Dimension Reduction Based Short-Term Voltage Security Preventive Control

With the development of HVDC transmission technology, several large-scale receiving-end power grids have been formed in eastern and southern China. Due to the insufficient dynamic reactive power reserve of the receiving-end power grids, the problem of short-term voltage insecurity is becoming increasingly prominent, which can be improved by appropriate preventive control. However, the mathematical model of short-term voltage security preventive control is essentially a large-scale mixed integer nonlinear optimization problem with differential equation constraints, which can hardly be solved online. In order to meet the requirements of online applications, this paper first defines a quantified short-term voltage security index based on voltage trajectory. Then, a dimension reduction method for short-term voltage security problem is proposed to achieve both contingency and space dimension reduction. Finally, based on the dimension reduction method, a fast algorithm for short-term voltage security preventive control optimization model with appropriate relaxation is proposed. Case studies based on IEEE-39 bus system and an actual power grid model verify the feasibility and effectiveness of the proposed method.