## 2 Methods and Data
### Topology and Inputs  
The modeled supply areas belong to the LV distribution network of western Hungary. Every area is modeled using an external grid element, a MV/LV transformer and all the elements from its LV side. The numbers denoting these areas are 18,680, 20,667, 44,333 and 44,600, consisting of 2, 4, 5 and 10 circuits, respectively. Topologies of the supply areas are shown in the Appendix A (see Figures 11-14). In all four cases, modeling essentially involves the building of three representations with different load placement accuracies, for practical reasons. E.ON stores the descriptive characteristics of these transformer areas in two ways. The first way is to use AutoCAD files with an *_dwg_ extension, and the second is to use the INIS system, from which the data can be exported on demand to Excel files. The first is the construction of the fully accurate model, but its disadvantage is that the network cannot be assembled from it automatically, so modeling must be carried out manually. The second contains approximations and simplifications. For example, it is possible that certain buses are neglected, or consumers and lines specified with Unified National Projection (UNP) coordinates are not actually in the defined position. However, the system can be created fast from this second dataset using the queried Excel files. Thus, the three representations with different levels of precision in terms of load placement built from these data are:  
* the system defined by the AutoCAD files with *_dwg_ extension,
* the data-driven system that can be defined by Excel queries from INIS,
* and the more precise data-manipulated system that can be defined by Excel queries from INIS. Of all the system types, the manually built one (referred to as the AutoCAD model) requires the fewest hardware resources, and it is the least challenging in a professional sense, as one does not need to understand the details of the structural elements of the INIS query. However, this simplicity cannot be declared in terms of human resources. The examined four supply areas together contain more than a thousand consumers. These and the connected lines, buses, switches and circuit breakers had to be represented one by one. In addition, the markings in the *_dwg_ files were not always clear regarding which \begin{table}
\begin{tabular}{c c c} \hline \hline
**Scenario** & \(\mathbf{u_{sc}}\) **of Residential Loads (\%)** & \(\mathbf{u_{sc}}\) **of Controlled Loads (\%)** \\ \hline
1 & 2.54047 & 123.225 \\
1m & 2.53925 & 123.146 \\
2 & 0.884116 & 119.048 \\
2m & 0.940834 & 119.195 \\
2 mm & 0.275357 & 127.572 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Uncertainty values of residential and controlled datasets for the scenarios. line belonged to which circuit, and due to the redundancy with the initial INIS query, continuous consultation with E.ON was required. In addition, the support of Google Street View and E-kozmta [32] tools were used, and on-site checks were also performed. The system that can be defined by Excel queries from the INIS system (referred to as the _INIS model_) consists of fifteen files: (1) the consumers file, (2) the recently connected consumers file, (3) the AAC data file, (4) the file of buses with connection data, (5) the file of buses with coordinates, (6) the file of switches with connection data, (7) the file of switches with coordinates, (8) the file of circuit breakers with connection data, (9) the file of circuit breakers with coordinates, (10) the transformer location data file, (11) the file about the technical parameters of the transformer, (12) the file of the lines, (13) the file about the location data of the lines, (14) the file of the assistant lines and (15) the file about the location data of the lines behind the meters. An input reader script was created using the _openpyxl_ module to build all four areas. Each network is built as follows. The types of lines are defined first, and then, the file containing the location data of the lines can be examined in parallel with the file of the lines.