Steam Turbine Operating at a Load of a 100MW with a field temperature of 0 degree celsius cause and effect.

What is the cause(s) of zero temperature reading on the field winding of a steam turbine generator and the effect of operating at a Load of 100MW

MOST field temperature values are the result of calculations done by the generator excitation system (commonly called the "AVR"). Because it's really difficult to read sensors on a piece of equipment that's running at 3000 RPM, or 1500 RPM. So, based on the known resistance of the rotor windings, and the temperature characteristics of the generator rotor windings at various voltages and/or currents the generator rotor temperature is calculated. So, it's likely NOT a generator rotor temperature sensor issue.

It would appear there is something amiss with the inputs to the calculation.

You need to get a knowledgeable person to site (knowledgeable with the generator excitation control system (the AVR)) to investigate the problem and resolve it.

If some work was just recently done on the generator and/or exciter (AVR) be prepared to tell the service person what was done and why.

Because, when a problem like this starts, it usually has some event that triggers it (maintenance outage; trip from load; high temperature event; etc.). And you have provided ZERO information about how long this problem has existed and when it started (after a maintenance outage; after a trip from load; after a high temperature event).

In fact, you haven't provided ANY useful information at all. The steam turbine-generator is operating at an output of 100 MW, but what is the nameplate rating of the steam turbine and of the generator?

How many amps are flowing in the generator rotor and the generator stator? How many volts is the generator stator producing? If available, what is the generator voltage at this load? What were the values of generator field current, field voltage and stator amperes and stator voltage when the generator field temperature was working and at 100 MW? What is the power factor of the generator at100 MW? (The KVA, and the KVAr, (or MVA or MVAr)???) We also don't know what the generator stator temperatures are, either. Pretty darn important piece of information, that, actually.

You haven't told if the generator field temperature value has ever worked on whatever piece of equipment the value is being shown on. It could be that the generator exciter (the AVR) doesn't even calculate generator stator temperature (it's usually a purchased option on many exciters--and perhaps it wasn't purchased when the equipment was ordered and has never displayed a working value). It could be that the generator exciter (AVR) was recently upgraded, and the field temperature has never worked or only worked intermittently and has now gone to zero. Or, that the field temperature measurement capability of the new generator exciter (AVR) was not purchased, or is not configured (scaled) properly.

It could be that you're looking at some kind of meter and it gets a voltage or current signal from the generator exciter (the AVR), and there's some problem with the meter, or the wiring between the meter and the generator exciter (the AVR).

Perhaps someone has tampered with the communication method between the field temperature display and now the system is reading or writing the field temperature value properly to the device you're trying to read the field temperature value on (perhaps an HMI display?).

There's so much you haven't told us, and probably don't know. These things can be very simple, and they can be very complicated. But we have no actionable data from you--other than the field temperature value you are seeing is indicating 0 deg C and the generator is operating at 100 MW (of an unknown capacity). We don't know how the field temperature value gets to whatever is supposed to be displaying it. It could be that someone inadvertently pushed the wrong button on the face of a meter (digital meter, probably). We just don't know, you haven't told us, and you probably can't tell us. You're just fishing for an answer, hoping that we know exactly what type of generator and generator exciter (AVR) is in use on the steam turbine-generator at your site and we can tell you exactly what the problem might be. Because, all generators and exciters are exactly alike and all have the same problems and someone can just intuitively know what to tell you to do.

Think about how you would respond to this question from someone you can't see and don't know: "Why isn't my watch working?" You don't know if it's an analog watch or a digital watch. You know know if it has a battery or a spring movement. You don't know if it's running fast or slow, or at all, You would have to ask a LOT of questions, and you still might not get an idea of what the problem might be. It might be as simple as winding the watch, or replacing the battery, or ... But, you have no information to work with. None. Zilch, Zero. Niente. Nada. Zippo, Nada. So, you're forced to ask questions--a LOT of questions, unless you get lucky and get a truly helpful piece of information.

And, 100 MW isn't helpful in your situation.

Best of luck with your problem, yawadu.

Please write back to let us know how the problem was resolved.