I'm analyzing power quality in low and medium voltage facilities (50/60Hz; 0.48 - 69 kV; factories, campuses, etc.) while trying to apply existing standards wherever possible. In addition to demand metering the main PQ metrics I'm tracking are:
- Voltage levels
- Harmonics
- Phase imbalance
- Power factor
While it's easy-ish to find a number that IEEE or IEC uses as a standard, it's harder to find how that number is specifically calculated. For instance, 0.8-0.85 is often cited as a minimum acceptable power factor for C&I facilities, but what value does that minimum apply to? The mean over an hour? The minimum instantaneous measurement that month? For most PQ measurements this specification is very hard to find.
I did find this detailed description of applying IEEE 519 to harmonics data which was great. They recommend testing 95th/99th percentile values daily and weekly. Are there detailed processes like that for the other metrics listed above? If not, any recommendations on what makes most sense to track for C&I facilities?
