In the lower reaches of the Yangtze River, along the Changjiang-Shui River rift, a huge enclosure separates a construction site on the bank of the Yangtze River. Head and location, the Yangtze River Xujing section of the river surface, the size of the shuttle boats passing, very busy. Lifting the view, the world's first ultra-kilometers span cable-stayed bridge - Sutong Bridge suspended in the river, spectacular. It will not be long before here, another Sly-GIL pipe gallery project will be born here.
Extra high pressure
Not heaven, they hide
Sutong GIL pipe gallery project is part of Huainan-Nanjing-Shanghai 1000 kV AC UHV power transmission project. As an important over-river project, after the completion of the Sutong GIL Pipe Gallery Project, the Huainan-Nanjing-Shanghai Project will be put into operation in conjunction with the Huainan-Wannan-Shanghai UHV engineering project that has been put into operation, , Zhejiang and Shanghai load center East China 1000 kV UHV AC ring network. Sutong GIL Pipeline Project can be described as East China UHV AC ring network operation of the throat and control engineering.
So, what is GIL? Why use GIL technology in Huainan-Nanjing-Shanghai UHV project? Speaking of these, really have a story to mention.
GIL is short for GasInsulatedMetalenclosedTransmissionLine. Chinese is called gas-insulated metal enclosed transmission line. It is a kind of transmission line insulated with pressure gas by using metal conductive rod to transmit electricity and enclosing it in a grounded metal shell. Sutong GIL Pipe Gallery Project is relying on this technology to the integrated pipe corridor as the carrier across the Yangtze River.
Initially, the Sutong Yangtze River crossing project originally used overhead crossing the river program, across the 5 km wide Yangtze River, feasibility study program main span of 2150 meters, 346 meters high across the tower, the need to build the tower across the tower 3 base. The feasibility study program has obtained all the agreements of environmental protection, soil and water conservation, land, transportation and local governments and passed the approval.
The Sutong Great Span is located in the Xu-Li Jing River in the lower reaches of the Yangtze River. This is the last section of the Yangtze River before it enters the sea. The upper reaches of the Yangtze River narrowed rapidly here and the lower reaches of the Xu-Liu Jing River rapidly widened. Here is the busiest "golden" fairway on the Yangtze River, with only 4.7 km of river surface and more than 3,000 vessels daily. Faced with this reality, in the construction permit process, the Jiangsu Maritime Safety Administration proposed: In order to ensure the safety of navigation, it is required to increase the span span, reduce the number of river neutral towers, and increase the basic anti-collision capability to meet the navigation safety requirements.
In January 2015, in accordance with the requirements of local maritime authorities and harbor authorities, in order to reduce the impact on the navigation channel and improve the navigation safety, the number of river neutral towers was reduced from 3 bases to 2 bases in the feasibility study plan and the maximum spanning span was increased from 2150 meters To 2,600 meters, across the tower from 346 meters to 455 meters, tower weight from 6000 tons to 12000 tons, the basic size from 90 meters × 90 meters to 120 meters × 130 meters, single base spanning tower base concrete from 100,000 Cubic meters to more than 20 million cubic meters. In November 2015, the Ministry of Transport organized an assessment on the "Evaluation Report on Waterway Conditions and Navigation Safety of the Great Leaping Project of the Sutong Yangtze River". The opinions of the reviewers are required to justify the irreplaceability of the overhead scheme and provide relevant supporting documents. In January 2016, the Yangtze River Water Conservancy Commission of the Ministry of Water Resources conducted an assessment of the Flood Control Report for the Great Leap Forward of the Sutong Yangtze River Project. According to the assessment opinions, given the sensitive river regime and high demand for comprehensive development and utilization, the tunnel crossing plan research work.
In view of this situation, on the basis of the previous research, SGCC urgently started the research and demonstration work of the Yangtze River Alternative (GIL Pipe Gallery Scheme) and held Huainan-Nanjing-Shanghai 1000 thousands on January 6, 2016 V AC EHV transmission and transformation project Sutong Yangtze River over the river program expert review meeting, the meeting considered, taking into account the technical, safety, construction period, investment, port planning and adjustment, social impact and other factors, recommended the use of GIL comprehensive corridor over the river program . The use of GIL technology construction of the river project seems to be the last resort of choice, but in fact, the State Grid Corporation has long had technical reserves. In 2009, during the feasibility study of Huainan-Nanjing-Shanghai project, preliminary demonstration was made on the crossing of GIL pipelines across the river. In early 2014, the feasibility study of 1000 kV GIL key technology research framework was formally launched. System analysis and research and equipment R & D work, determined to win this technical problem.
Since the world's first GIL was put into commercial operation in 1972, the development of GIL technology has been progressing slowly. Up to now, the voltage range of GIL products covers 73 kV to 800 kV. The total length of GIL products put into operation in the world is more than 700 km. It is mainly used for projects sent out underground by nuclear power stations and hydropower stations, and is rarely used in power transmission lines. Among the existing products, GIL applications of 550 kV and 420 kV are most common, and the UHV GIL has not yet had a formal product. In recent years, with the progress of UHV transmission technology, the development of UHV AC GIL prototype has been carried out domestically and R & D of UHV GIL prototype has basically been completed, and the demonstration application of substituting GIS bus in UHV substation has been realized. UHV GIL has the advantages of large transmission capacity, small loss, no environmental impact, high operation reliability and land saving. Compared with overhead lines or power cables, GILs have larger transmission capacities and lower power losses. Sutong GIL Pipeline Project is the first time in the world that UHV GIL is used in important power transmission channels. The two-way 1000kV GIL pipelines have a unidirectional length of 5.8km and a 6-phase total length of about 35km. It is the world's highest voltage level transmission The largest capacity, the highest technical level of ultra-long-distance GIL innovation project.
From a technical innovation point of view, Su Tong GIL Pipe Gallery project needs to break through many technical problems. "The GIL equipment is to be laid in a submarine gallery with multiple corners and slopes, each with a length of 18 meters and one pipe connected to a total length of 5880 meters. Each pipe needs an elbow connection And to ensure that the gas does not leak, which is a very crucial technology. "Yuan Power Transmission and Distribution Division, State Grid Corporation of Communications introduced," In addition, the rational design of UHV GIL structure, the use of effective metal particle printing measures And means to improve the reliability of GIL, is also very crucial. "
At present, the research of GIL engineering is steadily progressing. In the future, with the improvement of equipment manufacturing level, GIL will develop towards miniaturization, low loss, high reliability and green environmental protection. UHV transmission technology is suitable as overhead transmission mode or cable transmission capacity limited transmission power transmission technology, more for the construction of the global energy Internet has provided a new technical means.
R8 Tool Holders ;Good Surface finish , Increased feed rate
Layers with high heat resistance , can be high-speed processing
Grain size carbon tungsten has high toughness, ALTINcoating , high wear-resistance , special use for high speed cutting of CNC milling machine , alos can increase the smoothness , reduce the rubbing coefficient m and improve the lathe efficiency m save more production time
Tool Rigidity and good chip discharge , the most suitable for high-precision three- dimensional mold machining
R8 Tool Holders
R8 Tool Holders,R8 Collet Milling Chuck,Milling Tool Holder,R8 Milling Machine Tool Holder
SISHUI TELI TOOL CO.,LTD. , https://www.er-collets.com