A Communication-Assisted Distance Protection for AC Microgrids considering the Fault-Ride-Through Requirements of Distributed Generators

Table 1

Relay operating time (s) during a fault occurring at 87.5% of the feeder AB in the islanded mode.

ITA protection relay		Simulation results												Calculation results
		L-G			LL			LL-G			LLL
		Fault resistance (Ω)			Fault resistance (Ω)			Fault resistance (Ω)			Fault resistance (Ω)
		0.01	50	100	0.01	5	10	0.01	50	100	0.01	5	10
Primary protection	1	0.151	0.149	0.146	0.151	0.152	0.152	0.141	0.151	0.151	0.149	0.149	0.151	0.150
	2	0.001	0.001	0.001	0.002	0.002	0.002	0.002	0.001	0.001	0.003	0.001	0.001	0.001
Backup protection	1	0.559	0.572	0.581	0.560	0.559	0.562	0.570	0.561	0.563	0.589	0.563	0.565	0.581
	2	0.557	0.558	0.561	0.557	0.557	0.557	0.556	0.557	0.557	0.559	0.557	0.557	0.557
	4	0.632	0.614	0.608	0.634	0.631	0.626	0.625	0.626	0.624	0.600	0.623	0.621	0.607
	8	0.780	0.712	0.679	0.779	0.761	0.749	0.803	0.750	0.745	0.723	0.754	0.742	0.775
	9	0.761	0.654	0.619	0.713	0.730	0.741	0.722	0.741	0.728	0.603	0.707	0.717	0.776