In 3 phase transmission lines we have different voltages depending on how we measure it. Phase to phase voltage is going to be 1.73 times more than phase to neutral. So far I understand everything that I've just said. Now, phase to neutral has the same voltage as phase to earth. This means that phase has a higher potential than earth and that earth has a lower potential than phase which would in theory be 0 V. Why is earth at 0 V with respect to phase and not floating?
The only reason I think that earth is at 0 V (with respect to phase) is because at the power station there is a metal pole stuck to the earth which is connected to neutral thus allowing current to flow through the earth and up the neutral pole. If there weren't a pole, current wouldn't flow through earth and earth would not be at 0 V it simply would be floating. Right?
Any help is greatly appreciated.