1
GATE EE 2008
MCQ (Single Correct Answer)
+1
-0.3
An extra high voltage transmission line of length $$300$$ km can be approximate by a lossless line having propagation constant $$\beta = 0.00127$$ radians per km. then the percentage ratio of line length to wavelength will be given by
A
$$24.24$$%
B
$$12.12$$%
C
$$19.05$$%
D
$$6.06$$%
2
GATE EE 2008
MCQ (Single Correct Answer)
+2
-0.6
A lossless single machine infinite bus power system is shown below: GATE EE 2008 Power System Analysis - Power System Stability Question 19 English

The synchronous generator transfers $$1.0$$ per unit of power to the infinite bus. The critical clearing time of circuit breaker is $$0.28$$ s. If another identical synchronous generator is connected in parallel to the existing generator and each generator is scheduled to supply $$0.5$$ per unit of power, then the critical clearing time of the circuit breaker will

A
Reduce to $$0.14$$ s
B
Reduce but will be more than $$0.14$$ s
C
Remain constant at $$0.28$$ s
D
Increase beyond $$0.28$$ s
3
GATE EE 2008
MCQ (Single Correct Answer)
+2
-0.6
Given that: $$\,{V_{s1}} = {V_{s2}} = 1 + j0\,\,p.u,\,\, + ve\,\,$$ sequence impedance are $$\,{Z_{s1}} = {Z_{s2}} = 0.001 + j0.01\,\,p.u\,\,$$ and $${Z_L} = 0.006 + j\,0.06\,\,p.u,\,\,3\phi .\,\,\,$$ Base $$MVA=100,$$ voltage base $$=400$$ $$kV(L-L).$$
Nominal system frequency $$= 50$$ $$Hz.$$ The reference voltage for phase $$'a'$$ is defined as $$\,\,V\left( t \right) = {V_m}\,\cos \left( {\omega t} \right).\,\,\,$$ A symmetrical $$3\phi $$ fault occurs at centre of the line, i.e., at point $$'F'$$ at time 'to' the $$+ve$$ sequence impedance from source $${S_1}$$ to point $$'F'$$ equals $$(0.004 + j \,\,0.04)$$ $$p.u.$$ The wave form corresponding to phase $$'a'$$ fault current from bus $$X$$ reveals that decaying $$d.c.$$ offset current is $$-ve$$ and in magnitude at its maximum initial value. Assume that the negative sequence are equal to $$+ve$$ sequence impedances and the zero sequence $$(Z)$$ are $$3$$ times $$+ve$$ sequence $$(Z).$$

Instead of the three phase fault, if a single line to ground fault occurs on phase $$' a '$$ at point $$' F '$$ with zero fault impedance, then the $$rms$$ of the ac component of fault current $$\left( {{{\rm I}_x}} \right)$$ for phase $$'a'$$ will be

A
$$4.97$$ $$pu$$
B
$$7.0$$ $$pu$$
C
$$14.93$$ $$pu$$
D
$$29.85$$ $$pu$$
4
GATE EE 2008
MCQ (Single Correct Answer)
+2
-0.6
A lossless transmission line having Surge Impedance Loading $$(SIL)$$ of $$2280$$ $$MW.$$ A Series capacitive compensation of $$30$$% is emplaced. Then $$SIL$$ of the compensated transmission line will be
A
$$1835$$ $$MW$$
B
$$2280$$ $$MW$$
C
$$2725$$ $$MW$$
D
$$3257$$ $$MW$$