Fire emergency power switching method

The fire-fighting electrical equipment shall be powered by the main power supply when it is normal, and shall be powered by the emergency power supply in the event of a fire; when the main power supply is cut off during a fire for any reason, the emergency power supply shall be automatically switched in to ensure the reliability of the fire-fighting power supply. The switching methods of the fire power supply are as follows: 

1. Head end switching   
The independent feeders of the fire load are respectively connected to the emergency busbar, receive power centrally, and supply power to the fire-fighting electrical equipment in a radial manner. The diesel generator set provides emergency power to the emergency bus. The emergency bus is connected to the low-voltage bus of the main power substation by a separate feeder through an automatic switch (called a tie switch). Normally, the automatic switch is closed. The fire-fighting electrical equipment is powered by the main power supply through the emergency bus.
2. End switch   
The two independent feeders drawn from the emergency busbar and the main power low-voltage busbar are switched in the emergency power switch box at their respective ends. If the emergency feeder fails, it is also possible to lose power to the fire-fighting electrical equipment. For Uninterruptible Power Supply Units (UPS). Due to the two-level switching, no matter which circuit of the two feeders fails, the fire load is reliable.