How avoid overvoltages when there is loss of neutral in electricity supply system?

opampsmoker · Dec 11, 2020

loss of neutral at 50ms..note sudden jump in ph-Neut voltage.
This is from sim of #19 above

Nigel Goodwin · Dec 11, 2020

opampsmoker said:
loss of neutral at 50ms..note sudden jump in ph-Neut voltage.
This is from sim of #19 above

It doesn't really show anything, as there's no context - if you remove the neutral at the sub-station, then it depends entirely on the respective loads on each phase - if the phases are well balanced (as it's designed to try and be) then the voltage should remain the same.

By adding you own 3 phase transformer, all you're doing is moving the issue - if you lose the neutral on the output of the transformer you've got exactly the same situation.

Ramussons · Dec 11, 2020

Nigel Goodwin said:
Except he's asking about UK single phase supplies to domestic premises - so only two incoming wires, neutral and live - if either is disconnected you get no power at all.

Industrial three phase is somewhat different, and can be connected as either star or delta - where delta has no neutral at all. But any three phase system should have little current through the neutral anyway, as it's supposed to balanced across all three phases as much as possible, hence thick live wires and only a thin neutral.

opampsmoker said:
For a 10kW installation, supplied with three phase, how can we ensure that the Line-Neutral voltage does not rise up to the line-line voltage if there is a loss of neutral connection?

Is'nt this the question?

How avoid overvoltages when there is loss of neutral in electricity supply system?

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How avoid overvoltages when there is loss of neutral in electricity supply system?

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