Analysis of black start reliability strategy of transformer

With the growing electricity demand, the installed capacity of power grids and the number of transmission lines continue to increase, leading to a progressively complex power grid architecture and a higher likelihood of large-scale power outages. Consequently, the ability to rapidly and reliably restore normal power system operation has become a central focus of researc h in the field. Black start technology enables the swift recovery of the power system by utilizing generating units with self - starting capability. Wind power has emerged as a potential source for black start owing to its unique environmental advantages and operational characteristics. However, during the black start process of a wind farm, when long no-load transmission lines and transformers operate under no-load or light-load conditions, significant overvoltage and inrush current may occur. These disturbances can reduce grid voltage amplitude, distort waveforms, create asymmetry across the three phases, and even trigger relay protection mechanisms, ultimately leading to black start failure. Therefore, suppressing overvoltage and inrush current has become a critical step in ensuring the reliability of power system restoration. The study examines various suppression strategies to provide insights for enhancing the effectiveness of black start operations.