The PQ-Box 300 features the ability to measure and report up to the 3,400th harmonic voltage - way beyond the traditional 50th harmonic that most utilities PQ devices are capable of measuring. It was built in response to the need to see what effect modern PV inverters and EV chargers have on the power system. Not everyone needs that capability of measurement – but serious consideration should be given to use of PQ recorders with more than the traditional 10 kHz sampling /50th harmonic measurement capability.
The risk of using a PQ logger with lower sampling speed is that the device is not going to show you high-order effects that may be present on your network. You will get a ‘filtered’ view, not showing the true picture of what equipment on your network is actually being subjected to.
As a picture is worth a thousand words, the image below shows results obtained from monitoring the same power supply (at the same time) with a 10 kHz sampling device (the PQ-Box 100, with 50th harmonic capability) and a 40 kHz sampling device (the PQ-Box 200 with 200th harmonic capability). [Unfortunately a PQ-Box 300 was not available at the time this comparison was undertaken].
PQ-Box 100 shows a pure sine wave.
PQ-Box 200 shows sine wave distortion.