A method for operating an electric power converter and an electric power converter configured to convert DC power into AC power supplied to a three-phase AC network, conclude, during the converting, that a single-phase tripping has started in the three-phase AC network connected to the three-phase output of the converter, and after the concluding that the single-phase tripping has started in the three-phase AC network, control an active current in the three-phase output of the converter such that a negative sequence voltage in the three-phase output of the converter remains at or below a predetermined level, wherein the converter is configured to perform the controlling until concluding that the single-phase tripping has ended in the three-phase AC network.