With the increasing share of uncertain renewable energy generation and natural gas-fired power production in power systems

a deep integration between power and natural gas systems is highly desirable. We develop a three-stage coordinated operation model for two coupled systems

using stochastic programming to adapt to the uncertainty of wind power production. Compared with the conventional two-stage model

we introduce the intra-day-stage operation and obtain a more flexible adjustment. The natural gas system operation is a single stage (i.e.

day-ahead scheduling)

which is consistent with current practice. The fluctuation in gas demand associated with power generation caused by the intermittent wind power production at the intra-day and real-time operation is balanced by the line pack. Numerical results of two test systems verify the superiority of the proposed model over the two-stage model.