The first mixed line of 110 kV polypropylene insulated cable in China has been put into operation in Shenzhen
Recently, the first hybrid transmission line in China consisting of 110 kV polypropylene insulated cables connected to overhead lines was successfully put into operation in Futian, Shenzhen, and has been operating safely for over 192 hours, further enriching the application scenarios of domestic green cables and laying a solid foundation for their future promotion and application in large urban agglomeration construction, offshore wind power grid connection, and other fields.
It is reported that cross-linked polyethylene material is widely used as insulation material for high-voltage cables in China, which has a long production cycle and high energy consumption. In contrast, high-voltage cables made of "green" polypropylene materials have the characteristics of low production energy consumption, recyclability, high operating temperature, and increased cable transmission capacity, which have attracted widespread attention in the power industry in recent years. Compared to cross-linked polyethylene insulated cables of the same specifications and voltage levels, the carbon footprint of this cable production process has been reduced by about 4.6 tons of carbon dioxide equivalent, the production cycle of cable insulation has been shortened by 80%, the production energy consumption has been reduced by more than 40%, and the cable manufacturing efficiency has been greatly improved.
It is understood that the cable lines put into operation this time mainly use cable trenches, buried pipes and other laying methods, and are connected to overhead lines through outdoor terminals. The working conditions inside cable trenches are complex and variable, directly facing environmental tests such as high temperature baking, rainwater infiltration, and soil erosion. Compared to cable tunnels, cable trench laying is more in line with the real operating environment of urban high-voltage cables, and higher requirements are put forward for the insulation performance of polypropylene insulated cables. To ensure the compatibility between polypropylene insulated cables and outdoor terminal accessories, the Transmission Management Office of Shenzhen Power Supply Bureau of Southern Power Grid (hereinafter referred to as "Shenzhen Power Supply Bureau") has developed a complete set of fast and reliable cable accessory construction process operations based on the thermoplastic structural characteristics of the material.
In addition, to ensure the safe and reliable operation of cable lines, Shenzhen Power Supply Bureau has integrated digital intelligent devices such as circulating current monitoring, fault location, video monitoring, and infrared temperature measurement on this line, and developed a line information integration analysis system to monitor and evaluate the real-time operation status of cable lines. The successful operation and safe operation of the 110 kV polypropylene insulated cable and overhead line hybrid line for over 192 hours provide important data support for the safe operation of this type of cable in complex external environments in the future.
It is reported that in 2023, Southern Power Grid Company was selected as a key product and technology "one-stop" application demonstration and promotion organization for "high-voltage cable insulation and shielding materials" by the Ministry of Industry and Information Technology and the State owned Assets Supervision and Administration Commission. In order to enhance the widespread applicability of green and environmentally friendly high-voltage cables, the Southern Power Grid Research Institute has collaborated with upstream and downstream enterprises in the industrial chain to carry out technical research and overcome technical difficulties such as the 110 kV polypropylene insulation material shielding material system, cable production process, and testing and assessment technology. With the strategic approach of "changing lanes and overtaking", it has solved the embarrassing situation of long-term dependence on high-voltage cable materials in China and achieved the first batch of 110 kV polypropylene insulation cable engineering applications in China.
"The joint industry chain upstream and downstream enterprises actively carry out pilot applications of new green and environmentally friendly cables, which will continuously improve the resilience and safety of the power cable industry chain, and consolidate the industrial foundation." said Zhao Linjie, senior professional technical expert of Southern Power Grid and director of the High Voltage Institute of Southern Power Grid Research Institute.
In the future, with regard to the application and promotion of new green and environmentally friendly polypropylene insulated cables, Shenzhen Power Supply Bureau will fully demonstrate the spirit of daring to take the lead, continue to assume the responsibility of constructing and operating super large urban power grids, and make positive contributions to the green and low-carbon development of the Guangdong Hong Kong Macao Greater Bay Area.