Distributed Robust Power System State Estimation
This work addresses the need for scalable and privacy-respecting state estimation in power systems, offering a practical solution for grid operators, though it is incremental as it builds on existing PSSE solvers and compressive sampling techniques.
The paper tackles the challenge of implementing centralized power system state estimation (PSSE) in large-scale grids by developing a distributed algorithm based on the alternating direction method of multipliers, which achieves accuracy comparable to centralized methods within a few inter-area exchanges and outperforms largest residual tests in simulations on IEEE benchmarks up to 4,200 buses.
Deregulation of energy markets, penetration of renewables, advanced metering capabilities, and the urge for situational awareness, all call for system-wide power system state estimation (PSSE). Implementing a centralized estimator though is practically infeasible due to the complexity scale of an interconnection, the communication bottleneck in real-time monitoring, regional disclosure policies, and reliability issues. In this context, distributed PSSE methods are treated here under a unified and systematic framework. A novel algorithm is developed based on the alternating direction method of multipliers. It leverages existing PSSE solvers, respects privacy policies, exhibits low communication load, and its convergence to the centralized estimates is guaranteed even in the absence of local observability. Beyond the conventional least-squares based PSSE, the decentralized framework accommodates a robust state estimator. By exploiting interesting links to the compressive sampling advances, the latter jointly estimates the state and identifies corrupted measurements. The novel algorithms are numerically evaluated using the IEEE 14-, 118-bus, and a 4,200-bus benchmarks. Simulations demonstrate that the attainable accuracy can be reached within a few inter-area exchanges, while largest residual tests are outperformed.