Tuesday April 7th, 2020 6:44am, exactly one month after the previous grid level power quality event, we experienced another voltage sag affecting customers throughout the region. Transmission line voltage sagged to less than 68% of normal for 3.5 cycles, or about 58 milliseconds. This sag was captured in Oakland, San Francisco, and San Jose.
As before, customers reported several impacts from this widespread voltage sag on their sensitive loads and equipment. No root cause has yet been identified.
Especially when you are short staffed or not in your office, APT helps customers detect and prevent utility failures like this before they happen and capture the power quality data when they do. Understanding the changes in power is the first step, and surprisingly cost effective.
If this information is useful, please subscribe to APT’s power quality blog to be notified when this happens in the future.