ESE EE : Power Systems National Champion Test for ESE & GATE EE Exams

Question 1

One what basis is the insulation level of a 400 kV. EHV overhead transmission line decided?

Question 2

What is the correct expression for Area Control Error (ACE) for an interconnected 2-area power system, if

its incremental tie line power deviation,

is frequency deviation and b is frequency bias coefficient?

Question 3

The economics of power plant is greatly influenced by:
1) Load factor
2) Utilization capacity
3) Unit capacity
4) Type of load

Question 4

The incremental cot characteristics of two generators delivering a load of 200 MW are as follows:

For economic operation the generators P₁ and P₂ should be

Question 5

The incremental cost characteristics of two generators delivering a total load of 200 MW are as follows:

What should be the values of P₁ and P₂, for economic operation?

Question 6

Assertion (A): The short-circuit capacity of a bus in a large power grid is defined as the product of the pre-fault voltage and the 3-phase fault current at a point very close to the bus.
Reason (R): The larger short-circuit capacity, the larger would be the equivalent source impedance at the bus.

Question 7

The line currents of a 3-phase power supply are:
I_R=3+j5A
I_Y=2+j2A
I_B=-2-j1A
The zero sequence current will be

Question 8

How many relays are used to detect inter phase fault of a three-line system?

Question 9

Consider the following statements:
HVDC transmission is superior to HVAC transmission due to
1) Lack of reliable DC circuit breakers.
2) Lesser number of conductors for same power carrying capacity.
3) Nonsynchronous link between two different systems simplifying the problem of voltage stability and frequency control.
4) No costly terminal equipments such as converts and inverts are required.
Which of these statements is/are correct?

Question 10

In an HVDC system

Question 11

High voltage d.c. transmission requires filters for

Question 12

Consider the following statements regarding HVDC power transmission:
1) The modern HVDC systems use 12-pulse converters.
2) DC systems never use ground or sea return.
3) Most of present-day d.c. schemes are two-terminal links.
Which of these statements is/are correct?

Question 13

Consider the following statements:
The suitable configuration of HVDC converter is decided on the requirements
1) of high pulse number
2) of converter transformer utilization factor should be near to unity.
Which of these statements is/are correct?

Question 14

Assertion (A): In HVDC systems, the voltage should be as high as possible and the rectifiercontrol angle

should be as low as possible.
Reason (R): Control of dc voltage is exercised by the rectifier and inverter control angles

and

respectively.

Question 15

Which one of the following statements is correct?
The elements of each row of a Y_BUS matrix for load flow studies in power system add up to zero.

Question 16

Assertion (A): Bus admittance matrix is a sparse matrix.
Reason (R): In load flow studies, one of the buses is taken as a slack bus.

Question 17

A sample power system network is shown in the figure given below. The reactance marked are in p.u. What is the pu value of Y₂₂ of the Bus Admittance matrix (Y_BUS) ?

Question 18

Consider the following statements:

1) Equivalent-T circuit of a long line is preferred to equivalent-p circuit.
2) The nature of reactive power compensation is different for peak load and off-peak load conditions.
3) Ferranti effect is significant only on medium and long lines.

Which of these statements are correct?

Question 19

If a fixed amount of power is to be transmitted over certain length with fixed power loss, it can be said that volume of conductor is

Question 20

The locus of constant received power is circle of radius

Question 21

In a 3-phase, 5 kV, 5 MVA system, what is the base impedance?

Question 22

Taking the density of water to be 1000 kg/m³, how much power would be developed by a hydroelectric generator unit, assuming 100% efficiency, with 1.0 m head and 1.0 m³/s discharge?

Question 23

What is the correct expression for the electrical power developed by a hydro-electric plant in KW?

Question 24

The daily energy produced in a thermal power station is 720 MWh at a load factor of 0.6. What is the maximum demand of the station?

Question 25

If a line of surge impedance Z₀ is terminated in an impedance Z then the reflection for current and voltage surges at the termination are given respectively by

Question 26

A travelling wave due to lightning with an incident voltage V travels through the overhead line of surge impedance of

and enters a cable of surge impedance of

What is the voltage entering the cable at the junction?

Question 27

A long overhead lossless power transmission line is terminated with its characteristic impedance. While the line is in operation

Question 28

Which is the main relay for protecting up to 90% of the transmission line-length in the forward direction?

Question 29

Match list-I (Relay) with List-II (Protected power system component) and select the correct answer using the codes given below the lists:
List-I
A) Distance relay
B) Under frequency
C) Differential relay
D) Buchholz relay
List-II
1) Transformers
2) Turbines Relay
3) Busbars
4) Shunt capacitors
5) Alternators
6) Transmission lines

Question 30

Mho relay is usually employed for the protection of