Parameter Optimization Of TCSC And Its Damping Controller Based On The Analysis Of Trajectory Sensitivity

Whereas, the main purpose of the interconnection of the large area power net is to ameliorate the function of system which can be more economic and more stable, this interconnection brings several new dynamic problems, such as the augmentation of the rate of insatiability, the limitation of the power transmission, etc.Thyristor-controlled series compensation (TCSC), as a kind of FACTS facilities, has an equivalent reactance varied rapidly in a certain range. Therefore the TCSC can not only compensate the reactance on line, but also control the low frequency oscillation and the sub-synchronous oscillation in order to improve the steady stability and the dynamic stability.From the 90's on, damping controller becomes one of the most important topics of FACTS. It is applied in order to control the low frequency oscillation and to improve the steady and dynamic stability. Whereas, the most research still follows traditional method of small disturbance. Even though these linear control methods have already achieved some success in practice, they are only applicable according to certain initial points. Because of the non-linearity of the real power system, these methods are no longer suitable for controlling the non-linear oscillation, such as the power system in Northeast, China which was attacked by unreasonable oscillations caused by the non-linearity. Thus, a right analysis and control method against this non-linearity is the very key to solve this problem.Time Domain Simulation uses the dynamic and algebraic equations which are definitely non-linear. This method can take all the non-linear proprieties of the power system into consideration. Trajectory sensitivity is an accurate and reliable method which implies the sensitivity of trajectory according to the parameters. The purpose of this method is to eliminate the low frequency oscillation caused by small disturbances and the serious oscillation caused by big disturbances. In this dissertation, the technology of trajectory sensitivity is applied into the optimization of parameters of TCSC and its damping controller, with its objective function of minimization of the sum of the generator speeds, which represent the dynamic energy of the whole system's oscillation. First, the gradient information was obtained by means of the simulation of trajectory sensitivity;then TCSC parameters were optimized by conjugate gradient method. Under the condition of the small or severe disturbance, the effectiveness for multi-machine power system was verified by two typical test system under the proposed method.