Optimal Operation Analysis For Integrated Energy Systems With Consideration Of Uncertainty

As a kind of supplying systems that can dispatch energy optimally,integrated energy systems(IES)can improve the energy efficiency and sustainability of energy development.It is of great significance to study the issues concerning IES.This dissertation focuses on the energy flow,optimal operation and evaluation of IES considering uncertainties of sources and loads.The main contributions can be summarized as follows:1)In the analysis of energy flow of integrated electrical and natural-gas systems(IENGS),by studying the coupling units of electrical network and natural-gas network with the models of IENGS,interval energy flow model is firstly presented based on the steady-state energy flow model of IENGS.Then,the interval model considers the uncertainties of electrical power generation and electrical/gas loads of the operating IENGS.Lastly,in the computational procedures of interval energy flow,affine arithmetic is utilized to reflect the correlations of variables and the improved method for interval energy flow is proposed.This method can study the influences of fluctuations of power generation and loads and reflect the mutual affections of electrical network and natural-gas network.2)In the analysis of the optimal dispacthing for IENGS integrated with power to gas(P2G),based on the output models of the gas-fired generator,electrical energy storage system and P2 G device,the optimization model of IENGS is presented under deterministic conditions.Considering the uncertainties of photovoltaic and wind energy,the interval optimization model of IENGS is proposed firstly.Then the deterministic nonlinear model is converted to a mixed integer linear programming problem and the interval model is solved by interval linear programming method.By comparing the method with Monte-Carlo simulation method,the correction of the proposed method is analyzed.The economic influences of P2 G as well as the uncertain levels of the photovoltaic and wind energy on the operating IENGS are also studied.3)The electrical and gas demand response is implemented on the user side in the IES with combined cooling,heating and power(CCHP)system and the optimization model for IES is presented under deterministic conditions.Considering the uncertainty and correlation of power output of photovoltaic and heat output of solar collector,the interval optimization model of IES with CCHP considering uncertainties is proposed firstly.Affine arithmetic is then introduced to describe the correlation in the computational process and the improved interval linear programming method is proposed.Lastly,by comparison with the traditional interval linear programming method,the effectiveness of the proposed method is analyzed.The affections of demand response and the uncertain level of the light intensity on the IES are compared.4)In the evaluation of IES,considering the features of IES an evaluation criteria system including economy,environmental protection,energy efficiency and reliability is built firstly.Then the combined weighting model,which combines the advantages of subjective and objective empowerment,is presented to obtain the interval values of primary indexes.The evaluation method based on interval TOPSIS for IES is proposed considering the uncertainty of weighting.Lastly,by comparison with different scenarios of IES,the proposed evaluation criteria and method prove to be effective.