Under the sea crossing bridge connecting Beilun District of Ningbo, Zhejiang Province and Meishan island free trade zone, six "electric silver snakes" meander "along the bridge towards Meishan island port area. In June this year, with the commissioning of the 110kV Qixing power transmission and transformation project, this cross sea power channel will send a steady stream of power to the port area.
In 2008, the State Council approved the establishment of Ningbo Meishan bonded port area, which is the fifth bonded port area in China after Yangshan in Shanghai, Dongjiang in Tianjin, Dayaowan in Dalian and Yangpu in Hainan. In the same year, Ningbo Municipal Party committee and government made a decision on accelerating the construction of Meishan island.
In September, 2009, various construction projects known as "Meishan" speed were launched in an all-round way on the island. More than 400 mu of storage land began to be piled. More than 10 infrastructure projects were started. The power supply of only 35 kV Meishan substation on the island was tight, so the power construction was urgent. To this end, Ningbo Electric Power Bureau, adhering to the principle of handling special affairs on a special basis, has implemented a special power construction scheme tailored to Meishan island and meeting the long-term development needs of the port area without a stop.
Tailor made island "power accelerator"
Special power construction means that every link from feasibility study, design to construction will closely focus on the construction and development needs of the port area, and means more comprehensive, detailed and considerate construction and services. At the beginning of 2013, after nearly five years of efforts, the 110kV Qixing power transmission and transformation project fully entered the construction stage. In the face of such a rapidly developing island, Ningbo Electric Power Bureau has made every effort to protect the environment and save resources.
"Considering the long-term development environment of Meishan island port area, the overhead lines in this area are being transformed from the upper line to the lower line." The project design director said. From the perspective of the long-term development of the port area, the conventional overhead lines are bound to have an impact on the landscape of the gate of Meishan bridge and the future development and construction of the area through which the line passes.
For this reason, Ningbo Electric Power Bureau planned ahead. On the one hand, it transformed the overhead lines in the development area into the ground; On the one hand, 110 kV cables with a cross-section of 1000 mm2 are used for extremely difficult cross-sea laying to improve the "regional quality" of Meishan island with technical quality.
"In order to cooperate with the development of the island and in combination with the load characteristics of the port area, we have selected the voltage level of the distribution network in the port area as 20kV." The design director of the project said that at present, the power transmission and transformation project of seven surnames on Meishan island is under construction.
Previously, in order to save island resources and achieve the best power quality, Ningbo Electric Power Bureau mobilized technical forces, expanded the scope of research, intensified research, and fully combined with the characteristics of Meishan Island, which is "long from east to west and narrow from north to South", proposed to build a 20kV smart distribution grid on Meishan Island, reducing the number of 110kV substations planned on the island from 3 to 2, thus saving line channel resources and land resources to the greatest extent.
Laying "energy artery" in the port area across the sea
In April, the transmission line project from 220kV Xianxiang gan'ao line t to 110kV Qixing substation entered the most critical stage of cross sea cable laying of the whole project. This short span of 1.1km carries three firsts of Ningbo 110kV cable: the first time to lay the cable with a cross-section of 1000m2, the first time to construct the cable with the sea crossing bridge, and the first time to set the cable expansion joint device according to the bridge expansion joint. From the very beginning, the project construction was faced with various difficulties and challenges.
There are fast lanes on both sides of Meishan Island Bridge. The cable laying space in the middle of the bridge is very narrow. Each cable expansion device weighing up to 5 tons is faced with the dilemma of being unable to be in place after it is transported to the construction site. "Brothers, dismantle it first, transport it to the bottom and then assemble it." Ye Xuan, the leader of the cable team, cheered with his arms, and immediately disassembled the cable expansion devices into easy to lift and move parts with more than 20 hands.
Crane, shoulder, several times down, in this cool season, everyone has already been sweating. After the parts were transported to the designated location, in order not to affect the subsequent construction, the construction team simply "cat" in the narrow space for 5 days, and carefully assembled all the five expansion devices like building blocks.
The equipment problem has been solved, and new difficulties have come one after another. On April 12, in the sea breeze of Meishan Island Bridge, the cable straightener just stopped. Ye Peng and several construction workers discussed the construction scheme again. According to previous work experience, the relative position difference between cable straightening machines can be used to realize cable bending. However, after field trial, it is found that the straightening machine is cumbersome and slow to take effect. It can only be constructed for 100 meters a day. 6000 meters of cables need to be snake laid on the bridge, which will take 60 days to complete. However, the whole project must be put into operation in June. What should we do?
"We must find a way to complete this section of cable laying in the shortest time." In the fierce sea breeze, everyone heard Ye Yu's firm voice. After more than ten hours, six solutions and dozens of tests, the construction scheme of using the chain block as a cable orthotic tool was finally recognized.
"One, two, three, up!" While tightening the chain block along the cable diameter direction, the 10 pairs of hands with green tendons were trying their best to pry the 9-ton cable. Six silver "giant snakes" gradually surfaced, and the simple and efficient construction also reduced the construction period to 10 days.
"In just a few years, Meishan island has been built from a barren and barren saline land into a new" giant ship "on the southeast coast. The key is to rely on strong power support." Beilun sub district.
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