Abstract : With the widespread application of frequency converters in industrial production, the problem of harmonic interference from power grids has become increasingly important. This paper analyzes the harmonic interference in the application of frequency converters in power grids, proposes specific countermeasures for suppressing harmonic interference and solutions to practical problems, reflecting the significant economic and social value of studying the suppression of harmonic interference from frequency converters. Keywords: power distribution system; frequency converter; harmonic interference; analysis and measurement; suppression countermeasures 1 Introduction Motor systems driven by frequency converters are increasingly used due to their significant energy-saving effects, convenient adjustment, simple maintenance, and networking capabilities. Especially in recent years, with the continuous promotion and application of agricultural water-saving irrigation technology, frequency converters have been widely adopted as starting and speed-regulating equipment in the sprinkler and drip irrigation pumping stations of Aksu counties and townships and the First Agricultural Division of Alar City. However, the interference caused by the special working mode of frequency converters is becoming increasingly significant. The main types of interference from frequency converters are: ① Frequency converters commonly use nonlinear rectifier devices such as thyristors or rectifier diodes, which generate harmonics that will conduct interference to the power grid, causing voltage distortion (the voltage distortion rate is expressed as THDv, and the THDv caused by harmonics generated by frequency converters is around 10-40%), affecting the power supply quality of the power grid. ② The output section of frequency converters generally uses switching devices such as IGBTs, which will generate strong electromagnetic radiation interference on the output line while outputting energy, affecting the normal operation of surrounding electrical appliances. [b]2 Mechanism of harmonic generation from frequency converters 2.1 Types of harmonic sources in power distribution systems 2.1.1 Harmonic sources containing semiconductor nonlinear components[/b] UPS power supplies, DC power supplies, frequency converters, soft starters, gas discharge lamps, electronic ballasts, DC power supplies for household and office appliances, thyristor dimmers, AC voltage regulators, and other power electronic devices. The harmonic currents generated by these devices depend on their own characteristics, operating conditions, and the voltage applied to them, and are not significantly related to the parameters of the power system. The harmonic currents they generate are mainly odd harmonics, and are also the main harmonic sources in the power distribution system. [b][align=center]For more details, please click: Harmonic Interference and Suppression Countermeasures in Frequency Converter Applications[/align][/b]