Research In Transient Voltage Stability Analysis And Control Of Receiving-end Grid With High Percentage Of Receiving Power

With the increasing proportion of receiving power,the number of local generators in receiving-end power grid keeps decreasing,and the local dynamic reactive power margin decreases,which results in insufficient dynamic reactive power support of the receivingend power system after faults,and the risk of transient voltage instability increases greatly.In view of this,this paper focuses on the analysis method and control strategy of transient voltage stability of receiving-end power system under the background of large receiving power,and the main work of the paper is as follows:1)Based on the node impedance matrix,a fault impact factor index characterizing the transient voltage stability of power system after different nodal faults is proposed,which can be used for transient voltage high-risk fault screening and weak unit location.First,based on the node impedance matrix,a fault impact factor matrix reflecting the voltage impact characteristics of node faults is derived with the aid of Woodbury matrix identity.Then,the node fault riskiness index and generator instability riskiness index are further constructed and applied to the identification of high-risk fault nodes and weak generators in power networks,respectively.The results show that the high-risk fault nodes located by proposed indicators are the most critical to the overall voltage stability of the power network,and the screened weak units have the highest destabilization risk.2)Combined with the reactive power compensation sensitivity index,a reactive power optimization scheme is proposed for the receiving system considering the allocation of distributed regulators,which can effectively improve the transient voltage stability of the system.First,the reactive power compensation sensitivity is defined based on the quantitative transient voltage stability assessment index(TVAI),and then a mathematical model of the dynamic reactive power optimization problem of the power system is constructed;then,the reactive power allocation nodes are determined with the help of the reactive power compensation sensitivity.Finally,the optimal allocation strategy of the regulator capacity is derived using the particle swarm optimization(PSO)algorithm.The results show that the proposed dynamic reactive power optimization allocation scheme has a better improvement effect on the transient voltage stability of the power system under the same reactive power capacity.3)Combining relative sensitivity,a coordinated control strategy for transient voltage stabilization of the receiver system considering key generator regulator output limiting regulation and dynamic reactive power compensation is proposed,and the effectiveness of the method is verified by simulation.Firstly,the reasons for the limited strong excitation ability of the self-excited stationary excitation generator during the fault near the outlet are analyzed.Then.the key excitation parameters are screened out with the help of relative sensitivity,and the mathematical model of the coordinated optimization problem is constructed combining the idea of sensitivity linearization.Finally,the optimal coordinated control scheme is derived using the PSO algorithm.The results show that the proposed coordinated control strategy considering the adjustment of key generator parameters can effectively improve the economy of the control scheme and help to improve the efficiency of reactive power resources utilization and the reactive power distribution in the network.