Brief introduction to
State Estimation (SE) program
Rui Bo
1.State Estimation (SE) program (2)
1.1.Features (2)
1.2.Limitations (2)
1.3.Demonstration (2)
2.File Structure (3)
1.State Estimation (SE) program
This program intends to enhance the state estimation code included in MATPOWER (in sub directory ‘extras\state_estimator’) by defining a generic interface, adding system observability check, and rewriting some of the codes.
Book “Computational Methods for Electric Power Systems” authored by Mariesa Crow is referenced during implementation of the programs, and the notations are in accordance with those in the book.
Please note that execution of the program requires the MATPOWER package is included in the searching path of MATLAB environment.
The author would like to thank Fangxing Li for his help in developing the program. One of his courses taught at the University of Tennessee, Knoxville, “Computational Methods for Power System Analysis”, has been a valuable source.reactive to
1.1.F eatures
✓A generic interface of the state estimation is defined
✓8 types of measurements are supported including real power line flow through from end, real power line flow through to end, generator real power output, voltage angle, reactive power line flow through from end, reactive power line flow through to end, generator reactive power output, voltage magnitude (shortened for PF, PT, PG, Va, QF, QT, QG, Vm respectively)
✓Measurement variances for each of the 8 kinds of measurements could be separately specified.
✓Input data integrity check is provided such as completeness and consistency check ✓System observability check is provided and possible reasons are identified, such as not-in-observation variables, dependent variables, etc. This type of information can guide users in changing measurement settings to make system observable.
✓Source codes are self-explanatory
✓Sufficient comments are provided in the source codes
1.2.L imitations
✓Presently bad data detection is not implemented yet
✓The measurement indices of the interface may be further improved to facilitate the use of the program
1.3.D emonstration
Running ‘test_se.m’ will generate the following outputs. The test case is a 6 bus system, which is included in the state estimation program package.
Running ‘test_se_14bus_err.m’ will generate the following outputs. The program identifies some possible reasons for system being not observable, which are not-in-observation variables. This type of information can guide users in changing measurement settings to make system observable.
2.File Structure
The file structure is as follows.
1)Source code files.
run_se.m: run state estimation
doSE.m: perform state estimation
outputsesoln.m: show state estimation results on screen
checkDataIntegrity.m: check input data integrity
isobservable.m: check if system is observable through provided measurements
2)Case data files.
case3bus_P6_6.m: a 3 bus system in problem 6.6 in book 'Computational Methods for Electric Power Systems' authored by Mariesa Crow
3)Test files.
test_se.m: test state estimation solver on a 3-bus system
test_se_14bus.m: test state estimation solver on the IEEE 14-bus system
test_se_14bus_err.m: test state estimation solver on the IEEE 14-bus system
with measurement issues leading to system not
observable