also result. A power backup system is necessary to assure these
vital control systems remain viable in the event of the loss of
the primary utility power source.
To achieve the full functionality of the wind turbine and
•;Equipment dedicated to the continuous remote monitoring of
ensure the safe, reliable generation of power, a large number
of electrical and electronic equipment elements are required.
•;Main control computer, I/O modules, relays and components
for monitoring and control of the wind turbine.
wind turbine operation.
•;The Hub computer to control pitching of blades.
•;Frequency converter, yaw motor protection systems.
•;Power converter (full or dual-fed), flters, phase
•;UL-listed, wide-temperature range online
uninterruptible power supplies (UPS).
•;Communications computer, network and SCADA-
monitoring and control equipment.
•;High-voltage, medium-voltage and low-voltage
distribution control equipment.
As stated earlier, a wind turbine’s location can make it
subjectable to extreme temperatures swings, typically from
-30ºC (- 22 ºF) to 55ºC (131ºF). All of the electronic equipment
and circuits installed in the turbine must be designed to
operate reliably over the entire temperature range. A
source of backup power is essential, so the online UPS
designed into the system must be rated for these harsh
temperature environments. Further, due to its key function, it must have been specifcally designed to provide
years of operation while operating over the entire temperature range. As the UPS is located in the nacelle
at the top of the turbine tower with the rest of the equipment,
humidity and condensation can be another factor affecting reliability. Conformal coating of circuit boards is required to protect
circuitry on the board from becoming shorted out by moisture
condensing on the board. These environmental factors demand
the use of a special UPS.
to survive in a high humidity
environment is suspect. Batteries in these standard systems are typically not rated
for the higher temperatures
that are often encountered. At
these high temperatures, battery life can be reduced by as
much as 90 percent.
Figure 2. Falcon’s UL, cUL
Batteries – Te Weakest Link
and CE-listed SSG Series
UPS in a NEMA enclosure.
A standard off-the-shelf UPS is designed for 0°C to 40°C offce or
computer room environments; therefore its reliability and ability
The majority of UPS prod-
ucts rated under 10 kVA use
valve regulated lead-acid
(VRLA) batteries to provide
backup energy. Due to iden-
tical battery chemistries and
like construction, most bat-
tery manufacturers’ specif-
cations are very similar. Bat-
tery manufacturers rate their