## 5 Model Application  
In this section, an integrated gas and power network is constructed to demonstrate the previously discussed simulation framework implemented in SAInt. Three supply side scenarios (one non-disrupted scenario (base case) and two supply disruption scenarios) are presented in order to demonstrate the value of the proposed framework and to stress the importance of modeling the interdependence between gas and power systems with respect to security of supply. The proposed scenarios are performed on the test network depicted in Figure 4. (The test network applied in this paper is a model of a real gas and electric power network of an European region. Due to confidentiality reasons and the sensitivity of the presented results, the topology and facility names of the real network have been disguised. The network topology and properties used for the computations,however, are realistic data for the combined network). The scenarios are composed of a number of extreme events causing more than two network facilities to be deactivated or to cascade out of service. The sample network includes a power grid with 158 buses, 62 generating units with 22,076 ( MW) installed capacity based on different generation mix that mainly consists of lignite (33%), natural gas (28%), coal (20%), wind power (7%) and others (12%). The transmission system consists of 194 high voltage transmission lines with total line length of approx. 8000 (km). The base voltage levels for the transmission lines are distinguished between 200 (kV) and 400 (kV). The solution of the AC-OPF equations requires the knowledge of the voltage levels, admittances as well as the maximum thermal capacities of the transmission lines. The reactance of a line depends mainly on its physical properties. It increases proportionally to the geometric length of the line. Therefore, in the scope of this work, we assume equal physical properties for all lines and use the length to determine the reactance. A typical value for the reactance of a transmission line per unit length is 0.2 (\(\Omega\)/km). Regarding the thermal capacities of the transmission lines, we assume a transmission capacity of 800 (MW) for 400 (kV) lines and 530 (MW) for 200 (kV) lines. In AC-OPF analysis the reactive power has strong influence on voltage drop thresholds. Thus, during AC OPF analysis, the maximum and minimum voltage levels for buses are considered and a value between 1.12 and 0.96 (p.u.) is assigned, respectively. The gas network, comprises of 345 pipe segments with a total pipe length of roughly 4000 (km), 10 compressor stations and 352 nodes (54 exit stations to the local distribution system (CGS), 15 stations to direct served customers (14 GFPPs and one large industrial customer (IND)), two cross border export stations (CBE_1 & CBE_2), one cross border import station (CBI), one LNG terminal (LNG), one  
Figure 4: Integrated gas and power network applied in the case study. Map shows a real network of an European region, which has been disguised due to confidentiality reasons. The network data and properties used for the case studies, however, are original input data for the actual network. The solid black lines (lines 1–3, 7–12, 14–18) represent interconnections between Gas Fired Power Plants (GFPPs) in the power grid (**left**) and their fuel gas offtake points in the gas grid (**right**), while the dashed black lines (4–6, 13) represent interconnections between electric buses in the power grid (**left**) supplying electric power to connected facilities in the gas grid. and local distribution system. For all other exit stations (CBE_1, CBE_2, IND) a constant load profile corresponding to the steady state load is assumed. The absolute values of the load profile for CGS nodes are obtained by multiplying the steady state load with the relative values in Figure 5 (left plot). The load profiles of the 14 GFPPs in the gas model are provided by the power model based on allocating the results obtained from the AC-OPF analysis to the corresponding nodes in the gas model.