Optimal Protection Coordination for Microgrid under Different Operating Modes

Table 5

Relay operating times for bolted three-phase 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	0.245	0.445	0.2	0.215	0.415	0.2
FCB3	Main CB1	0.245	0.445	0.2	0.205	0.413	0.208
LCB4	FCB2	0.173	0.373	0.2	0.152	0.352	0.2
LCB5	FCB2	0.176	0.563	0.387	0.151	0.548	0.397
LCB6	FCB2	0.026	0.820	0.794	0.031	0.787	0.756
LCB7	FCB3	0.173	0.373	0.2	0.153	0.353	0.2
LCB8	FCB3	0.176	0.563	0.387	0.136	0.560	0.424
LCB9	FCB3	0.026	0.820	0.794	0.028	0.850	0.822
CB10	LCB4	0.011 (0.015)*	0.224	0.213 (0.209)	0.012 (0.015)	0.234	0.222 (0.219)
CB11	LCB5	0.012 (0.015)	0.228	0.216 (0.213)	0.014 (0.015)	0.236	0.222 (0.221)
CB12	LCB7	0.011 (0.015)	0.224	0.213 (0.209)	0.012 (0.015)	0.229	0.217 (0.214)
CB13	LCB8	0.012 (0.015)	0.228	0.216 (0.213)	0.014 (0.015)	0.215	0.201 (0.200)

∗The corrected values are shown in parentheses.