1.Identify the major difference among the Ring Bus Arrangement / 1 ½ BreakerArrangement  /  Double  Bus  Arrangement?    

(Hints  :  review  the  number  ofbreakers serve for each circuit and its limitation)                                   

2.What are the advantages in high voltage transmission? 

3.Calculate  efficiency  of  the  radial  power  grid  as  shown  in  Figure  B2a  andevaluate the efficiency if the power grid forms a ring network.  Compare theresults. 

Given that distance of AB is 3km, BC is 2km, and the ring line AC is 2.5km. Line  resistance is  0.001Ω/m.    Input  voltage  at  substation  A  is  33kV.    Circuit  output at substation B is 20A and circuit output at substation C is 10A.

 

4. A simple 3 phase 2 port symmetrical π network has a series impedance of 10∠30⁰, and each shunt admittance 2∠30⁰ mS.  The network has an output load of 50MW at 66kV with 0.9 lagging power factor.Given that  , calculate:

a) The ABCD parameters                                                                 

b)  The voltage, current and power factor at supply side