From Wikipedia:
WikipediaSolar energy gathered by photovoltaic solar panels, intended for delivery to a power grid, must be conditioned, or processed for use, by a grid-connected inverter. Fundamentally, an inverter changes the DC input voltage from the PV to AC voltage for the grid. This inverter sits between the solar array and the grid, draws energy from each, and may be a large stand-alone unit or may be a collection of small inverters, each physically attached to individual solar panels. See AC Module. The inverter must monitor grid voltage, waveform, and frequency. One reason for monitoring is if the grid is dead or strays too far out of its nominal specifications, the inverter must not pass along any solar energy. An inverter connected to a malfunctioning power line will automatically disconnect in accordance with safety rules, for example UL1741, which vary by jurisdiction. Another reason for the inverter monitoring the grid is because for normal operation the inverter must synchronize with the grid waveform, and produce a voltage slightly higher than the grid itself, in order for energy to smoothly flow outward from the solar array.
I was able to be in a class held by a Government Inspector who's job is to make sure solar installers were using Federal $$ in a effective manor. Let's just say he has many horror stories to tell. One of which was that In neighborhoods where there were many homes with solar the higher voltages were shutting down the grid-connected inverters. Many customers were not getting as much $$ back as say a year ago when they were the only solar customer in the neighborhood and were blaming the electric meters.
That's all I got.
