▷In general, overvoltage protectors are used to protect against power frequency overvoltages. Power frequency overvoltages often occur during operation, such as when the arc is disconnected before the switch crosses zero, or when the circuit is disconnected due to the superposition of voltage reflection waves caused by different circuit wave impedances. These overvoltages are all power frequency overvoltages, meaning that the frequency of their voltage waveform remains unchanged at 50Hz.
▷A lightning arrester is used to protect against lightning overvoltage. The waveform of this overvoltage is steep at the front end and has a high frequency, but the subsequent current is small. The lightning arrester can release the peak value of the lightning wave to ensure the safety of the electrical appliances behind it.
▷Lightning arrester is a short-circuit discharge device after overvoltage, while overvoltage protector is an overvoltage disconnect protection device. So which of these two has better protection performance against lightning overvoltage and operational overvoltage? Lightning arresters can discharge lightning overvoltage and protect lines and equipment.
▷Overvoltage protectors can provide protection against operating overvoltage.
▷Overvoltage protectors and lightning arresters both have the function of suppressing overvoltage protection of electrical equipment.
▷Overvoltage in the power system:
Temporary overvoltage (power frequency overvoltage, resonant overvoltage);
Operating overvoltage;
Lightning overvoltage.
▷The effectiveness of overvoltage protectors in suppressing lightning overvoltage depends on their design parameters.
▷Lightning arresters are not only used for protecting against lightning overvoltage. Surge arresters, also known as overvoltage protectors in power systems, are now commonly used as zinc oxide surge arresters (MOA). An overvoltage protector disconnects the power supply when the voltage exceeds the set value, providing protection.
▷When a lightning arrester is struck, it directly introduces high voltage and high current into the grounding system and disconnects the power supply to avoid the high voltage impact caused by lightning.
▷Overvoltage can be divided into external overvoltage and internal overvoltage. Internal overvoltage refers to operational overvoltage, and overvoltage protectors can not only solve external lightning overvoltage but also internal overvoltage, while lightning arresters can only solve external overvoltage.