Surge voltage and impulse voltage are both types of transient overvoltages that can occur in electrical systems, but they differ in their characteristics, causes, and effects:
Surge Voltage:
Surge voltage, also known as voltage surge or transient voltage, is a temporary and sudden increase in voltage that exceeds the normal operating voltage level of the system.
Surges are typically caused by external factors such as lightning strikes, switching operations, or power system disturbances.
Surge voltages can have various waveforms, including oscillatory waves, damped oscillatory waves, and transient waves, depending on the source and characteristics of the disturbance.
Surge voltages can cause damage to electrical equipment, insulation breakdown, and disruption of power systems if not adequately protected against.
Impulse Voltage:
Impulse voltage, also known as lightning impulse voltage or lightning surge voltage, is a high-voltage pulse with a fast rise time and short duration.
Impulse voltages are primarily caused by lightning strikes or switching operations in high-voltage power systems.
Impulse voltages have specific waveform characteristics, typically characterized by a rapid rise time (nanoseconds to microseconds) and an exponential decay.
Impulse voltages can cause insulation breakdown, flashover, and damage to electrical equipment due to the high peak voltage and energy content of the impulse waveform.
In summary, the main differences between surge and impulse voltage lie in their waveform characteristics, causes, and effects. Surge voltage refers to temporary increases in voltage that exceed the normal operating voltage level and can have various waveforms, while impulse voltage refers specifically to high-voltage pulses with fast rise times and short durations typically caused by lightning strikes or switching operations. Both surge and impulse voltages pose risks to electrical systems and equipment and require appropriate protection measures to mitigate their effects.