Problems with surge protectors?

Re: Problems with surge protectors?

From the Marketing Lit:

Three efficiency peaks
Greater power harvest for every system size: The unique automatic transformer switching function of the Fronius IG Plus makes enables not one, but three equal efficiency peaks. The result: Consistently high efficiency over a wide input voltage range.

In comparison: The efficiency of inverters without transformer switching declines steadily with an increasing input voltage. Devices without a transformer only have one efficiency peak.

With a 96.2 % maximum efficiency, the Fronius IG Plus series scores the highest grade among HF devices.

MIX™ Concept
Get the maximum power harvest out of partial load ranges, e.g., on cloudy days, through a clever combination of multiple power stages in each inverter. The power stages in Fronius inverters divide up the work depending on operating hours and only operate as many power stages as required to efficiently process available power from the PV array.

It almost sounds like during periods of low collection--that the unit will not run "all three converters" but just one or two... So, it is possible that you will see unbalanced output on your three phases.

One there is a minimum amount of solar power available--then all three converters will energize and you should see balanced power output.

By the way, how are you measuring the current in the legs? 3 phase power does not necessarily add current in a simple way. Are you reading the GT Inverter's LCD display for the L1/L2/L3 outputs? There should also be other information (total power, line/phase voltage, etc.).

Also, I would guess if you have 3 phase Delta power--your inverter is operating at 240 VAC--not 120 VAC. So, your "total power" reading at that time should have been around:

3a * 240 VAC = 720 watts
3a * 240 VAC = 720 watts
0.3a * 240 VAC = 72 watts
====================
Total = 1,512 watts

Regarding the surge suppressors Marc/Cariboocoot and your descriptions of "batteries" is that these are UPS (uninterruptable power supplies). Basically, they pass AC power from the utility to the computer when all is OK, and turn on an internal inverter (battery power) when it detects if the power is bad.

There are also versions that have transformers inside them that take a wide range of input voltage (something like 95-136 volts or so) and with a variable tap transformer will switch it closer to a stable 120 VAC. I do not know--but in a quiet office you may be hearing each time it changes tap voltage (enough change in input voltage to change the transformer settings, but not bad enough to cause the UPS portion to turn on).

Will switching the taps on the transformer cause computers to freeze--It should not, otherwise the "solution" (transformer) is worst than the "problem" (variable input voltage).

The reason you may be hearing more "clicks" (this is just guessing) is that the voltage point was just above your average utility voltage (more load, a big of sag, was not enough to change the transformer tap). Now, your solar power system, during the day, is enough to raise the building voltage a bit (20 kWatts of power from a the array causes a "voltage rise" in the wiring). And anytime there is changes in the sunlight (clouds, etc.) or other loads (A/C, etc.)--It is causing the UPS's to switch.

In any case, you probably need to get the model number(s) of the UPS's that are clicking and look up their specs/manuals and see exactly what they are.

Again--the above is all just wild guesswork on what I have read so far--more information would be helpful.

-Bill

Re: Problems with surge protectors?

By the way--as I was thinking about your discription and the marketing lit description (transformer in the GT Inverter allows the GT to have 3 peaks in the efficiency curve--my guess that they shut down one or two of the inverter sets to keep efficiency up may very well be wrong)--anyway more thinking (hey--got to start somewhere :roll:) made me think of this very long Fronius Thread:

Fronius MPP Hunting

You may be hitting another issue related to the above thread... The Fronius is hunting and its output current/voltage changes--and the UPS (and other constant power loads) are hunting/responding to what the GT Inverter is doing.

Constant Power Devices (computer power supplies, and motors to a degree) follow the P=I*V equation... P (power) is fixed, and as voltage falls, current consumed must go up to ensure that the device consumes "constant power".

You can get into "unstable" operating points between the power sources and the loads (or positive feedback loops). Basically, For example, the GT Inverter does something that causes voltage to go up (say it is generating more power/current as the sun comes out)--The computers see higher voltage and draw less current, and the voltage goes up even more. And a similar thing can happen as the voltage drops (clouds), the computers must draw more current to keep power use constant.

And--this "feedback loop" may be on the order of a few seconds, or it could happen 120x per second (every 1/2 cycle of 60 Hz AC). Couple that to an issue with the inverter possibly "MPPT Hunting" -- you can have a very difficult issue to diagnose (see the thread at top--turned out that this took a lot of work and the vendor admitted there are some design issues with that model of inverter).

mradtke wrote: »

... At some point a Fronius engineer talked about the performance hole being related to an MPP in the area of 230 volts with a high AC line voltage of around 250 volts.

I haven't heard anything more from Fronius on their recently promised fix....

There can be multiple issues... In the above case, it appears with Vmp~230 volts and Vac~250 volts--the inverter tends to hunt (and cause variable AC output power with constant Parray input.

And, as always--just guessing and offering suggested diagnostic paths to follow. I have no insight into your installation/GT hardware other than what you see here.

-Bill