Analysis on Primary Frequency Regulation Performance of the Units under DC Blocking Fault in UHV Receiving End Power Grid

The East China power grid has gradually formed a UHV (Ultra High Voltage) large receiving end grid. However, high voltage DC block faults occur occasionally, which brings high risk to the safety of power grid frequency. The consequences of some of the faults show that the primary frequency regulation performance of the units in the grid is not able to meet the new requirements, and the drop of the frequency is out of expectation. In this paper, the ideal primary frequency regulation capability and the actual response of the units in the grid are analyzed based on the DC bipolar blocking fault happened on September 19, 2015. Taking the units in Zhejiang Power Grid as an example, the factors that would affect the primary frequency regulation capability are proposed, and the technical requirements and measures for improving the primary frequency regulation ability of the thermal power units are put forward accordingly to provide reference for the optimization of the primary frequency regulation control strategy in the new power grid pattern.