The usual configuration involves monitoring all three voltage and current levels in the three lines and neutral. This is typical for three-phase current and voltage monitoring. There are two transformer stages to step the voltage down from the HV to the ADC input. The transformer stage closest to the ADC typically steps voltage down from 100V to +/-10V range. High channel count, simultaneous sampling ADCs with wide dynamic range are required. For the processor, low latency, fast FFT and filter processing, and Ethernet capability are important.