3.1 PV Panels:
A core of PV system consist of PV panels, many
PV cells or photodiode segments are connected in order to assemble a PV panel
to be manufactured and sold. Where upon installation, PV panels are then
connected in series or chains to form strings in which important factors are
considered to specify the PV panel`s specifications:
Types of PV Panel: Stiff and smooth
edged panels which are mostly used now a days and some are made from Silicon or
Cadium Telluride materials.
PV Power Rating: For a grid connected
PV system for housing choses panels with its rating power of range between
minimum from 10 to maximum approximately 350 Watts, this is a maximum power
that a PV panel can generate with 1000W/m2 of temperature 25oC
at standard condition.
Voltage of PV: Current PV systems
that aren’t battery based backup should provide an output voltage range between
235V to 600V. Also with battery backup system it is required to have higher
array voltage output, while the charger controllers need lower voltage of
12,24, or 48V to meet with battery requirements.
Cost of Panel per Watt: In an overall state,
materials which panels are made of, some are made with thin layers which have lower
cost than of made from Crystalline Silicon.
PV Panel Efficiency Watt per Area: panels that have high
efficiency or productivity it is proportionally to have higher rate of power
being produced for specified area.
3.2 PV Array attachments:
PV panels which are connected to form such structure like arrays,
these arrays are best regularly attached on building roofs or on steel poles
for street lighting or on oblique roofs of bricks, or in a large system for
feeding many houses it can be attached to ground level or on new technology is
a tree design structure, for such attaching installation of PV arrays noticing
some factors to be in consideration:
PV Array adjustment: changing the angle or slope of arrays when are
attached to a roof top settings may be difficult in certain places but also it
can be adjusted to meet longitude and altitude of array placement to seek sun
appearance to hit the panels.
Capability: a setup for the PV
arrays to be combined with tracking devices installations that let the arrays
routinely track the sun movement along the day and generates more energy and at
maximum power point output.
3.3 Grounding Equipment:
Grounding of these
components for such a system requires equipment that have a connection to a low
resistance route from the PV system to the grounding in order to protect it
from current surges occurred by lightning strikes, ground fault conditions or
failure of any component in the system.
The grounding protection
settings are used to let the voltages to be stable and avoid any faulty
impacts, such protection installation consists of two main groundings for such
PV system to be considered:
Grounding Tools: Tools used for grounding the components in the system is
responsible for the protection from short circuit with the ground or as ground
fault named, this happens when a conductor carrying current is in contact with
appliance, such issue is resolved by grounding all the components in the
Grounding of the PV
System: selecting a single wire
of the system to be grounded for protecting the inverter and arrays.
NEC Grounding Code: An improvement was done in 2005 for the National
Electrical Code in order to manage the requirements for PV or other systems
grounding codes and installments.
3.4 Combiner Box and Surge Protection:
Lines from multiple PV
arrays are summed up in a combiner box at input and these wires may be single
conductor after being connected together to an output of the box. The output of
the combiner box has the high voltage summed up. This box may contain a fuse
for safety and circuit breaker in order to disconnect for any fault occurring or
a voltage clamping device known as a metal oxide varistor MOV or by other name
called surge protector.
A voltage clamping device
or surge protector is used to for the protection of the PV system and
specifically the arrays from any strikes of lightning happened or from any near
power lines affected, power surges causes an increase of the voltage above the
rated one upon happening.
3.5 Metering of PV System:
PV systems metering installations are two types to be considered and
Grid Metering (KWh): the utility installs a bidirectional meters in order
for the electricity to be drawn from grid letting the meter to spin forward or
backward to feed the grid from PV system being functional.
System Meter: This meter is in the system that measures and displays the performance
and status of the functioning system which can include PV modules power
production, electricity used, and battery charging state if there is.