In many oil and gas fields throughout the world, power quality remains a major concern causing many up-time reliability issues. At times, the power supply can be “glitchy” and momentarily loses 3 Phase power to the Variable Speed Drive. The Instruct in many cases reports a trip event commonly shows up as Sys ON (x4) Power Unstable Guard. This fault could also be masked as a VSD communication fault.
See below typical log entry where such power “glitch” occurs.
Refer to PDF for full details and the new firmware that helps with these power glitches.