Improvement of stability analysis and assessment through wavelet decomposition

In an effort to improve the overall transient stability assessment process, this paper presents an enhancement of the Extended Ward Equivalent (EWE) model combined with a proposed level of signal processing and analysis. Due to the characteristic deviation of elements of the EWE model, the reduced network cannot be fully represented in a suitable form for transient stability studies. By employing the proposed Wavelet decomposition method along with the reduction procedure, it has been demonstrated that the stability analysis output can be improved considerably, thereby providing the level of accuracy required for offline system planning. This approach has been designed in line with the operational practices of the GB Transmission System Operator (TSO), National Grid and tested on the full dynamic offline model in DigSilent PowerFactory.