Assignment 5: A 3.5 MVA rated load is supplied from 33 kV system bus through a 40MVA and 33A/11Y kV transformer with a l

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Assignment 5 A 3 5 Mva Rated Load Is Supplied From 33 Kv System Bus Through A 40mva And 33a 11y Kv Transformer With A L 1 (48.61 KiB) Viewed 59 times

Assignment 5: A 3.5 MVA rated load is supplied from 33 kV system bus through a 40MVA and 33A/11Y kV transformer with a leakage reactance of 15%. The fault level (or short circuit MVA) at 33 kV is 2000MVA. The relays R1 and R2 are IDMT relays TDS with 5A rating. The time-current curve of the relay is represented by 0.14 M02-1 The TDSs are from 0.1 to 1 in the step of 0.1. The plug settings are from 50% to 200% of the relay rating in the step of 25%. The CT ratios for CT1 and CT2 are 400:5 and 300:5 respectively. a. Determine the PSs and the TDSs of the phase relays if the required discrimination time or CTI between R2 and R1 is 0.4s. b. Find the fault location and the minimum operating time of R2 based on the relay settings from part a. A 33 kV CT2 R2 CB2 B T 어 11 kV CTI R1 CB1 3.5MVA