I couldn’t wrap my head around this concept in my lectures, thank you very much for clearing it up !

A great video that helps you visualise rotor stability. I've never seen it explained so well in all my years in the profession!

One of the best simulations I have seen...great job Sir!👌

THANK YOU SO MUCH!!! Did could not understand that equation but now its so much clearer!!! thank you!! great video, great visualition, great explanation!

Great video George - Thank you so much

Thanks for making such a good simple explanation.

Excellent illustration Sir.

Great video Thank you so much 👍👍🌷

Thank you very much for this❤️❤️😍

Hello! Can you suggest free programs/ sites where you can model according to your conditions for course work?

Excellent explanations and graphical representations make this material easy to understand! Is this an alternator your describing?

@georgschett801

Жыл бұрын

Yes, it is the behavior of a typical synchronous power generator or of a group of such generators.

Thank you George, very interesting. It reminds me of a static 3-phase UPS topology from a company called Silcon in Denmark in the mid-1980's (Now part of Schneider Electric). The Silcon DP-300 used an input inductor (choke) as a power flow control reference. The control system algorithm used voltage vector control of the inverter to regulate the power flow with the input voltage as the inverter phase angle reference vector. Basically, same as a cogeneration generator without the mechanical limitations. I am curious what your simulation would be like with a static inverter and DC source replacing your motor-generator, e.g., to simulate a grid connected inverter with battery energy storage from wind or solar. Your thoughts?

@georgschett801

2 жыл бұрын

Hi Al There is an older video: kzread.info/dash/bejne/Zp6d0MaPo9Kre9o.html about a part of the topic you address. Be aware that I use quit a low time resolution to enable a kind of real time experience. There is a small typo: pcm should be pwm. Overall modern power electronics can interact with a grid in a similar manner than conventional generation but faster, power flow works in both directions. I make the case of a voltage control however alternatively one can control the current of an inverter. I will sooner or later make a better case.... All the best, George

Sir when there a short circuit the point moves but the mechanical powee doesnt move why and why when the brakers are open Pelec 0 there is only rotor magnetic

@georgschett801

2 жыл бұрын

I am not sure if I get the question right. While the breaker is closed the mechanical power is converted to electric real power and evacuated to loads. The torque is given by the turbine. When the breaker opens, there is no electrical power anymore, but still there is the mechanical torque from the turbine. Therefore instantly the generator accelerates until the mechanical control system starts to close the valves and so reduces the mechanical torque. The electrical time constant however is much shorter than the mechanical time constant and therefore a simplified assumption of a constant mechanical power in the critical time span of around 300 ms is OK. A detailed simulation however would consider a variable torque as a result of the acceleration.

Really nice and clear representation, thank you for your videos. My question is how do you visualize the deplacement of rotating magnetic field in reference to the the stator rotating field and the change in angle in your slides?. It really is a good animation and helps to get the concept.

@georgschett801

Жыл бұрын

Thanks for your kind feedback. I do this with power point visual basic or for even more complex graphics I use javascript.

@trinottuk

Жыл бұрын

@@georgschett801 Really good. thank you. Do you have presentation showing 2 generators or more working in parallels visualizing the way their angle interact to changes in the system? for example if system load is increased / decreased, etc.

@georgschett801

Жыл бұрын

@@trinottuk Maybe this one is what you are looking for: kzread.info/dash/bejne/hKyur6qKZNKXmqw.html and by the way, this is exactly what you can do with the proposed simulator on www.ecsp.ch

@trinottuk

Жыл бұрын

@@georgschett801 Thank you very much. Are these presentations available for registered members?

@georgschett801

Жыл бұрын

@@trinottuk No, it is for everybody. It's all on my channel: kzread.info/dron/ZEYX01Nvi3qHsby1Cnls1g.html The pro-version of the simulation tool is for registered members only: www.ecsp.ch

Did you do a single phase, two phase and three phase at the end?

@georgschett801

Жыл бұрын

The simulation at the end is 3-phase, the general explanations are based on a single phase scheme.

What name this program u used?

@georgschett801

2 жыл бұрын

Here is the link: www.ecsp.ch. The nice graphics however is made manually with support of powerpoint visual basic.

I don't think in rotor stability when short circuit happens that point needs to pass the horizontal line right to unbalanced state could occur. It can happen before, the moment where it happens depends of the energy stored in normal work, I remember that from lectures, I'm not sure 100% that's it, but I know that depends of the energy stored in rotor before short circuit happens

@georgschett801

2 жыл бұрын

You are right, it does not have to. It depends on the torque before sc.

It is really nice representation. However it seems to be based on classical model. The assumptions for classical model are: I. Transient stability is decided in the first swing. II. Constant generator main field-winding flux linkage. III. Constant Mechanical Power Today large system interconnections with the greater system inertias and relatively weaker ties result in longer periods of oscillations during transients. Generator control systems, particularly modern excitation systems, are extremely fast. It is therefore questionable whether the effect of the control equipment can be neglected during these longer periods. Indeed there have been recorded transients caused by large impacts, resulting in loss of synchronism after the system machines had undergone several oscillations. The dynamic instability problem, where growing oscillations have occurred on tie lines connecting different power pools or systems, hence it has also become increasingly important to ensure the security of the bulk power supply. Therefore reexamine the assumptions made in stability studies. Therefore we should: I. More information of the characteristic time response of our system loads to changes in voltage and frequency-develop new dynamic models of system loads. 2. Re-examine old concepts and develop new ideas on changes in system networks to improve system stability. 3. Update our knowledge of the response characteristics of the various components of energy systems and their controls (boilers, reactors, turbine governors, generator regulators, field excitation, etc.) 4. Reformulate our analytical techniques to adequately simulate the time variation of all of the foregoing factors in system response and accurately determine dynamic system response. Last but more important is to consider effect of HVDC ties and renewable energy. Hence we can say that the classical model is inadequate for system representation beyond the first swing. Since the first swing is largely an inertial response to a given accelerating torque, the classical model does provide useful information as to system response during this brief period. All above is from: P. M. Anderson, A. A. Fouad, Power System Control and Stability, 2 edition, IEEE Press

@georgschett801

3 жыл бұрын

Thanks for these clarifications! All of your comments are correct and appreciated. The lecture is about basics. People like you who are experts do not need such simple explanations of course. They understand the subject matter and work with much more sophisticated tools. Again, thanks for your feedback!