There is a multidimensional nonlinear relationship between the breakdown voltage of air gap and the electric field features before discharge inception. We established a prediction model by support vector classifier（SVC）. Taking 28 electric field features as the input of the SVC

and the output parameters as-1 and 1

respectively

we characterized whether the gap would withstand or breakdown under an applied voltage.Selecting 9 samples by the orthogonal design principle

we used the samples to train the SVC model.The hybrid prediction of the power frequency breakdown voltages of short air gaps including sphere-sphere

rod-plane and rod-rod geometries was successfully realized. The mean absolute percentage error（MAPE） of the predicted results of 72 test samples is only 2.39%. The power frequency breakdown voltages of sphere-plane

rod-sphere and big sphere-small sphere gaps were predicted. The predicted results are basically in accordance with the experimental values and the MAPEs are respectively 1.75%

2.78%

and 4.57%

which verifies the validity and generalization performance of the prediction method.