This part of GB/T 17626 is concerned with the immunity of electrical and electronic equipment in operation against non-repetitive fading oscillation transients (ringing waves) generated by low-voltage power supply, control and signal lines in public or non-public networks requirements and test methods. The purpose of this section is to establish immunity requirements and a common reference for evaluating the performance of electrical and electronic equipment in residential, commercial and industrial applications in the laboratory, and also applies to equipment in power stations and substations. The purpose of this section is to specify: - test voltage and current waveforms; - range of test levels; - test equipment; - test layout; - test process.