Implementation of Optimal Protection Coordination for Microgrids with Distributed Generations Using Quaternary Protection Scheme

Table 7

Directional primary and backup relay operating times for conventional scheme in grid-connected microgrid.

DG operating status	Fault location	Operating times (t) of relay in second; (Rp = primary relay; Rb = backup relay)
		Rp	Rb1	Rb2
Status 1	F-1	R1	R5	R3
		0.278	0.489	0.577
		R2	R4	R6
		0.129	0.349	0.446
	F-2	R3	R1	R5
		0.200	0.415	0.514
		R4	R6	R2
		0.259	0.471	0.499
	F-3	R5	R3	R1
		0.338	0.548	1.236
		R6	R2	R4
		0.272	0.580	0.799
Status 2	F-1	R1	R5	R3
		0.278	0.546	0.586
		R2	R4	R6
		0.133	0.369	0.509
	F-2	R3	R1	R5
		0.202	0.420	0.484
		R4	R6	R2
		0.259	0.439	0.591
	F-3	R5	R3	R1
		0.338	0.550	1.048
		R6	R2	R4
		0.274	0.522	0.636
Status 3	F-1	R1	R5	R3
		0.278	0.493	0.602
		R2	R4	R6
		0.142	0.360	0.397
	F-2	R3	R1	R5
		0.226	0.480	0.833
		R4	R6	R2
		0.259	0.649	0.679
	F-3	R5	R3	R1
		0.338	0.553	0.812
		R6	R2	R4
		0.309	0.525	0.788