At 5:56 on December 30, 2020, the Yan'an Wuqi 330kV Transmission and Transformation Project, which was constructed by the EPC general contract of the Shaanxi Institute of China Energy Construction Planning and Design Group, was successfully put into operation with power. After the project is put into operation, it will effectively improve the power supply guarantee capacity of the county power grid, promote the connection of new energy and large-scale external transmission, which can meet the transmission needs of the additional 700 MW of wind power in the Yan'an area and the demand for regional load growth. Play an important role in structure and benefiting people’s livelihood.

Project Overview

The new Yan'an Wuqi 330kV substation is located in Baishizui Village, Chengguan Town, northwest of Wuqi County, Yan'an City, Shaanxi Province, about 2.8 kilometers away from Wuqi County and 145 kilometers away from Yan'an City. The total investment is 35.226 million yuan.

Engineering characteristics

The project is a key construction project of the Shaanxi Provincial Government in 2020, and is the first government-enterprise cooperation EPC general contracting project won by the Shaanxi Institute. As the EPC general contractor, he participates in the planning, preparation, design, procurement and construction of the project to ensure that the project is completed on time and with high quality. Tight construction period and heavy tasks. Starting from the site selection at the end of November 2019, the project will start in March 2020, and it will be completed and put into operation in December 2020. It only took 9 months from the start of construction to the completion and commissioning, which was nearly half the construction period of a project of the same scale. During this period, it was faced with the big test brought by the epidemic. The engineering team of the Shaanxi Research Institute worked hard every day to promote the orderly development of various tasks, creating a miracle of Shaanxi power grid construction.

The construction of the project is difficult, because the construction site is mostly located in mountainous and forest areas, the construction site is narrow, and the geological conditions are poor. In order to ensure the construction progress, safety and quality, the project vigorously promotes mechanized construction.

Construction significance

After the project is completed and put into operation, Wuqi County's abundant wind and solar energy will be integrated and consumed through the project, which is of great significance for attracting foreign investment, providing jobs, and stimulating local economic growth. Satisfy the economic development needs of the old revolutionary base areas and ensure that electricity goes first. Satisfy the development of the wind power industry in Wuqi County and the connection and uploading needs of wind farms. Meet the needs of regional economic development and power supply capacity. Meet the power supply requirements of the transfer of power supply loads from outside the area.

Project highlights

In order to ensure that the project construction is completed safely, efficiently and with high quality within the performance period, the Shaanxi Institute optimized the design highlights, coordinated with the participating units, better served the site, met the site progress requirements, improved the project progress, and timely analyzed the problems that occurred on the site , And propose solutions.

As the EPC general contractor of this project, Shaanxi Institute has efficiently completed the preliminary procedures, design drawings, and material procurement of the project, which has played a positive role in the progress of the project. And signed a construction management agreement with the State Grid Yan'an Power Supply Company to give full play to the localization and construction management advantages of the local bureau, which plays an important factor in project coordination and promotion. The 11-type energy-saving transformer is adopted. The transformer has excellent electrical, mechanical and insulation heat resistance, strong resistance to short-circuit and overload, and greatly reduces no-load loss, no-load current and noise, and has a real energy-saving effect. Its structure adopts special wound core material instead of traditional structure, its no-load loss is reduced by 30%, no-load current is reduced by 50% to 80%, and noise is reduced by 6 to 10dB(A). It is a new energy-saving product. According to calculations, the annual comprehensive power consumption is reduced by 13% to 17% compared with the 9 type, which has a good energy saving effect. The wall is the main body of the building envelope, and the thermal insulation properties of the materials used directly affect the heat consumption of the building. In order to ensure that the energy-saving effect reaches the standard of more than 50%, the internal wall design adopts the gypsum board internal partition wall, and the external wall adopts the outer protection of the rock wool sandwich thermal insulation integrated board. Digging foundation is a kind of undisturbed soil foundation. The main feature is that it relies on the weight of the soil and the shear resistance of the soil to resist the uplift, which is the same as the large excavation foundation by the foundation floor. Compared with the flexible large slab steel, the amount of steel is correspondingly reduced, and the amount of foundation earthwork is less, which reduces the damage to the environment and protects the natural landform around the tower foundation. At the same time, the foundation does not require formwork when concrete is poured, making construction more convenient , Reduce construction cost, suitable for loess plateau and hilly areas.

Engineering background

In the face of difficult factors such as tight schedules and bad weather, the Shaanxi Institute organized the formulation of construction plans to refine the work to the sky, to the people, to find ways to implement it, to grasp the site during the day, to collect the progress and problems at night, and to strengthen the on-site construction Strength, using a 24-hour shift system to ensure that the project is delivered on schedule. In December, there was a sudden heavy snowfall. Since the average temperature in the area has been around minus 20 degrees since December, the snow has not melted. In order to ensure the progress of the project, the construction staff used human resources to transport materials.

Since December 15th, in order to ensure that the project is put into operation on schedule, overtime has become the norm. They sacrificed their lunch breaks and worked overtime until two or three in the morning. Sleeping time was less than five hours. Overnight work became routine and tired. Just squint at the desk for a while, conduct on-site matching, debugging, etc., solve various problems that affect the operation, and make every effort to prepare for the live operation.

Looking back on more than 9 months of construction work, the Shaanxi Institute has overcome difficulties such as "tight construction period" and "new crown pneumonia epidemic". The engineering team carried out close division of labor and coordinated with various departments of the company to strive to overcome each difficulty, ensure safety, and improve quality. Grab progress and successfully complete the project's commissioning goal.Editor/Xing Wentao