Locomotive main generator self-adaptive protection method

The invention discloses a locomotive main generator self-adaptive protection method. The method comprises the steps that S1, P1 and P2 are preset; S2, in a locomotive main generator running process, the excitation current value I1 of a main generator is detected in real time; and S3, according to excitation current value I1, protection control is carried out. According to the step of S3, if I1 is more than or equal to P1 and the duration of I1 does not reach preset time T1, the output power of the locomotive main generator starts to be reduced; if the duration of I1 does not reach T1 and I1 is less than P1, the main generator carries out normal power output; if the duration of I1 does not reach T1 and I1 is more than or equal to P2, pulse output is directly blocked, and an excitation current overcurrent fault is reported; and if the duration of I1 reaches T1 and I1 is more than or equal to P1, pulse output is blocked, and the excitation current overcurrent fault is reported. The method provided by the invention has the advantages of comprehensive protection, easy operation, high efficiency and the like.