Dear Mike, As co-author of upcoming book "The Handbook of Solar Water Pumping", we have expanded its definition to include micro and national grid-tied systems in which pumping is synchronized with power availability from PV. I had known about frequency-based load control for microgrids (from an SMA-based microgrid I toured in Israel). I had no idea it was a happening system on public grids until I read your response here. I love how it requires no communication lines or digital signals. It's a "natural" and logical concept from the old days of spinning generators under varying load.
I see your PG&E reference, but is there also a reference text you can recommend that I can use in the book as a universal explanation of how this works? It can be SMA documentation, or other ref. You can reply here if it's useful to the list, and/or contact me off-line. Thanks! – Windy > On Dec 1, 2022, at 5:47 PM, [email protected] wrote: > > From: Harry Mahon <[email protected] > <mailto:[email protected]>> > Subject: Re: [RE-wrenches] AC Coupling Standard? > Date: December 1, 2022 at 5:47:18 PM MST > To: RE-wrenches <[email protected] > <mailto:[email protected]>> > > > Definitely it is possible for newer grid-interactive inverters. However, for > grid-tied operation, the utility that runs the grid sets the rules (and sets > the setpoints as it were), and it can be confusing.... > > Looking at PG&E’s Rule 21 tarriff (submitted Aug 12, 2022, effective Nov 4, > 2022) Freq-Watt reuirements are: > “When system frequency exceeds 60.036 Hz, the active power output produced by > the Smart Inverter shall be reduced by 50% of real power nameplate rating per > hertz (5% of real power nameplate rating reduction per 0.1 hertz)” > Bottom of Sheet 207 of : > https://www.pge.com/tariffs/assets/pdf/tariffbook/ELEC_RULES_21.pdf > > So a 5kW inverter needs to ramp at 2.5kW/Hz. But if it is only producing > 2.5kW, it has to be at 0W at 61.036Hz..... > > Mike
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