An Online Method Based On Network Topology Optimization To Relieve Overloads And Voltage Violations

Due to the energy crisis and environmental pollution,the construction of smart grid has become the worldwide trend of the development of the power grid,including but not limited to the strong transmission network construction,namely network topology optimization.Transmission network topology optimization is an effective and economical control method for relieving overloads and voltage violations in power systems.During the real-time operation of power systems,operators will face all sorts of unsafe conditions.The most frequent problems threatening the stability of power systems are overloads and voltage violations.Those problems will influence the normal operation of the power equipment and may result in cascading violations and system blackouts.It is hence important to develop fast and effective control schemes for relieving or eliminating operational violations.This paper proposes a novel online network topology optimization model for obtaining fast and high quality solutions to eliminate overloading problems,especially for large-scale systems.The proposed online methodology is a hybrid of linear and nonlinear methods composed of screening stage,ranking stage and detailed analysis stage.It is well recognized that linear methods are usually fast but not sufficiently accurate while nonlinear methods are usually accurate but can be slow.We employ a linear method based on DC power flow model to identify effective candidate lines.Ranking stage will rank each remaining candidate lines according to the power flow decreases on overloaded lines.The last stage will calculate the exact operational information of each post-optimization system utilizing the AC power flow model.One distinguishing feature of the proposed methodology is that it is fast for online applications and it provides high-quality solutions which may contain the global optimal one for both single as well as multiple line switching.