Parallel Perturbed Gauss-Newton State Estimator Based on Fortescue Transformation for Unbalanced Power Systems

Abstract

This letter extends the complex-variable perturbed Gauss-Newton method to estimate the state of unbalanced power systems by exploiting the Fortescue transformation. It proposes a novel and efficient graph-based way to deal with singularities due to zero-sequence network parts bounded with delta transformer windings and isolated from the ground. The estimator can handle both phasor and complex power measurements. Compared with the standard complex-variable unbalanced state estimator, it achieves better numerical stability and a speed-up of around three times using a sequential implementation and five times using parallel execution.

A Survey of Power System State Estimation Using Multiple Data Sources: PMUs, SCADA, AMI, and Beyond

“…In addition to these major challenges introduced by incorporating multi-type measurements, many other issues are also interesting and worth investigation in DSSE. Examples include unbalanced three-phase DSSE decoupling to enhance the SE execution efficiency, such as the use of Fortescue transformation [165]- [168], the treatment of different load connections (delta/wye) and transformer connections (delta/wye, lagging/leading, grounded/ungrounded) in multi-phase unbalanced DSSE [165]- [166], [169]- [171], etc. As these issues are not strongly related to the main subject of this survey paper, they are not discussed in detail in this section.…”