Research On Reactive Power And Voltage Control Technology Under The Background Of Active Distribution Network

At present,with the strong support of our government,the new energy distributed generation(DG)system accessing the distribution network has presented a rapid development trend.Especially,in the resource-rich areas,the development of distributed new energy is faster and the grid-connected high-penetration photovoltaic(PV)power generation has become the normal development.As the growth of PV installed capacity is greater than the increase of regional load,day-to-day bi-directional tidal current of the regional distribution network has become the norm.However,the reactive power compensation and voltage regulation of distribution network are designed based on the original grid structure and control object.No consideration is given to the PV power generation’s capability of reactive power regulation,the problems of voltage over-limit and fluctuation are very prominent,which will bring new challenges and opportunities to the safe and stable operation of the power system.In the view of the above problems,this paper first has done the research and analysis on the influence of DG on the voltage level of distribution network theoretically.Then,the power flow calculation of the active distribution network(ADN)has been studied.Finally,an example analysis of the influence of DG access on the distribution network voltage has been made,which is clear that the DG access position,access mode,access power factor and DG volatility match have the effects on the grid voltage.This paper summarizes the current situation of reactive power voltage control.In the second chapter,the simulation analysis shows that the traditional reactive power voltage control method has some problems in voltage control of active power network with high permeability DG.The scheme of voltage global optimization control method is studied.The control scheme,data demand and communication requirements are small,which has certain practical value.Meanwhile,the practical method to solve the voltage/sensitivity in voltage global optimization control of ADN is studied.Moreover,according to the two scenarios of voltage upper limit and voltage lower limit,the objective function to be adopted in voltage global optimization is analyzed and studied,and the problem of engineering process in calculation of objective function is studied.In this paper,under the environment of DIGSILENT / PowerFactory,the simulation model of ADN is established according to the actual distribution network topology in a certain area.Simulation results show that the validity of the proposed scheme is analyzed and verified.