3 ms·
sorry for the nitpick, but what part of a load flow study is non-linear?
by snowwindwaves 7y ago
sorry for the nitpick, but what part of a load flow study is non-linear?
- new4thaccount 7y agoNot a nitpick at all...I wish I could talk about this more! Let me know if you want a good book list on this. There are several out there with full Matlab code to accompany the equations. It has trigonometric identities in all the equations (sin & cos) if you do the full AC method. We all generally use the Newton-Raphson iterative method for the large sparse models we have. Gauss-Seidel is great for small models, but takes ages to converge as your model size increases. There is a "Decoupled" version of the Newton-Raphson that zeroes out some terms that usually don't matter in the Jacobian to speed things up considerably. There are some other solver types being researched, but Newton-Raphson is fast, good at converging, and is well understood. The last and very popular method is the DC loadflow where you make a lot of assumptions and linearize the entire thing. This isn't used for important studies by itself, but is embedded in lots of things such as market commitment and dispatch as it is extremely fast and almost never diverges. There are also other useful sensitivities to derive from it.
- jhayward 7y ago> what part of a load flow study is non-linear? Sorry to give you a wiki reference, but I had literally just read the power flow study page [1] earlier today: "The problem is non-linear because the power flow into load impedances is a function of the square of the applied voltages" [1] https://en.wikipedia.org/wiki/Power-flow_study#Model https://en.wikipedia.org/wiki/Power-flow_study#Model
- new4thaccount 7y agoYea...you have a V^2 term as well from the voltage magnitudes I think...thought about adding that to my answer below afterwards, but didn't.