MGVCL Exam Paper (30-07-2021 Shift 2)
A generating station having 'n' section busbars each rated at Q kVA with ×% reactance is connected on the tie-bars systems through busbar reactances of b%. Determine the short circuit kVA if a 3-phase fault takes place on one section.

Q[(1/x) + (n+1)/(bn-x)]
Q[(1/x) + (n+1)/(bn+x)]
Q[(1/x) - (n+1)/(bn-x)]
Q[(1/x) + (n-1)/(bn+x)]

ANSWER EXPLANATION DOWNLOAD EXAMIANS APP

MGVCL Exam Paper (30-07-2021 Shift 2)
Interposing current-transformer (CT) is used in differential protection of a transformer to

match the standard ratio of CTs used on both sides of the transformer winding
limit the main CT secondary current
minimize the effect of saturation of the main CTs
increase the sensitivity of the relay

ANSWER EXPLANATION DOWNLOAD EXAMIANS APP

MGVCL Exam Paper (30-07-2021 Shift 2)
The line currents in amperes in phases a, b and c respectively are 500 +j150, 100 – j600 and – 300 + j600 referred to the same reference vector with phase sequence of abc. Find the symmetrical component of currents.

Ia₀ = (100+j50) AIa₁ = (200+ j107.75) AIa₂ = (200-j107.75) A
Ia₀ = (100+j50) AIa₁ = (546.41+j165.47) AIa₂ = (-146.41-j65.47) A
Ia₀ = (100+j50) AIa₁ = (546.41+ j165.47) AIa₂ = (546.41-j165.47) A
Ia₀ = (100+j50) AIa₁ = (146.41+ j65.47) AIa₂ = (546.41-j165.47) A

ANSWER EXPLANATION DOWNLOAD EXAMIANS APP

MGVCL Exam Paper (30-07-2021 Shift 2)
A 50 Hz synchronous generator is connected to an infinite bus through a line. The p.u. reactances of generator and the line are j0.3 p.u. and j0.2 p.u. respectively. The generator no load voltage is 1.1 p.u. and that of infinite bus is 1.0 p.u. The inertia constant of the generator is 4 MW-sec/MVA. Determine the frequency of natural oscillations if the generator is loaded to 60% of its maximum power transfer capacity and small perturbation in power is given.

1.32 Hz
1.62 Hz
1.42 Hz
1.52 Hz

ANSWER EXPLANATION DOWNLOAD EXAMIANS APP

MGVCL Exam Paper (30-07-2021 Shift 2)
When different types of consumers are charged at different uniform per unit rates, it is called as ____

maximum demand tariff
block rate tariff
flat rate tariff
two-part tariff

ANSWER EXPLANATION DOWNLOAD EXAMIANS APP