If I get this correctly, you are considering parallel paths between a
pair of nodes and taking the equivalent reactance.
in your model. If this is the case shouldnt you be reducing the number
of circuits between nodes to 1 and increasing the reactance accordingly.?
Are you using a loop equation approach?, If so, why? In general nodal
equations are better for load flow studies. I think that you will find
the approach much easier to use in that choice of busses is automatic
and building or modifying the Y matrix is simple. You will also end up
with fewer equations and eliminate the need to choose loops. Handling
parallel lines is not a problem - all you do is modify the Yii, Yij and
Yjj terms.
Don Kelly
On 20/05/2013 8:25 AM, P T wrote:
I think, Don is asking where do I divide a floating number by zero in load
flow calculations.
I am using DC load flow calculations and dividing circuit reactance with
number of circuits. Normally, in the incidence matrix, when there is no
connection between two buses, both reactance and no. of circuits are zero.
However, I am calculating load flow with one of the transmission lines out
of service. Instead of setting both reactance and no. of circuits to zero,
I just set the no. of circuits to zero and hence getting an infinity.
Thanks,
PT
On Mon, May 20, 2013 at 9:17 AM, Raul Miller <[email protected]> wrote:
I don't understand this question.
Can you restate it?
In other words are you asking whether floating point numbers are valid
in your code? Or are you asking why someone would divide epsilon by
zero? Or are you trying to express a problem? Or is it something
else?
That said, my generic reaction is that if you have practical issues
where the distinction between 0%0 and 1e_256%0 matters that probably
means your model is unstable.
Thanks,
--
Raul
On Sun, May 19, 2013 at 7:41 PM, Don Kelly <[email protected]> wrote:
On my machine (64 bit athlon) using J602 i find that 0%0 will give 0.
BUT
(0+1e_256)%0 will give infinity.
A question that I have is that in dealing with power system matrices-
where
does such a situation occur in manipulating the matrices in load flow or
converting Y to Zbus matrices for a realistic model? The only case
would be
one where one might like to connect two busses together through a "0"
impedance link in order to represent a case where switching is done to
connect/disconnect them.
Don Kelly
On 17/05/2013 8:04 PM, Brian Schott wrote:
I remember that years ago there was a verb to divide 0 by 0 and produce
_,
but I cannot find it anywhere. It was probably not the one I have
produced
tonight, but here it is, anyhow.
div =: 0:`%@.(+.&*)
0 1 2 3 3 _6 div 0 1 _5 6 0 0
0 1 _0.4 0.5 _ __
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