MGVCL Exam Paper (30-07-2021 Shift 3)
The complex power injections at a bus are shown in figure Two lines connected drawing the powers as shown in figure. The complex power in the line-2 "S2" is
The ratio of full load current to short circuit current = 1/6 Xsc = j/(1/6) External reactance required = j*((1/6) - 0.06)) = j*0.106 pu Full load current = (40*1000)/(√3*15) = 1539.6 A Per unit reactance = j*0.106 = (I*Xr)/V j*0.15 = (1539.6*Xb)/((15/√3)*1000)) = 0.60 ohm
Symmetrical breaking current is the moment when fault occurs maximum fault current is observed and decays with respect to time. Symmetrical breaking current = RMS value of ac component of short circuit current at the instant of separation of the contacts. Symmetrical breaking capacity is less than asymmetrical breaking capacity.
In this type of tariff, The total charge is divided into two components: fixed charges and running charges. The fixed charges depend upon the number of units consumed by the consumer. It can be expressed as Total Cost = [A (kW) + B (kWh)] Rs. A = charge per kW of max demand (A is a constant which when multiplied with max demand (kW) gives the total fixed costs.) B = charge per kWh of energy consumed (B is a constant which when multiplied with units consumed (kWh), gives total running charges.)
Bus Type - Known Parameter - Unknown Parameter Load Bus -P, Q - V, phase angle Generator Bus - P, V (magnitude) - Q, Voltage phase angle Slack Bus Voltage - magnitude and phase angle - P, Q
EXAMIANS