BBJ20905 : GENERATOR SYSTEM MAINTENANCE

TOPIC : APPLICATION OF GENERATION (AC) AT POWER PLANT

AC GENERATOR AT POWER PLANT

AIR COOLED GENERATOR

Open Ventilated (OV)

Outside air is drawn directly from outside the unit through filters, passes through the generator and is discharged outside the generator.

Totally Enclosed Water to Air Cooled (TEWAC)

Air is circulated within the generator, passing through frame mounted air to water heat exchangers.

Air Cooled Generator

Closed Cycle Air Cooled

HYDROGEN COOLED GENERATOR

Low density.
High specific heat.
Highest thermal conductivity (at 0.168 W / (m.K).
Easy detection by hydrogen sensors.
A hydrogen-cooled generator can be significantly smaller, and therefore less expensive, than an air-cooled one.

LIQUID COOLED GENERATOR

Use a specially made coolant or oil to cool down the internal parts of the generator.
It mainly uses a radiator or a water pump to circulate the coolant throughout the generator, which absorbs the heat and then passes through the radiator having another round of cooling.

EXCITATION SYSTEM

Excitation: Creation of the magnetic field that allows current to be induced in conductors that have relative motion with the magnetic field.

Alternator exciter: Exciter that uses brushes to feed current to the rotating main generator field.

EXCITER STATOR & EXCITER ROTOR

Function :

SALIENT POLE ROTOR

BRUSHLESS EXCITATION SYSTEM-MAIN EXCITER

ADVANTAGES OF BRUSLESS EXCITATION SYSTEM

Reliability. “ AC Exciter-Rotating Rectifier” mounted on a common shaft.
Maintenance cost is reduced because there is no brush, commutator and slip ring.
There is no troubles of insulation resistance since the adhesion of carbon duct is varnish.
All devices are placed in closed housing and not exposed to the atmospheric conditions.
Change of brush is needless during operation so that with an increase of safety, the operation can continue for the long term.

POWER GENERATION AT POWER PLANT

POWER GENERATION FOR POWER SYSTEM

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