Optimal Scheduling Of Renewable Energy Access To Distribution Network

Distributed generation,which uses renewable energy sources e.g.wind and light as fuel,had some disadvantages of randomness,fluctuation and uncontrollable.The complexity of optimal dispatching operation was increased after large-scale access to power distribution system.Distribution networks with controllable distributed power sources need to consider how to fully utilize active and reactive power regulation resources,gave consideration to economic and environmental benefits and improve the stable operation of the system.For the distribution network with high proportion of wind and optical distributed power sources,how to improve the flexibility of the system and the ability to deal with uncertain disturbances through effective called of flexible resources was primary goal.Firstly,the working principle of active and reactive output characteristics of uncontrollable and controllable distributed power sources,as well as the working principle and scheduling characteristics of flexible resources were analyzed in this paper.Secondly,in order to balance the economic and environmental benefits of controllable distributed power sources distribution network,reduce network losses and improved power quality,in this paper,the two-stage optimal dispatching model for active and reactive power of distribution network with controllable distributed power sources were proposed.Active power optimization stage: considering economic and environmental benefits,active power optimization was carried out with the objective of minimizing operating cost and pollution gas emission cost.Reactive power optimization stage: based on the results of active power optimization,considering the reactive power output characteristics of distributed generation,reactive power optimization was carried out with voltage off set as penalty function and minimum loss of active power network as objective.In this paper,a particle swarm optimization algorithm based on four aspects(inertia weight,learning factor,particle position and particle velocity)and synthetically improvement was proposed,and the two-stage model of active and reactive power optimization was solved.Simulation results showed that the model balanced the relationship between operating cost and environmental cost,reduced network loss and improved voltage quality.Finally,if the proportion of wind and optical distributed energy connected to the distribution network was too high,it was easy to cause system flexibility deficiency,random fluctuation aggravation,stability limitation and other effects,and the above model would not be applicable,interruptible load,energy storage and micro-grid were used as flexible scheduling resources in this paper.Based on the constraint condition of flexibility index,energy storage charging and discharging,and micro-grid interaction power,the optimal dispatching model of distribution network with high proportion of wind and light distributed power was constructed by taking the minimum fluctuation rate of operating cost and net load as the objective function,and determining its weight value through comprehensive index method,The model was solved by improved and unimproved imperialist competition algorithms.The simulation results showed that the model and algorithm can effectively improve the flexibility of distribution network,increased the line capacity margin,adjusted the fluctuation of net load and reduced the network loss,which had certain practical significance for high proportion intermittent power grid connection.