3 Protection and measurement functions
3.4 Power and energy measurements
22 PXR Electronic trip unit 01/21 MN012005EN www.eaton.com
3.4 Power and energy measurements
The following power and energy values can be measured.
Table 13: Power and energy measurements
The power and energy values are calculated and updated internally at a
frequency of 1 Hz.
Measurement
1)
Unit of
measure
Note
Power measurement
Active power kW Updated after approximately 1 second
Apparent power kVA Updated after approximately 1 second
Reactive power
kvar Updated after approximately 1 second
Active power requirement kW Fixed window of 5 to 60 minutes
Apparent power requirement kVA Fixed window of 5 to 60 minutes
Reactive power requirement
kvar Fixed window of 5 to 60 minutes
Active power requirement (peak)
kW Value is held until reset
Apparent power requirement (peak) kVA Value is held until reset
Reactive power demand (peak) kvar Value is held until reset
Power factor – Updated after approximately 1 second
Energy measurement
Active energy (forward) kWh From the source to the load
Active energy (reverse) kWh From the load to the source
Net active energy kWh “Active energy (forward)” - “active energy (reverse)”
Total active energy
kWh “Active energy (forward)” + “active energy (reverse)”
Apparent energy kVAh
Reactive energy (forward) kvarh From the source to the load
Reactive energy (reverse) kvarh From the load to the source
Net reactive energy kvarh “Reactive energy (forward)” - “reactive energy (reverse)”
Total reactive energy kvarh “Reactive energy (forward)” + “reactive energy (reverse)”
1) Accuracy: Class 1 (derived from IEC61557-12)