(Solved): 8. In Tan delta test for the insulation, Tan delta represents the ratio between : a) The capaci ...

8. In Tan delta test for the insulation, Tan delta represents the ratio between : a) The capacitive component to the resistive component of leakage current. b) The resistive component to the capacitive component of leakage current. c) The resistive component to the inductive component of leakage current. d) The inductive component to the resistive component of leakage current. 9. Directional over current relay is used for the protection of:. a) Long transmission lines. b) Power transformers. c) Radial distribution lines. d) Ring main distribution lines. 10. An electrical transformer with $$Z=0.25$$ PU to the $$11\mathrm{kV}\&650\mathrm{MVA}$$, the new impedance attributed to $$33\mathrm{kV}$$ equals: a) $$2.25\mathrm{pu}$$ b) $$0.083\mathrm{pu}$$ c) $$0.75\mathrm{pu}$$ d) $$0.028\mathrm{pu}$$ 11. Consider a power system with three identical generators. The transmission losses are negligible. One generator (G1) has a speed governor which maintains its speed constant at the rated value, while the other generators $$(G2$$ and $$G3)$$ have governors with a drop of $$5\%$$. If the load of the system increased, then in steady state: a) Generation of $$\mathrm{G}2\&\mathrm{G}3$$ increased equally while generation of $$\mathrm{G}1$$ is unchanged. b) Generation of GI alone increased while generation of $$\mathrm{G}2\&\mathrm{G}3$$ is unchanged. c) Generation of G I, G2 and G3 increased equally. d) Generation of GI, G2 and G3 increased in the ratio 0.5:0.25:0.25. 12. In the emergency mode of operation: a) Only system frequency maintained. b) Only maximum load demand is being met. c) System frequency and voltage are maintained. d) Both $$\mathrm{A}$$ and $$\mathrm{C}$$ are maintained. 13. Rapid changes in system voltage cause a) Flicker b) Corona c) Voltage dips d) Loss of synchronism 14. Which of the following is false: a) Synchronous motors operate with adjustable excitation. b) Synchronous compensators cannot give dynamic reactive power compensation. c) By supplying a synchronous compensator from a tertiary winding, need for separate transformer can be avoided. d) A synchronous compensator can even improve stability. 15. One of the statements about the $$DC$$ motors is correct: a) DC series motor has constant torque. b) DC cumulative compound motor has low starting torque. c) DC shunt used to drive the constant speed line shaft. d) DC differentially compound motor driving the variable speed line shaft.