I am a student just wanting to know how a steam driven generator works in sequence from-opening the steam chest-to sending power to the grid? please help me here!!

 

Try www.wikipedia.org or candu.canteach.org; there is very good basic information there.

A steam turbine is a device for converting temperature and pressure (in the form of steam) to torque. A generator is a device for converting torque into amps.

A steam turbine usually also has some kind of condenser on its exhaust, to convert the last of the steam back into water (condensate) and then the condensate is sent back to the boiler to be converted back to steam and the process begins all over again.

More steam flow equals more torque. More torque equals more amps.

The exact details of what happens from zero speed to full speed-rated load depend on the type and manufacturer of the steam turbine.

The generator is pretty simple. Again, it just converts torque into amps. More torque; more amps. Less torque; less amps. There is usually some kind of exciter, sometimes called an AVR (Automatic Voltage Regulator), which is used to control the generator's terminal voltage and the reactive component of the power developed by the generator. The load (real power; watts) of a generator is not controlled by the exciter; it's controlled by the amount of torque being produced by the prime mover. In your question, the prime mover is a steam turbine.

Hope this helps!

 

What exactly occurs on the generator, exciter, rectifier, gen field, breaker, etc. until we reach 52g/takeoff. sorry i am just wanting to understand in more detail what is going on when i see the operator turning on the sync scope to closing generator breaker, etc.

 

When the prime mover (because this is not peculiar to steam turbines) and generator reach approximately rated speed, the exciter is used to make generator terminal voltage equal to or slightly greater than the voltage of the bus being synchronized to (sometimes referred to as voltage matching).

The speed of the turbine and generator rotor are then adjusted to make the frequency of the generator equal to or just slightly greater than the frequency of the bus being synchronized to (sometimes referred to as speed matching). When the generator frequency is just slightly greater than bus frequency the synchroscope needle will be rotating slowly in the clockwise direction. The typical rate of rotation that most people feel is about right for synchronization is about one revolution of the synchroscope needle every 6 seconds or so, or about 10 rev/min.

The operator, when performing a manual synchronization, then monitors the synchroscope, and when the needle approaches the 12 o'clock position (usually around 11-11:30 o'clock) the operator twists the handle to close the generator breaker.

With the generator terminal voltage equal to or slightly greater than bus voltage, when the generator breaker closes the VAr meter will be at zero VArs or just slightly lagging.

With the generator frequency just slightly greater than bus frequency, when the generator breaker closes the real power, watts, will be slightly positive (amps "flowing out" of the generator). This ensures positive power flow, as negative, or reverse, power can damage the prime mover.

Synchronization can be done with the synchroscope needle stopped at the 12 o'clock position, but when this happens the real power output will be zero watts.

Automatic synchronization does the same things: voltage- and speed matching and monitors the phase angles (which is what the synchroscope indicates) and closes the breaker at the appropriate time (just around 12 o'clock).

Also, when the synchroscope is at the 12 o'clock position, the generator phase voltages are at exactly the same potential and angle--called in synchronization--and when the generator breaker is closed at this condition the voltage potential between the two contacts (generator and bus) of each phase is at a minimum, meaning that the minimum amount of force is required to close the breaker contacts.

The exact details of when the generator excitation is applied to the generator rotor are determined by the packager of the turbine/generator and exciter and the application.