Transient Stability Constrained Optimal Power Flow With Constraints Limiting The Number Of Controls Actions

The problem of power system’s transient stability has caused wide public concern over the recent years.The transient stability constraints are capable of ensuring the safe and stable operation of power system while giving due consideration to economy and security. However, There is not direct embodiment of constrains limiting the number of control actions in the traditional optimization model, all of the control means have moved at the optimal solution, so that the system operator(SO) is obliged to handle complicated operations.Based on the latest research, this paper introduces the concept of constrains limiting the number of control actions, constructs a new optimization model which is more suitable to power system’s realistic operation. This model enriches the operation strategy, provides an optimal operation which is more comprehensive and more reasonable.The model introduced by this paper constitutes a mixed integer nonlinear programming (MINLP)problem. We propose two key technologies to solve the model:1)Space transformation of transient stability—the differential algebraic equations are converted into only one inequality constrain.2)Leading in the complementarity fuction to handle the0-1discrete variables. After the conversion, the model belong to a general nonlinear programming problem, we can solve the problem by modern interior point algortthm, which has good performance in both convergence and robustness.Under the premise of satisfying operation constraints and transient constraints, the new model is able to consider economy or minimum control actions as target function, thus providing distinct operation strategy under different demand. The numerical results of three test systems(of39,118and216buses)show that the model introduced by this paper is available to handle discrete variables, provides a new idea for power system optimal operation, has a good prospects for research.