XZERES Wind Skystream 3.7, Руководство пользователя

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Skystream Owner’s Manual
3-CMLT-1054 Rev O XCO 1191
Pg. 27
KEY OPERATING CHARACTERISTICS
The Skystream 3.7 operates by converting the kinetic energy of the wind into rotational motion that
turns an alternator and ultimately produces usable electric power. In actuality this is a great
oversimplification of
Skystream’s operation since it must very precisely match the frequency and
voltage of the electricity supplied by the local utility company in order to power your home and its
appliances. Additionally, Skystream monitors and adjusts its performance to provide safe operation and
extract the maximum energy from even low speed winds.
Skystream will begin producing power in a wind of approximately 3.0 m/s. At that speed the blades will
rotate at approximately 120 rpm. Once it has started producing power, it will continue to produce power
at lower speeds down to 80 rpm and less than 3 m/s. As the wind speed increases, the blade speed will
also increase. At about 9 m/s the blades achieve a rotational speed
of 330 rpm. This is Skystream’s
rotor speed. Should the wind speed increase above 9 m/s, the blade speed will remain essentially fixed
at 330 rpm. If a condition occurs that causes the rotational speed to exceed 360 rpm, Skystream will
shut down for approximately 10 minutes after which it will resume normal operation unless a fault is
detected causing it to remain shut down. This is an unlikely scenario that should never occur in normal
operation.
If a wind gust exceeds 25 m/s, then the Skystream will shut down for 1 hour. After 1 hour, the
Skystream will turn back on and resume normal charging. If the wind is still above 25 m/s, then the
Skystream will shut down for another hour.
In addition to adjusting its operation in response to wind conditions, Skystream also monitors the
electrical utility grid and its own internal health. Should the electric utility voltage or frequency differ from
Skystream’s voltage, for example, due to a power failure, Skystream will disconnect from the grid and
enter a “braked mode.” While in this mode, the blades are held stationary while the Skystream monitors
the utility power. If Skystream determines that the power has returned to within specification, it will re-
connect to the grid and resume normal operation. This is the same cycle that occurs when Skystream is
initially powered. Additionally, should Skystream determine an internal fault exists, it will execute an
emergency shutdown
– an E-stop. An E-stop will only take place if a severe fault that requires servicing
internal components has occurred. For that reason resetting an E-stop requires gaining access to the
interior of Skystream. It cannot be reset from the ground.
Electronic Stall Regulation
The Skystream 3.7 has the ability to adjust the rotational speed of its blades or even stop the blades if
required by ambient conditions. This is referred to as Stall Control, and it is accomplished by adjusting
the current draw from the alternator. The higher the current draw, the greater the electromagnetic
torque applied to the rotor, and if enough torque is applied, the blades will slow or even stop. In simple
terms the inverter is demanding more power than the available wind can provide thus causing the blade
rotational speed to decrease.
As a safety feature, the alternator is capable of producing approximately five times the torque required
to control the turbine. This extra available power means that even if segments of the alternator windings
are damaged, there is still sufficient torque to stop the turbine.
While Skystream is connected to the utility grid it constantly monitors that all conditions, for example
grid voltage and frequency, are within limits. If the inverter determines that all operating conditions are
within limits, it opens three Normally Closed (NC) relays, RL1, 2 and 3, removing the short from the
alternator windings and allowing the blades to spin freely.