meirs Mar 31, 2011:

Parallel in in sync with the mains Not unheard of - not even several of even tens of generators in parallel with the mains (there is one such power station in Brasil - my company was involved). Keeping a genset in sync with the mains and balancing power outputs is no problem these days. See here http://www.telemenia.com/eng/gallery.php?op=cati&id=3 - the Goiania power station of 88 gensets of 1.64 MW each.

Tony M Mar 31, 2011:

@ Didier OK, yes, of course, the actual system will undoubtedly be complex; I was only seeking to point out that there may well be some perfectly logical explanation why this deceptively 'simple' expression was used here; I don't think all the technical speculation in the world is actually going to change the translation solution required here — though as I did explain in my answer, I somehow suspect Paul needs to consider the expression as a whole in order to meaningfully represent the whole technical implication of the source document.

Didier Fourcot Mar 31, 2011:

@Tony OK I understand the point if there are multiple generators, but the term "parallel" is a bit odd because putting alternative generators in parallel implies a rather complicated switching circuitry to avoid one generating into the other or phase issues. This is far from simple "both lamps into the same power strip" commonly called "parallel to mains".

Tony M Mar 31, 2011:

@ Didier I think there may be a clue to the reason for this expression in one of Paul's other questions, where he refers to generating sets; perhaps, therefore, this is the idea of connecting something (standby generator outputs?) in parallel, so that (for example) the emergency supply can take over in a truly 'uninterruptible' way in the event of a problem. It's probably not exactly this, but I feel sure the rest of Paul's context probably explains the reason for this as you say otherwise apparently unnecessary statement.

Didier Fourcot Mar 31, 2011:

Could be too simple? The curious thing is that the standard way to connect anything to mains at least in single-phased installations is precisely "multiple parallel" so mains, so why specify this when any user will do that?
There are some specific ways to connect a 3-phased motor, among whcih for example wye-paralle, that could be an other clue?

Paul Berthelot (asker) Mar 31, 2011:

exactly what is in the field multiple parallel to mains

Johannes Gleim Mar 31, 2011:

What is MPtM? MPTM Masters Program in Telecommunication Management
MPTM Multi-Parity Test Method
MPTM Mechanical Pre-cutting Tunneling Method (mining)
http://acronyms.thefreedictionary.com/MPTM
(None of these explanations make sense here)