Interactive system

Does the meter have a visible wheel for checking direction of rotation, or a digital display with ± sign to distinguish the direction of power? (And write it down somewhere to remember which is which....)

Negative. The systems are connected on the line side of the main disconnect. To rephrase the question: How can I tell if I'm using energy from the spvs or the main power provider? Is my spvs providing power to the whole network?

That puzzles me. In that scheme, what keeps the grid from burning up the SPVC at night? (Or am I just missing something?)

There are devices in the system that prevents feedback from the main power grid. The main distribution breaker trips when the main power source trip out. This prevents the spvs from feeding the island and overloading the spvs.

If you are using the correct type of inverter and not some home-made device it will show on the LCD how much kWHrs injected into the grid, and depending on which country you reside in, will either show on the utilities meter as a subtraction or will be read when the utility meter is read and will be detailed in your next power bill.