12 WL Circuit Breaker Selection and Application Guide
Alarm parameters
The metering function includes the following alarm 
set-point functions:
Extended relaying
Protective relays included with the metering function can 
monitor the following criteria and initiate a trip if the values
are exceeded.
  Protective relay function   ANSI device number   Setting range   Possible delay 
  Current unbalance   46  5 ... 50%  1 ...15 s 
  Total harmonic distortion - current  81 THDC  0 ... 50%  5 ...15 s 
  Voltage unbalance   47  5 ... 50%  1 ...15 s 
  Undervoltage  27  100 ... 1100V   1 ...15 s 
  Overvoltage  59  200 ... 1200V   1 ...15 s 
  Total harmonic distortion - voltage  81 THDV  0 ... 50%  5 ...15 s 
  Direction of phase rotation  47N     
  Active power in normal direction  32  1 ... 10000kW  1 ...15 s 
  Active power in reverse direction  32R  1 ... 10000kW  1 ...15 s 
  Under frequency  81U  40 ... 70 Hz  1 ...15 s   
  Over frequency  81O  40 ... 70 Hz  1 ...15 s
  Alarm function  Setting range  Possible delay
  Overcurrent   3 ... 10000A   0 ... 255 s  
  Overcurrent – ground fault   3 ... 10000A   0 ... 255 s  
  Overcurrent – N-conductor   3 ... 10000A   0 ... 255 s  
  Phase unbalance – current   5 ... 50%   0 ... 255 s  
  Demand – current   3 ... 10000A   0 ... 255 s  
  Total harmonic distortion – current   0 ... 50%   5 ... 255 s  
  Undervoltage   100...1200V  0 ... 255 s  
  Overvoltage   200...1200V  0 ... 255 s  
  Phase unbalance – voltage   5 ... 50%   0 ... 255 s  
  Total harmonic distortion – voltage   0 ... 50%   5 ... 255 s  
  Crest factor   0.01 ... 25.5%  0 ... 255 s  
  Form factor   0.01 ... 25.5%  0 ... 255 s  
  Active power in normal direction   1 ... 10000kW   0 ... 255 s  
  Active power in reverse direction   1 ... 10000kW   0 ... 255 s  
  Leading power factor   -0.999 ... 1   0 ... 255 s  
  Lagging power factor   -0.999 ... 1   0 ... 255 s  
  Demand – active power   1 ... 10000kW   0 ... 255 s  
  Apparent power   1 ... 10000kVA   0 ... 255 s  
  Reactive power in normal direction   1 ... 10000kvar   0 ... 255 s  
  Reactive power in reverse direction   1 ... 10000kvar   0 ... 255 s  
  Demand – apparent power   1 ... 10000kVA   0 ... 255 s  
  Demand – reactive power   1 ... 10000kvar   0 ... 255 s  
  Underfrequency   40 ... 70 Hz   0 ... 255 s  
  Overfrequency   40 ... 70 Hz   0 ... 255 s 
WL Circuit Breaker
Electronic Trip Unit (ETU)
Courtesy of NationalSwitchgear.com