Table 2 Infeed current impact on impedance value for impedance relay
Case | \(\vartheta_{{\text{i}}}\) | \(\emptyset_{{{\text{BF}}}}^{*}\) | \(\vartheta_{i} + \emptyset_{BF}\) | Impedance relay condition | ||
|---|---|---|---|---|---|---|
1 |  +  |  +  |  +  | – | Under reach | increased fault distance |
2 | - |  +  |  +  | \({\text{if}}\;\left| {\emptyset_{BF} } \right| > \left| {\vartheta_{i} } \right|\) | Under reach | increased fault distance |
3 | - |  +  | - | \({\text{if}}\;\left| {\emptyset_{BF} } \right| < \left| {\vartheta_{i} } \right|\) | Over reach | reduced fault distance |