QUESTION FROM PREVIOUS QUESTION PAPERS

1. Explain about the losses that occur due to VAR flow in power systems.

    

2. Discuss in detail about the generation and absorption of reactive power in power system components.

    

3. Explain the reason for variations of voltages in a power system and explain any one method to improve its voltage profile.

    

4. What is load compensation? Discuss its objective in a power system.

    

5. Write short notes on compensated and uncompensated transmission lines.

    

6. Explain briefly about shunt and series compensation of transmission lines

    

7. A three-phase induction motor delivers 500Hp at an efficiency of 0.91, the operating power factor being 0.76 lagging. A loaded synchronous motor with a power consumption of 100 KW is connected in parallel with the induction motor. Calculate the necessary KVA and the operating power factor of the synchronous motor if the overall power factor is to be unity.

    

8. Find the rating of a synchronous compensator connected to the teritary winding of a 132KV start connected, 33KV star connected, 11KV data connected three-winding transformer to supply a load of 66 MW at 0.8pf lagging at 33KV across the secondary. The equivalent primary and tertiary winding reactances are 32Ω and 0.16Ω respectively, while the secondary winding reactance is negligible. Assume that the primary side voltage is essentially constant at 132 KV and maximum of nominal setting between transformer primary and secondary is 1:1.1