Here is the my first program in J!
NB. Goal: To compute DC power flows in an electrical transmission network
NB. given transmission line reactance and bus injections and withdrawals
NB. Reference: R.D. CHRISTIE, B. WOLLENBERG, AND I. WANGENSTEEN
NB. "Transmission Management in the Deregulated Environment"
NB. Proceedings of IEEE, Vol. 88, N0. 2 Feb 2000
load 'files'
load 'jview'
tab=. 9{a.
NB. read the bus and branch data from files
NB. rawData=. <;._2 "1 (,.&tab 'm' fread 'E:\EMCAS Misc\J
Loadflow\Bus11.txt')
NB. bus=. _ ".&> rawData
NB. rawData=. <;._2 "1 (,.&tab 'm' fread 'E:\EMCAS Misc\J
Loadflow\Branch11.txt')
NB. branch=. _ ".&> rawData
NB. outFile=. 'E:\EMCAS Misc\J Loadflow\lineFLows11.txt'
rawData=. 1 1000 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0
10 0 11 _1000
bus=. 11 2 $ rawData
rawData=. 1 2 4 0.02 2000 1 3 4 0.025 2000 2
3 2 0.08 2000 2 4 3 0.01 2000 2 5 2 0.02
2000 3 8 4 0.04 2000 3 9 2 0.05 2000 4 5 2
0.01 2000 4 6 4 0.02 2000 4 7 3 0.01 2000 5
7 3 0.015 2000 6 7 2 0.01 2000 8 10 4
0.025 2000 8 9 3 0.03 2000 9 10 2 0.04 2000 6
11 3 0.02 2000 7 11 3 0.025 2000 10 11 2
0.04 2000
branch=. 18 5 $ rawData
netInj=. 1{"1 bus
circuits=. 2{"1 branch
reactance=. 3{"1 branch
fromTo=. 0 1{"1 branch NB. select branch from to nodes
fromTo=. fromTo - 1 NB. subtract 1 for zero based indexing
fromTo=. ,;/ fromTo
NB. create a nxn matrix for reactance with all zero values
size =. #bus
spReactance=. (size,size) $ 0
NB. amend the values in spReactance with values from reactance at locations
indicated by fromTo
spReactance=. reactance fromTo } spReactance
NB. spReactance is upper traingle. transpose and add
NB. why the hook +|: is not equal to y + (|:y) ?
tmp=. |: spReactance
spReactance=. spReactance + tmp
NB. create a nxn matrix for no. of circuits
spCircuits=. (size,size) $ 0
spCircuits=. circuits fromTo } spCircuits
tmp=. |: spCircuits
spCircuits=. spCircuits + tmp
lineReactance=. spReactance%spCircuits
lineSusceptance=._1 % lineReactance
NB. above two lines can be combined as shown below. But, need lineReactance
later
NB. lineSusceptance=. _1*spCircuits%spReactance
NB. replace all __ with 0
lineSusceptance=. (lineSusceptance=__)}lineSusceptance,:0
setDiag =: (>: * i.) @#@] }
NB. line susceptance with diagonal calculations
lineSusceptance =: (_1 * +/ lineSusceptance) setDiag lineSusceptance
NB. eliminate slack bus and column. Currently last row and last column
NB. In future should be deleting row and column specified by slack bus
NB. delete last row and column
lineSusceptance =: _1 }. "1 ] _1 }. lineSusceptance
NB. inverse the matrix
lineSusceptance =: %. lineSusceptance
NB. insert slack row and column with zero values (auto fills in 2nd
dimension)
lineSusceptance =: lineSusceptance, ((1, size) $0)
NB. define matrix product
mp=: +/ .*
NB. calculate bus phase angles
phase =: lineSusceptance mp netInj
NB. calculate line flows
Pij=: -/~@[ % ]
lineFlows=. phase Pij lineReactance
NB. replace all _ and __ with 0
lineFlows=. (lineFlows=_)}lineFlows,:0
lineFlows=. (lineFlows=__)}lineFlows,:0
]lineFlows
NB. write the results to a file
NB. lineFlows fwrites outFile
NB. Check and identify the lines that are over loaded
NB. TODO: use sparse matrices if possible
NB. TODO: there are some division by zeros. Can this be avoided?
NB. TODO: Handle arbitrary bus labels instead of 1 to n
On Tue, May 21, 2013 at 1:42 PM, P T <[email protected]> wrote:
> That works perfectly! All the assumptions you made are correct and thanks
> for reading my mind.
>
> Yes, I am dividing by zero and all those values are not applicable as
> there are no connections between those nodes in the network. After cleaning
> up, I will post the complete program along with sample data. It still looks
> like a Java program rather than a J program.
>
> Thanks,
> PT
>
>
> On Tue, May 21, 2013 at 1:11 PM, Raul Miller <[email protected]>wrote:
>
>> On Tue, May 21, 2013 at 12:49 PM, P T <[email protected]> wrote:
>> > I am almost close to finishing an initial version. But, I don't know
>> how to
>> > write a verb P(ij) = (phase(i) - phase(j))/lineReactance(ij) where
>>
>> Without looking at your data, this smells like:
>>
>> Pij=: -/~@[ % ]
>>
>> which you use as:
>> phase Pij lineReactance
>>
>> Here, phase is assumed to be 1 dimensional and lineReactance two
>> dimensional and square. And phase -:&# lineReactance should always be
>> true.
>>
>> I did not try this on your example data since I do not know what the
>> result would be.
>>
>> I will note that you are dividing by zero, which is worrying.
>>
>> --
>> Raul
>> ----------------------------------------------------------------------
>> For information about J forums see http://www.jsoftware.com/forums.htm
>>
>
>
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