The coupling characteristics of the integrated energy systems makes the security problems more complicated. For the integrated electricity and gas systems (IEGS), a security analysis method based on the vulnerability index, which quantitatively describes the influence of control variables on the security of state variables, is proposed. First, the IEGS steady-state model is given. Then, the gas pressure-electricity load sensitivity matrix is derived based on the IEGS model. Furthermore, the vulnerability index that considers the current value of state variables, operating limits, and the sensitivity of state variables to control variables is defined and a security analysis method based on it is established. The case study shows that the proposed security analysis method can accurately identify vulnerable state variables in the system.

integrated electricity and gas systems;sensitivity;vulnerability index;security analysis