Views: 0 Author: Site Editor Publish Time: 2023-08-28 Origin: Site
Surge, as the name implies, is an instantaneous overvoltage exceeding the normal working voltage, known as transient pulse voltage, transient overvoltage, surge or surge, etc. A violent pulse usually lasting about one millionth of a second. A voltage fluctuation of 5KV or 10KV that lasts for an instant (one millionth of a second) in the 220v circuit system is a surge or transient overvoltage.According to statistics, in the United States: the direct losses caused by power surges to various industries, such as production stoppage, time loss, equipment maintenance, and premature replacement of equipment, are as high as 26 billion U.S. dollars per year. In China, according to relevant statistics, problems occur during the warranty period, 63% of all electrical products are generated due to power surges.
Induced lightning surge overvoltage: The rapidly changing electromagnetic field generated by lightning strikes and lightning, the electric field radiated by lightning acts on the conductor, and induces a high overvoltage. This type of overvoltage has a very steep front and decays rapidly.
Direct lightning strike and surge overvoltage: directly falling lightning on the power grid, due to the huge instantaneous energy and strong destructive power, there is no device that can protect the direct lightning strike.
Lightning conduction surge overvoltage: It is conducted from distant overhead lines. Since the equipment connected to the power grid has different suppression capabilities for overvoltage, the conduction overvoltage energy is weakened with the extension of the line.
Oscillating surge overvoltage: the power line is equivalent to an inductance, and there is distributed capacitance between the earth and adjacent metal objects, forming a parallel resonant circuit. In TT and TN power supply systems, when a single-phase ground fault occurs, due to the high-frequency components resonate and generate high overvoltage on the line, which mainly damages the secondary instrument.
If during the test, the residual voltage of the surge is too high, resulting in damage to the equipment under test, you can add a level of protection behind the common mode coil (inside the red dotted line), and the selection of devices can be the same as the previous level，you can also choose pressure-sensitive and gas discharge tubes with a slightly smaller flow rate to save costs.
