Enhanced State Estimation by Advanced Substation Monitoring

1
Enhanced State Estimation by Advanced Substation
Monitoring

• PIs A. Abur M. Kezunovic
• Assistants S. Zhong S. Jakovljevic
• Texas AM University

PSerc Review Meeting College
Station, March 22, 2002
PSERC
2
Outline

• Introduction
• Statement of Work
• Project Status
• Computer Demos
• Conclusions

3
Introduction

• Project Objectives
• Improved state estimation
• Utilization of substation IEDs
• Technical Approach
• Merge information from substation into central
  state estimation
• Expected Results
• Prototype software for demonstration of the
  concepts

4
Statement of Work

• Two stage state estimator
• Formulation, implementation testing
• Substation state estimator
• Matlab based simulator development
• Three phase estimation
• Study effects of unbalances on the state
  estimate develop new solution algorithm
• Documentation of results

5
Project Status

• Prototype two-stage state estimator is
  implemented and being tested.
• Substation state estimator is implemented in
  Matlab and being tested.
• A new three phase estimator algorithm is
  developed and a prototype is implemented.
• Utility data for testing are missing.
• Actual topology error scenarios are missing.

6
Computer Demos
CB/Switch Status Info
Suspect Topology Error ?
1.Stage State Estimator
Analog Measurements
N
2.Stage State Estimator
Y
Substation Measurements
Next Scan
Estimated Status of CB/Switches
Substation State Estimator
7
Computer Demos

• Processing of Substation Measurements
• Verification of circuit laws
• Symmetrical components and balanced voltages
  check
• Branch status determination
• Consistency check of branch current values and
  topology data
• Time series consistency check

• Use of Matlab/Simulink
• Time domain simulator
• Multi or single phase models
• Consistent with the external operating
  conditions

Substation Measurements
Substation State Estimator
8
Computer Demos
CB/Switch Status Info
Suspect Topology Error ?
1.Stage State Estimator
Analog Measurements
N

• LAV Estimator
• Automatic rejection of BD
• Normalized residuals of rejected measurements
• Selection of suspect substations

Next Scan
9
Computer Demos

• Modified LAV Estimator
• Substation Model with CBs
• Flows through CBs
• Zero injections at inter. nodes

CB/Switch Status Info
Analog Measurements
2.Stage State Estimator
X
Substation Measurements
Estimated Status of CB/Switches
Augmented State
10
Conclusions

• Substation measurement processor is a valuable
  tool to enhance the SE and to monitor other
  substation functions.
• Topology error identification is demonstrated via
  the prototype software.
• Substation and central SE should still be
  integrated.
• Actual scenarios and network data are missing for
  testing the software.
• New 3-phase estimator can be implemented by using
  existing 1-phase estimators.