Dynamic Probabilistic Energy Flow Calculation For Interconnected Electricity—Gas Energy System Considering Uncertainties Of Integrated Demand Response

With the increasing proportion of renewable and clean energy such as wind power and photovoltaic in power grid,its randomness and intermittence bring great challenges to the safe and stable operation of power grid.The application of interconnected electricity-gas energy system(IEGES)provides an effective way to solve this problem.In IEGES,gas turbine(GT)has fast regulation speed and can be used for emergency peak shaving,which is in harmony with the randomness and intermittence of renewable energy.With the maturity of power to gas(P2G)technology,P2G equipment will provide more room for renewable energy consumption.With the in-depth coupling of power grid and natural gas network,the time transferability of homogeneous energy load and the complementary substitution of heterogeneous load in IEGES make the traditional demand-side response gradually develop towards integrated demand response(IDR),which is compatible with the conversion of different energy forms.In order to analyze the adjustable characteristics of different types of energy loads under IEGES and then effectively evaluate the impact of IDR on probabilistic energy flow in IEGES,it is necessary to study the uncertain modeling method of IDR and the corresponding calculation method of probabilistic energy flow.Firstly,based on IEGES system architecture,IEGES system model is established.Through the analysis of IEGES structure modules,the steady state models of power subsystem and natural gas subsystem are established,and the model of electrical interconnection coupling elements is established.Secondly,according to the characteristics of IDR implementation,an IDR uncertainty model based on Z-number method is established.According to load characteristics,under the guidance of energy market price mechanism,IDR is classified and corresponding elastic models of IDR are established respectively.Considering the natural randomness of user response behavior in non-direct-controlled IDR projects and the influence of basic information reliability on the modeling process,Z-number method is used to describe the uncertainty parameters in IDR elastic model to objectively reflect the real effect of IDR uncertainty in IEGES.Then,aiming at the IDR uncertain model,a dynamic probabilistic energy flow calculation framework considering the complex uncertainties of IDR is proposed.The probabilistic transformation of Z-number parameters in IDR model is carried out by using the method of fuzzy expectation and the method of gravity center.The unification of different uncertain variables is realized.The transformed load response is regarded as a new random variable and introduced into IEGES probabilistic energy flow calculation model.The probabilistic energy flow is solved by using cumulant method,and the cumulative distribution function of each state variable are obtained.Finally,the effectiveness of the proposed model and method is validated by taking IEGES composed of modified IEEE-14 nodes and 7-node natural gas as examples,and IEGES composed of IEEE-118 nodes and 20-nodes Belgium as examples to verify its effectiveness in large-scale scenarios.In addition,the simulation results show that the proposed method can effectively analyze the energy flow distribution and expected operating benefits of IEGES under uncertain supply-demand interaction environment,and can provide abundant information support for integrated energy operators to implement IDR and optimal control decision-making.