All electric aircraft circuit protection

Wei Kewei

In recent years, there have been more and more new types of aircraft, such as the Boeing 787, Airbus 380, and other all electric aircraft. Do we need to worry about the electrical hazards in the aerospace industry?

In my opinion, the protection of the entire aircraft circuit in the aerospace industry is particularly important.

Why worry about the "new" electrical hazards in aerospace?

Hydraulic systems are being replaced by electric actuators

These dangers are not fundamentally new. What's new is their frequency. On passenger planes, the usage of electric devices and equipment increases sharply from the nose to the tail, and then to the wings. This is not only due to the adjustable seats in the in-flight entertainment system and business/first class cabins driven by three-phase 115VAC motors. Hydraulic systems are being replaced by electric actuators for flight control ailerons, elevators, and rudders, while air brakes, landing gear, and wheel brakes are becoming more electrified. This trend requires more current to pass through wires that may be adjacent to the fuel tank, or through engine mounts, or in landing gear wells.

Does an arc equal a short circuit?

not always. There are two types of aviation arcs. The so-called parallel arc is a type of short circuit. Simply put, when a bare phase wire comes into contact with a neutral wire or another charged wire, it may cause one or more sparks, as if arc welding is being carried out, and significantly increase the temperature. On the other hand, the so-called series arc can be described as an intermittent short circuit, although the current is limited by the powered equipment, it can still cause sparks. In both cases, the risks of fire, mechanical rupture, and even explosion are real unless the power is turned off as soon as possible.

What does' fast 'mean?

This is where the problem lies! The faster the circuit breaker is opened, the lower the risk of temperature rise, fire, or rupture. This equation is very simple. Smaller transient current=less energy available for damage. Especially near the outer shell of the fuel tank, if pierced, it would be catastrophic.

GF-AFCB prevents electrical hazards

What solutions do you think are available in the market?

We clearly see the need for intelligent technology in ground fault circuit breakers (GFIs). This is the same principle as the 500mA residual current device (RCD) in your fuse box at home. Crouzet's GF-ACFB ground fault arc fault circuit breaker is an RCD, which goes further. It not only trips in the event of a ground fault, but the current distribution is monitored by an algorithm that not only detects series arcs, but also parallel arcs and phase to phase short circuits; Using classic technology, it only takes 15ms instead of 200ms to open. For the future, we believe in intelligent communication between devices and their upstream protection (here GFI). The power cord of the device is turned on by sensors inside the protected device, which measure temperature, stress, strain, or torque. Devices that detect internal abnormalities will send a signal to the smart circuit breaker: 'Cut off my power now, or I'll catch fire!' The era of smart circuit breakers is coming.

Weikewei Technology can provide arc detection circuit breakers, and our SSPC can also provide arc detection function.

If you have such concerns, we will provide you with free technical services.