Overvoltage Calculation Method for Sending System Under DC Fault Disturbance Considering the Influence of Renewable Energy

Bipolar blocking and commutation failure in the renewable energy transmission system through ultra-high voltage direct current will produce significant temporary overvoltage. This paper analyzes the physical process of sending end grid overvoltage caused by two types of DC faults and establishes a DC overvoltage model considering renewable energy sources. According to characteristics of the sending end grid, the influence of the system equivalent impedance, the proportion of renewable energy output, the active and reactive power coefficients of the renewable energy sources during the low voltage ride through process on the overvoltage is analyzed respectively, and the relationship between the proportion of renewable energy output and the short-circuit ratio under the overvoltage constraint is constructed. The validity and practicality of the model and analysis method proposed in this paper are verified by combining the typical transmission system at the sending end of the actual power grid and regional power grid systems.