استفاده از تجزیه و تحلیل حساسیت مسیر برای پیدا کردن مکان های مناسب جبران سری برای بهبود ثبات زاویه روتور

This paper proposes an approach based on trajectory sensitivity analysis (TSA) to find most suitable placement of series compensators in the power system. The main objective is to maximize the benefit of these devices in order to enhance the rotor angle stability. This approach is formulated as a two-stage problem, whose first-stage describes prior to fault occurrence and whose second-stage represents the power system behavior involving a set of severe faults. The first-stage focuses on small signal stability, while the second-stage deals with transient stability of power system. In this vein, the trajectory sensitivities of the rotor angles of generators with respect to the reactances of transmission lines are calculated. Two equivalent rotor angles are introduced to find stability indices corresponding to the first- and the second-stage of the proposed approach. Numerical results from IEEE 10-machine 39-bus test system demonstrate the usefulness of the proposed method.

Deregulation in electricity markets, increasing electricity demands and high penetration of renewable energy sources have increased the power transactions within and between regions in today's power systems. The installation of new transmission lines cannot be carried out easily because of its heavy costs and environmental concerns. As a result, this competitive environment pushes the existing transmission systems to be operated close to their critical conditions which may result in higher risk of transient instability. Moreover, small signal oscillations occur more frequently in a heavy-loaded interconnected power system. In this situation, rotor angle stability would be one of the main concerns of the power system operators. Series flexible AC transmission systems (FACTS) devices, e.g., Thyristor Controlled Series Capacitor (TCSC), can have a significant impact on operational flexibility and controllability of the power system. They can manipulate the reactance of transmission lines and control the power flow through lines in a way to increase the transient stability margins. These devices, equipped with the proper controller, can also be used to improve the small signal stability. Since the impact of these compensators on the system stability is strongly dependent on their locations, it is required to provide useful information to the system planners regarding the best possible locations to install them. In this paper, an effective approach is proposed to identify the most suitable placement of series compensators for improving both the transient and small signal stability of the power system.

A novel approach is proposed based on the trajectory sensitivity analysis to find the suitable locations of series compensators in order to improve the transient stability, and also enhance the damping of small signal oscillations of power system. In this method, trajectory sensitivities of the rotor angles of the generators with respect to the reactances of transmission lines are calculated for the pre-fault and post-fault systems considering the most severe contingencies. The proposed approach not only finds the most effective locations to install series compensators, but also demonstrates why installing series compensators in the transmission lines cannot always improve the power system stability. The numerical result on the IEEE 3-machine 9-bus and IEEE 10-machine 39-bus systems show validity, accuracy and efficiency of the proposed approach. Future research may extend this technique to cover the other types of FACTS devices.