Page 161 - Renewable Energy Devices and System with Simulations in MATLAB and ANSYS

148 Renewable Energy Devices and Systems with Simulations in MATLAB and ANSYS ®
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an optimal configuration because more material is needed for the cabling. Furthermore, a lower
input voltage results in high current, which at the end gives higher losses in the system. This
means that another inverter should be used for this particular design case. Many inverters have
a maximum input voltage of 1000 V , and by choosing such an inverter, the PR of the designed
DC
system could be optimized.

6.3.3 System Performance Monitoring

When a PV system is installed and commissioned, it is important that the system is properly main-
tained during its lifetime, which is expected to be above 25 years. Many PV systems have been
sold with the promise that no service or maintenance is needed. This is nearly true. However, faults
might appear in the system that will need to be dealt with. Failure in the different components might
happen during the early years of the PV system. Therefore, it is important to know how long the
standard warranty period for the different components is.

6.3.4 Warranty of Modules

PV modules always come with a limited product warranty; this is typically a 10–15 years’ repair,
replacement, or refund remedy. The warranty covers defects in materials and workmanship under
normal operating conditions.
There is also a standard in the PV business prescribing that the PV modules are delivered with a
limited power warranty. This warranty guarantees that the customer with an output performance of
the module in a period up to 30 years depends on the supplier conditions. The performance warranty
typically includes a 10–15 years power guarantee of, for example, 90% of nominal output power and
after 25–30 years of operation, 80% power output is guaranteed.
If the power output is below the guaranteed power values, the supplier has to replace such losses
in power by either providing the customer additional PV modules to make up for such a loss, by
providing monetary compensation equivalent to the cost of the additional PV modules, or by repair-
ing or replacing the defective PV modules.

6.3.5 Warranty of Inverters

Today, inverters are delivered normally with a minimum of 5 years, warranty. The warranty covers
defects in materials and workmanship under normal operating conditions. Most inverter suppliers
offer 5–15 years, extra warranty, which can be purchased before installation or for some suppliers,
up to 5 years after commission of the PV system.

6.3.6 Warranty of BOS Components

BOS components and the installation itself often come with a 10-year warranty.
When the PV plant is in operation, a minimum of surveillance is needed. Most new inverters
today have a built-in Wi-Fi connectivity, so the inverter and the performance of the plant can be
monitored through an app or over the Internet.

6.3.7 PV System Price

The price of PV systems has been decreasing since the start of their commercialization back in the
1980s. The chart in Figure 6.10 shows both the actual price for cSi and CdTe for the last 35 years
and also the production learning curves when the production is increased. The actual price follows