Research On Energy Storage Location And Capacity Planning Based On Peak Clipping Benefit Evaluation Of Distribution Network

The distributed generation(DG)represented by distributed photovoltaic(DPV)is widely connected to the distribution network,which will greatly change the original load peak characteristics of the equipments in the distribution network.The change in the peak load characteristics of these equipments will indirectly affect the expansion and transformation cost of the distribution network by affecting the equipment expansion and transformation time.Ultimately it will affect the asset utilization rate of the distribution network.On the other hand,energy storage(ES),as a representative of flexible load(FL),matches the peak-to-valley characteristics of the system load by changing the timing characteristics of the DPV,actively participates in system peak load regulation,and the overall effect of peak load regulation depends on the access location and access capacity of the ES.Based on this,this paper mainly carries out the following research work:(1)In order to study the influence of the uncertainty of DPV output on the expansion cost of distribution network,the influence of illumination and temperature on DPV output is analyzed firstly.The daily and seasonal characteristics of DPV output are studied.The generalized weather type clustering method based on photovoltaic output fluctuation characteristics is presented.The photovoltaic output time series model construction method based on the clearance theory is proposed.The construction method separates the deterministic and random components of the DPV output,and studies the time-series characteristics of the DPV output caused by the sun's sunrise and sunset,and the fluctuation characteristics of the DPV output due to cloud layer changes.Modeling the actual operational data of a photovoltaic panel verifies the validity of the model and has strong engineering application value.(2)Considering the uncertainty of load and photovoltaic output,the confidence peak clipping index is proposed to measure the influence of DPV access on the distribution transformer equipment,line equipment and substation main transformer equipment load peaks in the distribution network.And then changes in the expansion speed of various types of equipments are studied.Based on this,combined with the concept of the marginal capacity cost of the node,the evaluation model of the peaking clipping benefit evaluation for DPV distribution network is carried out by estimating the capital input cost changes caused by the advancement or delay of the expansion of the infrastructure projects.The simulation proves that the established evaluation model identifies the difference in the impact of DPV on the peak-clipping benefit of the distribution network in different locations,different voltage levels,different capacities,and different load types,and the accuracy and effectiveness of the model are verifies.The established model has important guiding significance for the research of location and capacity optimization planning of peaking units such as DPV.(3)The energy storage charge-discharge control strategy based on the peak load reduction of the aggregation node is proposed.Based on this strategy and under the condition of uncertainty,in the DPV-containing distribution network,the differences in the impact of energy storage with different capacities,different locations and different load types on the peak-clipping benefit assessment of the distribution network have been studied.And a two-level optimization planning model for energy storage site and capacity selection considering the peak-clipping benefit evaluation of the optical storage and distribution network is established.The actual grid simulation verifies the effectiveness of the model in improving the comprehensive peak-clipping revenue of the energy storage configuration.It also points out the economic irrationality of solving the low-voltage problem at the end of the distribution network by energy storage participating in voltage regulation.