The standards for harmonic current testing mainly include the following:
international standard
·IEC 61000-3-2: Electromagnetic compatibility (EMC) Part 3-2, specifies limits - Harmonic current emission limits (equipment input current ≤ 16A/phase). This standard classifies equipment into four categories: A, B, C, and D, and sets different harmonic current limits for different categories of equipment.
·IEC 61000-3-4: Applicable to equipment with a rated current greater than 16A.
·IEC 61000-3-12: Applicable to equipment with a rated current greater than 16A and less than 75A.
Domestic standards
·GB 17625.1-2022: Electromagnetic compatibility limits Part 1: Harmonic current emission limits (equipment input current per phase ≤ 16A). This standard was released on December 29, 2022 and implemented on July 1, 2024. It specifies the harmonic current emission limits generated by equipment operating in public low-voltage distribution systems.
Test exemption requirements
·Electrical and electronic equipment not connected to the public low-voltage distribution system: exempt from testing.
·Electronic and electrical equipment with a nominal voltage of DC power supply: not within the testing range.
·Electrical and electronic equipment with a nominal voltage less than AC 220V: enjoys exemption.
·Lighting equipment with a rated power of less than 5W: exempt from testing.
·Electronic and electrical equipment with a rated power of 75W or less (excluding lighting equipment): exempt from testing.
·Professional equipment with a total rated power greater than 1kW does not require harmonic current testing.
Test classification and limit values
·Class A equipment: Equipment not designated as Class B, C, or D should be considered Class A equipment, such as three-phase balancing equipment, household appliances (excluding appliances designated as Class B, C, or D), vacuum cleaners, high-pressure cleaning machines, etc. The harmonics of its input current should not exceed the limits specified in the standard.
·Class B equipment: such as portable tools, non professional arc welding equipment, etc. The harmonics of its input current should not exceed 1.5 times the corresponding harmonic value of Class A equipment.
·Class C equipment: such as lighting equipment. For lighting equipment with actual input active power greater than 25 watts, its harmonic current shall not exceed the relative limit given in the standard. For lighting equipment with a rated power between 5W and 25W, specific harmonic current limits or waveform requirements must be met.
·Class D devices: such as devices with a power of less than or equal to 600W (personal computers and personal computer monitors, TV receivers, etc.). The harmonic current limit is also clearly defined.
test method
Harmonic current testing usually uses instruments such as harmonic analyzers and power quality analyzers for measurement. The testing range is generally between 2nd and 40th harmonics. During testing, it is necessary to connect the sample to the testing equipment, use software to read harmonic current data, and compare it with the standard limit to obtain the results.
Guangdong Zhonghan Testing Technology Co., Ltd