MGVCL Exam Paper (30-07-2021 Shift 2) In a typical DC micro grid, hybrid storage system is a combination of None of these Lead acid battery and Lithium ion battery Lead acid battery and ultra capacitor / super capacitor Lead acid battery and Capacitor None of these Lead acid battery and Lithium ion battery Lead acid battery and ultra capacitor / super capacitor Lead acid battery and Capacitor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Hybrid storage system is a combination of microturbines, fuel cells, photovoltaics (PV), Lead acid battery and ultra or super capacitors etc.
MGVCL Exam Paper (30-07-2021 Shift 2) A coil having an inductance of 100 mH is magnetically coupled to another coil having an inductance of 900 mH. The coefficient of coupling between the coils is 0.45. Calculate the equivalent inductance if the two coils are connected in series opposing. 1135 mH 932 mH 1270 mH 730 mH 1135 mH 932 mH 1270 mH 730 mH ANSWER EXPLANATION DOWNLOAD EXAMIANS APP M = k√(L₁L₂)M= 0.45√(100*900)M = 135 mHL_eq for opposite connection of coils = L₁ + L₂ - 2ML_eq = 900 + 100 - 2*135L_eq = 730 mH
MGVCL Exam Paper (30-07-2021 Shift 2) In a short circuit test on circuit breaker, time to reach the peak re-striking voltage is 50 µs with the peak restriking voltage of 100 kV. Determine average RRRV (Rate of rise re-striking voltage)? 1 x 10⁶ kV/sec 4 x 10⁶ kV/sec 2 x 10⁶ kV/sec 3 x 10⁶ kV/sec 1 x 10⁶ kV/sec 4 x 10⁶ kV/sec 2 x 10⁶ kV/sec 3 x 10⁶ kV/sec ANSWER EXPLANATION DOWNLOAD EXAMIANS APP RRRV = Peak value of restriking voltage/time to reach the peak re-striking voltageRRRV = 100*1000/(50 μs)RRRV = 2*10⁶ kV/sec
MGVCL Exam Paper (30-07-2021 Shift 2) In the RLC series circuit shown in figure, resonance occurs when the value of C is 20 µF. The supply voltages is v(t) = 20 sin (500t) V. Find the value of L. 0.2 H 5 mH 5 H 0.2 mH 0.2 H 5 mH 5 H 0.2 mH ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Here,ω = 500 rad/sec = 2πf.At Resonance condition,ωL = 1/(ωC)L 0.2 HAlso at series resonace1. fr = 1/[2π√(LC)]2. PF = 13. Maximum current4. Source voltage = voltage across resistor.
MGVCL Exam Paper (30-07-2021 Shift 2) In the circuit of figure, the switch is closed to position-1 for a long time. At t = 0 the switch position is changed from postion-1 to postion-2. Find an expression for the current i(t). i(t) = (E/R) sin√(LC) t A i(t) = (E/R) cos[1/√(LC)]t A i(t) = (E/R) sin[1/√(LC)]t A i(t) = (E/R) cos√(LC) t A i(t) = (E/R) sin√(LC) t A i(t) = (E/R) cos[1/√(LC)]t A i(t) = (E/R) sin[1/√(LC)]t A i(t) = (E/R) cos√(LC) t A ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Standard eqution of current for this condition,i(t) = i(0+)*cos(wt)i(0+) = E/RFor LC circuit,w = 1/√(LC)i(t) = (E/R)*cos((1/√(LC))*t) A
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)] 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 Short circuit kVA of any bus is given by:Skva = Sbase*(100/% X)Where,Sbase - base rating in kVA% X - value of reactance in %
EXAMIANS