1.1.3 Rogowski Coil

Where:

60 Hz is the Rogowski coil scale factor at 60 Hz and it represents the coil sensitivity, measured in millivolts per ampere (mV/A) at 60 Hz.

Note: The scale factor K_Rogowski is defined at the reference frequency fr = 60 Hz because the Digital Integrator (DI) filter was designed for unity gain at 60 Hz. If it is desired to use K_Rogowski defined at another frequency, the gain of the DI filter must be accounted for in the computation as follows:

Where:

K_di(f) = 60 Hz/f

For example, a Rogowski coil is used with an output of 500 uV/A at 60 Hz (or 416.6 uV/A at 50 Hz) and a G_PGA = 4, then,

K_Rogowski(60 Hz) = 1000000 / 500 = 2000

K_lx = 2000 / 4 = 500

The metrology firmware uses uQ22.10 to represent both integer and fractional numbers; therefore, the value to set is:

K_lx = ROUND(500 * 2^10) = 0x007D000