My 6 kW grid-tie photovoltaic system is going into wait mode when my five ton AC cycles on. I have 200 amp service to the house, but these summer days the line voltage will drop from 240 to 225. The inverter is an SMA 6000U with a minimum grid tie operating voltage of 213 VAC. I think that when the AC cycles on, it either momentarily depresses line voltage below 213, or it just causes the line voltage to change too quickly for the inverter to maintain the sync (either one of these conditions will cause the inverter to "detach from the grid" and go into a wait mode monitoring the state of the grid).
Questions: - Maybe the line drop from the pole is undersized? (does not seem likely given that Edison must have connected it to the 200 amp panel). - How likely would the gauge of the line drop be the cause of this problem? - Does anybody know what gauge a 75 foot 200 amp line drop ought to be? - Has anybody had success in getting their utility to replace the line drop with a larger gauge drop? - Is there anyway to add something to the AC circuit so that it has a "softer start" so it does not depress the line voltage so much?
This is a real pain as the AC cycles about every 20 minutes and causes the array to go off-line for five or ten minutes each time. I am losing a great deal of electrical production and I can't believe it is good for the inverter, either.