**5. The simulation scheme and the reconfiguration simulator (RecSIM)**

The RecSIM represents the basic module of the proposed framework for the resilience assessment of the EDN. RecSIM enables to carry on a "crisis game" consisting in the estimation of all values resulting from the application of different perturbations. The simulator allows configuring different parameters allowing, in turn, the simulation of different electrical operational conditions (e.g., SCADA system not available, traffic jams, etc.) and the analysis of how the resilience indicator varies in these different operation conditions.

**Figure 4** shows the input of the RecSIM and its output (i.e., the consequence of a perturbation in terms of *i*). RecSIM inputs are:


**41**

*Modeling Resilience in Electrical Distribution Networks DOI: http://dx.doi.org/10.5772/intechopen.85917*

> operation times. RecSIM performs simulations by using these values as mean values of a flat distribution from which time values to be used in the simulation

• *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

The output of RecSIM is represented by the value of the impact of the damage scenario (caused by the perturbation *P* and by its cascading effects) on the EDN, considering all the restoration actions performed (in series or in parallel, if several technical crews were simultaneously available): the substitution with a PG of a damaged node and, whenever the case, of an isolated node; the manual reconnection of disconnected nodes by the available technical crews; and the automatic reconnections made through remote telecontrol operations. These actions are needed to restore the EDN and to bring it back to its normal operating condition. Upon these actions, all users are supposed to be reconnected to the grid. As previously said, 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 guaranteed by the PG. The impact of the perturbation *P* on the EDN is thus computed using Eq. (3).

In a previous work [19], the EDN of the metropolitan Rome, area (Italy), was deeply investigated by extensive calculations enabling to estimate its resilience score, according to the definition reported in Section 3. RecSIM has been used to study the behavior of the whole EDN of the metropoli-Rome EDN that is a large EDN grid composed of 139 PS and 14938 SS distributed along 1607 MV lines.

are randomly extracted from the flat distribution.

**6. Simulation, analysis, and discussion of the results**

finiteness of available PGs.

*The RecSIM input and output components.*

**Figure 4.**

*Modeling Resilience in Electrical Distribution Networks DOI: http://dx.doi.org/10.5772/intechopen.85917*

*Infrastructure Management and Construction*

, thus, represents the *impact* that the damage of an EDN element (the *i-th* node) can produce, by using an official KPI as a metric. The larger the value of *<sup>i</sup>*

different factors (described in detail in Section 4) ranging from the topology of the network and the employed technologies to the efficiency of operator restoration procedures; therefore, it would not be inappropriate to correlate the value of *<sup>i</sup>*

*R*<sup>−</sup>**<sup>1</sup>** ∝ *<sup>i</sup>* (5)

We can generalize the concept by checking the EDN behavior versus all possible perturbations. The overall operational network resilience will be thus associated with the inverse of the value of the integral of the distribution function of all the *<sup>i</sup>* values (*D*()) resulting from the failure of each one of the *N* nodes of the EDN

<sup>&</sup>lt; <sup>&</sup>gt; <sup>=</sup> <sup>∫</sup>*D*()*d* \_\_\_\_\_\_\_\_

The higher the impact, the lower is the resulting operational resilience of the

**5. The simulation scheme and the reconfiguration simulator (RecSIM)**

The RecSIM represents the basic module of the proposed framework for the resilience assessment of the EDN. RecSIM enables to carry on a "crisis game" consisting in the estimation of all values resulting from the application of different perturbations. The simulator allows configuring different parameters allowing, in turn, the simulation of different electrical operational conditions (e.g., SCADA system not available, traffic jams, etc.) and the analysis of how the resilience indica-

**Figure 4** shows the input of the RecSIM and its output (i.e., the consequence of a

• *Network topology—*expressed as the EDN graph and the perturbation *P* represented

• *SCADA system—*expressed in terms of the set of SS that can be remotely

• *Efficiency of SCADA system—*expressed in terms of the functioning status of the BTS bi providing communication service to the EDN and in terms of tlct the time needed to perform a remote operator action (using the EDN SCADA

• *Efficiency of restoration procedures—*expressed in terms of the time needed by

SS (or of other SS which will result to be isolated, thus needing a PG as they were damaged) (*PGt*). The input time values represent "mean" values as they have been provided by the electrical operator as resulting from its standard

), and to set in place a PG to feed the users of the damaged

∫*D*()*d* (6)

), to perform a manual recon-

the weaker the capability of the network to withstand the perturbation in terms

of impacts produced on the EDN customers. In general the value of *<sup>i</sup>*

the inverse of the resilience concept *R*. In other terms

(normalized with respect to the total number of nodes *N*):

*R* ∝ \_\_\_\_\_\_\_ **<sup>1</sup>**

tor varies in these different operation conditions.

perturbation in terms of *i*). RecSIM inputs are:

by the SS brought in the damaged state.

an emergency crew to reach a damaged SS (*trt*

telecontrolled.

functionalities).

nection action (*mt*

,

with

depends on

*i*

EDN network.

**40**

**Figure 4.** *The RecSIM input and output components.*

operation times. RecSIM performs simulations by using these values as mean values of a flat distribution from which time values to be used in the simulation are randomly extracted from the flat distribution.

• *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 (caused by the perturbation *P* and by its cascading effects) on the EDN, considering all the restoration actions performed (in series or in parallel, if several technical crews were simultaneously available): the substitution with a PG of a damaged node and, whenever the case, of an isolated node; the manual reconnection of disconnected nodes by the available technical crews; and the automatic reconnections made through remote telecontrol operations. These actions are needed to restore the EDN and to bring it back to its normal operating condition. Upon these actions, all users are supposed to be reconnected to the grid. As previously said, 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 guaranteed by the PG. The impact of the perturbation *P* on the EDN is thus computed using Eq. (3).
