Probabilistic transient stability constrained optimal power flow considering multiple uncertainties

Abstract

[Objective] In view of the various uncertainties of grid-connected power systems with a high proportion of renewable energy, in order to maintain the stability and economy of the system, a probabilistic transient stability constrained optimal power flow(PTSCOPF) method considering multiple uncertainties is proposed. [Methods] Firstly, taking into account the uncertain factors, probabilistic models of uncertainty variables of wind power output, load, fault type, fault location and fault clearance time are established. Secondly, the PTSCOPF model based on chance constraint optimization theory is constructed. Then, combined with the multipoint estimation method based on Gauss-Hermite integral and the Gram-Charlier series, the random variables are treated deterministically. Then particle swarm optimization(PSO) algorithm and ant colony optimization(ACO) algorithm are combined to realize the effective solution of PTSCOPF model. Finally, simulations are conducted on the modified IEEE 39-bus test system. [Results] The relative error and mean of the standard deviation of the output random variables computed using the multi-point estimation method based on Gauss-Hermite integration are less than 2.0%, and the method in this paper achieves the optimization of the way the system operates with a computation time of 27.9 s and an expected cost of 62 610 $·h^-1, and the value of the transient stability index of the system is 62.4 after the optimization. [Conclusion] The results show that after the occurrence of the fault, under the condition of considering multiple uncertain factors, the proposed method in this paper can realize the reliable improvement of the transient stability of the system with low computational time cost while taking into account the economy of the system, so that the system can transition to the transient stable state, which guarantees the safe and stable operation of the power system.

Keywords

transient stability constrained optimal power flow / Gauss-Hermite integral / multipoint estimation / particle swarm optimization / ant colony algorithm / influencing factors / renewable energy / power system