Micro Fit suspicion

[Peter Klaassen]

I am off grid rather than working with Hydro under Micro FIT so this is hearsay. It seems that some grid tie inverters are more sensitive to grid voltage variation than others and can be knocked off the grid if the voltage rises but is still within the 10 % limit hydro is allowed. During times of surplus power available Hydro may do this on purpose to reduce the solar input and knock out the Sunnyboy inverters feeding the grid. I have no proof of this- I am wondering if there are others using grid tie inverters that seem to disconnect for no obvious reason? An installer was making observations about this phenomenon and I wondered if anyone else found similar outages. Is Hydro pulling a fast one? It would make me a "little" upset if this were true.

[Ralph Day]

Hi Peter
My Enphase inverters initially didn't like the line voltage I was getting and would trip out with "out of phase and or voltage". The line voltage would sit around 250vac. Enphase, via the internet connection, reprogrammed the inverters to the High voltage limit of 260vac. We've had no dropouts since that time.

I think it's probably just rumour about the sinister plans, the voltage just moves about anyway and we see it when gt inverters drop out (maybe old incandescent lightbulbs blowing in the old days?).

Ralph

[Rob Beckers]

Peter, and this is from an installer's perspective, it's common to find that once the inverters start backfeeding 5 - 10 kW the grid voltage jumps up enough to get outside the inverter window. For Power-One this is +8%, so with the inverter set to 240V it kicks out at 259V. Especially in rural areas where lines are long and the grid 'soft' this is pretty common. I don't think there's any evil intent from the LDC (hydro company). It's just the way the grid is set up.

We've always resolved this by changing the inverter settings so it uses 245V as the 'central' voltage, making it stay online up to 264V. Never had a problem after that.

There are some inverters (or were, not sure) that simply could not be changed from their 240V setting. For people that had one of those installed I assume they are up the creek.

The trouble is not so much the line voltage, it's usually fine when nobody is backfeeding. It's the grid's impedance/resistance, which causes the line voltage to jump up when feeding power into it.

-RoB-

[Peter Klaassen]

So, Rob and Ralph, the ability of some equipment to deal with the quirks of Ontario Hydro is something to consider when installing grid tie systems. I am glad there are solutions for this variation in voltage but it is something to be warned of when considering working with Hydro.
My view of Hydro is rather jaded after seeing the senseless waste of money going on there. I don't know whether to finger the Liberal government or mismanagement in the crown corporation. In either case, I am trying to minimize exposure to them. Did you know that Hydro will give power away to industry if there is a power surplus? Too bad they don't reduce the rates to the average household. I haven't heard anything about lowering hydro rates lately.
Please excuse my rant such as it is. It seems unfair to the average tax payer.