# Operational Resilience Metrics for Complex Inter-Dependent Electrical Networks
## 3 The RecSIM Tool  
Figure 6 shows the input of RecSim and its output (i.e., the consequence of a perturbation in terms of \(\Gamma_{i}\)). In particular, Figure 6 highlights the relationships among the simulator input and the resilience properties introduced in Section 2. The RecSIM inputs are:  
* _Network topology_--expressed as the EDN graph and the perturbation \(P\) represented by the SS is in the **damaged** state. In this work, perturbation \(P\) is introduced by the user. However, the node in the **damaged** state can also result from the analysis of external perturbation (i.e., weather forecast) and result from an over-threshold probability of damage of a node induced by a natural hazard (e.g., in the CICCast platform, see [22; 34]);* _SCADA system_--expressed in terms of the set \(\Omega\) of SS that can be remotely tele-controlled;
* _Efficiency of SCADA system_--expressed in terms of the functioning status of the BTS \(b_{i}\) providing communication service to the EDN and in terms of \(tlc_{t}\), the time needed to perform a remote operator action (using the EDN SCADA functionalities);
* _Efficiency of restoration procedures_--expressed in terms of the time needed by an emergency crew (a) to reach a damaged SS (\(tr_{t}\)), (b) to perform a manual reconnection action (\(m_{t}\)) and (c) to set in place a PG to feed the users of the **damaged** SS (or of other SS, which will result in being isolated and thus needing a PG as they were **damaged**). The input time values represent \"mean\" values as they have been provided by the electrical operator. RecSim performed simulations by using these values as mean values of a flat distribution from which time values to be used in the simulation were randomly extracted;
* _Technical resources_--expressed in terms of the number \(C\) of technical crews available in the field. The number of available PGs is assumed to constitute an unlimited resource. Further development of the algorithm will consider the finiteness of available PGs. The output of RecSim is represented by the value of the impact of the damage scenario (represented by the perturbation \(P\) and by its cascading effects) on the EDN, considering all the actions performed (in series or in parallel, as many technical crews were simultaneously available): (a) the **damaged** node and, whenever the case, the isolated node substitution with a PG; (b) the manual reconnection of **disconnected** nodes by the available technical crews and (c) the automatic reconnections made through remote tele-control operations. These actions restore the EDN to a normal operating status and allow all users to be reconnected to the grid. As previously stated, **damaged** SS are just substituted by a PG and, at the end of the simulation, they are still in the **damaged** state although their function is recovered by the PG. The impact of the perturbation \(P\) on the network is thus computed using the Equation (2). Figure 7 shows the different elements of a RecSim EDN model. The electrical MV lines start from primary stations (the node A in Figure 7) and they connect the secondary substations forming, in general a tree structure. As it as already explained in the previous section, some of the secondary substations can be: normal, remotely tele-controlled, automated and \"frontier\" substations that are represented, respectively, as white, grey, orange and purple nodes in Figure 7. The automated substations are very important as they are able to perform automatically the isolation and restoration procedures needed to react to failures happening to they descendants substations (e.g., the substations P, Q, R, S in Figure 7 are the descendants of the automated substation F). The \"frontier\" substations can be used to restore a portion of an MV line from another MV line backup feeders. Figure 6: The RecSim simulator inputs and output.