Q. For what purpose metallic sheath is provided in underground cables? Ans. The metallic sheath is provided around the insulation to protect it against ingress of moisture, gas or other damaging liquids (acid or alkalies) from the soil and atmosphere. Q. Why is a layer of bedding provided over the metallic sheath in underground cables? … Read more
Q. On what factors does the power output of a hydropower plant depend? Ans. The power developed by a hydro plant depends upon the discharge and head and is directly proportional to their (discharge and head) product. Q. What is meant by catchment area? Ans. The catchment area is the area, bounded by water sheds, … Read more
Q. Name three important factors in choosing a site for an atomic power plant. Ans. Three important factors in choosing a site for atomic power plants are: (i) availability of water supply (ii) distance from a populated area (iii) transportation facilities. Q. Name three different types of fuels used in nuclear reactors. Ans. … Read more
Q. What type of tariff is employed for domestic consumers? Ans. Block rate tariff Q. What is two-part tariff? Ans. In the two-part tariff, the total charge to be made to the consumer is divided into two components namely fixed charge (proportional to connected load or maximum demand) and the running or operating charges (proportional … Read more
Q. How does a gas turbine differ from a diesel engine? Ans. The gas turbine is different from the diesel engine in the respect that the combustion region is external to the prime mover. Q. Why are the majority of gas turbine power plants employed as peak load plants? Ans. The majority of … Read more
Q. What is the basic difference between a diesel engine and a steam turbine? Ans. The main difference between a diesel engine and a steam turbine is that in the diesel engine the chemical energy of combustion is released inside the cylinder whereas in case of steam turbine the energy developed during combustion of fuel … Read more
Earthing or Grounding Grounding is the process of creating an alternative(different) path for the flow of fault(excessive) currents safely into the ground in the presence of minimal resistance or impedance. It connects non-current carrying parts of an equipment to the general mass of earth in such a manner as to ensure, at all times, an immediate … Read more
Insulating Materials for Cables The insulating materials (dielectrics) used for cables must have low discharge current, low dissipation factor (low loss tangent), and should be chemically stable. The materials generally used are impregnated paper, bituminous compounds, rubber, compressed air, mineral oil etc. In the present days, cross-linked polyethylene cables (XLPE) are manufactured for 11 kV, … Read more
The main components of a substation are Busbars Surge or Lightning Arresters Isolators or disconnecting switches Earth Switch Circuit Breaker Power Transformer Wave Trap Current Transformer Potential Transformer 1. Busbars It is a strip or bar of copper, brass or aluminium that conducts electricity within a switchboard of a substation. Its main purpose is to … Read more
Substation It is defined as the transmission and distribution network which receives electrical energy at a higher voltage and transfer to a consumer at low voltage. The points that should be kept in mind while setting Substations Substation should be located at a proper site as far as possible. Substation should be located at the … Read more