Patent ID: 9673619
Date: 2017-06-06
CPC Classifications: G01R,H02H

Claim:
1. A diagnostic method for a multiple-stage excess voltage protection apparatus, the excess voltage protection apparatus including: at least one gas discharge distance between an input and a reference potential as a first stage, at least one diode path between an output and the reference potential as a further stage, and at least one decoupling inductance interposed between the input and the output, the method comprising: measuring and evaluating a secondary voltage which is present at a secondary inductance, which is actively connected, inductively, to the decoupling inductance, and measuring and evaluating the secondary voltage with a view to excess voltage events in the excess voltage protection apparatus, wherein a derivative, with respect to time, of the secondary voltage is determined, and wherein a quotient of a maximum value of the derivative, with respect to time, and a maximum value of the secondary voltage is formed, the quotient is compared with values of a specification, and a signal is produced, when the quotient does not conform to specification.