What Are The Phenomena And Consequences When Ferromagnetic Resonance Occurs In The Power Fittings System?

What are the phenomena and consequences when ferromagnetic resonance occurs in the power fittings system?
Answer: When resonance occurs in the power system, overvoltage and overcurrent of several to dozens of times the rated voltage will occur, porcelain insulators will discharge, iron parts such as insulators and bushings will be corona, and the primary fuse of the voltage transformer will melt. In severe cases, the equipment will be damaged.
When three-phase AC power supply lines are passed through metal pipes, why can't single-phase branch pipes be used for wiring?
Answer: If a single phase line is passed through the pipe, since the metal pipe is a closed magnetic circuit, the induced magnetic flux in the metal pipe will increase with the increase of the current flowing through the wire, causing eddy currents and induced voltages in the metal pipe, causing the metal pipe to heat up, threatening the safe operation of the line, and also increasing the power loss of the line.
Fuse Link Under what circumstances should the pipe be protected?
Answer: To ensure that the cable is not damaged by external forces during operation, it should be protected in the following circumstances.
(1) Cable entry and exit buildings, tunnels, trenches, etc.
(2) Cable passing through roads, railways, etc.
(3) When the cable is led out or introduced into the ground, a protective tube should be installed from 2m above the ground to 0.1~0.25m underground.
(4) The intersection of the cable with various pipelines and channels.
(5) The area where the cable may be mechanically damaged.