Study On Analysis And Suppression Of Ferroresonance Overvoltage In Distribution Network

In the current development process of power system,smart grid as its main direction.When the system fails,smart grid is required to analyze system parameters in real time through real-time monitoring of power lines.In this way,it helps the power operation and maintenance personnel to analyze and deal with the system fault,and at the same time,by reporting the fault information to the management system and then dealing with the fault,the smart grid prevents the fault range from expanding,and improves the safety and stability of power consumption.Ferromagnetic resonance occurs in the circuit of nonlinear inductance and capacitance.When it meets the conditions,it will produce high voltage or high current,which seriously affects the safety of operators.The harm of ferromagnetic resonance has caused a lot of analysis and Research on its mechanism and basic characteristics by scholars at home and abroad.Ferromagnetic resonance has diversity and complexity,and the effect of current suppression measures needs to be improved.The generation of ferroresonance will lead to insulation damage and equipment damage to a large extent.As the power grid becomes larger and larger,the number of connected equipment is larger and larger,and the operation of distribution network is more and more frequent,the probability of ferroresonance is more and more large,which is likely to cause the occurrence of over-voltage more and more frequently.As the problem of power system becomes more and more serious,it is urgent to study the nonlinearity of ferroresonance.At present,the research of ferroresonance is based on the loop model,which is the basis of the dynamic model and provides theoretical and environmental support for the study of the law of ferroresonance.Because of the complexity of ferroresonance,it is usually difficult to obtain its accurate parameters,which can not be applied in practice.In order to solve the problems of identification and suppression of ferroresonance over-voltage,this paper firstly studies ferroresonance by studying its voltage time series to analyze its resonance characteristics.Then,the phase space reconstruction of the voltage time series is carried out,the hidden information of the resonance system is mined,and the special characteristics of ferroresonance are analyzed.On this basis,the type identification of ferroresonance is carried out to realize the real-time monitoring and on-line analysis of ferroresonance overvoltage,which provides support for resonance suppression.The main research contents are as follows:(1)According to the generating mechanism of ferroresonance overvoltage,by studying the classical resonance circuit model to analyze its characteristics,on the basis of the theoretical derivation and the first basic equation of state,according to the power system of the specific parameters for the construction of the model,through the commonly used method and analysis tool to analyze the dynamics characteristics of the ferromagnetic resonance system.(2)For the identification of ferroresonance overvoltage,the phase space reconstruction algorithm is selected to reconstruct the obtained voltage time series through the obtained voltage time series,and then the improved C-C algorithm is used to optimize the reconstructed phase space reconstruction parameters.After the phase space of the voltage time series is reconstructed,the characteristic quantity of ferroresonance can be extracted.Finally,based on the extracted characteristic quantity,the least squares support vector machine optimized by particle swarm optimization algorithm is used to establish the ferroresonance recognition system.(3)For the suppression measure of ferroresonance,the model of the system can be identified by the time series of voltage,and the suppression method of overvoltage can be obtained on this basis.In order to control the ferroresonance overvoltage within the ideal voltage range when the ferroresonance overvoltage occurs,with the development of power electronics technology,this paper proposes a flexible suppression scheme to realize the suppression of ferroresonance overvoltage in this way.Its dynamic characteristics are simulated and verified by test,with both results coinciding each other.