Jose, Let me clarify. If you run a power flow you can obtain all the currents and transfer the constant P/Q loads into constant RLC you can rebuild your admittance matrix with this new RLC values. From here, calculating the electrical distance using Z matrix is nothing new. However, as soon as the load changes you have to do it all over again. My point is, you cannot have a single electrical distance matrix for a given system.
Paul, I know Paul Hines and I have read a couple of his group's papers on electrical distance. If memory serves, their approach suffered from the same problem of ignoring the load. This was a 3-4 years (or more) ago and they might have made a breakthrough but I'd have to do some reading, Another interesting approach that I ran into was based on the Jacobian but I do not remember the details. I have the paper somewhere and if somebody is really curious how it was done I can look for it. In that approach calculating the equivalent RLC load is not needed but again, the Jacobian changes with the load. I hope I made clear what I meant by my previous e-mail. Jovan On Tue, Feb 17, 2015 at 11:26 AM, Jose Luis Marin <mari...@gridquant.com> wrote: > Jovan, > > I agree it's not fast and efficient, as it involves inverting the > admittance matrix. However, I do not see why not Klein's impedance > distance could be used in power networks. I mean, the fact that some (ok, > most) injections are expressed as constant power does not invalidate the > fact that it's an electric circuit governed by Kirchoff laws. > > Incidentally, we have sometimes used the path of greatest admittance > between two given nodes as an heuristic measure of "closeness" (actually, > the net impedance of such path). It all depends what you want to use these > distances for. > > -- > Jose L. Marin > Gridquant España SL > Grupo AIA > > > On Tue, Feb 17, 2015 at 4:35 PM, Jovan Ilic <jovan.i...@gmail.com> wrote: > >> >> Paul, >> >> I would not call calculating Zbus "fast and efficient". Also, using >> resistance distance >> might make sense in standard electric circuits but it does not make sense >> in power >> networks with constant powers. >> >> As far as I know there is not a very good, theoretically sound, way of >> calculating electrical >> distance in power systems. I would love to be corrected on this one. >> >> Jovan >> >> >> >> On Tue, Feb 17, 2015 at 10:20 AM, Paul Cuffe <paul.cu...@ucd.ie> wrote: >> >>> Hi Hans, >>> >>> There is indeed a fast and efficient way to calculate this, though you >>> don't encounter it often in the power systems literature. >>> >>> You can use the Klein resistance distance, as defined here: >>> http://link.springer.com/article/10.1007/BF01164627 >>> >>> Once you have inverted your Ybus matrix to get the Zbus, you can >>> calculate the Thevenin impedance between any two nodes, i and j, as follows: >>> >>> >>> >>> Of course, the reciprocal of the Zthev impedance value will give the >>> effective admittance between any two nodes. >>> >>> Hope this helps, >>> >>> Paul >>> >>> >>> On 17/02/2015 15:06, Barrios, Hans wrote: >>> >>> Hello everybody, >>> >>> >>> >>> I was wondering if somebody had already the following issue: >>> >>> I would like to create a “full version” of the Y-matrix, i.e. a matrix >>> where (as long as there is only one synchronous grid) the admittance >>> between each bus is given, even if the bus are not connected directly by >>> one branch. >>> >>> If I am not missing anything, the Admittance between each bus should be >>> a simple calculation of parallel an series admittances. >>> >>> But I was wondering, if anyone knows a fast and efficient way I can used >>> to calculate this also for big grid structures. >>> >>> >>> >>> Thank you in advance for your contributions! >>> >>> >>> >>> Best regards >>> >>> Hans >>> >>> >>> >>> >>> >>> *Hans Barrios Büchel, M.Sc.* >>> >>> >>> >>> Institut für Hochspannungstechnik / Institute for High Voltage Technology >>> >>> - Nachhaltige Übertragungssysteme / Sustainable Transmission Systems >>> - Wissenschaftlicher Mitarbeiter / Research Assistant >>> >>> >>> >>> RWTH Aachen University >>> >>> Schinkelstraße 2, Raum SG 115.1 >>> >>> 52056 Aachen >>> >>> Germany >>> >>> >>> >>> Tel. +49 241 80-94959 >>> >>> Fax. +49 241 80-92135 >>> >>> >>> >>> Mail. barr...@ifht.rwth-aachen.de >>> >>> Web. www.ifht.rwth-aachen.de >>> >>> >>> >>> >>> -- >>> Dr. Paul Cuffe, >>> Senior Researcher, >>> Electricity Research Centre, >>> University College Dublin. >>> >>> Phone: +353-1-716 1743 >>> >>> >> >
