| With the introduction of carbon peaking and carbon neutrality goals,and in recent years the progress of the medium and long-term planning of new power system which includes green energy and electric cars has attracted more and more attention.Power supply capacity of the distribution network in a certain power supply area to meet the maximum power consumption of users under the N-1 condition.Power supply capacity is an important indicator to judge the system performance.At present,the academic research on AC system power supply capability has gradually become mature,while the related research on DC system power supply capability is still in the initial stage.In this paper,a general calculation model of the power supply capacity of DC distribution network is established,and the power supply capacity of DC distribution network is analyzed.Firstly,N-1 is taken as the boundary condition of the system operation,and the power supply capacity of the DC distribution network is calculated by constructing the contact unit of the main converter when the main converter is considered.On this basis,the capacity constraint of the contact line between the main converter is considered,and the calculation method of power supply capacity is improved.The power supply capacity margin of DC distribution network is calculated considering the actual load of converter.In order to study the power supply capacity of DC distribution network with new source load access,the output and energy usage characteristics of typical DC users in DC distribution network are analyzed.The output of photovoltaic power station and wind power plant is analyzed according to different time scales of year,month and day.The output of wind and photopower generation is obviously random and fluctuating under the influence of natural conditions.The DC load of electric vehicles and data centers under different usage scenarios,such as working day,rest day,regular business and periodic business,was analyzed.The load of such DC users showed significant volatility influenced by user behavior.Based on the research on the energy consumption characteristics of photovoltaic,wind power,electric vehicle and data center,these four typical DC users are introduced into the calculation and analysis of the power supply capacity of DC distribution network,and the influence of the randomness and volatility of DC user output and load power on the power supply capacity and margin of DC distribution network is studied.In order to improve the utilization level of the converter load rate and the absorption ability of the new source load,energy storage is introduced to smooth the load rate fluctuation of the DC distribution system connected by the new source load.The particle swarm optimization algorithm with improved inertia weight and learning factor is used to obtain the charging and discharging strategy of energy storage so as to minimize the fluctuation index value of power supply capacity.Finally,the simulation calculation of a DC distribution network with a new type of source load access is carried out to verify the validity of the analysis method in this paper,which provides a theoretical basis for the planning and design of the DC distribution network with a new type of source load access. |
