Question

select one Best match

11) A 12 kV radial system is given below, Assuming using relay CO-7, 3 cycles breaker operation time and 0.5 second coordination time delay, what are the best settings to protect the system shown below: (10 points) 12 kV Typical time curves ype Co-7 C.T.R-400/5 C.T.R-200/5 Current tap settings: 4.5,6,78,10,12 amperes 4 MVA Isc-1.6 kA 4 MVA Isc-1.2 kA Time dial TS1 TDS1 TS2 TDS2 A) 51/252 B) 41/24 C) 51/25 D) 41/24 2 4 5 6 7 8 9 10 12 14 16 18 20 Current as a multiple of tap setting 12) A three-phase, 250 MVA, 230 kv A/ 132 kV Y transformer is protected by differential relays with taps, Select CT ratios and its CT connections. (5 point) Current Ratios 100:5 500:5 1600:5 300:5 1000:5 3000:5 400:5 50:5 450:5 15005 4000:5 50:5 600:5 2000:5 6000:5 200:5 800:5 2400:5 250:5 900:5 2500:5 12005 3200:5 Primary Primary CT Secondary Secondary CT CT Ratio connection CTRatio connection A) 800:5 B) 600:5 C) 800:5 D) 600:5 1200:5 1200:5 1000:5 1000:5 13) What are the differential relay tap setting and the mismatch ratio for the previous question? (5 point) Tap settings Mismatch % Less than 1% Less than 1% Less than 2% Less than 2% A) c)

Answer 1

eMM 6여 5