An aviation power/aviation electrical system is essentially an independent mini electrical system, which includes aviation power sources (providers of electrical energy), aviation cables (transmitters of electrical energy), aviation circuit breakers (distributors of electrical energy), and aviation electrical equipment (consumers of electrical energy).
On December 17, 1903, the Wright brothers in the United States successfully tested their invented airplane, marking the beginning of humanity's touch with the sky. Since the 1860s, the advent of the Second Industrial Revolution brought humanity into the electrical age, with the widespread emergence of power supply systems and electrical appliances. In the early 20th century, with the increasing demand for electrical appliances, aviation power sources began to appear on airplanes. However, unlike ground systems, aviation power sources are often designed considering three key factors:
1. Due to the need for aircraft to operate smoothly both on the ground and at high altitudes, taking the Boeing B787 as an example, as shown in the speed-altitude range diagram below, the aircraft can reach up to 43,100 feet, approximately 13 kilometers. At this altitude, the atmospheric temperature drops to -56.5 degrees Celsius, and the atmospheric pressure is only 18% of sea level, making the environment extremely harsh. Passengers may not feel the adverse conditions due to the aircraft's environmental control system, but the onboard equipment does not have such favorable conditions. This harsh environment primarily affects two aspects: the low temperature may cause certain materials to fail, and the low pressure can significantly reduce the heat dissipation capacity of air-cooled equipment, posing a risk of overheating.
To ensure the safety of the crew on board, a high degree of redundancy is necessary. Modern aircraft are already extremely safe; in 2018, there were only 15 civil aviation accidents, with the B737 MAX series being the notable exception. Other Boeing and Airbus passenger jets have had virtually no incidents. This is largely due to the consideration of redundancy in aircraft design, meaning that critical equipment during flight usually has backups, preventing a single component failure from causing the aircraft to crash. Therefore, the reliability of aviation power is significantly higher than that of ground power.
3. There are strict weight limitations for airborne equipment. Planes can only take off with the power provided by their engines, meaning heavier planes require more powerful engines. However, engine output is always subject to a certain upper limit due to the pace of technological development. Moreover, according to the law of conservation of energy, the greater the engine output, the higher the fuel consumption, which not only affects economic considerations but also contributes to environmental issues related to fossil fuel consumption. Therefore, we aim for the aviation power source to be as lightweight as possible, with a much higher power density compared to ground power sources.
