Hybrid protection algorithm for power system with renewable energy generation using Stockwell transform and Wigner distribution function.

Rapid technological development in grid integration of renewable energy (RE) plants has increased the RE penetration level in power utility network. This dramatic change in power scenario challenges the protection and stability of grid. Therefore, this work proposed a protection scheme algorithm (PSA) for the RE integrated hybrid power system. This PSA is implemented in the following steps: (1) calculate Wigner distribution function powered fault index (WFI), (2) calculate Stockwell transform powered combined FI (SCFI), (3) calculate hybrid FI (HFI) using WFI and SCFI, (4) classify the faults using number of faulty phases and fault ground index. Proposed hybrid fault index is used for the identification of faults. It also considers the change in magnitude and waveform distortions of current signals. The proposed PSA effectively identifies and classifies the faulty events such as single phase to ground, two phase, two phase to ground and all phases to ground. PSA is successfully tested for the recognition of faults under various operating scenarios like noisy scenario, different magnitudes of fault impedance, fault location node and fault incidence angle, lines comprising of overhead section and underground cable with availability of transformer. This PSA is effective to discriminate the operational switching events compared to faulty events. It is concluded that performance of the introduced PSA is better and fault detection time is less compared to wavelet energy spectrum entropy based PSA, discrete wavelet transform (DWT) based PSA and Stockwell transform supported PSA. [ABSTRACT FROM AUTHOR]