1) Single bus-bar arrangement_________
A. Is cheapest in initial as well as maintenance cost
B. Provide simple operation and relaying system
C. Has the drawback that there will be complete shut down when a fault occurs on the bus itself
D. All of the above
2) In a single bus bar system there will be complete shutdown when_______
A. Fault occurs on the bus itself
B. Fault occurs on neutral line
C. Two or more faults occur simultaneously
D. Fault occurs with respect to earthing
3) The main factor in favour of the use of aluminium as bus bar material is its_____
A. Low-cost
B. Low-density
C. Low melting point
D. High resistivity
4) In a power system the maximum number of buses are
A. Generator buses
B. Load buses
C. Slack buses
D. P-V buses
5) Which among these types of bus bars can be used outdoor?
a. Tubular
b. ACSR
c. AAC
d. All of these
e. None of these
6) Which material is used for indoor bus bar?
a. Copper
b. Aluminium
c. Silver
d. Both (A) and (B)
7) How many cores are used in a cable for the transmission of voltages upto 66 kV?
a. Single core.
b. Two core.
c. Three core.
d. All of the above.
8) Why is the single core cables not provided with armouring?
a. Avoids excessive loss in the armour.
b. Make the cable more flexible.
c. Make the cable non hygroscopic.
d. None of the above.
9) Which among the following cables are generally suited for the voltages upto 11 kV?
a. Belted cables
b. Screened cables
c. Pressure cables
d. None of these.
10) The cable best suited for the transmission of voltages from 33 kV to 66 kV is_______________.
a. Belted cables
b. Screened cables
c. Pressure cables
d. None of these.
11) What is the advantage(s) of screened type over the belted cables?
a. Reduced possibility of core to core faults.
b. Increased current carrying capacity.
c. No possibility of formation of voids within the dielectric.
d. All of the above.
12) What is the gas pressure of SF6 for a compressed gas insulated cable?
a. 10 – 20 mm Hg
b. 80 – 100 mm Hg
c. 3 – 5 kg / cm2
d. 40 – 50 kg / cm2
13) Why solid type of conductors is not preferred for the voltages exceeding 66 kV?
a. A danger of breakdown of insulation.
b. Skin effect dominates the conductor.
c. There is corona loss between conductor and sheath material.
d. Insulation melts due to overheating.
14) On which factor does the capacitance of the cable depend upon?
a. Length of cable.
b. Relative permittivity of dielectric used in cable.
c. Ratio of sheath diameter and core diameter.
d. All of the above.
15) The charging current drawn by the cable _____________.
a. Lags behind the voltage by 90°.
b. Leads the voltage by 90°.
c. Are in phase with each other.
d. Leads the voltage by 60°.
16) What is the source of heat generation in cables?
a. Copper loss in conductor
b. Dielectric losses in cable insulation
c. Losses in metallic sheathings and armouring.
d. All of these.
17) What is the safe working temperature for a conductor in case of armoured cables?
a. 50° C
b. 75° C
c. 65° C
d. 40° C
18) Which tests are conducted to locate the fault location in the cables?
a. Murray loop test.
b. Varley loop test.
c. Both (a) and (b).
d. None of these.
19) A Battery is a series or parallel combination of electrolytic cells.
1. True
2. False
20) Quotations are letters of enquiry.
a) True
b) False
Explanation: The statement is true. Quotations are letters of enquiry in which an organisation or an individual asks another organisation or individual to quote its or his rates and terms of payment for the goods intended to be purchased.
Energy Audit Instruments:
The requirement for an energy audit such as identification and quantification of energy neces-sitates measurements; these measurements require the use of instruments. These instrumentsmust be portable, durable, easy to operate and relatively inexpensive. The parameters generallymonitored during energy audit may include the following:Basic Electrical Parameters in AC &DC systems - Voltage (V), Current (I), Power factor, Activepower (kW), apparent power (demand) (kVA), Reactive power (kVAr), Energy consumption(kWh), Frequency (Hz), Harmonics, etc. Parameters of importance other than electrical such as temperature & heat flow, radiation, airand gas flow, liquid flow, revolutions per minute (RPM), air velocity, noise and vibration, dustconcentration, Total Dissolved Solids (TDS), pH, moisture content, relative humidity, flue gasanalysis - CO2, O2, CO, SOx, NOx, combustion efficiency etc.
An electric power distribution system can be classified according to its feeder connection schemes or topologies as follows -
1. Radial distribution system
2. Parallel feeders distribution
3. Ring main distribution system
4. Interconnected distribution
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