Multi-DC-feed (multi-direct current-feed) AC (alternate current) grid fault calculating method taking DC control characteristics into consideration

• Main Authors: SHOU HAINING, LIU JINPING, LUO MEILING, WANG GANG, WEN JINGHUA, LI HAIFENG, MAI GUOHAO
• Format: Patent
• Language: English
• Published: 13.05.2015
• Subjects: CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTINGELECTRIC POWER; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRICITY; GENERATION; SYSTEMS FOR STORING ELECTRIC ENERGY

The invention discloses a multi-DC-feed AC grid fault calculating method taking DC control characteristics into consideration. The multi-DC-feed AC grid fault calculating method comprises the following steps of inputting system parameters, DC control strategies and fault parameters of an MODC (multi-outfeed direct current) system; forming an AC system sequence network chart through the system parameters and the fault parameters of an AC grid, establishing an AC constraint equation, and establishing a DC constraint equation between the DC voltage and the DC current of a DC side through the DC control characteristics; setting initial values for all variables; establishing converter switch function models SI and SU of every DC subsystem; according to the AC constraint equation, the DC constraint equation and voltage and current switch functions, solving the transient state parameters of the AC side and the DC side of the MODC system; performing iterative computation, and when variable errors meet computational requirements, outputting the computation results of the transient state parameters of the AC side and the DC side of the MODC system. The multi-DC-feed AC grid fault calculating method taking the DC control characteristics into consideration is high in computation speed, accuracy and adaptability and has high engineering practical value in the aspect of setting and cooperation of fault computation and relay protection of multi-DC-outfeed AC grids.