Kamis, 17 November 2011

power supply outage

When the main power supply outage (PLN), the electricity supply required reserves and the conditions of the Generator-Set is expected to supply power mainly to priority loads. Generator can be used as a backup electrical system or "off-grid" (which depends on the resources the user needs). Generators are often used by hospitals and industries that require a steady source of power and reliable (high level of supply reliability), and also for rural areas that do not have access to commercially supplied electricity through the existing distribution network PLN.

A diesel engine generator set consists of:
1. Prime mover or mover first, in this case diesel engine (in English is called diesel engines)
2. Generator
3. AMF (Automatic Main Failure) and ATS (Automatic Transfer Switch)
4. Battery and Battery Charger
5. Panel ACOS (Automatic Change Over Switch)
6. Security for Equipment
7. Installing the Power Supplies

Diesel engine

Including diesel engines with internal combustion engines or motor fuel referred to, in terms of how to obtain thermal energy (heat energy). To generate electricity, a diesel engine connected to a generator in one axis (the axis of diesel engine is coupled with shaft generator).

An advantage of using diesel engines as a first mover:
* Design and installation is simple
* Auxilary equipment (auxiliary equipment) simple
* When loading a relatively short

Losses use diesel engines as early Mover:
* Weight machines are very heavy because it must be able to withstand vibration and high compression.
* Starting the initial weight, because the compression height is about 200 bar.
* The greater the power the diesel engine is the greater dimension, it causes trouble if the engine power is very large.
* Fuel consumption using fuel oil relatively more expensive compared to power plants that use fuels other types, such as gas and coal.

How it Works Diesel Engine

Prime mover or early mover is a device that functions produce mechanical energy required to rotate the generator rotor. In the diesel engine / diesel engine ignition occurs alone, because the process works based on pure compressed air in the cylinder at high pressure (± 30 atm), so that the temperature inside the cylinder rises. And at that time the fuel is sprayed in the cylinder-temperature and high pressure beyond the flash point fuel injected so that the fuel will burn automatically. The addition of heat or energy is always performed at a constant pressure.

Pressure of gases of combustion of fuel and air will push the piston which is connected to the crankshaft using a piston rod, so that the piston can move back and forth (reciprocating). Back and forth motion of the piston is converted into rotational motion by crank shaft (crank shaft). And contrary motion of the crankshaft rotational motion is also converted into alternating piston on the compression stroke.

Based on analyzing how the system works, diesel motors can be divided into two, namely diesel motors that use airless injection system (solid injection) were analyzed with a dual cycle and diesel motor that uses a water injection system is analyzed with the diesel cycle (while motor gasoline was analyzed by
otto cycle).

The difference between diesel and motor gasoline motor is noticeable is located on the fuel combustion process, the combustion of gasoline motor fuel is due to the fire jumps the electricity generated by two-electrode spark plug (spark plug), while the diesel engine combustion occurs due to a rise in temperature the mixture air and fuel due to compression of the piston until it reaches the flame temperature. Because the principle of pressure due to ignition of the fuel then the motor is also called a compression ignition diesel engine while the motor is called spark ignition gasoline engine.

In diesel engines, piston perform two short steps towards the cylinder head on every step of the power.
1. The first step upwards a step entry and exploitation, here the air and fuel into the crank shaft while spinning down.
2. The second step is a compression step, continue rotating the crankshaft causes the piston to rise and push the fuel, causing combustion. Both of these processes (1 and 2) including the combustion process.
3. The third step is a step expansion and work, here the two suction valves and exhaust valves are closed while the crankshaft continues to rotate and retract the piston downward.
4. The fourth step is the removal step, here the exhaust valve opens and causes the gas due to combustion of residual waste out. Gas can be due out in the fourth process is moving up the piston back up and cause the gas to exit. These two latter processes (3 and 4) including the disposal process.
5. After the fourth process, then the next process will repeat the first process, where air and fuel re-entry.

Based on the above process then the speed diesel engines can be classified into 3 parts, namely:
1. Low-speed diesel (<400 rpm) 2. Medium speed diesel (400 - 1000 rpm) 3. High speed diesel (> 1000 rpm)

Starting the system or process to turn on / run diesel engines are divided into three kinds of starting the system, namely:

1. Start System Manual
The system is used to start diesel engine with a relatively small engine power is <30 PK. The way to revive a diesel engine on this system is to use the drive crank start on the crankshaft or connecting shaft to be moved by human power. So start the system is highly dependent on human factors as the operator. 2. Electric Start System This system is used by diesel engines that have power are the <500 PK. This system uses a DC motor with power supplied by the battery / batteries 12 or 24 volts to start the diesel. At the start, the DC motor gets power supply from the battery or batteries and produces torque used to drive a diesel until it reaches a certain round. The battery or batteries used must be used to start the 6 times without recharged, since the required startup current DC motor is large enough so worn armature that serves as a DC generator. Recharging the battery or batteries used tool of a battery charger and belt tension. At the time diesel battery charger does not work then get a supply of electricity, while at work then the supply of diesel battery charger obtained from the generator. The function of the voltage security is to monitor the battery voltage or battery. Therefore, when the voltage of the battery or the battery has reached the 12/24 volts, which is the default voltage, then the relationship between the battery charger to the battery or batteries will be disconnected by a safety voltage. 3. Start the system Compression Start system is used by the diesel that has a great power that is> 500 PK. These systems use motors with high-pressure air to the start of the diesel engine. How it works is by storing a bottle of air into the air. Then the air is compressed so that the hot air and diesel fuel is inserted into the Fuel Injection Pump and sprayed through a nozzle at high pressure. The result will occur foggy and combustion in the combustion chamber. At the time the pressure in the tube down to the minimum limit, then the compressor will automatically raise the air pressure inside the tube until the pressure in the tube sufficient and ready for use to perform starting diesel engines.

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