Optimization Of Active Distribution Network Source-Grid-Load Interactive Operation Considering The Uncertainty Of Source-Load

With the large-scale distributed power supply,flexible load and other adjustable resources access to the distribution network,the traditional passive distribution network gradually evolved into an active distribution network.Based on the controllability of "source","grid" and "load" of active distribution network,this thesis studies the related problems of source-grid-load coordinated operation optimization of active distribution network.The main research work and research results are summarized as follows:(1)For the uncertainty of distributed PV power output,this thesis establishes a discrete photovoltaic active output model based on rough meteorological data.Firstly,the basic method of describing the uncertainty of the normal distribution equal probability function is analyzed.Further,considering that the small-capacity photovoltaic power supply has only rough meteorological information(such as the probability of sunny,cloudy and rainy days),it does not have high-precision power forecast function.Therefore,the study proposes the use of discrete probability distributions to describe the uncertainty of output in different weather conditions.(2)In order to reduce the power loss of active distribution network,this thesis proposes an optimization method based on two-layer combination optimization algorithm for source-grid-load coordination operation.Firstly,considering the power loss of active distribution network is related to the power output,load,and network topology.With the goal of minimum power loss,the source-grid-load coordinated operation optimization model(non-convex nonlinear mixed integer optimization model)is established.Considering that the optimization model is difficult to solve directly,the thesis proposes a two-layer combination optimization algorithm.In the lower layer of the algorithm,the NLP method is used to find the local optimal solution for different network topologies.In the upper layer,the best local optimal solution is obtained by comparing the values.Finally,the simulation results on the IEEE 33-node power distribution system show that the optimization of the active distribution network source-grid-load coordination operation can effectively reduce the power loss.(3)Based on the above research contents,considering the uncertainty of distributed PV output and load forecasting,this thesis proposes an optimization of active distribution network source-grid-load coordination operation considering the uncertainty of source-load.Firstly,the probability distribution of discrete random variables based on rough meteorological data is established to describe the uncertainty of PV output.The normal distribution is used to describe the uncertainty of load forecasting.Secondly the optimization of active distribution network source-grid-load coordination operation considering the uncertainty of source-load is established.Considering the problem of source-load uncertainty,it is transformed into a deterministic expectation model,and then solved by a two-layer combination optimization algorithm.Finally,the simulation results show that the proposed method can effectively reduce the power loss while considering the source-load uncertainty.