POWER SYSTEM TIME SYNCHRONIZATION DEVICE AND METHOD FOR SEQUENCE OF EVENT RECORDING

摘要

The invention relates to the field of power distribution systems and more particularly to power monitors within such a system. A time synchronization device and method for synchronizing an internal clock of the power monitor to a periodically stable frequency is provided. Cycles of the periodically stable frequency are counted after each elapse of a predetermined time period. The elapse of the predetermined time period defines a present window and a previous window. A counting error and a change in counting error are calculated, wherein the change in counting error is the difference of a counting error calculated for the present window and a counting error calculated for the previous window. The present method detects when a change in counting error is within a predetermined range. When the counting error is within the predetermined range, the internal clock of the power monitor is adjusted to the line frequency according to the counting error calculated for the present window.