FFNet: An automated identification framework for complex power quality disturbances

• We construct FFNet framework that can automatically identify complex PQD. • FFNet can fuse multiple features and has a high time-frequency resolution. • The PQD classification accuracy of FFNet can reach 99.47% in 20 dB noise level. Effective identification of complex power quality (PQ) disturbances is the premise and key to improve power quality issues in the current complex power grid environment. However, the influx of nonlinear loads and impact loads makes power system disturbance signals distorted and complex, which increases the difficulty of PQ disturbances identification. To address this issue, this work presents a novel feature fusion network (FFNet) for the automated detection and classification of complex PQ disturbances. Firstly, an adaptive double-resolution S-transform (ADRST) algorithm is proposed for PQ disturbance time-frequency analysis. The adaptive window parameters optimization method is developed in ADRST to improve time-frequency resolution based on energy concentration maximization. Next, an improved convolutional neural network (CNN) method is presented for feature automatical extraction and multiple disturbances classification. Integrating ADRST and improved CNN, a classification framework called FFNet is further proposed to identify various complex PQ disturbances. Finally, experiment cases based on simulation and experimental PQ signals are conducted, where the results demonstrate that the classification accuracy of proposed framework can reach 99.47% even in 20 dB noise level.