While extensive effords are undertaken to prevent earth faults in high voltage systems, there cannot be absolute certainty that such events will never occur. Therefore, it is important to have a clear understanding of what happens after one or more phases of an AC system make contact with ground potential. While an earth fault can be catastrophic for the equipment in question, it can also endanger other devices on the same grid or, even worse, persons who are in the vicinity.
In order to choose the best grounding solution for a given system, one must be aware of each variant's advantages and disadvantages. This way, a good compromise can be made between uninterrupted supply of electrical power and safety of operation, without putting people's health or life at risk.