本指南描述了低压[高达1000 V均方根（rms）]交流电源电路中的浪涌电压、浪涌电流和TOV环境。该范围不包括其他电源干扰，如凹口、凹陷和噪声。本指南中考虑的浪涌持续时间不超过正常电源波形（基频）的一半。它们可以是周期性或随机事件，可以出现在线路、中性线或接地导体的任何组合中。它们包括振幅、持续时间或变化率足以导致设备损坏或操作混乱的浪涌（见图）。虽然主要作用于电压幅值的浪涌保护器（SPD）通常用于转移破坏性浪涌，但扰乱性浪涌可能需要其他补救措施。本指南中关于喘振环境的说明中包含TOV的基本原理如所示。

This is a guide describing the surge voltage, surge current, and TOV environment in low-voltage [up to 1000 V root mean square (rms)] ac power circuits. This scope does not include other power disturbances, such as notches, sags, and noise. The surge considered in this guide do not exceed one-half period of the normal mains waveform (fundamental frequency) in duration. They can be periodic or random events and can appear in any combination of line, neutral, or grounding conductors. They include surges with amplitudes, durations, or rates of change sufficient to cause equipment damage or operational upset (see Figure ). While surge protective devices (SPDs) acting primarily on the amplitude of the voltage are often applied to divert the damaging surges, the upsetting surges may require other remedies. The rationale for including a description of TOVs in this guide on the surge environment is given in.