According to OES4, The Voltage Drop Tolerance limit for 3 Phase 4 Wire System with power circuit is----- a. 9.60V b. 7.20V c. 12.45V d. 16.60V

The single line diagram of a power system is shown in Figure Q2.1 includinggenerator and transformer winding connection and earthing details. The parametersfor this system have been calculated on a common 100 MVA base and are given inTable Q2.1. All resistances and shunt susceptances are neglected. This systemexperiences a single line to ground fault at a point F on line L1. The point F is at adistance d from Bus 4 along the line L1. The total length l of the line L1 is 50 km.Note that the location of d is not drawn to scale in Figure Q2.1. The fault current atthe fault point F is measured to be 6.106 kA. i) Determine the zero, positive, and negative sequence Thevenin equivalentimpedances as seen at the fault point F. These should be evaluated in per unitand shown as a function of d.ii) Use the sequence impedances calculated in part (i) to determine the distance dof the fault (in km) from Bus 4.  It's different from the answer, please don't send it

Problem 2. A 150-MVA, 220/22-kV, three-phase has the following parameters (in 2): R, = 0.1 R2 = 0.001 Xm= 7800 X, = 0.25 X, = 0.002 R = 30250 %3D The transformer is operating in step-down mode and delivering hafl of rated load at 22.5kV and 0.86 power factor lagging. a) Determine the equivalent circuit referred to the high-voltage side; b) Find the primary voltage and current; c) Determine the voltage regulation. d) Determine the efficiency.

What is practical application of PWM?