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

Table 8

Directional primary and backup relay operating times for conventional scheme in islanded 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	0.549	0.637
		R2	R4	R6
		0.145	0.392	0.507
	F-2	R3	R1	R5
		0.210	0.438	0.466
		R4	R6	R2
		0.259	0.490	0.518
	F-3	R5	R3	R1
		0.338	0.582	1.018
		R6	R2	R4
		0.286	0.601	0.691
Status 2	F-1	R1	R5	R3
		0.278	1.106	1.188
		R2	R4	R6
		0.203	0.995	1.139
	F-2	R3	R1	R5
		0.216	0.460	0.493
		R4	R6	R2
		0.333	0.557	0.611
	F-3	R5	R3	R1
		0.508	0.873	0.893
		R6	R2	R4
		0.291	0.517	0.556
Status 3	F-1	R1	R5	R3
		0.474	0.696	0.699
		R2	R4	R6
		0.189	0.418	0.443
	F-2	R3	R1	R5
		0.616	2.000	2.010
		R4	R6	R2
		0.283	1.090	1.102
	F-3	R5	R3	R1
		0.363	0.601	1.252
		R6	R2	R4
		0.867	1.086	1.099