How AC power is generated on the Boeing 787
The AC power is mainly a three-phase way generator
at ii5VAC with a 400Hz. The 400Hz has been a standard for years as the power
can be generated with lighter and smaller generators that 50/60Hz systems.
Although using higher frequencies is not ideal for transmitting power at long
distances, it is ideal for airspace application because of the lighter system.
The power distribution systems used in the 787 aircraft creates a complexity to
impact the power generation system design to enable it route power around the
localized faults to maintain the airworthiness of the aircraft (Dornheim, 2005).
The 787 aircraft run power from the generator directly to the electrical
equipment bay from where it is distributed to various locations within the
aircraft. The Boeing 787 Dreamliner is known to use less pneumatic and more
electricity to power the systems like the wing-ice protection, hydraulic
systems, and to start the engine. Systems electrification is a major focus of
aircraft architectures. Its electrification is important as it enables the
design, maintenance, and manufacturing optimizations. Correct electrification
is beneficial because:
It improves the
overall system performance
It is more
reconfigurable and flexible
streamlined manufacturing and assembly
The AC power
frequency depends on the engine speed hence variable. The Boeing 787 Dreamliner
has four generators, two on the auxiliary power unit and the other two on each
The system that
feeds the systems run from these generators to the electrical equipment
There are 17
electrical sub-stations provide power to localized bays.
generator in the 787 is to hell the aircraft generate more electricity as it
uses more than the other Boeing aircraft.
On the ground,
the Boeing 787 Dreamliner can start without power generation.
The APU generators
start to power the engine generators using the APU battery and then these
generators start the engines.
source of electrical power when the aircraft is on flight mode are the four
engine generators while the APU generators are the secondary sources. The power
generated by these generators are used as the four alternating current buses.
In the AC, the
power is either distributed to be used as 235 VAC or converted to what the
The other power
sources for the AC system in the Boeing 787 include the main battery. The main
battery is used to generate power for ground operations, such as braking the
The generated ground
power produced by the APU battery is capable of connecting via the three power vessels.
The APU and
main battery, and ram-air turbine serve as the power backups in the flight in
case the aircraft experiences a power failure.
The state-of-the-art technology has developed an
alternating current generator starter. The main functions of the AC Starter-Generator
include to electrically generate power to start the engine as well generate
main electrical power for the aircraft network which is a system that can be
used to generate AC power in the 787 aircraft.
Summing up, the Boeing 787 Dreamliner has four main
GCUs that are associated with the engine mounted to the six generators (Norris
and Wagner, 2009). If all of the GCUs are powered up at the same time, after
about two hundred and forty-seven days of continuo power, all the four GCUs
will fail at the same time; thus the AC power will not be generated anymore
regardless of the flight phase.
Dornheim, M. A. (2005).
Massive 787 Electrical System Pressurizes Cabin. Aviation Week &
Space Technology, 47.
Norris, G., & Wagner, M.
(2009). Boeing 787 dreamliner. Zenith Press.