|
With the increasing scale of long-distance DC transmission, new energy off grid accidents caused by DC faults occurs frequently. In order to ensure the safe and stable operation of the system, it is necessary to analyze the key factors leading to the disconnection of new energy. Therefore, firstly, the mechanism of transient overvoltage of new energy units caused by DC fault is analyzed. Then the restraining effect of reactive power equipment, electrical distance and other factors on transient overvoltage is simulated and analyzed, and the short-circuit ratio index to maintain the stable operation of the system is quantitatively analyzed according to the disconnection of new energy. Finally, based on the analysis results, the strategy of restraining new energy off grid is proposed, and verified by a planned DC transmission system. The results show that the transient voltage rise can be suppressed by increasing the short-circuit capacity. According to the electrical distance between the new energy station and the converter station, reasonably formulating the short-circuit ratio index can assist the power grid planning and prevent the new energy off grid.
|
