotor side, or establishing a second DFIG equivalent negative sequence impedance model under the condition that the Crowbar protection loop is put into the power grid DFIG rotor side; based on the first DFIG equivalent negative sequence impedance model or the second DFIG equivalent negative sequence impedance model, establishing a node voltage equation of a power grid negative sequence network and a fault boundary condition equation of the power grid; the node voltage equation and the fault boundary condition equation are combined, solving is carried out to obtain the negative