| With the continuous and rapid increase of photovoltaic(PV)penetration in the distribution network(DN),the analysis and optimization of PV hosting capacity(PVHC)in DN have been paid more and more attention.In this dissertation,considering the influences of multiple uncertainty factors in DN,the research on interval and affine method for PVHC modeling,analysis and optimization planning is carried out.The research of this dissertation can provide decision-making basis for DN planning and operation under uncertain environment,and is of certain guidance significance for ensuring safe and stable DN operation,promoting PV hosting,and realizing China’s carbon neutral target.The main work is as follows:1)From the multiple perspectives of connotative definition,influence factors,conceptual model and mathematical model of PVHC,the PVHC analysis models are established.The connotative definitions and influence factors of PV absorption capacity and PVHC are compared,and their similarities and differences are clarified.Based on the barrel principle,a multi-dimensional conceptual model of PVHC is established,which vividly depicts the mapping relationship between PVHC and various influence factors,and can excavate the key influence factors of PVHC.The deterministic and uncertain analytical models of PVHC are established respectively,with emphasis on the interval analytical model and affine analytical model of PVHC.Thus,the multi-angle modeling of PVHC in DN is realized.2)Considering the probability and severity of overvoltage problem caused by the uncertainty of PV configuration in DN,an interval and affine method for PVHC analysis based on interval overvoltage risk(IOR)is proposed.The stochastic analysis methods of PVHC based on interval overvoltage probability(IOP)and IOR are proposed respectively,which can overcome the shortcomings of analytical method and intelligent optimization method that are biased to optimistic analysis,and can reduce the computation conservativeness.By introducing the correction coefficient of overvoltage severity,the interval and affine methods for PVHC analysis based on IOP and IOR are proposed respectively,which can precisely quantify the interval varaition characteristics of real overvoltage risk in DN.Meanwhile,the accuracy and adaptability of PVHC analysis can be improved when the uncertainties of PV output,load demand and PV configuration are considered simultaneously.The sensitivity analysis of key parameters and the comparative analysis of solution efficiency are carried out for practical cases,which verifies the effectiveness of proposed method in improving the accuracy and adaptability of PVHC analysis.3)Aimed at the complex mapping relationships between multiple uncertainties of DN and the multi-constraint sensitivity,an interval and affine method for PVHC analysis based on multi-constraint uncertain sensitivity is proposed.The affine three-phase voltage sensitivity equations based on Jacobian matrix and nodal admittance matrix are derived respectively.The interval and affine methods for PVHC analysis based on three-phase Jacobian matrix and three-phase nodal admittance matrix are proposed respectively,which can ganrantee the accuracy and efficiency of PVHC analysis simultaneously.A multi-constraint uncertain sensitivity model is established,and an interval and affine method for PVHC analysis based on multi-constraint uncertain sensitivity is proposed,which can further improve the comprehensiveness,accuracy and efficiency of PVHC analysis under uncertain environment.Through the case study and method comparison,the feasibility and applicability of voltage sensitivity analysis and multi-constraint analysis in PVHC analysis with uncertainties are verified.4)Aimed at PVHC improvement,an interval and affine method for DN bi-level multi-objective adaptive joint planning is proposed.The affine model of DN bi-level multi-objective adaptive joint planning is established,which can improve the adaptability of PV hosting while ensuring the economy of DN planning.An interval and affine method for PVHC improvement oriented DN bi-level multi-objective adaptive joint planning is proposed,which can obtain the non-dominated optimal planning schemes that meet both economy and PV hosting adaptability goals under uncertain environment.Furthermore,the affine dominance relation weakening criteria and the affine Pareto optimal front modification method based on comprehensive deviation distance are proposed,which can effectively eliminate bad solutions and improve solution quality.The comparison with interval method and Monte Carlo simulation method demonstrates the advantages of affine planning method on its high computation accuracy,fast speed and low conservativeness. |
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