## 4 The Proposed Use Case: Data Model and Scalability Analysis
### The Smart Campus Use Case

Table 1: List of information packed into each data sample transferred by a single low voltage smart power meter. Each information is computed as the average of all of the measured samples over the given monitoring time interval. For reactive power measurements, positive values represent inductive loads, while negative values represent capacitive loads. THD: Total Harmonic Distortion, RMS: Root Mean Square. \begin{table}
\begin{tabular}{l c c} \hline \hline
**Information** & **Range** & **Resolution** & **Size (B)** \\ \hline Identification code of the sensor & - & - & 2 \\ Timestamp of the set of information & - & 1 s & 5 \\ Single measurement & - & - & 2 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: List of information packed into each data sample transferred by a generic single sensor. Each information is computed as the average of all of the measured samples over the given monitoring time interval. twelve uplink messages), by using a confirmed LoRaWAN message. In this case a 8 B synchronization message (including the identification code of the sensor and the time reference) is sent by the EMS or the BEMS every 3 h, corresponding to a data throughput of about 0.00046 B/s. When it comes to independent generators (i.e., power generators directly supervised by the smart campus EMS or by a single BEMS), the set of transferred information usually include the monitoring of energy flows, power quality measurements, such as well as specific operating parameters, and alarms. In Table 3, the reference set of information provided by power generators is reported, by considering the case of a photovoltaic (PV) inverter, which is one of the most diffused power assets in distributed generation scenarios. In this case, the nominal power of the generator was assumed to be on the order of 200 kVA. As detailed in Table 3, the maximum size of each set of information transferred by power generators to the supervisory entity is on the order of 30 B every 15 min, leading to an expected data throughput of about 0.033 B/s. Concerning the transmission of information from the supervisory entity to independent generators, a set of control instructions is sent every 3 h, by using a confirmed LoRaWAN message (with the side benefit of not influencing the radio duty cycle of the gateway). The set of transferred information, such as detailed in Table 4, includes the identification code of the device, the time reference signal (for synchronization purposes), an active power profile representing the power limitation request to the specific generator (with a time resolution of 15 min), and the initial timestamp of the job schedule. In this case a 36 B message is sent to each supervised generator by the EMS or the BEMS every 3 h, corresponding to a data throughput of about 0.003 B/s. In Table 5 the reference set of information provided by an independent equipment is reported, by considering the case of a HVAC system. In this case, such assuming that the monitored HVAC system \begin{table}
\begin{tabular}{l c c c} \hline \hline
**Information** & **Range** & **Resolution** & **Size (B)** \\ \hline Identification code of the generator & - & - & 2 \\ Synchronization Timestamp & - & 1 s & 5 \\ Initial timestamp of the job schedule & - & 1 s & 5 \\ Requested power profile & 0 \(\div\) 200 kW & 3 W & 24 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: List of information packed into each data sample transferred to a single photovoltaic inverter. Each power profile is defined as an active power limitation request, with a time horizon of 3 h, and a time resolution of 15 min.