“…The BPNN model is the most popular one among various neural network algorithms and has been widely employed in different fields of fault diagnosis, such as power electronic system [34], transformer [35], battery [36,37], photovoltaic systems [38,39], etc. However, the BPNN model still has some intrinsic defects, for example, slow convergence speed and over-fitting problem [40][41][42][43]. Fortunately, a large collection of optimization algorithms have been developed to optimize the BPNN model, such as GA [44,45], MEA [46], particle swarm optimization (PSO) [47,48], simulated annealing (SA) [49], bat algorithm (BA) [50,51], etc.…”