## 2 Materials and Methods  
### Experimental Layout  
According to the experiment requirements, various electromechanical and smart meters were tested for direct comparison. Installation was conducted on an existing company site, titled \"H.E.C. Systems\", using a three-phase supply with 25 kVA apparent power, monitored via a 400 V, 10-60 Amp meter (ABB, Zurich, Switzerland). All components were installed inside the distribution panel after the main breaker to measure the total energy that is consumed, so the panel layout is presented in Figure 4.  
Figure 3: Smart grid application with distinct energy suppliers [17].  
Two different schemes were applied: direct connection to the meter and connection through current transformers, depending on the power required, as shown in Figure 5[21].  
The meters utilized, electromechanical, digital or smart, were 5 in total, with distinct specifications. All three meters were 3 phase, and the information provided on their manufacturer labels is summarized in Table 1[22; 23; 24; 25].  
Figure 4: The experimental layout installed at the main control panel.  
Figure 5: Meter connectivity schemes: (**a**) direct connection; (**b**) exploitation via current transformers.  
The MM2600 (Landis&Gyr, Cham, Switzerland), a typical electromechanical meter manufactured in 2002, measures only active power, with every 75 rotations standing for 1 kilowatt-hour, while the Mk10A (EDMI, Singapore), introduced in 2014, measures each kWh with 500 impulses, which can be observed through the led activation. Both meters are directly connected to the load. The Atlas model is attached to a GSM modem with Sim card for data transmission to the Independent Power Transmission Operator (IPTO or ADMIE) every 15 min on a daily basis. It may also operate through GSM at a 850-1900 Mhz frequency range at a 100 ms time interval, with a typical consumption of 2 watts via the IEC 62056 protocol, using the port number 12212 [27]. The Sim card cannot be removed, and a possible breach triggers an alarm at the operator's end, while the seal on the MM2600 can be removed, requiring personnel to check it during counting. The layout of the two meters is depicted in Figure 6 below.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Meters** & **Landis\&Gyr** & **EDMI Mk10A** & **ELControl** & **ABB** & **Zennio** \\  & **MM2600** & **L** & **Microip3** & **DMTME** & **KES-Plus** \\ \hline Ref.Voltage (V) & 230/400 & 230/400 & 600 & 550 & 230 \\ Range (V) & N/A & 0.8–1.15 Un * & N/A & 10–500 & 100–230 \\ I\({}_{\text{MAX}}\) (A) & 10–60 & 100 & 1000 & 5 & 120 \\ \hline Accuracy Class & 2 & 1 & 1 & 1 & B \\ Consumption (VA) & N/A & \textless{}0.5 & 4 & 0.45 & 0.413 \\ \hline Connectivity & N/A & RS232, IP, MOD & N/A & N/A & KNX \\ Temp.Range (\({}^{\circ}\)C) & \(-\)20 to 50 & \(-\)25 to 60 & \(-\)10 to 50 & 0 to 50 & 0 to 40 \\ Protection Class & N/A & CAT II & CAT III & N/A & CAT II \\ IP Rating & IP20 & IP53 & IP40 & IP50 & IP20 \\ \hline Weight (kg) & 3 & 2 & 2.9 & 0.32 & 0.10 \\ Dimensions (mm) & 260 \(\times\) 150 \(\times\) 130 & 210 \(\times\) 166 \(\times\) 74 & 251 \(\times\) 239 \(\times\) 104 & 105 \(\times\) 90 \(\times\) 63 & 67 \(\times\) 90 \(\times\) 35 \\ \hline \hline \end{tabular}  
* Nominal voltage.  
\end{table}
Table 1: Meters Specifications.  
Figure 6: Testing of the most widely available energy meters: Landis & Gyr MM2600 and Atlas Edmi Mk10A.