Interview Questions and Answers : Power Plant Instrumentation and Electrical Engineers
- Name the four major circuits in steam power plant. • Coal and ash circuit • Air and flue gas circuit • Feed water and steam circuit • Cooling water circuit
- What consists of cooling water circuit and coal & ash circuit in steam power plant? The cooling water circuit consists of a pump, condenser and cooling tower. The coal and ash circuit consists of coal delivery, preparation of coal, handling of coal to the boiler furnace, ash handling and ash storage.
- What is the main purpose of the reservoir? The main purpose of reservoir is to store water received from catchments areas during the rainy seasons and supply the same during the dry season.
- What is the main purpose of the dam? The main purpose of the dam is to increase the height of water level and also to increase the working head of the hydraulic power plant.
- What is the use of surge tank? The surge tank is used to provide better regulation of water pressure in the system. The surge tank controls the water when the load on the turbine decreases and supplies water when the load on the turbine increases. Thus, surge tank controls the pressure variations resulting from the rapid changes in water flow in penstock and hence prevents water hammer.
- Explain about penstock? The pipe between surge tank and prime mover is known as penstock. It is designed t o withstand high pressure. It is made up of reinforced concrete. In very cold areas, the penstock is buried to prevent ice formation and to reduce the expansion joints.
- What is the use of spill Ways? Spillway is like a safety valve of the dam. It discharges major flood without damaging the dam. It keeps the reservoir level below the maximum level allowed.
- What is the main purpose of high-pressure boilers? The high-pressure boilers are used to increase the efficiency of the plant and to reduce the cost of electricity production.
- State important advantages of high-pressure boilers? • The amount of scale formation is less, since the velocity of water through pipes are more. • All parts of the system are heated uniformly, so there is no danger of overheating.
- Name important high pressure boilers? • La Mont boiler • Benson boiler • Loeffler boiler • Velox boiler.
- Name the different types of coal transforming equipments? A. Belt conveyors B. Screw conveyors C. Bucket elevators D. Grab bucket elevators E. Skip hoists F. Flight conveyors. The coal transfer starts by carrying of coal from-unloading point to the storage site.
- Define forced draft and induced draft cooling towers If the fan is located at the bottom of the tower and air is blown by the fan up through the descending water it is called as forced draft cooling towers If the fan is located at the top of the tower and air enters through the louvers located on the tower’s side and drawn up and discharge through the fan casing, it is called as induced draft
13 Name the different components of nuclear reactor?
- Nuclear fuel
- Control rods
- Reactor vessel
- Biological shielding
14 Define speed. Speed is a variable which refers to the revolutions per minute of some piece of rotating equipment.
15 Which is the most frequently used speed measuring instrument? Tachometer
16 What are the types of tachometer?
a) A.C. tacho generator b) D.C. tacho generator
17.What are the types of D.C.tacho generator?
a) Permanent magnet type b) Separately excited field type
18.What are the disadvantages of D.C. tacho generator? A.C. ripple is present in the output signal. The magnitude of the ripple is 2% of the out[ut D.C.level.
19.Name the types of rotor used in A.C.tacho generators. a) Drag cup rotor b) Squirrel cage rotor
20.What are the advantages of Squirrel cage rotor? *Cheaper *Occupies less space