China's First Petal Type Power Distribution Net
In the end of June, 2014, Transmission Project of Power Transformation with 220 kilovolts started in Guangzhou Knowledge City. It is said that, China Southern Power Gird Corporation will draw experience from Singaporean practice on the power grid and adopt the 20 Kilovolts petal type connection mode which is effective and reliable.
This will be the first practice of petal type connection mode in China. Once it is successfully founded, the total blackout time annually for the customers will be limited within one minute. The grid then will be as superb as those of international top cities.
Zhongxin Guangzhou Knowledge City is a strategic project that jointly built by Guangdong Province and Singapore. As one of model knowledge cities in China, Guangzhou Knowledge City covers totally 123 square kilometers, and will reach a maximum load at about 218 kilovolts high.
Due to the widespread high-tech industries in the city, the load density in it is highly centralized while higher power distribution reliability is required. Under this circumstance, China Southern Power Gird Corporation targeted future-oriented model smart power grid and work out the plan on Knowledge City’s power grid. According to the plan, there will be nine substations totally supply 220 kilovolts and another one with 110 kilovolts.
What’s more, they will firstly adopt the petal type connection mode with 20 kilovolts medium voltage distribution network and area protection technology of 20 kilovolts.
Petal type connection mode refers to the network that electric wires of a closed loop network are offered by two substations so that there’s connection exist even in the closed loop network. Therefore, the whole power distribution network will be founded into a petal type mode with all users realize “N-1” (N-1 means double circuit power supply which makes sure at least one circuit available when there’s line fault for another, similarly hereinafter. ) and VIP users can even achieve “N-2”.
It is estimated that, the petal type connection frame will be completed by 2015. Compared with the traditional power network, this new kind of distribution will effectively decrease the amount of equipments and length of electric transmission lines. It is predicted to save over 2 billion RMB of investment as well as abundant land source.