01․ Which of the following is/are base load plants?
Base load plants:
A base load power plant is a power station that usually provides a continuous supply of electricity throughout the year with some minimum power generation requirement. Base load power plants will only be turned off during periodic maintenance, upgrading, overhaul or service. Base load power plant has the character of slow demand respond, a mechanism to match generation with the load it supplies.
Some examples of base load plants are
1. Thermal plants
2. Hydro plants
3. Nuclear plants
4. Tidal power plants
02․ Peak load power plants is/are
Peak load plants:
A peaking power plant is a power station that only runs during high demands of electricity throughout the day during peak hours. Because of that, the price of electricity it generates is generally higher than the electricity generated by base load power plant, which operates continuously throughout the year.
Some examples are
1. Pumped storage plant
2. Diesel plants
3. Hydro plants ( when water availability is less)
4. Gas fired power plants
03․ Ideal plant load cfactor is
Plant load factor is defined as the ratio of average power generation to the maximum power generation.
Therefore, ideal plant load factor is one and practical load factor is less than 1.
Therefore, ideal plant load factor is one and practical load factor is less than 1.04․ Plant capacity factor value is
Plant capacity factor (Pcf) is defined as the ratio of average power to the plant capacity.
The average power output of a plant is less than the plant capacity. So, therefore, the value of plant capacity is less than 1.
The average power output of a plant is less than the plant capacity. So, therefore, the value of plant capacity is less than 1.05․ The value of diversity factor is
Diversity factor is defined as the ratio of sum of individual maximum demand to the station maximum demand.
Maximum demand of each consumer does not occur at the same time. They occur at different time of the day. So their sum is always greater than the maximum demand a particular time. Therefore, diversity factor value is more than 1.
Maximum demand of each consumer does not occur at the same time. They occur at different time of the day. So their sum is always greater than the maximum demand a particular time. Therefore, diversity factor value is more than 1.06․ Demand factor of a plant is
Demand factor (Df) is defined as the ratio of station maximum demand to the sum of connected load.
The maximum demand is less than the connected load. Therefore, demand factor of a plant is less than 1.
The maximum demand is less than the connected load. Therefore, demand factor of a plant is less than 1.
07․ A power generating station has a plant capacity of 200 MW and maximum power demand is 150 MW. If average power generation is 110 MW, then find the load factor and capacity factor respectively?
08․ Highest pressure generating pump inside the thermal plant is
A boiler feed water pump is a specific type of pump used to pump feed water into a steam boiler. These pumps are normally high pressure units that take suction from a condensate return system and can be of the centrifugal pump type or positive displacement type. Boiler feed pump is the highest pressure generating pump inside the thermal plant with build up the pressure up to 165 kg.
09․ Which of the following relationships are not valid for short transmission lines
ABCD or transmission line parameters:
Vs = AVr + BIr
Is = CVr + DIr
Where,
Vs = Sending end voltage
Vr = Receiving end voltage
Is = Sending end current
Ir = Receiving end current
For short transmission line, line capacitance is neglected.
Therefore, Is = Ir, i.e., C = 0 and D = 1
Vs = Vr + Z Is i.e., A = 1 and B = Z.
10․ The most commonly used material for insulators of overhead lines is
The insulators provide necessary insulation between line conductors and supports and thus prevent any leakage current from conductors to earth.
In general, the insulators should have the following desirable properties :
1. High mechanical strength in order to withstand conductor load, wind load etc.
2. High electrical resistance of insulator material in order to avoid leakage currents to earth.
3. High relative permittivity of insulator material in order that dielectric strength is high.
4. The insulator material should be non-porous,free from impurities and cracks otherwise the permittivity will be lowered.
5. High ratio of puncture strength to flash over.
The most commonly used material for insulators of overhead line is porcelain but glass, steatite and special composition materials are also used to a limited extent. Porcelain is produced by firing at a high temperature a mixture of kaolin, feldspar and quartz. It is stronger mechanically than glass, gives less trouble from leakage and is less effected by changes of temperature.
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