TIRUMALA ENGINEERING COLLEGE, BOGARAM.                                        

                                          II B.Tech II Semester II Mid Examinations, March-April 2011                         Max Marks: 10

                                                                     POWER SYSTEMS-I                                                         Time: 1 hour                                                

           Answer any TWO Questions     (Electrical & Electronic Engineering)              All Questions carry equal marks

1.       A synchronous motor improves the pf of a load from 0.7 to 0.9 lagging. The losses and other mechanical load on it amount to (250 +200) KW, while the load for which power factor is considered is 1,500 KW. Find out the input to the synchronous motor in KVA and its power factor.

2.       Classify substations by considering the constructional features?

3.       A factory has a maximum demand of 500 KW, the load factor being 60 % during working hours.

The following two tariff's are available:

      ( i ) Rs 8 per KW of maximum demand plus 3 paisa per KWh            ( ii ) A flat rate of Rs 0.1 per KWh. 
      Determine the working hours per week above which tariff  will be cheaper.

4.       Compute the generation cost per KWh from the following data:  Installed capacity = 200MW;

capital cost = Rs 3000 per KW; Interest and depreciation = 12%; Fuel consumption= 0.9 Kg/KWh;

Fuel cost = Rs 70 per 1000Kg; other operating costs = 30% of fuel costs; load factor = 80%; peak load=170 MW.

                                   

                          TIRUMALA ENGINEERING COLLEGE, BOGARAM.                                         

                                          II B.Tech II Semester II Mid Examinations, March-April 2011                         Max Marks: 10

                                                                     POWER SYSTEMS-I                                                         Time: 1 hour                                                 

           Answer any TWO Questions     (Electrical & Electronic Engineering)              All Questions carry equal marks

1. The load connected to a station is 100 MW and the demand factor of the consumers is 1.25. Estimate the capacity of the generating station when load factor is 60%, capacity factor is 50%, diversity factor of distribution is 1.33 and that of transmission is 1.5. Take the efficiency of transmission and distribution as 90%.
2. A consumer is offered power at Rs 50 per annum per KVA of maximum demand plus 5 paise per unit. He proposes to install a motor to carry his estimated maximum demand of 300 b.h.p. The motor available has a power factor of 0.83 at full load. How many units will be required at 30 % load factor and what will be the annual bill? The motor efficiency is 90%
3. A consumer has an average demand of 400 KW at a p.f of 0.8 laging and annual load factor of 50%. The tariff is Rs 50 per KVA of maximum demand per annum plus 5 paise per KWh. If the power factor is improved to 0.95 lagging by installing phase advancing equipment, calculate the capacity of phase advancing  equipment.
4. Write a short notes on the construction aspects of a Gas Insulated Substation.

                                        TIRUMALA ENGINEERING COLLEGE, BOGARAM.                                         

                                          II B.Tech II Semester II Mid Examinations, March-April 2011                         Max Marks: 10

                                                                     POWER SYSTEMS-I                                                         Time: 1 hour                                                 

           Answer any TWO Questions       (Electrical & Electronic Engineering)              All Questions carry equal marks

1. Draw the layout & schematic connection of a pole mounted substation
2. A synchronous motor improves the pf of a load from 0.7 to 0.9 lagging. The losses and other mechanical load on it amount to (250 +200) KW, while the load for which power factor is considered is 1,500 KW. Find out the input to the synchronous motor in KVA and its power factor.

     3.  A factory has a maximum demand of 500 KW, the load factor being 60 % during

working hours. TH e following two tariffs’ are available:

            ( i ) Rs 8 per KW of maximum demand plus 3 paisa per KWh

            ( ii ) A flat rate of Rs 0.1 per KWh.

            Determine the working hours per week above which tariff ( i ) will be cheaper.

 4.   Compute the generation cost per KWh from the following data:          Installed capacity = 200MW;

        capital cost = Rs 3000 per KW; Interest and depreciation = 12%; Fuel consumption= 0.9 Kg/KWh;

        Fuel cost = Rs 70 per 1000Kg; other operating costs = 30% of fuel costs; load factor = 80%; peak load=170 MW.

                                    

                          TIRUMALA ENGINEERING COLLEGE, BOGARAM.                                       

                                          II B.Tech II Semester II Mid Examinations, March-April 2011                         Max Marks: 10

                                                                     POWER SYSTEMS-I                                                         Time: 1 hour                                                 

           Answer any TWO Questions         (Electrical & Electronic Engineering)              All Questions carry equal marks

1. The load connected to a station is 100 MW and the demand factor of the consumers is 1.25. Estimate the capacity of the generating station when load factor is 60%, capacity factor is 50%, diversity factor of distribution is 1.33 and that of transmission is 1.5. Take the efficiency of transmission and distribution as 90%.
2. A consumer is offered power at Rs 50 per annum per KVA of maximum demand plus 5 paise per unit. He proposes to install a motor to carry his estimated maximum demand of 300 b.h.p. The motor available has a power factor of 0.83 at full load. How many units will be required at 30 % load factor and what will be the annual bill? The motor efficiency is 90%

.     3.  a) Write a short notes on the construction aspects of a Gas Insulated Substation.

           b) Write short notes on the advantages of a Gas Insulated Substations.

           4.  A consumer has an average demand of 400 KW at a p.f. of 0.8 lagging and annual load    factor of 50%. The tariff is

                Rs 50 per KVA of maximum demand per annum plus 5 paisa per KWh. If the power factor is improved to 0.95
        lagging by installing phase advancing equipment, calculate the capacity of phase advancing equipment.

STLD IMP QUESTIONS

1.      Simplify this by using TABULAR METHOD.

f(A,B,C,D)= ABCD + ABD + BCD + ABD + ACD

2.      Design a 4:1 MUX with neat diagram.

3.      Implement the following by using a 4:1 MUX and 2:1 MUX.

F(A,B,C)=∑m(0,2,3,6,7)

4.      Design 1:4 DEMUX and design the combinational circuit for even and odd parity bit generators.

5.      Design the combinational circuit which converts the given BCD code into GRAY CODE.

6.      Explain about the classification of sequential circuits and different methods of triggering.

7.      Draw the truth tables and excitation tables of various flip-flops.

8.       Design a 5 bit ring counter and 6 bit Johnson counter.

9.      Design serial binary adder.

10.  Design sequence detector.

11.  Explain about the mealy and Moore models of seq.circuits.

12.  Design a mod-7 syn counter by using T- flip flops.

13.  Explain about the state diagram and draw the state diagrams of J-K ff, S-R ff, T-ff and D-ff.

14.   Get the characteristic equations for J-K ff, T-ff and D-ffs.

15.  Design the combinational circuit for 3 bit magnitude comparator.