An Online Decision-Making Method for the Overload Preventive Control of Transmission Equipment Based on the Control Objects Relaxation

The linear programming model based on active power sensitivity ignores the influence of voltage and network loss, the preventive control strategy is difficult to meet the calculation accuracy requirements after AC power flow. An online decision-making method for the overload preventive control of transmission equipment based on the control objects relaxation is proposed. According to the overload safety margin to determine the key equipment which participating in the control and the active power sensitivity under the corresponding expected fault, and convert the allowable current carrying capacity of the line and transformer into the active power limit, establish a linear programming model for online decision-making of overload preventive control. According to the active power precision of preventive control, the active power limit of key equipment is relaxed into multiple gears, different calculation schemes are formed through enumeration-combination, and the online control strategy is determined according to the control cost and checking result of each calculation scheme. Reduce the dimension of the search space of preventive control measures by cluster analysis, and use the parallel computing method to solve the preventive control strategy and static safety checking in two stages, which improves the solution efficiency. The correctness and effectiveness of the proposed method are verified through the analysis of the actual power grid.