Solar Array & Pv Selection - Zener ECODRIVE 8000 Installation Manual Supplement

ZENER VARIDRIVE SOLUTIONS
THE SOLAR ARRAY & PV SELECTION:
The Solar Array consists of a number of Photovoltaic (PV) modules
connected in a series & parallel combination to achieve a certain
voltage, current and power. It is important to select these carefully as
the PV modules are a major cost of an installation and can be very
expensive to rectify. Incorrect selection may result in damage to the
equipment or not provide sufficient energy to operate the motor and
the load it is driving. An array would normally consist of a number of
PV modules in series, known as a 'string'. Strings of PV modules are
then connected in parallel to achieve the required current (Amps) to
form an 'Array'.
Voltage:
The quantity of series connected PV modules determine the DC
voltage of the Solar Array which determines the output motor
voltage. This can have a direct impact on the maximum motor speed
achievable. If rated speed of the pump is not required then the Vmpp
of the system can also be reduced. In this case the power
requirement is also reduced.
There are two variables that are critical for system operation:
TOTAL Voc = The sum of the 'Open circuit voltages' of the PV
modules connected in series. The total open circuit voltage must
be <800Vdc under all possible conditions.
TOTAL Vmpp = The sum of the 'voltage at maximum power' of
the PV modules connected in series. This voltage under max load
conditions is the voltage level for Maximum power point tracking.
Current & Power:
The quantity of 'Strings' connected in parallel will impact the current and power available to operate the pump. If the current
required to pump is higher than what can be delivered by the solar array, the pump speed will be reduced. Graph 5a illustrates
the reduced current & power based on the instantaneous solar intensity.
The incorrect amount of PV modules or an incorrectly installed array may result in the following:
• Pump will not operate at the required speed.
• Pump will not operate at the desired solar intensity (such as filtered sunlight, cloudy periods).
•
Pump will not operate for the desired period per day.
•
Damage to the equipment.
The PV modules and solar array should be selected by an experienced and accredited person.
The PV modules must be installed by a qualified and experienced person to ensure all equipment is installed to best
practice, local codes and regulations.
Unsure about your Solar Array configuration?
For guidance with selecting the correct Solar Array configuration complete the ' ECODRIVE Checklist' available on our website
and email to us.
http://zener.com.au/images/solar_ecodrive_checklist.pdf
IM00130
ZENER ECODRIVE® 8000
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Graph 5a. PV voltage & current at different solar intensity
20/07/2018 3:59 PM