Abstract: Nonvolatile memory and random access memory（RAM） are two major types of memory used in relay protection devices. Both types of memory could have unexpected bit changes（single event effect） which lead to key data loss, abnormal program operation, maloperation, and device function failure. A scheme of real-time monitoring and recovery is designed to deal with unexpected bit changes in RAM, which can avoid function failure of relay protection devices. In addition, a redundant reinforcement method for file storage is designed to deal with unexpected bit changes in nonvolatile memory, which eliminates the influence of unexpected bit changes in nonvolatile memory on relay protection devices. The proposed scheme is verified by the spallation neutron test and applied to extra-high voltage relay protection devices operating in power grids, which proves the effectiveness of the scheme.