PSERC Project PSERC Project Power System State Estimation and Optimal Measurement Placement for Distributed Multi-Utility Operation A. Abur and G.M. Huang (PIs) J. Lei and B. Xu (Students) Texas A&M University

Outline  Objectives  Technical Approach  Implementation  Results  Conclusions

Objectives  Optimal Meter Placement  FACTS Device Monitoring  Distributed State Estimation

Technical Approach  Three step meter placement – Choice of the minimum set – Choice of candidates – Optimal selection from candidates  FACTS device monitoring – Modeling with constraints – Incorporation into SE

Meter Placement Problem  Choice of Essential Measurements Set. – If the system is observable: Factorize H matrix – Else: Run LAV estimator  Candidate Identification – Form Contingency–Measurement incidence matrix  Optimal Candidate selection – Use of integer programming

Contingencies Types of Contingencies :  Line Outage  Measurement Loss  Bus Split Robustness Options:  Against user defined contingency list  Bad data Detectability  All single line outages

Graphic User Interface Add injections at bus 3 and 4

FACTS Device Monitoring UPFC Modeling :  Two V-source model  Four parameters  Constraints Integration into the SE:  Use Hachtel’s formulation  Inequality and equality constraints

Model of UPFC  Physical Model of UPFC

Model of UPFC  Steady State Model of UPFC The constraint P B + P E = 0 implies that no real-power is exchanged between the UPFC and the system.

Measurements  Real and reactive power through k-m

Constraints  Equality and inequality constraints of UPFC V B, θ B, V B and θ B are the control parameters of UPFC

Hachtel ’ s Method

 KKT first order optimality conditions :

Example From (bus)To (bus)XBXB XEXE V B,max V E,max S B,max S E,max Parameters of the installed UPFC device  FACTS device (UPFC) is installed on line 6-12, near bus 6

Estimation Results  Function of the program as an estimator  Function of the program as a power flow controller Note that P B + P E = 0 and V B < 1.0, V E < 1.0, S B < 1.0, S E < 1.0, which correctly satisfy all the constraints. Voltages and powers of UPFC Set power flow in line 6-12 to be j0.1 Voltages and powers of UPFC VBVB θBθB PBPB SBSB VEVE θEθE PEPE SESE VBVB θBθB PBPB SBSB VEVE θEθE PEPE SESE

Conclusions  Optimal meter placement accounting for contingencies and loss of measurements  State estimation of systems with FACTS devices and their parameters  Setting of parameters of FACTS devices for desired power flows