Research Article
Optimal Protection Coordination for Microgrid under Different Operating Modes
Table 7
Operating times and CTIs for bolted single line-to-ground faults in utility-only mode and in grid-connected mode.
| Primary relay | Back-up relay | Operating time (sec) | Utility-only mode | Grid-connected mode | Primary | Backup | CTI | Primary | Backup | CTI |
| FCB2 | Main CB1 | 0.261 (0.379)* | 0.636 (0.636) | 0.375 (0.257) | 0.256 (0.370) | 0.637 (0.636) | 0.381 (0.266) | FCB3 | Main CB1 | 0.261 (0.377) | 0.636 (0.636) | 0.375 (0.259) | 0.253 (0.364) | 0.637 (0.636) | 0.384 (0.272) | LCB4 | FCB2 | 0.100 (0.144) | 0.300 (0.379) | 0.2 (0.235) | 0.099 (0.140) | 0.299 (0.370) | 0.2 (0.23) | LCB5 | FCB2 | 0.101 (0.133) | 0.365 (0.379) | 0.264 (0.246) | 0.099 (0.126) | 0.372 (0.384) | 0.273 (0.258) | LCB6 | FCB2 | 0.016 (0.019) | 0.458 (0.461) | 0.442 (0.442) | 0.017 (0.019) | 0.463 (0.467) | 0.446 (0.448) | LCB7 | FCB3 | 0.100 (0.144) | 0.300 (0.379) | 0.2 (0.235) | 0.099 (0.140) | 0.299 (0.358) | 0.2 (0.218) | LCB8 | FCB3 | 0.101 (0.133) | 0.365 (0.379) | 0.264 (0.246) | 0.099 (0.122) | 0.380 (0.381) | 0.281 (0.259) | LCB9 | FCB3 | 0.016 (0.019) | 0.458 (0.461) | 0.442 (0.442) | 0.018 (0.019) | 0.496 (0.505) | 0.478 (0.486) |
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The corrected values are shown in parentheses.
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