1 / 2021-04-09 10:45:42

Analysis of lightning impulse response of ground network based on a distributed π model

In order to simulate the transient characteristics of the earth grid under lightning impulse and provide theoretical guidance for the design of lightning protection in substations, this paper proposes a distributed π earth grid calculation model based on the field circuit coupling idea. The transient model of a 220kV substation is established, and the response characteristics of the grid at different lightning current injection positions are simulated. It is found that the maximum transient potential of the grid is 172.5kv when the lightning current is injected into the corner node, and 64.2kv when the lightning current is injected into the internal node. The maximum current of the grounding grid is 8731.6a, and the closer to the lightning current injection point, the greater the current. When the lightning current is injected into the internal node, the oscillation time is  shorter and the evacuation is faster than when the lightning current is injected into the corner node. With the increasing distance from the injection point, the wave head time of the voltage wave of each node on the ground network is gradually longer, the peak value of the voltage wave decays exponentially, and the peak value of the voltage wave of each node is inversely proportional to its wave head time.