Suppression of Core Saturation Instability in Converter Transformer for UHVDC Power Transmission System From Yunnan to Guangdong

The core saturation instability of converter transformer will endanger important components as well as the secure operation of power grid.The mechanism causing core saturation instability of transformer is researched, and the additional control circuit to suppress core saturation instability is designed.Based on the operational data of South China power gird in the year 2010 and by use of PSCAD/EMTDC,a detailed electromagnetic transient simulation model for ±800 kV DC power transmission system is built by which the effectiveness of the proposed additional control circuit is validated.