MGVCL Exam Paper (30-07-2021 Shift 2)
In transformer, bushing failure occurs due to (i) transformer vibrations (ii) dielectric losses (ii) partial discharge
Frequency of natural oscillation is given by, fn = {((dPe/dδ)at(δo))/M)} dPe/dδ = ((V1*V2)/X*(cosδ)) = (11/05)*cosδ = (11/0.5)*0.5 M = (H*s)/(πf) = 4/(50π)
For lagging power factor = (IR*cosφ + IXsinφ)/V_r For leading power factor = (IR*cosφ - IXsinφ)/V_r Zero voltage regulation occurs on leading power factor only.
MCCB stands for Moulded Case Circuit Breaker. MCB stands for Miniature Circuit Breaker. ELCB stands for Earth Leakage Circuit Breaker RCCB stands for Residual Current Circuit Breaker.
EXAMIANS