There is strong wind and thunder weather today, which causes the voltage fluctuation of the power grid. Why didn't the high voltage system trip, but the low voltage 380 circuit breaker tripped?

Lightning weather, once spread to the power grid, the high voltage system must be tripped and protected according to the design theory! Because the current generated by lightning is instantaneous and large, it is necessary to trip the high-voltage circuit breaker for protection! In general, the outgoing lines of substations are equipped with reclosers, which also have the function of current protection. Generally, the switching current value is quick break, overcurrent delay, single-phase grounding and other functions! The high-voltage system you're talking about is protection. One possibility is that the protection of high-voltage equipment is insensitive and lightning current cannot be protected. This is too common in the power grid. Equipment manufacturers basically have no problem biting equipment! Your low-voltage circuit breaker was right to trip. It should trip when it thunders to protect the safety of your electrical equipment.