Early fault diagnosis method and device for electric vehicle charging facility

The invention discloses an early fault diagnosis method for an electric vehicle charging facility. The method comprises the steps of 1, scanning and counting three-phase current Ia, Ib and Ic, residual current Iah, Ibh and Ich and harmonic current Ir of a power-on pile leading to a three-phase switch circuit in a period in real time; 2, generating time sequence data of a charging process; step 3, carrying out data normalization processing; 4, calculating a feature sample of the charging process; step 5, calculating an average distance Kd between the current charging feature sample and k nearest neighbors of the first n feature samples in the statistical period by adopting a KNN algorithm; and step 6, comparing the Kd with a threshold value, and if the Kd is greater than the threshold value, giving an alarm. According to the invention, the charging pile can be pre-detected quickly. 本发明公开了一种电动汽车充电设施早期故障诊断方法，包括步骤1，实时扫描统计周期内的通电桩通向三相开关电路的三相电流Ia、Ib、Ic，剩余电流Iah、Ibh、Ich和谐波电流Ir；步骤2，生成一次充电过程的时序数据；步骤3，数据归一化处理；步骤4，计算本次充电过