1. Python
Power systems analysis in PSS®E using
In the Name of God
Isfahan University of Technology
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programming language
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2. Python?
• Name of a kind of snakes
• Developed By Guido van Rossum at CWI in the early 1990s in the Netherlands
Download it from http://www.python.org
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3. Why Python?
Simple
Easy to Learn
Free and Open Source
High-level language
Portable
Interpreted
Object Oriented
extensible
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4. How to programming Python?
Some Python interpreters:
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5. Getting started with Python
1- Command line mode
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6. Getting started with Python
2- Script mode
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7. Getting started with Python
3-Python syntax colors
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8. Getting started with Python
4- Blocks of Code
Note: Dots indicates blank spaces before the code !!
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..two spaces means this is part of block 1
..two spaces means this is still a part of block 1
....four spaces means we just started block number 2
....four spaces means we are still in block number 2
........eight spaces means we started block number 3
....four spaces means we want this code to be grouped with block 2
........eight spaces for block 3
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9. Getting started with Python
5- Operators
The most common operators are:
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10. Getting started with Python
6- Using Python as a Calculator
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11. Getting started with Python
7- Strings
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12. Getting started with Python
7- Strings
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13. Getting started with Python
8- Variables
You can name a variable almost anything and use symbols like the _underscore !
But don’t use these words:
Note: No need to define variable Types! The first assignment to a variable creates it.
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14. Getting started with Python
9- Logical operators and Boolean data types
The words “and, or,” and “not” are logical operators.
A simple condition:
A compound condition:
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15. Getting started with Python
10- Sequence types
Tuple
A simple immutable ordered sequence of items
Items can be of mixed types, including collection types
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16. Getting started with Python
10- Sequence types
Dictionary
Mutable
key-value pair
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17. Getting started with Python
10- Sequence types
List
Mutable ordered sequence of items of mixed types
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18. Getting started with Python
11- Copy a variable
• For simple variables:
# b is a copy of the old value!!
• But mutable variables are always equal to each other!!
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19. Getting started with Python
12- Conditional statements
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20. Getting started with Python
13- Loop statements
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21. Getting started with Python
14- Define a Function
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22. Getting started with Python
15- Class
• A class is a User-Defined variable
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23. Getting started with Python
16- Module
• Modules are imported from other scripts using the import command
• As an example:
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24. Getting started with Python
17- Work with files
Note: Read function didn’t skip the blank character!!
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25. Getting started with Python
18- Input Data:
There are some simple ways to request data from user:
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26. Getting started with Python
19- Try and except:
You can try to do something in your script and make an exception for the time that
Python can’t run your code!!
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27. Getting started with Python
20- Help
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28. Getting started with Python
Simple examples
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29. Getting started with Python
Simple examples
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30. Getting started with Python
Simple examples
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31. Getting started with Python
Simple examples
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32. Getting started with Python
Simple examples
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33. Getting started with Python
Simple examples
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34. Getting started with Python
Simple examples
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36. Program Automation?
Provides the mechanism to control PSS/E other than by direct interaction!
• PSS/E Automation file languages:
• Response files
• IPLAN commands
• Fortran call statements
• Python commands
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37. Program Automation?
• Response files
• Often referred to as “idv” files or “Batch” commands!
• A set of instructions and inputs emulating the program manual operation
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38. Program Automation?
• IPLAN commands
• A simple programming language designed for PSS/E
• Has limited capabilities compared to modern programming languages!
• Described in the IPLAN manual:
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39. Program Automation?
• Fortran call statements
• A well-documented language
• But we don’t use it here!!
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40. Program Automation?
• Some important modules:
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41. Python & PSS/E
• ways of connecting:
1.The Embedded Interpreter Environment
• Allows PSS/E to execute Python files and commands.
• Run Program Automation File in PSS/E
2.The External Interpreter Environment
• Python programs access PSS/E functions without running GUI
• Faster and better Way
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42. Python & PSS/E
1.The Embedded Interpreter Environment
Select the Python file type and specify the file name
Execute operations through the PSS/E GUI
click the Stop Recording button
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43. Python & PSS/E
2.The External Interpreter Environment
Code that is suggested in the PSS/E manual to get an External Interpreter
Environment:
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44. Python & PSS/E
Functions
Most of useful functions are in psspy module. For example:
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45. Python & PSS/E
Functions
Most of useful functions are in psspy module. For example:
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46. Python & PSS/E
Functions
Most of useful functions are in psspy module. For example:
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47. Python & PSS/E
Functions
How can I find them?
1-The API file
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48. Python & PSS/E
Functions
How can I find them?
2-The record mode
I. Click the Start Recording button
II. Select the Python file type and specify the file name
III. Execute operations through the PSS/E GUI
IV. click the Stop Recording button
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49. Python & PSS/E
Functions
How can I use them?
1-Option mode
2-Array mode
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psspy.fnsl(
options1=0, # disable tap stepping adjustment.
options5=0, # disable switched shunt adjustment.
)
psspy.fnsl([0,_i,_i,_i,0,_i,_i,_i])
50. Python & PSS/E
Important functions
Power Flow Operation (API-Chapter 1)
Describes the API routines corresponding to the operational functions of the PSS®E Power Flow and
Fault Analysis.
Example:
fnsl (Newton-Raphson power flow function)
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51. Python & PSS/E
Important functions
Power Flow Data Changing (API-Chapter 2)
Describes the API routines used to add or modify power flow data.
Example:
branch_data (Modify the data of an existing non-transformer branch in the working case or to add
a new non-transformer branch to the working case)
If you want to change the reactance of the branch from bus 456 to bus 459 circuit 1 to 0.025 pu:
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ierr = psspy.branch_data(456,459,"1",[_i,_i,_i,_i,_i,_i], [_f,0.025,_f,_f,_f,_f,_f,_f,_f,_f,_f,_f,_f,_f,_f])
Equal to:
ierr = psspy.branch_data(456,459,"1", realar2 = 0.025)
52. Python & PSS/E
Important functions
Single Element Data Retrieval (API-Chapter 7)
Defines API routines that are used to retrieve data for a single element (e.g., bus,
branch, area, etc.) from the PSS®E engine and test on various program states.
Example:
busdat (Use this API to return real bus values)
If you want to retrieve the pu voltage at the bus 1:
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busNumber = 1
paramStr = 'PU'
ierr, Vpu = psspy.busdat(busNumber, paramStr)
53. Python & PSS/E
Important functions
Remove Elements From a Power Flow Case (API-Chapter 1)
Example:
purg(delete specified outaged equipment items from the working case (activity PURG).)
purgbrn(delete the specified non-transformer branch or two-winding transformer from the
working case (activity PURG).)
If you want to remove the line from bus 201 to bus 202 circuit "1“:
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fromBus = 201
toBus = 202
ckt = '1'
ierr = psspy.purgbrn(fromBus, toBus, ckt)
54. Python & PSS/E
Silencing PSS/E Output
• PSS/E prints a voluminous amount of information to the command line when you are running a program
• silence is a function that turn off this outputs and save logs in a file
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55. Python & PSS/E
Simple example
• Optimum placement of a fixed capacitor (100 MVAR) on feeders of “savnw” grid
• Scaling loads (5%) with fixed power factor for making disturbance in network and save case file as “savnw1”
• Log will save in a “psse_logfile.log” and report output is a file named “report.txt”
• Before allocating capacitor, total losses were as below:
69.04 MW & 1267.50 MVAR
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56. Python & PSS/E
Simple example (Code)
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57. Python & PSS/E
Simple example (Results)
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MW Losses
MW
58. Python & PSS/E
Simple example (Results)
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200
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MVAR Losses
MVAR
