A method to prevent lightning counterattack of power distribution cabinet

Abstract

The invention discloses a method for preventing lightning counterattack of a power distribution cabinet, which belongs to the technical field of lightning protection of a power distribution cabinet. The method includes the following steps: setting an isolation transformer on the power supply line of the power distribution cabinet, There is a shielding layer between the primary winding and the primary winding; when the lightning strikes the fan, the ground potential of the lightning strike point rises, and the potential of the ground side of the power distribution cabinet below the fan rises with the rise of the ground potential; when the potential of the ground side of the power distribution cabinet rises , the high potential side of the power distribution cabinet rises synchronously; by setting the shielding layer to ground, and at the same time the power distribution cabinet is connected to the secondary winding, the voltage difference added to the equipment in the power distribution cabinet is always the power supply voltage, and the potential difference is constant, eliminating the ground grid Counterattack caused by high potential difference to avoid equipment damage. Through equipotential technology and reference potential floating technology, the potential reference point of the lightning strike point is the reference point of the power supply voltage, and the potential difference between the two ends of the equipment in the power distribution cabinet is constant, which solves the problem that the equipment in the cabinet is damaged due to lightning strikes.

Description

technical field [0001] The invention relates to the technical field of lightning protection of a power distribution cabinet, in particular to a method for preventing a lightning counterattack of a power distribution cabinet. Background technique [0002] With the rapid development of electric power construction, single power equipment is becoming larger and larger, and the impact of lightning strikes on the safe operation and economic benefits of power distribution equipment is becoming increasingly prominent. [0003] Years of research on wind turbine lightning accidents have shown that the lightning accident rate per 100 wind turbines per year is as high as 8%. The components that are vulnerable to lightning strikes are mainly electrical communication systems, control systems, blades and generators. Among them, the control system has the highest probability, about 40% to 50%. Lightning damage to the wind turbine control system is mainly concentrated in the PLC control mod...

AI Technical Summary

Problems solved by technology

[0004] The height of wind turbines is generally more than 100 meters, and most of the wind turbines are located in the wilderness, hills or mountains, which are easily affected and damaged by the outside world; the hills and mountains where the wind turbines are located have relatively stable geological conditions and high soil resistivity, resulting in leakage The current flow capacity is reduced, and the lightning strike current cannot flow into the ground quickly, resulting in the occurrence of lightning counterattack accidents

The blades of wind turbines, the control system of power distribution cabinets, the control system of wind measuring towers, the remote control of wind field central control communication, transmission lines, and electronic equipment are prone to failure due to lightning strikes, mainly because of the erosion of harsh environments that cause wind turbines and transmission towers to The grounding resistance of the grounding grid becomes higher. When struck by lightning, the ground potential rises to form a counter-attack overvoltage, which causes damage to the fan equipment

The higher the grounding resistance, the higher the counter voltage formed, and the greater the probability of equipment damage

At present, surge protectors are used in central control and fan power distribution cabinets, but accidents of surge protectors being damaged by lightning still occur from time to time, and the probability of damage to the control system due to lightning strikes is also quite high

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