Research On Chaotic Synchronization And Suppression Of Ferroresonance In Neutral Grounded Power System

With the expansion of the scale of power system, the improvement of voltage class and operating increasingly, the rate of ferroresonance overvoltage occurs in the neutral grounded power system is getting higher, the consequent problem is becoming more and more serious, that threaten to the safe and stable operation of transmission and transformation equipment of power system. Especially the amplitude of overvoltage is very high, when ferroresonance overvoltage has chaotic features, if that occur will cause huge economic losses. Therefore, the research of method that suppresses ferroresonance overvoltage has practical significance.The paper takes a110kV substation in neutral grounded power system as the prototype, simplifies the circuit and establishes the mathematical model of ferroresonance. Analysing the dynamic characteristics of each resonance state of ferroresonance using the nonlinear dynamics tools such as Bifurcation map, Phase plane, Poincare map and the maximum Lyapunov Exponent, that provide a theoretical basis of researching the method to suppress the ferroresonance overvoltage.Considering the mathematical model of each resonant state of ferroresonance is known precisely, the paper designs a new method of suppress ferroresonance overvoltage according to the generalized projective synchronization theory, and designs a unified form of nonlinear feedback controller that suppresses each resonance overvoltage system of ferroresonance. The controller not only can realize the synchronization between each resonance overvoltage system of ferroresonance with drive system with same structure, but also can realize the synchronization with drive system with different structure. And the controller can suppres the ferroresonance overvoltage with chaotic features effectively.Finally, the paper makes a study to suppress the ferroresonance overvoltage with chaotic features, and considers the precise mathematical model is difficult to get in the actual operation of power system. So the paper designs a new control method to suppress ferroresonance, the method does not rely on accurate mathematical model of ferroresonance chaotic system. The control method approximates the chaotic overvoltage system of ferroresonance using the clustering function of RBF neural network, and adjusts the network weights adaptively online, and combines the theory of sliding mode variable structure control, and designs two controllers based on the way of adjusting network weights. At last, the paper confirms the effectiveness of the proposed control method by time domain simulation. And compare the performance of the controllers.