Grid Tie (Grid Connected) Solar PV System
In photovoltaic solar energy systems, light is converted into electrical
energy that is used immediately or stored. In a grid connected photovoltaic
system, the generated direct
current is transformed into an alternating
current that can be used in the house immediately.
In case of a remainder
of energy, it can be delivered into the grid.
Grid connected systems avoid the need for electricity storage in batteries
by essentially using
the utility as a battery system. When your solar or
wind system produces more electricity
than you need, the excess is sold back
to the utility. When your system doesn't produce
enough electricity, you can
draw power from the grid. All this is done automatically through
metering or net billing program. In most cases, a special or second utility
be added to keep track of how much electricity has been sold to
Advantages of utility interconnection include having access to standard
AC power all of the
time, not just when your system produces electricity,
and avoiding the cost of a battery
back-up system. A disadvantage is the utility
interconnection fee, which varies with each utility.
The size of a utility
connected project depends on how much of your electric consumption
to displace and how much money you are able to invest.
Typical grid tie solar PV diagram:
Grid Connected PV Systems Include:
1. PV Array or Generator: A number of PV panels connected in series and/or
giving a DC output out of the incident irradiance. Orientation
and tilt of these panels are
important design parameters, as well as shading
from surrounding obstructions.
2. Inverter: A power converter that inverts ± the DC power from the
panels into AC power.
The characteristics of the output signal should match
the voltage, frequency and power
quality limits in the supply network.
3. Loads: Stands for the network connected appliances in the building
that are fed from the
inverter, or, alternatively, from the grid.
4. Meters: They account for the energy being drawn from or fed into then
local supply network.
5. Local Supply Network: A single or three-phase network managed by a
Supplier. The supply network acts both as a sink for
energy surplus in the building or as
a backup for low local generation