WLS distribution system state estimator based on voltages or branch-currents: Accuracy and performance comparison

This paper presents a comparison between the two main classes of Weighted Least Squares (WLS) state estimators used in distribution systems: state estimators based on node voltage state variables and estimators based on a state expressed in terms of branch-currents. In particular, the actual accuracy achieved for the estimated quantities by these estimators and their modified versions is analysed in details along with their performance, considering different types of real-time measurements (traditional or phasorial), different configurations of the measurement system and the impact of the network parameters uncertainty. Results obtained on two distribution networks with different scale, 18-bus and 95-bus, are presented and discussed.

[1]  M.E. Baran,et al.  A branch-current-based state estimation method for distribution systems , 1995 .

[2]  Timothy C. Green,et al.  Optimal power flow for autonomous regional active network management system , 2009, 2009 IEEE Power & Energy Society General Meeting.

[3]  A. Abur,et al.  Effect of Phasor Measurements on the Choice of Reference Bus for State Estimation , 2007, 2007 IEEE Power Engineering Society General Meeting.

[4]  Jen-Hao Teng,et al.  A highly efficient algorithm in treating current measurements for the branch-current-based distribution state estimation , 2001 .

[5]  Paolo Attilio Pegoraro,et al.  Harmonic Source Estimation in Distribution Systems , 2011, IEEE Transactions on Instrumentation and Measurement.

[6]  J. Teng,et al.  Distribution system state estimation , 1995 .

[7]  Paolo Attilio Pegoraro,et al.  Branch current state estimator for distribution system based on synchronized measurements , 2012, 2012 IEEE International Workshop on Applied Measurements for Power Systems (AMPS) Proceedings.

[8]  Paolo Attilio Pegoraro,et al.  On the uncertainty evaluation in distribution system state estimation , 2011, 2011 IEEE International Conference on Smart Measurements of Future Grids (SMFG) Proceedings.

[9]  Paolo Castello,et al.  Impact of the Model on the Accuracy of Synchrophasor Measurement , 2012, IEEE Transactions on Instrumentation and Measurement.

[10]  N.N. Schulz,et al.  A revised branch current-based distribution system state estimation algorithm and meter placement impact , 2004, IEEE Transactions on Power Systems.

[11]  Tevfik Sezi,et al.  Distribution system state estimation using unsynchronized phasor measurements , 2012, 2012 3rd IEEE PES Innovative Smart Grid Technologies Europe (ISGT Europe).

[12]  Bikash C. Pal,et al.  Choice of estimator for distribution system state estimation , 2009 .

[13]  Thomas E. McDermott,et al.  Including voltage measurements in branch current state estimation for distribution systems , 2009, 2009 IEEE Power & Energy Society General Meeting.

[14]  J. Thorp,et al.  Real Time Voltage-Phasor Measurements for Static State Estimation , 1985, IEEE Power Engineering Review.

[15]  Paolo Attilio Pegoraro,et al.  Robustness-Oriented Meter Placement for Distribution System State Estimation in Presence of Network Parameter Uncertainty , 2013, IEEE Transactions on Instrumentation and Measurement.

[16]  Ke Li,et al.  State estimation for power distribution system and measurement impacts , 1996 .

[17]  J.-H. Teng.  Using voltage measurements to improve the results of branch-current-based state estimators for distribution systems , 2002 .

[18]  A. W. Kelley,et al.  State estimation for real-time monitoring of distribution systems , 1994 .