Study On Reactive Power Optimization Of Regional Power Grid With Small Hydropower

There are a large number of small hydropower stations in Jieyang Power Grid,with the characteristics of remote and large radius in power supply,which cause the long distance of transmission and the small cross section of conductor capable.Furthermore,they are deeply influenced by seasonal changes,which lead to the unreasonable flow of reactive power,cause the upper limit or lower limit voltage of the system,increase the line loss rate.Lack of reasonable and sufficient capacitance,inductivity and dynamic reactive power compensation,the operation of system is inefficiency,the voltage is hard to control,the line loss is increased and the qualified rate of the voltage is decreased.Some local areas cannot achieve the reactive power balance in some operating conditions.In view of these,this paper analyzes the characteristics of small hydropower and the influence of the voltage and reactive power in Jieyang Power Grid,to intensively study the problem of reactive power voltage and the optimal control strategies of Jieyang distribution network with small hydropower.Completing the following tasks:First,study on the power flow calculation method of systems with small hydropower: The power flow problems of the operation of small hydropower and its calculation method are the key basic issues of power system's planning and operation.Furthermore,they are also the key basic issues to analyze its reliability and safety.According to the operation characteristics of small hydropower,this paper establishes node processing method of small hydropower in power flow calculation and power flow calculation model of the system with small hydropower.Second,study on the influence of the attachment of reactive power of small hydropower in Jieyang Power Grid: The paper analyzes the current situation of the reactive power compensation in Jieyang Power Grid and the small hydropower's distribution.Meanwhile,through ubiquitous problems of the attachment of reactive power of small hydropower,and the influence of different access nodes of small hydropower on the grid voltage,the paper detailed analyzes the reactive power problem to the operation of power grid when small hydropower is attached.Third,study on the reactive power optimization and compensation of Jieyang Power Grid with distributed power: The reactive power compensation and voltage of generator and transformer tap stalls as control variables,the minimum network loss and annual expenditure of the least investment costs the minimum as the objective function,meet the basic trend equation and operation constraints as basis,the paper establishes models of optimal reactive power compensation in Jieyang Power Grid with small hydropower,simulates reactive power optimization under different operating modes in Jieyang Power Grid,reaches the parameters of Jieyang Power Grid's actual reactive power compensation capacity and transformer tap under different operating modes,provides reference for the configuration for reactive power optimization device in Jieyang area and the adjustment of transformer tap,and provides guidance for the design of reactive power compensation.