In these plants the chemical energy of fuel(petrol) is converted into mechanical energy with combustion in the cylinder of a diesel engine which convert the mechanical energy of engine into electrical energy.
Advantages of Diesel Power Plant
The diesel power plant has the following advantages as compared to other power plants.
- Quick starting and stopping
- No need warming period
- No stand by losses
- No need of large amount of cooling water
- Cheaper as regard to initial capital cost
- Require less space for a whole unit as compare to other power stations.
- These are no transmission losses
Disadvantages of Diesel Power Plant
- It is expensive
- This type of plant is not suitable for high load
Uses of Diesel Power Plant
Main application of diesel power plant are given below
The area where the load is initially growing the diesel electric plant can be used as a central station for 5000kw capacity.
It can be used as standby plant with a larger power plant. In order to supply the uniform electric power to the load if the large power plant are shut-down for maintenance purposes.
Peak Load Plant
It is particularly suitable to supply electric power during the peak period on the running power plant due to quick starting.
It is used to supply the auxiliary load of steam or hydal power station, in case of total tripping or station major failure for longer period of time.
It can be used as a mobile power plant for small load of temporary nature in the remote area where the grid system does not exist.
Private Power Plants for Industries & Hospitals
These are suitable for use in industry and hospital where the interruption in supply can not be afforded.
Site Selection for Diesel Power Plant
The following factors are to be considered while selecting side for a diesel power plant.
- Distance from the load center should be short.
- Cheaper land and source of water should be available.
- The soil strength should be sufficient to sustained the weight of foundation building and machinery.
- Transportation facility should be available
- Local condition of the area should be keep in mind
Main Components of Diesel Power Stations
The main components of diesel power plant are as follow.
- Engine fuel System
- Engine Air intake System
- Engine Exhaust System
- Engine Cooling System
- Engine Lubrication System
- Engine Starting and speed control System
- Electric Generator
This is the main component of the diesel power plant which develop the mechanical power, the engine is directly coupled to the generator
Engine fuel System
It includes the fuel storage tanks, fuel transfer pumps heater and connecting pipe work.
Engine Air intake System
This includes air filters, ducts and super charger. The purpose of air filter is to remove dust from the air to be supplied to the engine. This system supplies the required quantity of air for combustion.
Engine Exhaust System
This includes silencers which reduces the noise level.
Engine Cooling System
This includes coolant pump, cooling towers and spray ponds. Its purpose is to carry heat from the engine cylinder and to provide safety to the cylinder against over temperature
Engine Lubrication System
This includes lubricating oil pumps, oil tanks, filters and connecting pipe work. Its function is to reduce fraction of moving parts of the engine.
Engine Starting and speed control System
This includes storage compressed air tanks and self start. The function of this system is to start the engine. The speed control also used within this system consist of the speed. Governing and corresponding regulation.
It is directly coupled to the engine. It converts mechanical energy of the engine into electrical energy.
Types of Engines used in Diesel Power Stations
There are two types of engines used in diesel power plants.
- Four Stroke Engine
- Two Stroke Engine
Four Stroke Engine
In four stroke engine the complete cycle of operation is perform in four stroke. In 4 stroke or two revolution of engine. These four stroke are
- Suction Stroke
- Compression Stroke
- Expansion Stroke
- Exhaust Stroke
In this stroke the charge (air) is sucked into the cylinder valve is kept closed during the suction stroke.
In this stroke the piston moves forward towards the cover end of the cylinder. During this stroke both the inlet and exhaust valve are kept close. The air is compressed during this stroke.
At the end of compression stroke fuel is injected in the engine for ignition or combustion.
In this stroke the piston goes or moves again forward. The exhaust valved being opened and gases products of the combustion being expelled out from the cylinder.
Two Stroke Engine
In 2 stroke diesel engine the whole cycle of operation is completed within two stroke of the piston or during one revolution of the engine. The working of two stroke engine is given below.
The power and exhaust operation are completed during travel of piston in the backward direction while the suction and compression operation are completed during the forward travel of piston.