Backup transformer assures ongoing power for bridge

A 110kv transformer substation at the Zhuhai-Macao frontier port island of the Hong Kong-Zhuhai-Macao Bridge (HZMB) went into operation on Nov 16 -- a standby power supply for the one already in use.

All three parts of the power transmission project have now been completed. The earliest is a 10kv switching station, which went online on Sept 28.

This completes a closed electric circuit. The 220kV Jida and Gongbei substations connect the 110kv island and bridge-dedicated substations respectively, the latter two also in junction. Now there is a reliable connection with Zhuhai's main electric power grid. 

Supporting the grand project spanning the Lingding Sea, the new power generation facility is located in the northwest of the Zhuhai-Macao Port amid installations allocated for the bridge's Zhuhai section.

The substation powers not only the main bridge structure, but also Zhuhai Highway Port, while safeguarding steady operation of the regional comprehensive transport system and relevant expressway networks for Guangdong, Hong Kong, and Macao.

Operations room at substation [Photo provided by Zhuhai Power Supply Bureau]

The project along with the 110kv bridge-dedicated transformer substation promises"double-insurance" electricity, each a reserve for the other, according to Liu Ying, project manager of Infrastructure Department of the Zhuhai Power Supply Bureau of Guangdong Power Grid.

Liability and stability of the power supply should be assured in operation of the world's longest sea bridge, said Cai Junfu, an engineer at the China Railway Construction Electrification Bureau and transportation engineering project head for the bridge.

A 110kv sent from the substation has to be sustained during transmission along the 22.9-km main bridge. Upon arrival at West Artificial Island in the middle of the broad bay, a transformer will reduce voltage to 35kv before it traverses the 6.7-km subsea tunnel to access East Artificial Island, according to Cai.

The accomplishment is credited to constant pursuit of technological innovation, explained Liu. Guangdong Power Grid had used many advanced-level techniques during design and construction stages before tailoring them for the mega project. Solutions include a 10kv grid installation, the technology of Mould Melt Joints (MMJ) for cable head wielding, and network spare power automatic switching devices.

In harmony with the environment, the substation sticks to the overall design style, with sapphire blue lines embellished on the facade. This is created by joining a curtain wall with aluminous buckle plates, according to a project designer.