| In recent years,with the large-scale of new energy merging into the power grid,new problems have been brought to,such as,protection and control of the power system.The high level penetration of photovoltaic(PV)power generation merge into large-scale AC-DC power grid from the sending and receiving area.The PV power supply is non-rotating,generating direct current converted into alternating current through the inverter.Because the characteristics of PV power generation system are different from those of conventional power supply,high level PV penetration into power grid will inevitably affect the transient response characteristics of the power grid.Aiming at analyzing the problem of transient voltage response characteristics of the power grid merged into PV power,this paper firstly introduces the electromechanical transient model of the PV power generation system briefly.Based on the BPA simulation platform,the receiving grid scene with high level PV penetration was built,analyzing the influence of permeability,control mode and electrical distance on transient voltage response characteristics of the power grid.The result shows that the East China power grid with close electrical connection and sufficient reactive power reserve can absorb the decrease of reactive power reserve caused by regional grid-connected PV power supply system access and the negative effects brought by the transient characteristics of low voltage and large current.Then,the influence of high level PV penetration on transient voltage of receiving grid is studied based on rational fraction fitting method.The feasibility of introducing rational fraction fitting method into power grid transient analysis is proved,based on trapezoidal integration and Cramer's rule.Finally,the parametric relationship between the PV terminal voltage and the control parameters of the inverter during the fault-on and recovery stage is studied by rational fraction method,which shows the effectiveness of proposed method in this paper. |
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