# Power Quality Impact and Its Assessment: A Review and a Survey of Lithuanian Industrial Companies
## 3 Materials and Methods
### Impact Assessment
2b--the weights are taken from Table 8. In the first case, the input matrix **X** is equal to the result matrix **Y**. In other cases, the result matrix **Y** is obtained by multiplying each element of the input matrix **X** with its corresponding element in the weight matrix **S**, i.e., by finding the Hadamard product (also known as the element-wise product). Mathematically, this operation is written as follows: \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \begin{tabular}{c} **Voltage, p.u.** \\ \end{tabular} & \begin{tabular}{c} **0.01 \(\leq\) t \(\leq\) 0.2** \\ \end{tabular} & \begin{tabular}{c} **0.2 \(\leq\) t \(\leq\) 0.5** \\ \end{tabular} & \begin{tabular}{c} **Duration, s** \\ \end{tabular} & \
\begin{tabular}{c} **1 \(\leq\) t \(\leq\) 5** \\ \end{tabular} &
\begin{tabular}{c} **5 \(\leq\) t \(\leq\) 60** \\ \end{tabular} \\ \hline
0.9 \textgreater{} U \(\geq\) 0.8 & 0.40 & 0.67 & 1.00 & 1.00 & 2.00 \\
0.8 \textgreater{} U \(\geq\) 0.7 & 0.80 & 1.32 & 2.00 & 2.00 & 4.00 \\
0.7 \textgreater{} U \(\geq\) 0.4 & 1.20 & 1.98 & 3.00 & 3.00 & 6.00 \\
0.4 \textgreater{} U \(\geq\) 0.05 & 1.60 & 2.64 & 4.00 & 4.00 & 8.00 \\ U \textless{} 0.05 & 2.00 & 3.33 & 5.00 & 5.00 & 10.00 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Voltage sag severity calculated by using the worst-case method. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \begin{tabular}{c} **Voltage, p.u.** \\ \end{tabular}  & \begin{tabular}{c} **0.01 \(\leq\) t \(\leq\) 0.2** \\ \end{tabular}  & \begin{tabular}{c} **0.2 \(\leq\) t \(\leq\) 0.5** \\ \end{tabular}  & \begin{tabular}{c} **Duration, s** \\ \end{tabular}  & \ \begin{tabular}{c} **1 \(\leq\) t \(\leq\) 5** \\ \end{tabular}  & \begin{tabular}{c} **5 \(\leq\) t \(\leq\) 60** \\ \end{tabular}  \\ \hline
0.9 \textgreater{} U \(\geq\) 0.8 & 0.39 & 0.67 & 1.00 & 1.00 & 1.90 \\
0.8 \textgreater{} U \(\geq\) 0.7 & 0.79 & 1.32 & 2.00 & 2.00 & 3.81 \\
0.7 \textgreater{} U \(\geq\) 0.4 & 1.19 & 1.98 & 3.00 & 3.00 & 5.72 \\
0.4 \textgreater{} U \(\geq\) 0.05 & 1.59\[ \begin{bmatrix}y_{11}&y_{12}&y_{13}&y_{14}&y_{15}\\ y_{21}&y_{22}&y_{23}&y_{24}&y_{25}\\ y_{31}&y_{32}&y_{33}&y_{34}&y_{35}\\ y_{41}&y_{42}&y_{43}&y_{44}&y_{45}\\ y_{51}&y_{52}&y_{53}&y_{54}&y_{55}\end{bmatrix} = \begin{bmatrix}x_{11}&x_{12}&x_{13}&x_{ 14}&x_{15}\\ x_{21}&x_{22}&x_{23}&x_{24}&x_{25}\\ x_{31}&x_{32}&x_{33}&x_{34}&x_{35}\\ x_{41}&x_{42}&x_{43}&x_{44}&x_{45}\\ x_{51}&x_{52}&x_{53}&x_{54}&x_{55}\end{bmatrix} \bigodot \begin{bmatrix}S_{11}&S_{ 12}&S_{13}&S_{14}&S_{15}\\ S_{21}&S_{22}&S_{23}&S_{24}&x_{25}\\ S_{31}&S_{32}&S_{33}&S_{34}&S_{35}\\ S_{41}&S_{42}&S_{43}&S_{44}&S_{45}\\ S_{51}&S_{52}&S_{53}&S_{54}&S_{55}\end{bmatrix} . \tag{15}\]  
Lastly, a few words must be written about the answer filtering. The tables cannot be filled in a chaotic manner and the certain patterns must be matched: if the equipment is not resistant to the voltage sags with the lower severity values, it probably will not be resistant to the more severe sags too--for example, \(x_{11}\) cannot be larger than \(x_{12}\), \(x_{21}\), and \(x_{22}\). On the other hand, this rule can be ignored in the case of solid argumentation from the respondent. There was only one such answer, which is given and discussed in Section 4. In other cases, illogical answers were discarded.