Study on the Uneven Distribution of Breaker Circuit Current in UHVDC Sending-end Converter Station AC Field

In recent years, China's UHVDC construction, operation and maintenance technology have gradually matured. In the process of DC capacity and actual conveying power are constantly refreshing the world records, the unknown risk of DC high-power operation has also been exposed one after another. Among them, for the first time, the contradiction between precise work current demand of the switch CT and the uneven current distribution in converter station AC field caused the partial breaker circuit current exceeds the upper limit appeared. In view of the above problems, starting from main wiring connection and line power, bus resistance distribution and the interval circuit resistance, this paper study the independent and coupling situation on the uneven distribution of breaker circuit current in UHVDC sending-end converter station AC field. Based on the analysis conclusion, the Changji converter station case was analyzed, and the prevention measures and operation suggestions were put forward.