GATE EE
Power System Analysis
Parameters and Performance of Transmission Lines
Previous Years Questions

## Marks 1

The geometric mean radius of a conductor, having four equal strands with each strand of radius r, as shown in the figure below, is ...
In the figure, the voltages are $${v_1}\left( t \right) = 100\cos \left( {\omega t} \right)$$ $${v_2}\left( t \right) = 100\cos \left( {\omega t + {\p... A source is supplying a load through a 2-phase, 3-wire transmission system as shown in figure below. The instantaneous voltage and current in phase-a ... The normal -$$\pi $$circuit of a transmission line is shown in the figure. Impedance$$Z = 100\angle {80^ \circ }$$and reactance$$\,X = 3300\Ome...
The undesirable property of an electrical insulating material is
In a long transmission line with $$r, l, g$$ and $$𝑐$$ are the resistance, inductance, shunt conductance and capacitance per unit length respectively...
A single phase induction motor draws $$12MW$$ power at $$0.6$$ lagging power. A capacitor is connected in parallel to the motor to improve the power f...
A single load is supplied by a single voltage source. If the current flowing from the load to the source is $$10\angle - {150^0}$$ A and if the volta...
A nuclear power station of $$500$$ $$MW$$ capacity is located at $$300$$ km away from a load center. Select the most suitable power evacuation transmi...
For enhancing the power transmission in along $$EHV$$ transmission line, the most preferred is to connect a
Consider two buses connected by an impedance of $$\left( {0 + j5} \right)\Omega .$$ The bus $$1$$ voltage is $$100$$$$\angle {30^ \circ }\,\,\,V,$$ an...
Consider a step voltage wave of magnitude $$1$$ pu travelling along a loss less transmission line that terminates in a reactor. The voltage magnitude ...
For a fixed value of complex power flow in a transmission line having a sending end voltage $$V$$, the real power loss will be proportional to
An extra high voltage transmission line of length $$300$$ km can be approximate by a lossless line having propagation constant $$\beta = 0.00127$$ ra...
Consider the transformer connections in a part of a power system shown in the figure. The nature of transformer connections and phase shifts are indic...
Consider a bundled conductor of an overhead line consisting of three identical sub-conductors placed at the corners of an equilateral triangle as show...
The concept of an electricity short, medium and long line is primarily based on the
A $$400$$ V, $$50$$ Hz, three phase balanced source supplies power to a star connected load whose rating is $$12\sqrt 3$$ kVA, $$0.8$$ pf(lag). The r...
The insulation strength of an EHV transmission line is mainly governed by
Total instantaneous power supplied by a $$3$$-phase ac supply to a balanced $$R$$-$$L$$ load is
The rated voltage of a $$3$$-phase power system is given as
The phase sequence of the $$3$$-phase system shown in figure is ...
Bundled conductors are mainly used in high voltage overhead transmission lines to
A $$3$$-phase, $$11$$-$$kV$$ generator feeds power to a constant power unity power factor load of $$100$$ $$MW$$ through a $$3$$-phase transmission li...
Consider a long, two-wire line composed of solid round conductors. The radius of both conductors is $$0.25$$ cm and the distance between their centers...
A long wire composed of a smooth round conductor runs above and parallel to the ground (assumed to be a large conducting plane). A high voltage exists...
Corona losses are minimized when
An overhead line having a surge impedance of $$400$$$$\Omega$$ is connected in series with an underground cable having a surge impedance of $$100$$$$... The load carrying capability of a long AC transmission line is The reflection coefficient for the transmission line shown in figure at$$P$$is ... Series capacitive compensation in$$EHV$$transmission lines is used to For a$$500$$Hz frequency excitation, a$$50$$km short power line will be modeled as The insulation level of a$$400$$kV, EHV overhead transmission line is decided on the basis of The insulation resistance of a cable of length$$10$$km is$$1M\Omega $$. For a length of$$100$$km of the same cable, the insulation resistanc... The surge impedance of a$$400$$km long overhead transmission line is$$400\Omega $$. For a$$200$$km length of the same line, the surge impeda... In a$$400$$kV network,$$360$$kV is recorded at a$$400$$kV bus. The reactive power absorbed by a shunt reactor rated for$$50$$MVAR,$$400$$kV ... A three phase overhead transmission line has its conductors horizontally spaced with spacing between adjacent conductors equal to 'd'. If now the cond... The inductance of a power transmission line increases with The selection of size of conductors for a distributor in a distribution system is governed by ## Marks 2 Consider the two bus power system network with given loads as shown in the figure. All the values shown in the figure are in per unit. The reactive po... A load is supplied by a$$230V,50Hz$$source. The active power$$P$$and the reactive power$$Q$$consumed by the load are such that$$...
A 3-phase 50 Hz generator supplies power of 3 MW at 17.32 kV to a balanced 3-phase inductive load through an overhead line. The per phase line resista...
Consider an overhead transmission line with $$3$$-phase, $$50$$ $$Hz$$ balanced system with conductors located at the vertices of an equilateral trian...
A single-phase transmission line has two conductors each of 10 mm radius. These are fixed at a center-to-center distance of 1 m in a horizontal plane....
A three-phase cable is supplying $$800$$ kW and $$600$$ kVAr to an inductive load. It is intended to supply an additional resistive load of $$100$$ kW...
A composite conductor consists of three conductors of radius $$R$$ each. The conductors are arranged as shown below. The geometric mean radius (GMR) (...
A distribution feeder of $$1$$ $$km$$ length having resistance, but negligible reactance, is fed from both the ends by $$400$$ $$V,$$ $$50$$ $$Hz$$ ba...
A two bus power system shown in figure supplies load of $$1.0+j0.5$$ $$p.u$$ The value of $${V_1}$$ in $$p.u$$ and $${\delta _2}$$ respectively are...
For a $$400$$ $$km$$ long transmission line, the series impedance is $$(0.0 + j0.5)$$ $$\Omega /km$$ and the shunt admittance is $$(0.0 + j5.0)$$ $$\... The complex power consumed by a constant-voltage load is given by$$\left( {{P_1} + {J_{q1}}} \right).\,\,$$Where,$$\,1\,\,kW \le \,\,{P_1} \le \,\,...
The horizontally placed conductors of a single phase line operating at $$50$$ $$Hz$$ are having outside diameter of $$1.6$$ cm, and the spacing betwee...
For the system shown below, SD1 and SD2 are complex power demands at bus $$1$$ and bus $$2$$ respectively. If $$\left| {{V_2}} \right| = 1$$ pu, the V...
A lossy capacitor $${C_x}$$, rated for operation at $$5$$ $$kV,$$ $$50$$ $$Hz$$ is represented by an equivalent circuit with an ideal capacitor $${C_p... Consider a three-core, three phase,$$50Hz$$,$$11kV$$cable whose conductors are denoted as$$R, Y$$and$$B$$in the figure. The inter-pha... A$$50Hz$$synchronous generator is initially connected to a long lossless transmission line which is open circuited at the receiving end. With t... Consider a three-phase,$$50Hz,11kV$$distribution system. Each of the conductors is suspended by an insulator string having two identical p... Match the items List-$${\rm I}$$(To) with the items in List-$${\rm II}$$(Use) and select the correct answer using the codes given below the lists. ... A lossless transmission line having Surge Impedance Loading$$(SIL)$$of$$2280MW.$$A Series capacitive compensation of$$30$$% is emplaced. T...$$230V$$(phase)$$50$$Hz, three-phase,$$4$$-wire, system has a sequence$$ABC$$. A unity power-factor load of$$4$$kW is connected between ph... The total reactance and total susceptance of a lossless overhead$$EHV$$line, operating at$$50Hz,$$are given by$$0.045$$pu and$$1.2$$pu re... Single line diagram of a$$4$$-bus single source distribution system is shown below. Branches$${e_1},\,\,{e_2},\,\,{e_3}\,\,$$and$${e_4}\...
The $$A, B, C, D$$ constant of a $$220$$ $$kV$$ line are: $$A = D = 0.94\,\angle \,10,\,\,\,B = 130\,\angle \,730,\,\,\,C = 0.001\,\angle \,900.\,\,... At an industrial sub-station with a$$4MW$$load, a capacitor of$$2$$MVAR is installed to maintain the load power factor at$$0.97$$lagging. I... A lightning stroke discharges impulse current of$$10$$kA (peak) on a$$400$$kV transmission line having surge impedance of$$250\,\Omega $$. The ma... A$$800kV$$transmission line is having per phase line inductance of$$1.1mH/km$$and per phase line capacitance of$$11.68nF/km.$$Ign... The generalized circuit constants of a$$3$$-phase,$$220kV$$rated voltage, medium length transmission line are$$A = D = 0.936 + j\,0.016 = 0.9...
A $$110$$ $$kV,$$ single core coaxial, XLPE insulated power cable delivering power at $$50$$ $$Hz,$$ has a capacitance of $$125$$ $$nF/km.$$ If the di...
A balanced delta connected load of $$\left( {8 + j6} \right)\Omega$$ per phase is connected to a $$400$$ $$V$$, $$50$$ $$Hz$$, $$3-$$phase supply lin...
The ABCD parameters of a $$3$$-phase overhead transmission line are $$\,A = D = 0.9\angle {0^ \circ }.\,\,B = 200\,\angle {90^ \circ }\,\,\Omega \,\,\... A dc distribution system is shown in figure with load currents as marked. The two ends of the feeder are fed by voltage sources such that$${V_P} - {V...
A surge of 20 kV magnitude travels along a lossless cable towards its junction with two identical lossless overhead transmission lines. The inductance...
Consider the model shown in figure of a transmission line with a series capacitor at its mid-point. The maximum voltage on the line is at the location...
The conductors of a $$10$$ km long, single phase, two wire line are separated by a distance of $$1.5$$ m. The diameter of each conductor is $$1$$ cm. ...
A transmission line has equal voltages at the two ends, maintained constant by two sources. A third source is to be provided to maintain constant volt...
The corona loss on a particular system at 50 Hz is 1 kW/km per phase. The corona loss at 60 Hz would be
For a single phase overhead line having solid copper conductors of diameter $$1$$ cm, spaced $$60$$ cm between centers, the inductance in $$mH/km$$ is
A 3-phase, 11 kV, 50 Hz, 200 kW load has a power factor of 0.8 lag. A delta connected 3-phase capacitor is used to improve the power factor to unity. ...
A single phase AC distributor supplies two single phase loads as shown in figure. The voltage drop from A to C is ...
$$A$$ $$220$$ kV, $$20$$ km long, $$3$$-phase transmission line has the following $$A, B, C, D$$ constants. $$A=D=0.96$$$$\angle {3^0},$$ $$\,B = 55\a... A shunt reactor of$$100$$MVAR is operated at$$98$$% of its rated voltage and$$96$$% of its rated frequency. The reactive power absorbed by the rea... A cable has the following characteristics.$$L = 0.201\,\,\mu H/m\,\,$$and$$\,C = 196.2\,pF/m.\,$$The velocity of wave propagation through the cabl... For equilateral spacing of conductors of an untransposed$$3$$-phase line, we have The rated load of an underground cable is always _______its natural load. Consider a three-phase,$$50Hz$$,$$11kV$$distribution system. Each of the conductors is suspended by an insulator string having two identi... The charging current of a$$400$$kV transmission line is more than that of a$$220$$kV line of the same length. ## Marks 5 In a transmission line each conductor is at$$20kV$$and is supported by a string of$$3$$suspension insulators. The air capacitance between eac... A long lossless transmission line has a unity power factor (UPF) load at the receiving end and an ac voltage source at the sending end. The parameters... A 132 kV transmission line AB is connected to a cable BC. The characteristic impedances of the overhead line and the cable are 400$$\Omega $$and 80$$...
A $$275$$ $$kV,$$ $$3$$-phase, $$50$$ $$Hz,$$ $$400$$ $$km$$ lossless line has following parameters: $$x=0.05$$ $$ohms/km,$$ line charging susceptance...
A 66 kV, 3-phase, 50 Hz, 150 km long overhead transmission line is open circuited at the receiving end. Each conductor has a resistance of 0.25$$\Omeg... A 6.6 kV, 50 Hz single core lead sheathed cable has the following data: Conductor diameter: 1.5 cm, length: 4 km. Internal diameter of the sheath : 3 ... Each conductor of a$$33kV,3$$phase system is suspended by a string of three similar insulators. The ratio of shunt capacitance to mutual c... A factory draws$$100$$kW at$$0.7$$p.f. lagging from a$$3$$-phase,$$11$$kV supply. It is desired to the p.f. to$$0.95$$lagging using series ca... The increase in resistance due to non-uniform distribution of current in a conducto$$r is known as _______effect
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Joint Entrance Examination