The Risk Assessment Method of Large Power Grid Voltage Sag Considering the User Side

The existing grid voltage sag assessment has considered the factors affecting the voltage sag on the grid side, and has not modeled the user tolerance characteristics and the voltage sag governance. Therefore, it is difficult to accurately reflect the level of voltage sag risk. Aiming at the above problems, we proposes a method to evaluate the voltage sag risk of large-scale power grids, which takes into account the user's tolerance characteristics and governance level. Firstly, considering that the detailed modeling is difficult to be applied, the method of establishing the external characteristic model of user tolerance and governance equipment is proposed. Secondly, the above two types of external characteristic models are implemented in the grid model of PSD-BPA, and the effect of the external equivalent users and the governance scheme is simulated. Thirdly, a comprehensive voltage sag evaluation index based on entropy weight method is proposed, and the voltage sag value and load loss of each node in the whole network are obtained by parallel simulation, and the risk of voltage sag is evaluated. Finally, the IEEE118 node system is used for simulation analysis, and the accuracy and practicability of the method are verified.