Wide area measurement systems based Power System State Estimation using a Robust Linear-Weighted Least Square method

Abstract

The accuracy and robustness of Power System State Estimation (PSSE) are paramount for monitoring and surveillance of Energy Management Systems (EMS). To enhance the PSSE accuracy, phasor measurement units (PMUs) are widely used in Wide-area measurement systems (WAMS). The essential aspects of enhancing PSSE accuracy are systems observability and redundancy. These can be accomplished through an optimal PMU placement strategy. Iterative-based algorithms for estimating power system states using PMU and traditional Supervisory Control and Data Acquisition (SCADA) measurements face challenges such as non-linearity and lack of convergence. In this paper, a Robust Linear Weighted Least Square (RLWLS) estimator is proposed by combining conventional SCADA data with phasor measurements. Further, The RLWLS state estimator overcomes the issues mentioned above. Extensive simulations on various test systems, including traditional IEEE 14, 30, 57, and IEEE-118 bus systems and the real-time Indian Northern Region Power Grid (INRPG)-246 bus system in India, have shown to prove the resilience of this technique. Finally, compared to the prior PSSE approaches, the RLWLS methodology significantly improves the efficacy and performance of the state estimate solution.

Keywords

• Optimal PMU placement
• Redundancy
• Weighted least square
• Power system state estimation
• Accuracy