# Adaptive Impedance-Based Fault Location Algorithm for Active Distribution Networks
## 3 Adaptive Fault Location Algorithm for Active Distribution Systems
### Step 5: Iterative Process to Determine the Fault Current
#### 3.6.3 Case Studies  
The proposed method was validated with a modified IEEE 34-node test feeder [33]. This feeder is located in the state of Arizona (USA) and operates at a voltage of 24.9 kV. Figure 11 presents the IEEE 34-node test feeder.  
Figure 11: IEEE 34-node test feeder.  
The relevant characteristics of the test feeder are the presence of single, two-phase, and three-phase laterals, multiple wire sizes, and unbalanced loads of concentrated and distributed nature. This system is simulated with the software Emitter-ATP, and modified by inserting a DER. This test feeder has been widely used for fault location studies in distribution networks [13; 20; 21; 22; 23]. Two considerations for validation of the algorithms are made. The first consideration is to assume that IEDs have been installed in the substation and the DER location. It is also assumed that the information gathered is sufficient to determine the voltage and current phasors during the prefault and fault periods. The second consideration assumes that there is no available information collected by IEDs at the DER location; therefore, the electrical model of the DER is used. Under these conditions, the method is validated by considering three scenarios:  
Scenario 1: This scenario considers only the influence of the fault resistance and the fault type. Table 1 presents the description for this scenario.  
Scenario 2: This scenario considers only the influence of the load. Three ranges of nominal load are considered, according to the information given in Table 2. For each of these ranges, a uniformly distributed value is used as the system load.  
Scenario 3: This scenario considers only the influence of the DER penetration level. Three different values of penetration level are considered in Table 3.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Parameters**} & **Information Available** & **Factors** & **Located Faults** \\  & **of IEDs** & & \\ \hline DER penetration level: 10\% & Yes & Faults resistance between: 0–100 \(\Omega\) in steps of 5 \(\Omega\) & 5481 \\ \hline \multirow{2}{*}{Load condition: Nominal} & NO & Fault types: A-g, B-g, C-g, AB, BC, CA, AB-g, BC-g, \\  & DER type: INDER & CA-g, ABC, and ABC-g & 5481 \\ \hline \multicolumn{3}{c}{Total faults} & 10,862 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Simulation data for scenario 1. DER: distributed energy resources; IED: intelligent electronic devices.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Parameters**} & **Information Available** & **Factors** & **Located Faults** \\  & **of IEDs** & & 129 \\ \hline \multirow{2}{*}{\
\begin{tabular}{c} DeR penetration level: 10\% \\ \end{tabular} } & NO & Random load variation: 30–60\%, \\  & DER type: INDER & 60–100\%, 100–140\% \\ \hline \multirow{2}{*}{
\begin{tabular}{c} Fault type: Three phase faults \\ \end{tabular} } & NO & 129 \\  & DER type: INDER & Total faults & 987 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Simulation data for scenario 2.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Parameters**} & **Information Available** & **Factors** & **Located Faults** \\  & **of IEDs** & & \\ \hline \multirow{2}{*}{\
\begin{tabular}{c} Load condition: Nominal Fault \\ resistance: 10 \(\Omega\). \\ Fault type: Three phase faults \\ \end{tabular} } & NO & 129 \\  & DER type: INDER & 10\%, 20\%, 30\% \\ \hline \multirow{2}{*}{
\begin{tabular}{c} Load condition: Nominal Fault \\ resistance: 10 \(\Omega\). \\ Fault type: Three phase faults \\ \end{tabular} } & NO & 102 \\  & DER type: INDER & Total faults & 987 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Simulation data for scenario 3.