The world's first all electric aircraft,787 power systemThe control is the core of the drive and control of this aircraft, includingIntelligent power distribution SSPCAnd the relevant information about why he used intelligence to replace circuit breakers and contactors is presented one by one.

The architecture design of the 787 power system is based on the fact that there is no traditional pressurization/deflation system in the aircraft, so the power system needs to drive more loads. Next, we will focus on how to implement load control in the power system.

Attention: Please refer to the application of multi electric aircraft in 787 for the architecture of the power system.

The power distribution system includes the main distribution system PPD, the auxiliary distribution system SPD, and the remote distribution system RPD. The distribution control is implemented by the ELCU distribution control module, SPDU secondary distribution module, and RPDU remote distribution module.

How to achieve command communication and load control through the power system?

CDN Universal Data Network

Can control LAN

TTP time triggered protocol, TTP/C is the version of TTP

BPCU bus power control unit

GCU - Generator Control Unit

The 787 adopts the ARINC664 standard network, and communication between systems is implemented by CDN. Can convert non arinc664 networks through RDC (e.g. possible)

The control signals of various aircraft systems communicate with BPCU through CAN or CDN, and BPCU enables the system to be powered directly or indirectly from RPDU, SPDU, and ELCU through the internal network TTP/C.

Connect the contactor or control switch to the load

It mainly includes the following aspects:

ELCC power load control contactor

SSPC Solid State Power Controller

TCB thermal trip switch

Elcu supplies power to loads with 235vac/115VAC or over 45A through ELCC

SPDU supplies power to loads less than 50A (e.g. 115VAC/28vdc) through SSPC

Rpdu supplies power to loads less than 10A, such as 115VAC/28VDC, through SSPC

TCB is used to power critical systems such as aircraft start-up, safe flight, and landing

How are the on/off of these contactors or control switches controlled?

The power load of 787 is very large. If fully controlled by traditional thermal jump switches, it will not only increase weight, but also be detrimental to the maintenance of the jump switches. Therefore, most of them use electronic jumper switches and are controlled by the following software:

Indication and control of CBIC trip switch

ESIC Power System Indication and Control

Firstly, let's understand the control of ELCC

Each ELCC has a corresponding electronic jump switch name, named ckxxxxxx

The ECB in the above picture is the electronic trip switch of ELCC, which can be controlled by CBIC or ESIC. ESW is an electronic switch that is directly controlled by DSC system or load management. The closure and shutdown of ELCC should at least meet the following conditions:

CBIC or ESIC does not have a disconnection command from ELCC

DSC issues command

Load management did not perform uninstallation operation

ELCC unprotected trip command (control and protection signals)

Different levels of control and protection are divided into the following three levels:

The highest priority ELCC is directly controlled and protected by BPCU or GCU

Secondary priority ELCC is monitored by ELCU and protected by BPCU or GCU

The ELCC with the lowest priority is controlled and protected by elcu

The second is the control of SSPC

Each SSPC also has a corresponding jump switch name, called cexxxxxx

The ECB in the above figure is an electronic trip switch of SSPC controlled by CBIC, while the ESW is an electronic switch controlled by DSC and load management. Therefore, SSPC should at least meet the following conditions:

CBIC does not have a disconnect command from SSPC

DSC issues command

Load management did not perform uninstallation operation

Note: Some SSPCs are also controlled by fire alarm signals

For detailed information about SSPC, please refer to the application of SSPC in the 787 aircraft power system.

Finally, the control of TCB

Each TCB also has a corresponding jump switch name

CTxxxxxxx

TCB is only controlled by its own rated current and manual mechanical control. CBIC can only check the status of the trip switch, but cannot control it.

Attention: TCB on P49 of APU startup distribution board cannot view data in CBIC

If you need to learn more about aircraft power supply and distribution systems, please discuss and exchange ideas with the engineers at Weikewei.