This paper is aimed at analyzing the influence of fluctuation by gas load in the integrated electrical and natural-gas system (IENGS). To address this issue, an affine method is proposed to calculate energy flow in IENGS considering uncertainties. In the distribution network, the power flow is solved by affine arithmetic based on forward-backward sweep method after obtaining the solutions of coupling units in the gas system. A numerical test, in which an IENGS is made up by a 13-bus distribution network and a 7-node gas system, shows the correctness and effectiveness of the proposed method. The results draw the conclusion that the fluctuation of gas load leads to the fluctuation of the whole IENGS.
Keywords integrated electrical and natural-gas system, uncertainty, affine mathematics, energy flow