Full explanation
Causes of high THD: (1) cheap solar inverters with simple PWM circuits; (2) variable-frequency drives on pumps and fans; (3) switched-mode power supplies; (4) unfiltered LED lighting. Negative effects: (1) motors overheat by 10–30°C; (2) UPS and protective breakers misoperate; (3) higher grid losses; (4) electronics glitches — breakers, scales, milking parlours, combine PLCs. Measurement: Fluke 1735, HIOKI PW3198 professional power analyzers, USD 4–12k. Mitigation: (1) quality inverter (Fronius, SMA, Huawei <3% THD), (2) Active Power Filter (APF); (3) LC filter on the grid input. DSTU EN 50160:2014 defines public electricity-supply quality in Ukraine — if the local oblenergo supplies THD >8%, the farmer can demand compensation or obenergo-funded filter installation.