It does assume that the reader knows what it is all about. For learning
it is veryy skimpy.
A more thorough reference is:
http://nptel.iitm.ac.in/courses/Webcourse-contents/IIT-KANPUR/machine/ui/chap3.pdf
The advantage of the Ybus is that it is easy to build -just choose a
reference node and go with the process at the other nodes. In power
systems the reference is generally the ground.
I have found a reference which discusses the Ybus and Zbus methods and
the way to build the latter without inversion of a large matrix.
Here is a simple example-- a square of 4 1 ohm resistors (conductance =1
Siemen (mho)
1 o---/\/\--o 2 At each node there are 2 resistors
each of 1 so the Y00 =Y11 =Y22
| | Between 2 and 1 there is a coupling of
1S so Y01=_1 Y02=0 as there is no
/ / direct connection.
\ \
| |
0 o---/\/\--o reference
] y=:>2 _1 0;_1 2 _1;0 _1 2
2 _1 0
_1 2 _1
0 _1 2
this gives
]z=:%.y
0.75 0.5 0.25
0.5 1 0.5
0.25 0.5 0.75
The resistance from node j to the reference is the Zjj term
The resistance from node j to node k is zjj+zkk-2zjk
nodes (buses) that are not of interest can be eliminated by simply
removing the row and column corresponding.
Don.
On 11/01/2013 6:47 AM, Raul Miller wrote:
On Thu, Jan 10, 2013 at 11:07 PM, Don & Cathy Kelly <[email protected]> wrote:
A wee bit of a mix up between what I said and what Aai said (no 'quotes'
appeared to distinguish between the two).
the 9:23 message was from Aai but the
f=: 13 : '+/-: %>: +:i.y'
and the result corresponds to a specific immediate "calculator' solution
that I gave
]R100K=:+/0.5*%1+2*i.100000
I had not put it in the form that you present and I thank you for the
re-programming as a function-Gee-I can interpret it- I must be learning
something!!!.
Note that
R=:13 :'+/0.5*%1+2*i.y'
would be equally valid.
As for an example of the Z-Bus method I gave a small example in a post at
6:12PM yesterday
I can give more examples but the practical ones I have on hand do involve
complex impedances.
Wiki gives little information so it appears that I will have to put together
some notes that I have - it appears that this approach is something known
mainly in power system analysis.
This is the best I have found so far on line and it is inadequate:
http://en.wikipedia.org/wiki/Impedance_parameters#The_Z-parameter_matrix
Inadequate because it assumes the typical application is for a 2-port
network.
What do you think of http://en.wikipedia.org/wiki/Ybus_matrix ?
Thanks,
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