EFFECTS OF LIGHTNING STRIKES ON CIRCUITS

Energy Meter Test Bench is one of our products. Let me introduce to you the influence of lightning strike on the circuit.

　　The factors affecting the safety of transmission lines can be roughly divided into two categories, namely, wear and aging caused by the accumulation of daily time and sudden failures caused by external factors. Both of these two factors can cause fault tripping, interrupt the power supply operation, and in severe cases, the power grid can be paralyzed. Among them, the time accumulation factor can be controlled manually, and the probability of causing failure is extremely small, while the external environmental meteorological factors (including lightning strikes, typhoons, wildfires, ice damage, pollution, temperature and humidity, air pressure, bird damage, etc.) are uncontrollable. The probability of causing failure is extremely high and the destructive power is large.

　　Thunder and lightning weather are common in the rainy season, and the randomness is large. A large number of transmission lines erected in the field have the characteristics of large span of towers and large height difference, which makes the lightning resistance level of the lines relatively poor and easy to be struck by lightning. In bad terrain, there are many single-circuit lines, and there is no shielding and shunt protection provided by parallel lines, which increases the incidence of lightning strikes. Lightning tripping accounts for the largest proportion of transmission line faults, and the lower the voltage level, the higher the lightning strike failure probability.

　　When lightning discharges, the charge of the cumulonimbus cloud layer accumulates, forming a strong electrostatic high-voltage electric field, which collides and neutralizes with a large number of negative charges carried by the earth, and releases high energy, the voltage can be as high as several million volts, and the current can be as high as several thousand amperes, resulting in The overvoltage wave has a high steepness and a large amplitude, causing the line insulation flashover trip. Flashover tripping is an instantaneous fault, the reclosing action has a high success rate, and the conductive path can be restored, but in severe cases, it will lead to line disconnection, insulator breakage, or intrusion into the substation along the line, high temperature fuse wires, threatening to damage the insulation strength of power equipment .

　　In order to reduce the probability of lightning accidents on transmission lines, it is necessary to prevent flashover, arc construction, direct strike, and line interruption of power supply. The following protection measures are adopted: ①Establish lightning protection wire; ②Add coupling ground wire; ③Reduce the impact grounding resistance of the tower; ④Use the neutral point indirect grounding system; type arrester; ⑧ using unbalanced insulation, dual-circuit ring network power supply and other methods.

　　Three-phase Reference Standard Meter is also one of our products, welcome to visit our website!