Usually one year,this depends on time interval
Yes,you can find THD measurement in harmonic mode,range from 0% to 100%.
The operating time can up to 6 hours when the screen brightness is in level 3. The battery charge time is about 6 hours.
Class A Power Quality Analysers that must meet Class A performance requirements of IEC61000-4-30 international standard, when instruments are connected to the same signals will produce the same results. Class A instruments must meet the highest performance and accuracy requirements in this standard.
Class A defines the measurement time accuracy (better than +/- 0.3 sec/day) for parameters such as voltage, current and harmonics. With defined methods and measurement uncertainties for Power Supply Voltage, Flicker, Voltage Unbalance, Voltage and Current Harmonic.
Suin SA2200 power quality analyzer complies with the IEC61000-4-30 Ed. 3 Class A standard. So far, the certified by IEC62856-2 is being prepared and will made public once get this certification.