Evaluation Method For Substation Substitution Capacity Of High-voltage Distribution Network With Generalized Power Source

In order to overcome the impact of distributed renewable energy access to the distribution network,active distribution network and micro-grid adopt intelligent control measures,which can not only solve the problem of consumption,but also effectively improve the economy and power quality of the grid.With continuous increases in distributed generation(DG),energy storage system(ESS),and demand-side response resource penetration,they can be used to replace the substation capacity to carry part of the load in distribution network.In this paper,these distributed resources are collectively referred to as generalized power source(GPS).GPS access to the distribution network is divided into two autonomous levels:one is the active distribution network,the other is the micro-grid.In this paper,the evaluation for substation substitution capacity of high-voltage distribution network with GPS is the research object,the main research work of this paper can be summarized as follows:Firstly,combined with literature at home and abroad,the definition of GPS in distribution network is proposed.Considering the uncertainty of the GPS and the internal control strategy,the model of GPS operation strategy and the micro-grid power output are respectively established.At present,scholars use the concept of credible capacity to evaluate the contribution of DG on capacity margin.Therefore,the GPS capacity credit in high-voltage distribution network is proposed.Since the substation capacity is not only related to the distribution of users under the substation area,but also closely related to the structure of the high-voltage distribution network.The typical wiring modes and the transfer modes analysis of the high-voltage distribution network are carried out.On this basis,this paper takes a specific distribution area under the premise of forecasting certain values of GPS penetration and GPS scattered distribution in the planning level year to study its substitution capacity.Based on the principle of equal reliability and sequential Monte Carlo,the evaluation method of the GPS capacity credit of the high-voltage distribution network is proposed.The analysis of the two scenarios is given in the case study.One is the control of GPS through active distribution network,the other is the scenario with a large number of micro-grids access.The credible capacity of various typical connection modes of the high-voltage distribution network is quantitatively analyzed to verify the validity of the proposed method,which can provide a reference for the follow-up substation upgrading.