1. College of Electrical Engineering, Zhejiang University, Hangzhou 310027, China;2. Economic Research Institute of State Grid Zhejiang Electric Power Co. Ltd., Hangzhou 310008, China;3. State Grid Zhejiang Electric Power Co. Ltd., Hangzhou 310007, China

With the development of power-to-gas technology, the coupling between a power system and a natural gas system concerned is gradually strengthened. The traditional mode of separately planning a power system and a natural gas system is no longer applicable for a closed-loop operated electricity-natural gas energy system or an integrated electricity-gas energy system(IEGES). On the other hand, demand side management can optimize the power load profile, contribute to load shifting and enhance the capability of accommodating intermittent renewable energy generation, and hence promote the secure and economic operation of the whole IEGES. Given this background, the collaborative planning problem of IEGES is studied, with demand side management(DSM)taken into account. First, DSM is modeled with the satisfaction of customers respected. On this basis, a mixed-integer nonlinear programming model is presented for the planning of natural gas-fired units, power to gas(P2G)devices, transmission lines and natural-gas pipelines in an IEGES, with an objective of minimizing the total costs including the investment cost, operation cost and compensation cost for DSM. To speed up the solving procedure, this mixed-integer nonlinear programming model is transformed into a mixed-integer linear programming one by linearizing nonlinear terms and then solved by the commercial solver AMPL/CPLEX. Finally, the presented model and method are demonstrated by an IEGES including a modified version of the IEEE 39-bus power system and the Belgium 20-bus natural gas system, and the effects on cost saving and the promotion of the accommodating capability for wind power generation are examined as well.