A Study Of Distributing Solution For Optimal Power Flow With Transient Stability Constraints

Optimal power flow with transient stability constraints (OTS) is a nonlinear optimization problem in functional space that is not easy to deal with precisely even for small-scale power systems. This problem will be formulated as a nonlinear programming model with hybrid constraints consisting of algebraic and differential equations, which is difficult to solve. The trend of today's power system is continuous network expansion and complicated topology. And the need of solving OTS problem on-line is becoming urgent. With the development of modem power industry, the traditional serial algorithm for OTS can't fulfill the requirements of on-line security analysis and real-time simulation. The research on high-powered parallel OTS algorithm and its distributed implementation become a question for discussion.This paper firstly presents a formulation of transient stability constrained optimal power flow in which multi-contingency is considered and converts OTS equivalently into an optimization problem in the Euclidean space that is a limited-dimensional Optimization problem. Then solves the transformed OTS problem, a distributed algorithm based on modern interior point method for OTS is proposed. According to the distributed algorithm, the paper proposes distributed computing program based on a PC-cluster with Matlab distributed computing engine (MDCE). PC-cluster has a high performance and price ratio. And MDCE is powerful in numerical computing. By simulation in Matlab distributing environment with PC-cluster, large-scale OTS problem is solved successfully. Comparing with serial computing, the results verify that the proposed distributed algorithm possesses a good convergence property in a distributed environment, much CPU time is saved, and hence, the method is quite promising for large-scale applications. Some problems are handled effectively, such as communication flux, load balance, and the good accelerate rate and efficiency is obtained. The results of Simulation also indicate that distributed computing PC-cluster system based on MDCE is a promising distributed parallel computing platform for large-scale power system computing problems.